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9

By Joseph McCabe

A Candid History of the
Jesuits

Life of Peter Abelard

Crises in the History of
the Papacy

The A B C of Evolution

Evolution of Civilization

Ice Ages: The Story of
the Earth's Revolutions

V/onders of the Stars

The

A B C of Evolution

By

Joseph McCabe

Author of "The Story of Evolution," ''Evolution from Nebula
to Man," "The Evolution of Mind," etc.

cgJ

G. P. Putnam's Sons
New York and London
;rbe ftnicFiet&ocfier pteee

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Copyright, 1920

BY

G. P. PUTNAM'S SONS

First printing, January, 152 1
Second printing, March, 1924

**04

Made in the United States of America

PREFACE

During several years' experience of lecturing on
Evolution I have been more and more impressed with
the need of a new primer of the subject. The lecturer
or writer on Evolution is too apt to think that the ele-
mentary stage is passed. This is a mistake. The
field of science is now so large and so thoroughly cut
up into distinct plots that a man or woman may have
quite a good knowledge of one section, yet need ele-
mentary assistance on a general subject like Evolu-
tion. The man who could teach me much about
wireless telegraphy or chemistry asks me for the plain-
est possible instruction on Evolution. Moreover,
there are other things to study besides science. There
are art, literature, history, and political economy. And
for most people there is much work to do, and little
time to study anything.

Hence I quite understand the demand for a very
clear, elementary, and short text-book. There are
several manuals in existence, and they have their
merits ; but they fail in one or other respect to meet
the particular need I have in mind. Some are a little
out of date. Some are too large. Some are not
general enough. There is a large section of the public

iii

iv PREFACE

that would like to have a quite modern and quite
simple account of this wonderful thought which now
runs through the whole of our culture. They want
the A B C of the matter, but they want it up-to-date,
so that they may understand what scientific men are
talking about to-day. I trust that this little work
will meet their wishes.

J. M.

CONTENTS

CHAPTER PAGE

I. Evolution the Key to Nature . i

II. The Evolution of the Universe . ii

III. Life in the Primitive Ocean . . 22

IV. Land Life Begins .... 36
V. In the Grip of an Ice Age . . 48

VI. The Brontosaur and Its Cousins . 59

VII. The Evolution of the Flowers . 71

VIII. The Coming of the Birds . . 82

IX. The Triumph of the Mammals . 92

X. The Origin of Man . . .105

XI. Social Evolution . . . .117

^%

The A B C of Evolution

CHAPTER I

EVOLUTION THE KEY TO NATURE

If you want to understand what evolution is, and why
some scientific men — who are not usually poetic —
have compared it to a sun rising in the nineteenth
century to illumine the darkness of nature, try to put
yourself in the position of some thoughtful man of
the days of George IV. There was already quite a
respectable science in those days. There was a
Royal Society. There were geologists and chemists
and astronomers. For two hundred years English-
men of great ability had been working hard to attain
the kind of knowledge which we call ** science"; that
is to say, knowledge based as carefully a^ possible on
actual observation.

Yet nature as a whole, and myriads of separate
things in nature, were so dark and unintelligible that
we may really say that they awaited the rising of the
sun. Your grandfather, supposing that he were of a
thoughtful turn, would ask endless questions to which

2 EVOLUTION THE KEY TO NATURE

science could give no answer. Why had he this thin
and useless coat of hair on his body? Why was his
cat so like a tiger? Why did miners bring petrified
fish-bones out of the deepest mines? Why was the
negro black and the Chinaman yellow? Why was
the moon cold, the sun hot, and the earth between
the two? Why were Englishmen civilized and
Africans not? Why had flowers different colours?
Why was there such an immense variety of animals ?
Why were there tape-worms? Why had the shark
no bones? Why was England an island? Why were
there fiords in Norway?

You could fill an immense book with questions that
could not be answered eighty years ago. And, apart
from the fact that science was very young and needed
more time, all these things were obscure, and
threatened to remain obscure, because one single,
simple idea had not yet been grasped. That idea was
to be the starting point of the explanation of all these
and hundreds of thousands of other problems. It was
this: That nature, and all things in nature, had
grown, during tens of millions of years, to be what
they were. They had been shaped very slowly and
gradually, and had passed through numerous earlier
forms. They had been "evolved."

The word "evolution" is the Latin word for
"unrolling." Roman books were written on parch-
ment and rolled on wooden or ivory rods, as maps
are to-day. Unrolling one, to read it, was "evolu-

EVOLUTION THE KEY TO NATURE 3

tion." About the seventeenth century the word
began to be used in English for the "unrolling" of
the scroll of history, of the fates, etc.; then the
unrolling or expanding of anything which had been,
as it were, folded or rolled up. The body "evolved"
from the germ. A nation, like the Romans, evolved
from the pastoral tribe which history represented as
its first stage.

This sort of evolution was going on so obviously
all round our grandfathers that one may wonder why
they did not perceive that it was a law of nature.
For instance, one understood the striped pole outside
the barber's shop because the modern barber was
evolved from the barber-surgeon of the Middle Ages,
who used to put this red pole, with a white bandaging
tape wound round it, outside his shop to show that
he bled people. One understood why a "gentle-
man" had two buttons on the back of his coat and
the workman had not, because they were evolved from
the mediaeval gentleman, who buttoned his sword
there, and the medieval worker, who wore a smock,
or at least had no sword. One understood the
richness of the English language because it had
grown out of a mixture of the tongues of the British,
Anglo-Saxons, Danes, Normans, and other invaders.
All history was really part of a science of evolution.
All the political struggles of the time were processes of
evolution. Every new machine, or fashion in dress,
or improvement in the home, was an example of

4 EVOLUTION THE KEY TO NATURE

evolution. Our fathers were painfully familiar with
the use of weapons; and every museum put clearly
before their eyes "the evolution of weapons."

It is clear to us now that they needed only to
believe that everything had similarly grown, and they
would find numbers of mysterious things lit up. If
man had grown from a non-human type of animal,
just as the modern Englishman had grown out of the
Druidic Briton, it explained any number of puzzling
features. If the flowers had grown to be what they
are, and some had grown more rapidly than others,
one understood the variety of nature. If the hills
and fiords and valleys had been under the shaping
forces of nature for hundreds of thousands of years,
the face of the earth could be gradually explained.
The English race, scattered over the world, was easily
understood. It had a common root in mediaeval
England, and its later growth and dispersion might
be read in history. Suppose that all the animals and
plants of the world likewise had a common root, and
had been growing and branching out, like a great
oak, for millions of years ! There was the great key :
a key that would unlock the secrets of stars, and
flowers, and oysters, and social forms.

It is hardly necessary to recall how it was that
until recent times this simple fact was not appre-
ciated. In many previous ages thoughtful men had
drawn the natural conclusion that all the things in
the world had grown. Numbers of the Greek

EVOLUTION THE KEY TO NATURE 5

thinkers had said so. The chief Roman writer on
nature, Lucretius, had repeated it. St. Augustine
himself, in his best days, thought that all the different
species of animals and plants had "grown" out of
seeds that had been put in the earth at the begin-
ning of time. The wonderful Italian monk of the
Middle Ages, Giordano Bruno, taught evolution. But
the fate of Bruno reminds us why it was that so few
accepted the plain truth of evolution, which had been
suggested by the Greeks 2,500 years ago. It was
"heresy." All Europe was now convinced that sun
and moon and stars, oak and lily and wheat, cat and
bird and man, had been created as we know them.

With this belief science was bound to struggle.
Scientific men naturally wanted scientific explana-
tions of things, if it were possible. In a sense they
wanted to conceive nature as a work of art: a statue
that had been slowly carved out of a rude block, or a
wonderful fabric that had been gradually woven on
"the looms of time." If they could discover the
chisels which had carved the statue, or the threads
that had been blended in the fabric of nature, it was
more intelligible. They very soon learned that
nature had grown, during millions of years, to be
what it is. The study of the rocks, which was very
fairly advanced by the year 1840, was sufficient to
prove this.

The rocks are the vaults of the great living family.
When they were opened up, in the eighteenth and

6 EVOLUTION THE KEY TO NATURE

nineteenth centuries, it was quite easy to see that
burials had been going on for tens of millions of
years. And it was noticed that the deeper you went
the simpler the forms became and the more they
approached each other. The facts themselves sug-
gested that the animal-forms we know to-day, so
different from each other as they are, had common
ancestors in the past. Life was a great many-
branched tree, with a single root in the soil of "dim,
remote ages."

Several writers had suggested this before Charles
Darwin became convinced of it in 1836, but that
patient and gifted naturalist took twenty years to
work out his theory and collect facts in support of it,
so that his Origin of Species, which was published in
1859, was irresistible. One set of scientific men after
another now began to apply the principle of evolution,
or gradual growth, and each department of nature
which they studied was lit up as it had never been
before. Sir Isaac Newton had traced a remarkable
unity in lifeless nature when he discovered the law
of gravitation. A far more intimate unity was now
discovered, both in living and lifeless nature, in the
light of the new truth.

Everything known to us had been evolved. From
distant suns to our social and religious institutions,
from diamonds or oceans to the human struggles of
to-day and the ideals of to-morrow, the whole contents
of the known universe fell into one grand and intel-

EVOLUTION THE KEY TO NATURE 7

ligible scheme. It was like looking down upon a
hilly region in the early morning, when the summits
of the hills stand out, far from each other, but a mist
lies on the valleys and conceals the connections.
Then the sun rises, and the entire panorama of hill
and dale becomes a connected whole before your eyes.
Merely recognizing the fact that nature had been
evolved had that effect upon man's mental picture
of it, or his "science" of it.

It is important to understand this clearly. The
mind of man leaped forward, all the culture of the
world advanced rapidly, when the fact of evolution
was seen. But the fact of evolution is a different
thing from the methods or agencies of evolution. Even
if we knew nothing of the agencies which brought
about evolution, the fact would remain a most
important and permanent gain to every branch of
knowledge. No scientific man in the world now
doubts it, or has done so for several decades past.
He would as soon think of doubting the existence
of the sun. All the controversies which puzzle the
reader of larger works on evolution relate to the
agencies or machinery of evolution, not to the fact.
To say that things "grow" is, of course, only a
childish expression. When a geranium is "growing"
in a pot there is a most wonderful machinery in it
developing the stems and leaves and flowers. For
the whole of nature the machinery is colossal, and it
may be a long time before it is really known. I will

8 EVOLUTION THE KEY TO NATURE

try to make it clearer that evolution is a great dis-
covery in spite of all the disputes about its machinery.

Evolution is not a "force" or an agency that does
things. Strictly speaking, ''forces" and "laws" are
not agencies that do things, though we often speak
of them as if they were. ^ But evolution is not a force
or energy; and it is a "law" only in the strict sense.
It is an invariable /flc^. It is the fact of the unrolling
of the scroll, not the hand that unrolls it. So there
may be perfect certainty about the fact of evolution,
and complete uncertainty about the machinery or
agencies at work. Some say that, if this is so, evolu-
tion explains nothing. There could not be a greater
mistake. It is literally true that the whole of nature
is lit up when we recognize the fact that it was evolved.
Any thoughtful person can see how intelligible man
and his institutions become if we recognize that they
were evolved. Hundreds of features which puzzled
us before are now understood. This will become
quite clear in the course of the book.

Now, Darwinism is not evolution. It is a theory of
the way in which the evolution of living things was
brought about: a theory of the machinery of a part
of nature. Even if Darwin's theory comes to be re-
jected, his magnificent service in getting the fact of

^ Force is an abstract word used in physics to express certain
features of work or movement. It is matter or ether that really
works. Law — a "law of nature" — is also an abstract word to
express the fact that things do actually move or behave on certain
definite lines.

EVOLUTION THE KEY TO NATURE 9

evolution recognized makes him immortal in science.
His theory is, as a matter of fact, very much disputed.
Darwin looked about him, and saw that far more
living things are born than nature can sustain or the
earth hold . He saw that this caused a great ' ' struggle
for life," and that the ''fittest" — those best equipped
to meet their particular struggle — survived. Nature,
in other words, ** selected" the fittest; and so his
theory is called "natural selection." Take the hawk.
Its success in life depends on keenness of eye and
strength of wing. Every time a few hawks are
hatched some will have slightly better eyes or wings
than others. They have more chance of surviving;
and they will hand on their improved eyes and wings
to the next generation. In the course of hundreds of
thousands of years these minute improvements at
each birth will have brought about a much higher
type of bird. "Natural selection," he said, was the
agency of evolution.

That this process does actually go on throughout
nature, and even in our social and economic order,
any person can see ; but it is now disputed if it is the
general machinery of evolution. The pioneer in any
new field of research generally makes some mistakes.
Some now think that the embryological machinery,
not the destructive or "selective" work of nature, is
the great agency. Some think that the gradual
strengthening during a long period of small improve-
ments in each generation is not a satisfactory explana-

10 EVOLUTION THE KEY TO NATURE

tion. They believe that there are sometimes very
marked advances at a single birth (which they call
" mutations " = changes) , and it is these which are the
great agency of progress. So you get three chief types
of theory, and, passing over other shades of opinion
as unsuitable for this small work, we may express
them thus :

1. Darwinism. Progress is due to the selection
by nature of the fitter to survive. This really means
the destruction by nature of the less fit to survive,
so that strength, weapons, senses, etc., are gradually
improved, just as we gradually improve our sheep
and cattle. Few now hold that this is as complete
an explanation as Darwin thought.

2. Weismannism. That the action of nature is
secondary, and the advances of animals and plants
are determined in the germ (or "germ-plasm").
Progress is gradual, by small improvements in each
generation. This theory of Professor Weismann is
not held as much as it was twenty years ago.

3. Mutationism or Mendelism. Small changes or im-
provements in offspring would be lost or "swamped."
Large changes, in which the offspring differs consider-
ably from the parent, often occur, and these make
new species. This theory provides a very elaborate
scheme of the elements of heredity. It takes its name
from Abbot Mendel, but is chiefly due to Professor
Hugo de Vries. It has to meet many difficulties, and
is far from generally received.

CHAPTER II

THE EVOLUTION OF THE UNIVERSE

The moment we begin to apply the principle of
evolution we see the truth of the simple statements I
have asked the reader to bear clearly in mind. The
first is that the fact of evolution is the greatest dis-
covery the mind of man ever made, no matter what
controversies there may be about its machinery. The
second is that Charles Darwin perceived a truth of
the greatest importance when he discovered * * natural
selection." Even if you live in a village, you have
only to open your eyes to see the reality of natural
selection. You see the struggle of a litter of young
pigs for food; the struggle of a swarm of grubs that
hatch from a caterpillar's eggs; the struggle of men
for employment, of shopkeepers for prosperity. The
weakest, for the particular struggle, "go to the wall."
The fittest, for the particular struggle (not necessarily
the best or the strongest), survive. That is natural
selection.

Now, this may not prove to be an explanation of
everything in living nature. There are certainly
many features of animals and plants that it does not
easily explain. In any case, it does not go far enough,

II

12 THE EVOLUTION OF THE UNIVERSE

because it throws no light on the living machinery
(the embryonic machinery) which causes the varia-
tions at birth. Also, it may be true that new species
are often formed by sudden, large changes at birth;
though few instances of this are positively known.
However that may be, Darwin pointed out a truth,
and we now know that it was in some ways more far-
reaching than he thought. He was a biologist, and
was concerned only with living things. We know to-
day that this truth more or less embraces the entire
universe.

What we call the ''universe" to-day is a collection
of, perhaps, 2,000,000,000 suns or stars, to which our
sun or star belongs. No one can possibly count
them, as the greater part of them are represented
only by very faint points of light on photographic
plates which have been exposed for many hours in
giant telescopes. They crowd together, making little
clouds of light on the plates; and we can merely
roughly estimate that there are about 2,000,000,000
of them in the system or collection to which our sun
belongs. No 'doubt many of them have planets, as
our sun has. No doubt there are living populations,
with ideas and institutions, on many of these planets.
All these are contents of our universe. There are
also incompletely developed stars, dead stars, and
masses of loose material that may one day form stars.
That is our universe.

I keep repeating the word *'our" because it is

THE EVOLUTION OF THE UNIVERSE 13

to-day an open question whether there are "other
universes than ours." Many people think that the
word ' ' universe * ' means the * ' whole ' ' of existing things ,
and the word is generally used in that sense outside
of modern astronomy. But that is not the literal
meaning of it, ^ and astronomers choose to call a vast
collection of stars which form one immense family —
that is to say, which control each other's movements
by gravitation — a universe. There may be other
great systems of stars which are so far from ours
that they are practically independent. Many dis-
tinguished astronomers to-day think that we do
dimly see such "island universes," as they call
them, shining faintly, as blots of light, on the dark
background of space. I will say more about this
presently.

Our universe, then, is a collection of hundreds, and
possibly thousands, of millions of worlds; if we call
each star and its planets a world. They are separated
by millions of miles of space from each other. They
are stupendous globes of white-hot metal and gas, at
a temperature of something between 3,000° C. (red
stars) and 30,000° C. (bluish-white stars). Our sun,
860,000 miles in diameter, is a fair average, or a little
above the average, in size, as far as we know. But
some are so much more intense in their light that,

^The Latin Word "universum" is often said to mean "the
unity of all things"; but it does not contain the word "all." It
means a unified system.

14 THE EVOLUTION OP THE UNIVERSE

whatever allowance we make for higher temperature^
they must be far larger. We cannot measure the size
of stars, but, when the distance is known, we can
measure their brilliance. Professor Pickering has
recently calculated that the star Rigel, in the con-
stellation Orion, gives out 87,000 times as much light
as our sun; and our sun has a temperature of 7,000° C.
at its metallic surface, and possibly 1,000,000° C. in
its interior. The star Canopus is said to be equal in
light-power to 50,000 suns like ours.

Here we have a first suggestion of evolution in our
universe. The colours of the stars may have various
causes, but in the main they are determined by
temperature. Some are blue, some white, some yellow
(like our sun), and some red. That sounds like
globes of metal cooling down ; and the astronomer now
has instruments by which he can fully confirm this
first impression. The stars are masses of white-hot
metal, surrounded by flaming gas, which rise up to a
certain highest point of temperature (probably about
30,000° C. at the surface) and gradually cool down
until they cease to give out light. By an instrument
called the spectroscope — the most wonderful instru-
ment ever invented by man — we can analyse their
light and trace the different stages of their cooling.^

^ I wish to be brief and simple here, but the reader who would
like to know more about this fascinating branch of the science of
evolution will find the material of this chapter, fully and clearly
developed, in my recent work, The End of the World (Watts; 6s.
6d. net ; with many illustrations) ,

THE EVOLUTION OF THE UNIVERSE 15

The millions of stars in the sky are of different ages.
Some are in the prime of life. Some (like our own)
are beyond middle age. Large numbers— astronomers
now generally hold — died long ago.

This is one half, the latter half, of the evolution
of worlds. The next step is to trace the first half,
to discover their origin and early stages. Here
there is a good deal of dispute, but we may choose
a very clear starting point which is admitted by
all. If you leave your room full of fine dust at
night, you will find all this gathered together on
the floor in a layer the next morning. The floor
(or the earth) "attracts" it, we say. Now, sup-
pose an enormous cloud of this dust were in
space, millions of miles away from any solid globe
to attract it. Suppose this cloud were millions or
billions of miles in extent, and it consisted of a
mixture of particles of all the metals and gases. How
wotdd it behave?

We should say that if the dust were quite evenly
distributed, and nothing entered it to disturb it, it
might remain as a cloud for indefinite ages. But, as
a matter of fact, the chances of such a cloud being
quite equally distributed are very slight. There
would be sure to be some parts denser than others.
Then we know what would happen. These thicker
parts or centres would begin to "attract" the dust
from all round them. Even if there were no denser
centres to begin with, there soon would be. As we

i6 THE EVOLUTION OF THE UNIVERSE

know from our shooting-stars, which are fragments
of metal (from grains to large blocks) that shoot
rapidly into our atmosphere at night, and are burned
up by friction, soace is far from empty. Countless
myriads of these solid particles or blocks travel
through it at a great speed. The "ocean of ether"
is as full of them as the sea is of fishes. A great
cloud of dust billions of miles in extent would capture
countless numbers of them.

So there would be sure to be denser centres in our
imaginary dust cloud. These would draw the sur-
rounding dust by the same law of gravitation as the
earth gathers the dust in your room. They would
grow larger and denser. The spaces between the
thick centres would grow thinner and thinner. More-
over, as these centres would be, so to speak, sus-
pended in space, they would draw particles freely
from all sides, and would take the shape of large
loose globes. If you imagine this going on for mil-
lions of years, you see at once that in the end prac-
tically all the dust of the cloud will be gathered
into so many large globes, with great empty spaces
between them. You will also see that the heavier
particles, the metals, will go to the centre, and the
lighter particles, the gases, will remain at the fringe.
You will have gaseous atmospheres round globes of
metal.

The mathematician can tell us a good deal more
about what would happen. We understand him well

THE EVOLUTION OF THE UNIVERSE 17

enough when he says that this coming together, or
condensation, of the particles of dust would cause
heat. Compression always causes heat. And when
you are thinking of a mass of metal dust weighing
trillions of tons, as a star does, the heat will in the
end be prodigious. The concentrated dvist would
become a star. We need only say further that these
great centres of fiery concentrated dust would tend to
turn round on their axes; and that, although they
were tens of millions of miles apart, they would be
sucked into each other and destroyed unless they
travelled rapidly through space in orderly' paths. At
first, we suppose, they would be a disorderly crowd.
Then ** natural selection" would set in. The small
irregular masses would be sucked into the larger.
No doubt some of the giant suns I have mentioned
have fed on others in this way. In the end the great
cloud of dust would be a collection of fiery globes
travelling in circular paths at a safe distance from
each other.

That is how we understand the origin of stars.
Such clouds do exist in the heavens in great numbers.
Astronomers call them *' nebulae," which is the Latin
for clouds. They already have heat enough to be
visible to us. One large class of them, which we call
the "spiral nebula," are much disputed. Some
think that, as I said on an earlier page, they are
separate imiverses at a prodigious distance from us.
I do not share this view. Most astronomers believe

1 8 THE EVOLUTION OF THE UNIVERSE

that the spiral nebula are masses of glowing metal
being formed into worlds. They are nebulae in an
advanced stage of evolution. Other nebulae are
plainly proved by the spectroscope to be clouds of
billions of miles of glowing gas. At all events, our
"cloud" is not an imaginary thing at all. Turn it
into the Latin *' nebula," and there are about 200,000
of them known to us.

Apart from a few recent speculations, which do not
seem likely to be accepted, the general belief is that
the stars were made by the gathering together into
solid globes of vast loose clouds of material in this
way. Whether the material was gas, or solid particles,
or both mixed together, is disputed ; and we need not
go into the point. ^ How far metals like radium add
to their heat is also disputed. These things must be
studied in larger books. The general truth is enough
here. The stars are evolved from great clouds of
loose matter by condensation.

Sometimes you read in the papers that a "new
star" has appeared in the heavens. It is not thought
that this is the ordinary birth of stars. They grow,
and die down, too rapidly. The life of a star,

^ Some may care to have a word on these disputes. There are
three chief theories. The Nebular Hypothesis conceives the cloud
as mainly of gas. The Msteoritic Hypothesis thinks the starting
point was an immense swarm of meteors. The Plantesimal Hypo-
thesis takes as its starting point a vast cloud of solid particles, and
these are supposed to have come from the ripping open (by another
star) of a dead sun.

THE EVOLUTION OF THE UNIVERSE 19

normally, must be hundreds, if not thousands, of
millions of years. Of course, the great sudden blaze
which we call a new star is a blaze of white-hot gas;
not the star itself. Still, these things seem to be
"accidents." A few think that two stars have come
into partial collision — "grazed" each other, so to say.
If two masses of metal, each weighing trillions of
tons and travelling at a hundred or more miles
a second, were to do this, we would certainly expect
a terrific "blaze." But collisions must be very rare,
and new stars are frequent. Probably a dead or
invisible star has rushed into one of the great dust
clouds (nebulae) and been raised to white heat, in
part, by friction. Whatever be the real explanation,
the fact is impressive. The millions of stars of our
universe are living, dying, and being born again all
round us.

Modern science goes a step further than this.
Here I am going to say something which is by no
means settled, but the speculation is so vast and
interesting, and gives such a wonderful unity to
the evolution of the universe, that it cannot be
omitted.

Everybody now knows that a mysterious some-
thing called "ether" runs from end to end of the
universe, and passes through the most solid matter
that we know. The stars are like great sponges in
an ocean of ether. It contains those other "island-
universes" (if they are such) of which I spoke, as

20 THE EVOLUTION OF THE UNIVERSE

well as ours, or else their light woxild not reach us.
What if all our stars and planets and nebulas — all
the matter of the universe — were evolved out of this
ether ! Clearly this is one of the greatest and most
comprehensive ideas that physical science ever gave
to man.

. There is now very strong reason to believe this.
Since the discovery of radium, and all the other dis-
coveries to which this led, our scientific men are con-
vinced that the atom of matter is built of very minute
centres of energy in ether (electrons). The simplest
atom may contain more than a thousand of them,
whirling round at speeds approaching 100,000 miles a
second. The atoms of the heavier metals contain
hundreds of thousands of them. The atoms are
orderly "systems" of electrons, just as universes are
orderly systems of stars. And it is probable that
natural selection has been at work in checking the
evolution of both systems: the one, the atom, so
small that trillions would go into a pin's head; the
other, the universe, thousands of billions of miles
in extent.*

Here, then, we have the answer to the last ques-
tion: Where did the matter which makes the stars
come from? Apparently from ether. Where did
the ether come from? We have no reason to sup-
pose that it came from anywhere. It may be the
fundamental reality, from the bosom of which
matter rises, to form stars which glow for hundreds

THE EVOLUTION OF THE UNIVERSE 21

of millions of years and then die, to be born and glow
again. ^

I What about Einstein's theory, which, some tell you, does not
admit ether? As a matter of fact, it admits a different kind of
ether, in which light does not travel in straight lines, and it gives
a new idea of gravitation. Einstein's theory cannot be popularly
explained, as every scientist who has tried to do it admits. The
best attempts are an article by Sir Oliver Lodge in the Nineteenth
Century, December, 1919, and an article by Professor Eddington
in the Contemporary Review for the same month. It is a matter
of the highest mathematics, and, even if it were ever proved
(which is doubtful), it will not modify the ordinary teaching of
science as much as some say.

CHAPTER III

LIFE IN THE PRIMITIVE OCEAN

From this broad picture of the universe we must now
come down to our little earth, and study the evolution
of life on it. There used to be writers who told us
how we were ** dwarfed" by the vastness of the
universe. It really makes no difference whatever to
us how vast the universe is. We remain just the
same size, however much the universe grows. Then
there were writers who tried to console us by saying
that probably we were the only living inhabitants of
the universe. No man of science would now entertain
that. We cannot prove that there is life anywhere
except on the earth; but we will study the develop-
ment of the earth and the life on it, and we shall
realize that the same t?iing has probably happened in
countless parts of the universe.

I spoke of a great dust cloud which might condense
into patches, and these in turn into stars. Now, in
each patch, or region of concentration, there are sure
to be irregularities. Some parts will be denser than
others. The dust will, therefore, not all be drawn to
the central part. Some will gather round the other
denser centres. In other words, the last result will

22

LIFE IN THE PRIMITIVE OCEAN 23

be a great central globe and a number of smaller
globes (or planets) connected with it.

These smaller globes would, of course, be sucked
by gravitation into the central globe unless they
moved round it at a great speed. There are several
ways in science of showing how this circulation of
the planets round the sun might be caused, but they
are too advanced for this little primer. If the reader
will look at the photograph of a spiral nebula in some
astronomical book, he will see the fiery matter con-
densing into a large central sun and a large number
of smaller fiery masses all round it. We know that
they are moving round it. The whole structure is
turning round.

But how do the planets come to follow orderly
paths round the central sun, at such distances and
such speeds that the system may last for millions of
years? Natural selection gives the answer. At first
there were probably far more planets circling round
our sun than there are now. Those which followed
unsuitable paths were drawn in by the others or by
the sun until only the "fittest" survived. Our eight
planets are the survivors of a mighty struggle for life.

We have every reason to suppose that the other
stars were formed in the same general way as our
sun. It is therefore probable that they have, unless
there v^ere special conditions, planets of their own.
These planets are made of the same material as ours.
The spectroscope can tell us what even the most

24 LIFE IN THE PRIMITIVE OCEAN

distant star in the universe is made of, and it reports
to us that much the same material is found throughout
the whole universe, and even in the universes beyond
(if there are any) . When you have the same material,
following the same general laws, you naturally expect
results of substantially the same nature. The metals
would keep to the centre, and form solid globes. The
free gases would remain at the fringe, and form atmos-
pheres and oceans. This is the reason why men of
science regard it as highly probable that there are
countless planets with living populations. We have
no reason to suppose that our earth was made in
any special manner. There are probably globes
in all parts of the universe with the same condi-
tions of life: chemicals, air, water, and a certain
temperature.

But we must study the making of our earth a little
more closely. Originally, as I said, it was one of
many fiery globes which circled round the sun. They
gradually cooled. The planet Mars, being very much
smaller than the earth, cooled before it. That is why
we suppose that, if there is life on Mars (we are not
quite sure of its conditions), it began before life on
the earth, and is probably more advanced. However,
our earth gradually cooled, and at length the oxygen
and hydrogen gases in its atmosphere were able to
unite and form water. But the earth was still red-hot.
Water could not settle on its surface. So the whole
mass of water which now forms our oceans then

LIFE IN THE PRIMITIVE OCEAN 25

existed in a state of cloud or steam in the atmosphere.
The earth was still a fiery metal globe, surrounded
by a tremendous shell or mantle of steam. That
is how we find the planets Jupiter and Saturn to-day.
They are so large that they have not cooled down as
far as the earth. They are red-hot at the surface,
and all that we see of them is the great mantle of
cloud or steam that surrounds them. You see, every
feature of our solar system is just as we should expect
to find it on the theory of evolution which I gave in
the last chapter.

Under a great canopy of moisture like this, the
metal surface of the earth might remain molten until
it sank to about 800° C. ; but its heat was being
discharged into space all the time, and its temperature
sank steadily. It was, remember, a block of iron
cooling down; or, rather, it was a mass of molten
iron, like the liquid, glowing stuff you may have seen
in a furnace. As the temperature sank the steam
would approach closer to the surface, and at last
would be able to settle as water. This would, of
course, take a long time. At first the water would
boil, and be blown back in the form of steam. This,
however, would hasten the cooling of the earth, and
the time soon came when the surface of the globe
was covered with a boiling ocean. It was not at first
salt water. The salts of the sea have been gradually
washed out of the rocks. But as the primitive atmos-
phere was very far from pure, the waters which settled

26 LIFE IN THE PRIMITIVE OCEAN

on the earth would also contain great quantities of
acids and chemicals.

Here, then, we have three features of the earth
explained: its molten interior, its solid crust, and its
oceans.^ A globe of molten metal naturally cools
first at its surface, and forms a crust or "slag," as
molten iron does in the foundry. It is now at least
a hundred million years, and may be very much more,
since the earth began to cool. The solid crust has
become from fifty to seventy-five miles in thickness,
and the great mass inside remains at a terrific tempera-
ture. The pressure is too great to allow it to be fluid,
but there are leaks and irregularities in the crust, and
at times it oozes through as white-hot lava. There
you have the explanation of volcanoes, and partly of
earthquakes.

At first the crust would be a fairly equal scum or

slag all round the globe, and the ocean would be

fairly equally distributed over it. At the most a few

ridges of land might peep out of the hot ocean. But

there would be for ages, probably for millions of

years, a mighty battle between the crust and the

molten matter below it. In cooling, the surface or

crust would naturally shrink. The skin, so to say,

would always tend to be too small for the globe, and

* I ought to warn the reader that many geologists now follow
the Planetesimal Hypothesis, which I mentioned on p. i6. Ac-
cording to this, the earth was formed with less heat, and was
never all molten. The accoimt I am following is the one generally
received, and most probably correct.

LIFE IN THE PRIMITIVE OCEAN 2^

would burst. Then the molten masses below would
pour up and over the crust. This would go on for
long ages, until the crust was thick enough to confine
the fiery giant below it. That is why we find the
earliest rocks, which represent half the life of the
earth, mainly volcanic. When the crust had set firm,
the great process of wearing down the rocks would
start, and the sand and fragments would begin to
form our "sedimentary" rocks at the bottom of
the sea.

After these great upheavals the crust of the earth
would no longer be fairly even. There would be hills
and ridges, with corresponding valleys and depres-
sions. The waters would settle in the depressions,
and the division of "dry" land and water would
commence. As the crust becam.e thicker and more
irregular, great masses of it might be undermined by
water, far below, and sink or "subside," making
mighty hollows in the surface of the earth. Probably
our ocean-beds were formed in this way. It drained
the shallow seas off the rest of the crust, and made
more "dry" land. The land, in other words, has
been gaining on the water all through the history of
the earth. There was very little dry land at first,
and there were no mountains. There is more dry
land than ever to-day.

This may seem to you to be not a very important
matter to dwell up n, when I have, for reasons of
space, to omit thousands of interesting features. On

28 LIFE IN THE PRIMITIVE OCEAN

the contrary, it is most important. What I want
especially to give in this little work is the general
machinery of evolution, the broad principles of the
subject. And this constant change of land and water
is a most important part of the machinery of the
evolution of life. You might poetically imagine it as
the struggle of the land to free itself from the water.
In the course of time it has thrown the bulk of the
waters into deep ocean beds, and has reared itself in
high mountain-chains and broad continents. The
changes which this restless struggle has brought about
from age to age have very deeply inlBuenced the
development of life, as we shall see.

But first we have to introduce life itself. It ap-
peared at a very remote date in the warm, shallow
ocean of the primitive earth. How long ago that was
we cannot say. Most geologists would say between
fifty and a hundred million years ago. There is,
however, a new school which professes that what are
called the "radio-active" minerals (minerals whose
atoms break up, like those of radium) in the older
rocks show that the earth must be more than a
thousand million years old. There is really no reason
why we should be in a hurry to decide how old the
earth is. It is enough that the story of life on it
began at least tens of millions of years ago.

Where did the first living things come from, and
what were they like? That is a mxOre interesting
question. Unfortunately, science is not yet able to

LIFE IN THE PRIMITIVE OCEAN 29

give a confident answer. This is hardly surprising.
Man is at least half a million years old, but science
is only about two centuries old; and to expect it to
take a very wonderful and complex change that
occurred a hundred million years ago and tell us
confidently ' ' all about it " is to expect too much. We
can only speculate, and there are two chief lines of
speculation.

It must be quite understood that every scientific
authority in the world now believes that life was
naturally evolved from the chemicals of the early
earth. Everything that we can satisfactorily study
was evolved. We have therefore a right to assume
that all things were evolved, unless such a natural
evolution is in any particular case shown to be impos-
sible. No one has ever shown that the natural evolu-
tion of the first living things is impossible, or even
improbable, so we take it for granted. That is per-
fectly sound logic as well as sound science. There
is one distinguished scientist, Professor Arrhenius,
who thinks that the germs of life came to us from
another planet. That is not only difficult to imagine,
but it only puts the problem on th e shelf instead of
solving it. Life was naturally born in the shallow
oceans of our early earth.

There are many theories of how it was born, and I
would recommend the reader who wants to examine
them to try to see a valuable work by a group of
American professors, called The Evolution of the Earth

30 LIFE IN THE PRIMITIVE OCEAN

and Its Inhabitants (191 8). In a chapter on "The
Origin of Life" Professor Woodruff gives all the
theories. You need a good knowledge of chemistry to
understand them fully, and I need only say here that
both chemists and biologists agree that a natural
chemical evolution could produce the first living
things. But you must be careful not to suppose that
even the lowest living things in nature to-day — say,
the simplest bacteria — were directly evolved out of
inorganic matter. A very long evolution, with
thousands of phases, would be required. It would
take ages. First the stuff of which living things are
made, protoplasm, would have to be formed by a long
series of chemical changes and combinations. Then
this stuff would have to break up into the distinct
units which we call "cells"; for each of the simplest
animals and plants is a single cell.

When I spoke of "two chief lines of speculation,"
I meant that you may suppose that the natural
development of life — what used to be called "spon-
taneous generation" — is going on now in nature, or
that it only occurred under the very special conditions
of the early earth. Both these views are held by
distinguished biologists. Professor Benjamin Moore
has an excellent little work on the former line — that
life is still being evolved in nature — in the "Home
University Library." It is called The Origin and
Nature of Life (1912). He and other eminent au-
thorities (such as Professor Thomson, of Aberdeen)

LIFE IN THE PRIMITIVE OCEAN 31

believe that what many call the "mystery" of the
origin of life is really an ordinary event in nature's
life to-day. It would be below the level of the micro-
scope, so that the old controversy about "spon-
taneous generation" does not settle the question.
Other scientific men, perhaps the majority, believe
that it was the very extraordinary conditions of the
early earth which begot life. The temperature of the
ocean was very high, the chemical conditions are
unknown to us, the electrical conditions were more
pronounced than now, and there may have been a
good deal of radio-activity. It seems more probable
that the evolution of life was due to these special
conditions, which have passed away for ever.

It is hardly necessary to point out that much the
same conditions would be found at one timiC or other
on all the planets in the universe of any size. They
are globes of (generally) the same m.aterial as ours,
cooling down. That is why we expect life in myriads
of other places besides the earth. And as we saw
that other stars are older than ours, and some have
actually run their course and died, it seems likely
that the full story of life had been played out on
countless globes before man began his career on earth.

Well, we return to the first living inhabitants of the
earth, which must have been far simpler than the
lowest bacteria that we know. In fact, it would be
correct to say that there were no "first " living things.
Inorganic matter slowly developed into organic, and

32 LIFE IN THE PRIMITIVE OCEAN

this was slowly shaped into living units. This
particular evolution must have taken ages. There
was no more a "first" living thing than there was a
"first" man. Many difficulties will be avoided if we
bear in mind the extremely slow and gradual nature
of these evolutions.

The next great point was the division of early life
into plant and animal. There is really no essential
difference between the two. They are made of, sub-
stantially, the same plasm, and in the lower circles of
life to-day it is often impossible to say whether a
living thing is a plant or an animal. But some of
the early inhabitants continued to feed on inorganic
matter — the chemicals in the soil — and this is mainly
what we mean by a "plant" of vegetal organism.
As the soil holds the chemicals they need practically
everywhere, they do not, as a rule, require locomotive
organs. They "take root." And as sensitiveness is
of no use to stationary beings, they do not develop
sense organs. Thus you get the evolution of a plant-
world. The earliest, of course, floated in the water;
but some took root in the soil at the bottom of the
ocean, and in time great thickets of giant sea-weeds
arose. We will trace these to the land in the next
chapter.

Some of the early living things formed the habit of
devouring their neighbours, instead of building up
plasm out of inorganic matter. This is the beginning
of the animal. It is quite plain that this means a

LIFE IN THE PRIMITIVE OCEAN 33

precisely opposite development from that of the plant.
It means "hunting"; so the hunter and the hunted
develop, very gradually, organs of locomotion, sense-
spots, mouths, stomachs, weapons, armour, etc.
Even in the microscopic life of the pond, where every
organism is still a single cell, you get bewildering
variety of developments of this kind. But we cannot
linger here over this stage.

In tim.e the cells cling together, and larger animals
("man^^-celled") are formed. This affords a better
opportunity for specializing. Some cells become
muscle-cells, some nerve-cells, some stomach-cells,
some weapon-cells, and so on. You can see all this
in a primitive way, under the microscope, in the
common pond hydra. The jelly-fish or the anemone
you find at the coast are advances of the same type.
The animals grow larger and larger, and the develop-
ment of their separate parts increases. Eyes and
other senses begin as little pits in the skin lined with
sensitive cells, and slowly improve. After a time (in
lowly worms) these are connected with each other and
with a group of nerve-cells in the head : the primitive
brain.

¥7hat I have described in the last four paragraphs
certainly took millions of years, and probably tens of
millions of years ! During all that time animals were
soft-bodied, and have left no ''fossils." It is by
studying them in nature to-day that we trace the
lines of their evolution. But at last animals with

34 LIFE IN THE PRIMITIVE OCEAN

hard parts were developed, and we begin to find these
preserved as fossils in the rocks. Some began to
form coats of lime (shells), and the great family of the
Molluscs (mussels, cockles, oysters, etc.) spread over
the floor of the ocean. Natural selection is very
useful in explaining protective parts of this kind.
Others had their bodies drawn out into sections, with
a tough coat on each section (crabs, water-fleas,
shrimps, etc.). Others had long wriggling bodies
(worms). The seas now teemed with life, and there
was a mighty struggle for food and safety. The less
fit perished, age by age. Organization crept higher
and higher.

But I will close this chapter with an illustration of
the way in which the geological changes which w^ere
going on all the time influenced the living things,
even in the water. I have said that the land was
rising above the water, as the ocean sank into deeper
beds. We have strong reason to think that these
changes were often acute and violent. The man who
says that the secret of progress is "evolution, not
revolution," may be talking very good social philo-
sophy— I have nothing to do with that — but he is not
talking science, as he thinks. In every modem
geological work you read of periodical "revolutions"
in the story of the earth, and these were the great
ages of progress — and, I ought to add, of colossal
annihilation of the less fit.

We will see some of these later. Here I refer to

LIFE IN THE PRIMITIVE OCEAN 35

one which occurred at the period we have reached.
There were violent changes of land and water. Great
continents, which had for ages spread out very fiat
and swampy, were tilted. Mountain-chains arose,
with mountain torrents. The rivers, which had been
sluggish for ages, became far swifter. This meant a
great change for the swimming population. Already
the hunt for food and escape was developing swifter
means of locomotion. Now the water itself would
wash them away if they did not develop more power
and speed. No doubt whole vast populations of
floating and swimming things perished, and the speed
of others was more rapidly developed.

At the close of these great changes the fish, the
king of the early ocean, appears. You see how
beautifully his long boat-like body, his powerful fins,
his eyes and nose and mouth and teeth at the fore-
end, respond to the new conditions. They were the
outcome of a very long and hard struggle. And the
same geological changes which brought about, or
hastened, this struggle and new ''adaptation" are
now going to open a new and most important chapter
for us.

CHAPTER IV

LAND LIFE BEGINS

More than half the story of life was over at the time
of the appearance of the fish, which we have reached.
That half of the story is not only very imperfectly
known to us, but it is difficult for people who have
not a fair knowledge of science to follow it. I have
therefore dealt with it on very broad lines. Those
who wish to know more may consult my larger work,
Tht Story of Evolution, in which the development of
each branch of the lower animal world is fairly traced.
The second half of the story of life, mainly of life on
land, I will now tell more in detail. It is easier to
follow, and it will illustrate every principle of
evolution.

First, then, you must begin by thoroughly grasping
the immense influence of environment on the evolu-
tion of living things. There is a warm controversy
in modem science as to the respective shares of
environment (surroundings, climate, etc.) and
heredity. If you read some of our English writers,
often men of distinction in science, you will get the
impression that it is old-fashioned to talk about the
influence of environment; that all changes and ad-

36

LAND LIFE BEGINS 37

vances are caused and settled in the germ-plasm (the
seed). Do not believe it. The science of heredity-
is still very obscure and imperfect, so I am saying
little about the internal causes of those changes in
animals and plants which make evolution possible.
They are of the very first importance, but are still
obsciire. What is clear is that the changes in the
earth itself have had enormous influence in directing
these variations at birth into the formation of new
species.

Here we have a striking illustration. The land
rises, the rivers flow more rapidly, and the need for
speed, which was already great on account of the
struggle of hunter and hunted, becomes greater than
ever. The fish family appears in the waters, begin-
ning with uncouth forms that no longer exist, passing
on to the shark, then branching rapidly into hundreds
of types. The fins were probably at first folds of the
skin, which were gradually strengthened by ribs of
cartilage. Bones were not yet developed. The lower
fishes of to-day (sharks, rays, etc.) have no bones.
They are the survivors of one of the earliest families.
The backbone is the chief new departure. The great
"back-boned" (vertebrate) family has begun. But
the backbone was at first not a bone at all. It was
just a stiffening rod of cartilage, and its evolution is
easily traced.

We must turn now to another momentous con-
sequence of the geological changes which I have

38 LAND LIFE BEGINS

described. It is useful to try to picture this early
earth on which a new act of the drama of life was
opening. There was little solid land. A warm ocean
rolled over the greater part of the surface of the globe,
and in it the story of life had so far proceeded. The
atmosphere was foul and thick, quite unsuitable for
such land animals as we know, and generally saturated
with moisture. The enormous quantities of carbon
and moisture in it let only a sombre light of the sun
pierce through; but, on the other hand, they pre-
vented the heat from being freely reflected back into
space, and an almost tropical climate existed all over
the earth. There was no winter season. Frost and
snow were unknown anywhere.

The land now began to gain on the water. Ridges
of hill no doubt arose, but most of the new "dry"
land would be broad swamp and mud-flat. Upon
these shores life began to crawl from the overcrowded
ocean. Plants must have led the way, since animals
would need them for food. We know that the con-
ditions— steamy swamps and an atmosphere rich in
carbon — were good for such types of vegetation as
there were at the time, and as they became adapted
to land life, or swamp life, the}^ throve and evolved.
Low types of ferns and mosses appeared, and in the
rich, warm, low-lying earth they found a golden age.
As time went on they grew to gigantic proportions.
Most of them are now extinct, but the little "mare's
tail" which you find beside a stream to-day had a

LAND LIFE BEGINS 39

cousin among the early plants. It grew to a height
of forty or fifty feet, ordinarily, and sometimes to
nearly a hundred feet ! It was an age of giants. Club
mosses ran to a height of a hundred and fifty feet;
and even tree ferns sometimes spread their graceful
dark green canopies at fifty or sixty feet above the
soil.

The animals had meantime followed the vegetation.
Their skeletons or shells are now buried in the soil,
which has become our rocks, and we can fairly trace
the invasions from the sea. Snails were among the
earliest arrivals. Worms of various kinds became
adapted to land life. Presently we find traces of
insects — "primitive bugs" and "primitive cock-
roaches," to translate the learned names which are
given to them. There is in South America and a few
other places to-day a very primitive little creature,
called the Peripatus, which you would take to be
a very strange caterpillar if you met it in the wood.
It is one of the beings of the remote past, which has
somehow survived the struggle of ages, and it helps
us to understand the origin of the insects. Apparently
some of the worm-like creatures which invaded the
land from the sea developed tubes in the skin (a sort
of tiny "lungs") for breathing air. They flourished,
and, as is almost always the case with these large
prosperous families, they scattered and evolved in
various directions. From them, we think, in the
course of time, came our insects, spiders, scorpions.

40 LAND LIFE BEGINS

and centipedes. All these developed gradually in the
age I am discussing.

But I am hurrying over these lowly creatures in
order to give more time to a more important invader
of the land. This was the fish. You may think it
easy enough to imagine snails and worms being
adapted to life on land, but the idea of a branch of
the fishes leaving the water and becoming land ani-
mals must seem strange to those who have not a
good knowledge of natural history. If it be clearly
understood that, as I have so often said, these changes
and adaptations to a new life were very slow and
gradual, the difficulty lessens. But it disappears
altogether when you take a good work on natural
history and zoology, and read what the author has to
say about "lung-fishes."

He will tell you that in certain rivers of Queensland
there are short, stumpy fishes which have a lung as
well as gills. The water of those rivers runs low in
the summer, and the lung then comes into play to
help out the animal's breathing. You v/ill next learn
that in certain rivers of Egypt and of South America
there are fishes of the same family with two lungs
(like ourselves) as well as gills. The rivers in which
they live dry up entirely in the summer. The gills
(for breathing in water) are then useless. The fishes
bury themselves in the dry mud, and breathe by
their lungs until the waters flow once more. They
can walk on their fins; and, in fact, the fins of some

LAND LIFE BEGINS 41

of them are more like slender and badly-made limbs
than fins. So here is "a fish out of water" that is
not less comfortable than in water. It is the first
amphibian; a connecting link between life in water
and on land.

But were there such fishes in the remote age which
we are considering? We have only to compare the
fossil remains of certain fishes belonging to that age
with the skeletons of our lung-fishes, and we know
that there were. These fishes are survivors of a great
family of lung-fishes of early times; and as we find
them so far apart as Queensland, Egypt, and Brazil,
it seems that this family must at one time have been
spread over the entire earth. Some branch of the
family, or some branch of the fish-world closely re-
lated to them, left the primitive waters and began the
important story of the evolution of the quadrupeds.
We are not quite sure from which branch of the
ancient fishes the quadrupeds came. If it was not
the lung-fishes themselves, it was some common
ancestor of the lung-fishes and another group.

Let us come back for a moment to the gradual rise
of the land. It meant that enormous shallow seas
which had become densely peopled with fishes now
disappeared. It meant swifter and narrower rivers.
It meant less lakes and lagoons. It meant more
circulation of the moisture in the atmosphere. These
are the things to study, not dreamy speculations such
as you find in Professor Bergson, if you want to

42 LAND LIFE BEGINS

understand the evolution of life. The decreasing
lakes and rivers and shallow seas were overcrowded.
There was a fearful fight for oxygen and for food.
For those which ventured back into the deep seas
there were sharks thirty feet long, with teeth five
inches long, and other great fishes with jaws two feet
in width, waiting. There was, in a sense, a race
for the land — that is to say, an increased development
of adaptation to land life. Lungs for breathing air
were the chief things required ; and we find lungs (or
other air-breathing organs) developing on all sides.
The fish would develop its lungs out of the ''floating
bladder," or gas-bag, which it already had for swim-
ming purposes. In some fishes this bladder is double,
and is already connected with the gullet by tubes.

Naturally, I can give here only a very superficial
account of what happened, but all the details of the
change to land life will be found worked out in larger
scientific works. For my purpose it is enough to
describe how, at the time when the primitive ferns
and mosses spread over the warm earth (in what a
geologist calls the "Devonian Period," because its
most characteristic rocks are those red sandstone
cliffs you may have seen in Devonshire), a great
swarm of uncouth lung-breathing fishes covered the
land. No doubt they "kept one leg in the water/'
so to say. They preferred to live in water as far as
they could. But there was a desperate struggle for
food in the crowded waters, while the land had as yet

LAND LIFE BEGINS 43

no other large animals on it, and was becoming rich
in insect food. As these lung-fishes lived more and
more on land, walking on their fins, the broad paddle
of the fin was slowly converted into a strong and
flexible bony stem — the leg. These ancestral quad-
rupeds had at first two pairs of fins, as some fishes
have to-day. The two pairs of fins gradually became
legs, with five toes (made out of five rays of the fin)
at the end. The lungs continued to improve. The
amphibian — father of our frogs and newts — made his
appearance. The quadruped race was born.

Let us glance again at the vegetation. I have said
that there was no cold or winter anywhere on the
earth. We know this because the fossil plants we
find are all of a semi-tropical character. As there
was thus no winter chill, the plants throve luxuriously,
from pole to pole, all the year round. The whole
earth was semi-tropical in temperature, and most of
it was very damp, low-lying, steamy. This suits
ferns and mosses, and they, as I said, grew to gigantic
sizes. It suited them also that the air was rich in
carbon, and with all these favourable conditions the
plants of the time grew denser and denser. This
period of "perpetual summer " lasted millions of years,
and we are not surprised to learn that before the close
of it the earth was covered with such forests as have
never been seen since.

Here another interesting question has been answered
by the story of evolution. By the beginning of the

44 LAND LIFE BEGINS

nineteenth century it was well known that there were
great seams of coal in the crust of the earth, and it
did not take long to discover that these seams are the
decomposed remains of extraordinary forests which
at one time covered the earth. The tree trunks and
fern leaves are often quite plain in the coal. But
they all belonged to one particular and remote period
(the Carboniferous, or Coal-bearing, period) in the
story of the earth. Why had there been such vast
and unique forests at that period? I have given the
answer. The conditions were unique for that kind
of vegetation. It was the golden age of ferns and
mosses and similar types. It has given us the coal
seams of the world.

How and why the great forests came to an end, and
have never re-appeared, we shall see in the next
chapter. Let us look more closely at them before
they pass away. On- the west coast of New Zealand
I have looked down, from the summit of the hills a
mile or two inland, upon forests of tree ferns spread-
ing above a great carpet of every variety of mosses.
This is a degenerate patch of the great coal forests
of long ago. It has no longer the luxurious conditions
of the coal forest. The winter there is almost as cold
as in London. But close at hand, in fact often under
the tree-fern woods, are seams of coal which suggest
that these great stretches of fern and moss have
lingered on until to-day ; though hardier types of fern
and moss have taken the place of the old types.

LAND LIFE BEGINS 45

Trees and flowers from the east coast, which got
them from the warm islands beyond, now mingle
with the fern forests of New Zealand ; but in the coal
forest there were no flowers. There were merely
certain crude green seed-organs, that we might call
flowerets, on some of the ferns; and in a later chapter
we will trace the evolution of the flowers from these.
There was a monotonous sombre green everywhere.
No birds had yet appeared. No moths or butterflies,
no bees or wasps, would be seen. There was no grass.
Beetles, fat and stumpy spiders, and centipedes were
everywhere. Great flying insects, unlike any that
we know, measuring three feet across the wings, were
the only creatures of the air. Wings began to be im-
portant, for the amphibious creatures that were
evolved from the lung-fishes swarmed in the forests,
and grew fat on the rich insect world.

We have innumerable fossil skeletons of these
amphibians of the coal forests. Our frogs and toads
were not yet born, but creatures of the newt and
salamander type ran to a prodigious size. In the
swamps was a giant salamander, about five feet long,
which seems to have been the monarch of creation in
those days. Almost in every case where a new family
appears its members quickly run to a great bulk of
body. Food is very abundant, and at first the com-
petition for it is not so keen. After a time over-
population begins to tell. The fat, sluggish types,
which had had no work to do but eat, are very much

46 LAND LIFE BEGINS

reduced. Food is less, and it must be hunted. Can-
nibalism is apt to begin, and the struggle of hunter
and hunted brings out new forms, just as surely as a
great war does.

^ So we find the amphibia of the coal forests branching
out in many directions. Some small types become
tree climbers, and no doubt they found a rich diet of
insects in the trees. This reacted on the insects, and
caused fresh developments among them. Some, as
we saw, developed wings, and could at least soar from
tree to tree. As these enjoyed good security, for
there were then no birds or flying reptiles, it is
natural to find them growing to a large size. They
had fat, heavy bodies eighteen inches long. Other
insects were fitted for survival by gradually develop-
ing such a shape and colour that they could not be
seen at any distance. These were the "stick insects "
which belong to the ancient order. They are very
common in Australia to-day, precisely because Aus-
tralia and New Zealand have the most primitive
animal populations on the globe.

Other amphibia of the coal forest lost the use of
their limbs, and developed long snake-like bodies.
These give us an excellent clue to the development of
the later serpent. The struggle for life among the
amphibians themselves had become very severe, and
some had taken to hiding and living among the ex-
posed roots of the trees by the side of the swamps. If
you have ever seen a picture of a mango forest at a

LAND LIFE BEGINS 47

river's edge, you will understand this. The roots form
a dense thicket, into which the giant salamander or
large fish could not follow the little amphibian. But
legs are useless in such a world. A strong wriggling
body is needed; and the fossil skeletons we have
show us that this branch of the amphibians slowly
changed until they must have looked externally like
water snakes.

These illustrations of the machinery of evolution
during the long forest period will suffice. It seems
to have lasted about a million and a half years; or
the whole period we have just surveyed may have
lasted ten million years. In spite of all the changes
we have noticed, it was a period of slow evolution.
Life is never quite stagnant, unless some race of
living things is removed entirely from competition
with others and has easy conditions. I mean that
for a living family of low intelligence, which depends
on almost mechanical stimulation from its surround-
ings, such conditions generally mean stagnation.
They are rarely found, however, and we saw that
there was a brisk struggle in the coal forests. Yet,
when we think of the enormous period occupied
by these developments, the pace of life was slow.
Fat salamanders, fat insects, fat spiders, and so on,
lived out the warm days sluggishly and contentedly.
Now a fearful "revolution" is at hand, and new
dynasties are to come to the throne.

CHAPTER V

IN THE GRIP OF AN ICE AGE

We have already begun to realize what a deep in-
fluence changes in the surroundings may have on
the earth's inhabitants, although I have been able to
give only a few illustrations. The struggle of land
and water, which I have described, caused a great
number of other new developments. Suppose, for
instance, a vast marshy region, that had lain stagnant
for hundreds of thousands of years, were tilted and
drained, so as to form a great tract of dry country
with a few swift-running rivers. The whole animal
and plant population must change. The fish and
shell-fish, the luscious plants and all that fed on
them, down to the microscopic animalcules, the in-
sects and amphibians, must give way to new types.
If the changes are very gradual, the new types are
largely their own descendants. There is time for
evolution to adapt them to the new surroundings.

This was happening in very many parts of the earth
during the period we have just considered; and we
will glance at one further effect of such changes before
we come to the great transformation which crowned
them all. It is quite plain that the amphibious

48

IN THE GRIP OF AN ICE AGE 49

animals which lived in one of the regions that were
being gradually drained would become simply land
animals. As long as they have both elements, land
and water, they use both. But even in nature to-day
we have frogs that live in trees or in almost waterless
regions. We will suppose then that, as the waters
are drained, these large primitive salamanders, as
described in the last chapter, take m.ore and more to
the land. They will lose their gills. Their legs will
grow stronger, and their feet firmer. In short, the
salamander will become a reptile with a short, stump}''
tail.

This new branch of the tree of life appeared before
the end of the coal forest period. The reptile was the
new m^onarch of the earth. He was very different
from the snakes and lizards, crocodiles and turtles,
of to-day. He had a thick, squat body, several feet
long, a very short tail, and a head more like that of
a frog. He was the patriarch of the reptile family,
and the descendant of the salamander and the lung-
fish. But he appeared for the same reason as they
did : the land was gaining on the water.

At first the reptile also had a golden age. He can
live in water, like a crocodile, or in a waterless desert,
like some of the Australian lizards. What he chiefly
wants is warmth. He is a cold-blooded animal. That
is to say, his heart has only three chambers, so that
the blood purified in the lungs is not kept completely
separate from the unpurified blood, and it does not

50 IN THE GRIP OF AN ICE AGE

keep a constant high temperature. In cold weather
his blood grows colder. Also he lays his eggs — I
mean Mrs. Reptile lays her eggs — in the open, and
nature must supply the warmth to hatch them. In
fine, a coat of scales is not particularly warm. He
loves to be in the sun. But we saw that he appeared
in an age of perpetual semi-tropical summer, and he
prospered and multipHed exceedingly.

If there had been such things as scientists among
those early reptiles, the}^ would have made a strange
and disturbing discovery. Let us suppose that they
had records of the preceding ten million years. The
climate would be recorded as "perpetual summer,"
as we saw. Surely it would last for ever ! But these
reptile scientists would presentl}^ make an unpleasant
discovery. The earth was growing colder. If they
could have got reports from all parts of the globe, it
would have been the same story. Century by century
the earth was growing steadily colder. In many
places the land was rising, slowly, to unknown
heights. Whole regions had to be deserted. The
warm-loving vegetation of the tim^e could not live
in them. There was no food. The other regions
became over-populated. There was the usual fierce
struggle and active evolution. The hardier specimens
had a better chance. They could live where most of
the others could not. Some of them became gradually
adapted to a cold climate.

To drop this little parable, and state the facts in a

IN THE GRIP OF AN ICE AGE 51

word: the long perpetual summer of the early earth
ended in a great Ice Age. That is to say, about four
million square miles of the earth's surface were
covered with a permanent sheet of snow and ice, as
our Arctic and Alpine regions are to-day. We can
detect traces of glaciers, or rivers of ice, millions of
years after they have disappeared. Their weight is
such that they grind pebbles deep into granite rocks,
and the scratches remain almost for ever, in suitable
places. There had been two earlier Ice Ages in the
story of the earth; but, as we saw, there was then no
life on land, and we have not considered them. This
new ice sheet stretched from India to Australia and
Africa. A great continent spread over that area at
the time, and it must have been one vast Arctic
region. I have seen the marks of glaciers of, say,
nine or ten million years ago — the periods we have
reached — in Australia.

Four million square miles are by no means the
entire land surface of the earth, but the climate of the
whole earth seems to have changed. No doubt there
were smaller sheets of ice in other regions. Wherever
there were mountains there would be at least a frozen
winter-time. And there were now, for the first time
in millions of years, many mountains. That is, in
fact, probably the great cause of the Ice Age. I have
carefully studied Ice Ages in my Story of Evolution
and End of the World, and am convinced that, as
many geologists think, the cause of Ice Ages is a great

52 IN THE GRIP OF AN ICE AGE

elevation of the land. We saw that during the pre-
ceding period the earth was generally low-lying and
steamy. A very thick atmosphere brooded over it,
and, like the panes of glass of a hot-house, it kept the
heat down at the earth's surface. This thickness of
the atmosphere was partly due to the enormous
masses of carbon (in the shape of carbonic acid gas,
or carbon dioxide) in it. The great forests, which
absorb carbon and give out oxygen, had altered this.
But the dense moisture of the early atmosphere had
the same effect. The great rise of land now altered
the moisture. It swept up the cooler hill-sides and
was turned into rain, or "precipitated." There was
more running water, and less brooding moisture and
stagnant water. This purification of the atmosphere,
combined with the rise of mountain chains high up
above the sea level, is enough to explain an Ice Age.

The change may have taken a hundred thousand
years. Indeed, it was really the last stage of a change,
the struggle of land and water, that we have traced
for some time. There was no evident upheaval.
What geologists mean when they call it a revolution
— this period they call "the Permian Revolution" —
is that the story of the evolution of life, taken as a
whole, shows at this point a more rapid and funda-
mental change.

It is quite easy to see that the change of climate
would certainly mean a revolution for animal and
plant life. You m-ay bring a negro chief from Africa

IN THE GRIP OF AN ICE AGE 53

to Norway without much risk to-day, because you can
give him Jaeger vests, a tweed suit, and a fur coat.
But, if clothing were unknown, what would be the
effect of transporting a party of Zulus to Northern
Siberia? Well, as we saw, practically the whole of
the earth's inhabitants had been living in an African
climate, and the worst kind of moist African climate,
for millions of years. No doubt there were some
drier regions, as the land rose; but the fossil remains
show that they were few. Nearly all the plants and
animals of the time were suited only to a moist, hot
climate, and were too sluggish to be re-adapted.

As a natural result, there was a prodigious carnage
of the living inhabitants of the earth. This is the
worst aspect of "natural selection." It is a fearfully
effective method, but slow and costly and ruthless.
We should say that it is a cruel and stupid method,
only nature is not intelligent and responsible. People
who call it a *'law of nature," and so say that we must
follow it to-day, are rather confused. It was a law of
nature. That is all that science can say. However,
we will return to this point later.

It has been calculated, from the fossil remains of
the period before and after the Ice Age, that thirty-
nine out of forty of all the species of animals and
plants on the earth during the coal forest age were
destroyed. They disappear from the calendar alto-
gether. The luscious vegetation withered away. The
dense forests died, and their remains were packed

54 IN THE GRIP OF AN ICE AGE

underground, to become the coal seams of man's early
industrial age. Nearly every type of the old vegeta-
tion was blotted out. We can trace some of the ferns
and other trees gradually becoming hardier. We
find pines and yews and firs, or their ancestors, now
for the first time appearing on the earth. But it
was a very thin diet they provided compared with
what had gone before, and the fat salamanders and
insects and other large-feeding, sluggish animals went
the way of all flesh. Only a few types were pre-
served in warmer regions, to give us the amphi-
bians, stick insects, beetles, spiders, etc., of the new
age.

It was a great annihilation. Up to that time in the
story of the earth motherhood consisted merely in
shedding eggs on the surface of the earth or in its
waters. To put it poetically, * ' nature ' ' mothered the
eggs. The warm ground or water gave heat enough
to stimulate the wonderful mechanism in the eggs.
In the colder age we are considering there would not
be heat enough. Even if the mother got sufficient
food to reach the egg-laying stage, the old habit of
entrusting the eggs to nature was out of date; ex-
cept, as I said, in favoured localities which kept the
old conditions more or less, and must have been
greatly overcrowded. A new habit, the practice of
caring for one's eggs or young, was needed in a cold
climate.

Then there was the direct effect of the cold. The

IN THE GRIP OF AN ICE AGE 55

reptiles would have, at first, thin scaley coats of little
use. The amphibians had the clammy skins of our
frogs and newts. None of the animals had had
occasion to develop warm coats. None of them had
hearts so constructed as to keep the blood at an even
temperature. However, the climate changed. I have
walked on the brink of Niagara and by the lake side
at Chicago in just the same clothing as I wear in
the early summer in London, without any particular
discomfort. The mammal has a four-chambered
heart, and the blood is so well supplied with oxygen
to burn its "fuel" that it keeps warm. None of the
animals before the Permian Revolution had "warm
blood." There had been no need of it, and needless
things are not evolved. If some theories of evolution
were true, they might be. On the lines of natural
selection they are not.

But on the theory of natural selection they are
evolved when they are needed, and this is the positive
or constructive side of the matter. We have seen
that the three great new requirements in the higher
animals were care of the eggs or young, a four-
chambered heart, and a warm coat. You probably
know that these are the chief points in which the
mammals and birds are superior to the reptiles. You
will understand half of familiar nature better in future
if you remember that these superior qualities were
made necessary by a great Ice Age, nine or ten million
years ago, and were evolved in the latter part of the

56 IN THE GRIP OF AN ICE AGE

Ice Age. The bird and the mammal are products of
an Ice Age.

We will try to picture what happened. The ice
sheet spread over South Africa and the continent
which then spread from Africa to Australia in the
east and India in the north-east. Suppose we take
the northern part of Africa, which was free from ice.
Our African tropics would then be a "temperate
zone." Further north there would still, no doubt,
be large regions with warm conditions. But the
overcrowding would be terrible. How many million
' ' refugees ' ' would there be from the icy continent ? I
do not, of course, mean refugees in the modern sense.
The change had taken ages. The animals would
migrate gradually. But in the height of the Ice Age
the warm region would be packed.

On the fringes of such a region natural selection
would be at work. If you take a thousand people at
random in London, you find that some stand cold
better than others. There are little variations of all
kinds in every species. Now the power to stand
cold would be an advantage in the conditions we are
studying. Such individuals would be more active, and
could get food enough in regions where others would
starve. These would prosper in the ' ' temperate zone, ' '
which would not be so densely inhabited. The more
tender and sluggish among their offspring would
perish. The hardier and more active would multiply.
The standard of the population would rise. As they

IN THE GRIP OF AN ICE AGE 57

increased, and the struggle for life increased, the
hardier and more active would tend always to push
into the more temperate parts. Any useful variation,
such as the overlapping of the scales or an improve-
ment of the blood circulation, would be fostered by
natural selection. Just as lungs were the great thing
needed at the earlier stage, so warmth — for the parent
and eggs — is now the chief need. The machinery of
natural selection worked, age after age, in develop-
ing heating-apparatus. The bird was one result; the
mammal was another.

If we could accept the theory called " Mendelism,"
which I have mentioned in the first chapter, this
would in one sense be easier to understand. Ac-
cording to this theory, evolution does not work by
very slowly and gradually adding together little
changes in successive generations, but by occasionally
producing young that differ very materially from the
mother. Such things are known, and used to be
called "freaks." Many scientists believe that they
are sometimes the beginning of new species. If we
could imagine a mother with a three-chambered heart
(a cold-blooded mother) laying an egg which hatched
into a reptile with a four-chambered heart (a warm-
blooded animal), or a long step towards it, evolution
would be easier. But it is a large order, and the
supposition does not seem to be justified by the facts.
Most men of science still believe in gradual advances;
though they lay far more stress than Darwin did on

58 IN THE GRIP OF AN ICE AGE

the embryonic machinery which must be the cause of
all advances. Surroundings only select the variations
which are provided by the embryonic machinery.

These, however, are deeper matters than we can
discuss here. The Ice Age may have lasted a quarter
of a million years. It put the population of the earth
through a sieve, as it were. The great majority of
the plants and animals could not stand the test, and
they were rejected. A few types struggled through,
and they begin the story of higher animal life: the
life of the birds and the mammals. But this figure of
speech is very faulty in one sense. If the severe
conditions of life had been spread all over the earth,
it would be a good figure. But they were not, as we
saw. There were still warm regions, where modified
survivors of the old Golden Age huddled together. If
the old warm conditions returned to the earth, they
would spread over it once more. This is what
happened. The ice-sheet gradually melted away,
probably because the land gradually sank once more,
and a new and curious chapter of the story of life
opened.

CHAPTER VI

THE BRONTOSAUR AND ITS COUSINS

The entire period we have covered so far is called
by geologists the ''Ancient Age" of the earth. It
embraces more than two-thirds of the life of the
earth. If you want to know the correct scientific
names, there was first a very long period, probably
as long as all the others put together, called the
Archcsan Era, which we may call the Very Ancient
or Primordial Era. If you take, for convenience, the
age of the earth as 100,000,000 years, this part lasted
50,000,000 years. There was life only in the later
part of it, and no life on land. Then there was a
long period of 35,000,000 years (on the same scale)
which geologists call the Primary or Palaeozoic
(Ancient Life) Era. That is the period we have
covered in the last three chapters. In this chapter
we are going to survey the "Middle Ages" (the
Secondary or Mesozoic Era) of the earth's story.

And some very quaint mediaeval creatures there
were in it, you will say ! It was the age of the giant
reptiles, whose hundred-foot-long skeletons you see
in museums or works of science. It was the age
of the Brontosaur, v»rhich was photographed and de-

59

60 THE BRONTOSAUR AND ITS COUSINS

scribed in all our newspapers a year ago. I am, as
usual, not so much going to describe these things as
to explain them.

We saw that reptiles had been developed from
amphibians in the latter part of the coal forest age.
They were a plain response to the change of con-
ditions. Dry land was increasing. The salamander
took to dry land, and became a reptile. But the dry
land increased so much, and rose so high, that it
threatened to strangle the new monarch of the earth
very speedily. Fortunately for him, there were still
warm regions, and there he awaited his turn. I im-
agined a group of reptile scientists keeping accounts.
For a hundred thousand years or more they would
report increasing cold, and dire would be the pro-
phecies. Then for a hundred thousand years or more
they would report decreasing cold, and hope would
animate the chilly reptile breast. Never believe
prophets who venture more than forty-eight hours
ahead. (In the end of this work I will venture ten
million years ahead — but that is different.)

The sun shone again upon the whole world. The
new age was not as hot as the previous one, for the
atmosphere was now purified of its great masses of
carbon and moisture. But it was again perpetual
summer all over the earth ; no cold or frost or winter
anywhere. It was more brilliant sunshine than be-
fore. Sombre trees like the yews and firs remained in
temperate regions, but the new types of trees — very

THE BRONTOSAUR AND ITS COUSINS 6i

largely the palm-like trees called "cycads" — spread
luxuriantly, as the cold retreated from level to level.
Large yellow flowers, the first touch of colour (except
dark green) the earth had yet known, responded to
the bright sun. These I will reserve for a later chap-
ter, and the reader must go to larger books for the
names and pictures of the new plants. It is enough
here to say that in the new Golden Age the vegetation
wove once more a thick mantle over the earth, and
food became again enormously abundant.

The height of the land explained the cold. The
lowness of it now explains the warmth. It was as if,
in our great struggle of land and water, the land,
which seemed to triumph in the Permian Revolution,
was again worsted for a time. This may remind you
of the French Revolution, and it is a very good
parallel to remember. The sluggish old types of
monarchs were dethroned at the Permian Revolution,
with great bloodshed, and progressive new rulers of
the earth were introduced (the bird and the mammal).
But there was a great reaction, and the sluggish old
monarchs cam^e back. The reptiles are now to lord
the earth for a few million years. The bird and
mammal will slink into such obscurity that we need
not notice them. To complete the parallel, we shall
see that this reaction will be shattered by a new
revolution (which we may compare to the revolution-
ary movement of 1830-2), then there will be a moder-
ate reaction, and finally another great revolution

62 THE BRONTOSAUR AND ITS COUSINS

(which we may compare to the period 1848-70). It
is said that there will be another Ice Age some day !

To return to our Middle Ages and Brontosaurs.
The earth was again generally low-lying, but sunny
and with a clearer air. Europe was mostly under
water. Only the summits of its higher hills peeped
above water, apart from a few regions which are now
elevated table-lands. Europe was, in fact, mainly an
archipelago, like the Pacific Islands. A warm blue
ocean, with prodigious sharks and swimming reptiles,
covered the greater part. Coral reefs of great beauty
fringed the islands; we find their remains now high
up on our mountains. There was more land where
the North Atlantic now is than in Eurpoe. A swampy
continent stretched from Scotland to America, and the
great animals wandered (as species) from continent
to continent.

These conditions explain the Brontosaur and its
cousins. Probably most of the larger reptiles were
swamp animals, floating their great bulk on the
water like the hippopotamus. If you notice carefully
the very small allowance of leg to the monstrous
skeleton of the Diplodocus in the South Kensington
Museum, and the breadth of foot, you will realize
this. One can hardly imagine it walking, much less
running ! Probably most of these larger " Deinosaurs,"
as this group of the reptiles is called, were aquatic
animals. Food was very abundant, and they were
vegetarians, taking in, lazily, tons per day of the

THE BRONTOSAUR AND ITS COUSINS 63

luscious vegetation that abounded. The Brontosaur
was quite a modest member of the family. He
weighed only about twenty tons when he was fully
grown! But as his length was only sixty feet, the
Diplodocus (eighty feet) must have been much
heavier; and we now know, from bones we have
found in America, that some of these Deinosaurs
were about twice as long as the Diplodocus, or a
hundred and sixty feet long.

Another branch of the family were leaping reptiles.
Some stood only about two feet high, when they were
erect, and others thirty or forty feet. There were
some with hollow bones, like birds, so that we must
not allow the lazy monsters of the swamp to mislead
us. The new ''Golden Age" was not long an age of
tranquillity and mere feeding. The inevitable struggle
for life began. At all periods in the history of the
earth part of a family has been apt to turn carnivorous
and prey upon its fellows, and the skeletons and teeth
of the great reptiles show that this terrible struggle
set in in the Mesozoic Age. Teeth grow larger and
more numerous and more carnivorous, until at last
we get appalling fiesh-eating monsters with two or
three hundred formidable teeth in their jaws.

Armour, as is usual, keeps pace with the develop-
ment of teeth. Ponderous and sluggish vegetarians,
forty feet long, developed rows of great plates of bone
standing upward from their backbones. Others had
massive coats of horn over their heads and necks,

64 THE BRONTOSAUR AND ITS COUSINS

running to sharp points in front. Towards the
close of the period we find perfectly weird de-
velopments of jaws, teeth, and armour. Professor
Huxley was quite right in saying that "Nature,
red in tooth and claw," had been the great agency
in evolution. It is only at a much later stage
that we shall find the gentler influence of social
life becoming a factor of any consequence in de-
velopment.

The struggle of vegetarian and carnivore explains
much more than the development of arms and
armour. If you go into the fossil reptile gallery of
a great geological museum, you are amazed at the
variety of types which grew out of the primitive
simple family. In the centre of the gallery you will
find the monstrous thigh bones, and perhaps whole
skeletons, of the vast Deinosaurs, which lazed in the
swamps. Near them are mounted skeletons, standing
up twenty or thirty feet, of reptiles whose long and
powerful back legs make them look like kangaroos.
They were the leapers. On the walls are the fossil
remains of others which lived entirely in the sea;
some with fish-like bodies and well-developed paddles,
some with long necks that could reach to the bottom
in search of food, some with eyes fifteen inches in
diameter or jaws like crocodiles. In other cases are
the skeletons of flying reptiles, from small creatures
about the size of a wild goose to villainous-looking
"dragons" with a stretch of twenty feet across the

THE BRONTOSAUR AND ITS COUSINS 65

expanded wings and jaws that would bite a square
foot of flesh out of an elephant.

This variety is an expression of the struggle for
life. Every little advantage for escape was favoured
and strengthened during hundreds of thousands of
years of conflict, and the branches of the family
spread in all directions. Some went down into the
sea, where great sharks v/ere their only competitors.
Some developed powerful back legs, and could outpace
even a running carnivore. They were often far larger
than the giant kangaroo, and must have been able to
do a remarkable "long jump." Some climbed trees,
and it is probably from these relatively small and
active creatures that the flying reptiles were evolved.
Some think that flying began with running, but it
seems more likely that its origin was in leaping down
from low branches of trees when a pursuer mounted
the tree. Webby fore-feet would be an advantage.
The animal could, in our aeronautical language, glide
or plane down to the ground; and a long course of
this evolution of "webbiness" would at last give a
powerful membrane from the first toe (which grew to
a length of several feet) to the side of the body — the
plane or wing of the flying reptile.

As far as general principles are concerned, therefore,
we very fairly understand the wonderful family of
reptiles — some writers strangely persist in calling
them "lizards" — which filled the land, the waters,
and the air of the earth's Middle Ages. There are a
5

66 THE BRONTOSAUR AND ITS COUSINS

great many controversies about the origin and rela-
tions of different tj^pes, but these things cannot be
discussed here. It is only necessary to add that the
remainder of the animal world continued to make the
sam^e progress, though while these monstrous and
curious brutes occupy the Mesozoic stage the others
have little interest.

The bird and the mammal were there, in very
primitive forms, all the time; but the reptiles, if they
had had the power to reflect, would have considered
them very insignificant. They were so small and
furry, or feathery, that they were not even good food.
A reptile philosopher would have regarded them as
freaks of the family. He might have said that they
were what we now call "anachronisms"; that is to
say, things that had had a sensible meaning at one
time or other, but ought to have died out in the age
to which they really belonged — the Ice Age. What
use were fur and feathers, four-chambered hearts, and
making a fuss over one's eggs or young, in a gloriously
warm age like the Mesozoic? Their one advantage
was brain, for better blood meant a better-nourished
brain. But their advantage in this respect was not
overpowering — they had less brain than a rabbit or a
goose — and, in any case, brain was not much regarded
in that age of brawn. A twenty-ton reptile like the
Brontosaur had a brain no larger than a man's fist.

So we leave the mammals and birds for later
chapters. The amphibians naturally throve like the

THE BRONTOSAUR AND ITS COUSINS 67

reptiles in the return of the conditions of the golden
age. There was again plenty of water, warmth, and
food. Early in the Mesozoic Age they spread over
the earth, and grew to enormous proportions, owing
to the abundance of food and the relative scarcity of
enemies. "Amphibian" to-day means to us a frog
or toad or newt, a small and despised thing. In the
Mesozoic Age you might have met one peeping out of
the water-vegetation with a head three feet long and
two feet wide. But the reptiles occupied the same
world as they did, and had greater advantages.
The amphibians grew less numerous and smaller,
approaching more and more to the types that we
know to-day.

The insect world was developing, and we will con-
sider this later. In the waters the population was
making the same steady and sanguinary progress.
The fishes made great advances, the types with bony
skeletons now appearing for the first time. Most
people are so familiar with fish bones that they can
hardly think of a fish without them. Many know,
however, that fishes of the skate family have not
real bones, but a frame of cartilage. As we should
naturally expect, the earlier fishes had skeletons of
cartilage, which always precedes bone.

But the waters were now a worse scene of terror
than ever. New types of shark, with the formidable
cutting teeth of our shark, though enormously larger,
had been evolved. In addition to these there were

68 THE BRONTOSAUR AND ITS COUSINS

now the swimming reptiles, some of which had, as
I said, swift fish-like paddles, eyes fifteen inches in
diameter, and crocodile-like jaws adorned with about
two hundred teeth. We do not wonder that the
geological chronicle shows a rapid improvement of
the fishes — especially of their power of getting away —
but we will not go into the details.

Every section of living nature had new terrors and
new enemies. There was, as yet, no social life, except
among such animals as corals and sponges and polyps,
which have no intelligence (and most probably no
consciousness whatever) to profit by it. Carnage, and
changes of land and water, were the great stimulants.
Besides the sharks and Ichthyosaurs, for instance,
there now appeared in the ocean the king of the
shell-fish family, the Ammonite. He lived in a great
curved shell, like a coiled snail's shell, which was
sometimes three or four feet in diameter. At the
opening of this he watched for his prey, with great
eyes and a huge expectant mouth. He greatly helped
the world of small invertebrate animals of the sea to
move on to a higher level.

But we will keep to the broad lines and general
principles of the subject. This Mesozoic Era was, as
I said, a period of reaction between two revolutions.
With the second revolution we open, not exactly the
modern period, but the period of the ancestors of our
modern types, and we move in a world that is less
strange. The revolution was, of course, another

THE BRONTOSAUR AND ITS COUSINS 69

severe chill of the face of the earth. There are
traces of glaciers here and there, but they do not
amount to very much, and we do not speak of an
Ice Age. But there is a real revolution in the life of
the planet. The Mesozoic Era ends with the time
when the great chalk-beds, composed of the " .shells "
of m3rriads of dead animalcules, are laid down on the
floor of the ocean. During this Cretaceous (Chalk)
Period there is a slow transformation of the world of
life. The great reptiles disappear; and most of the
smaller t3^pes, the survivors of that powerful dynasty,
retire into the tropics. This obviously means a chill.
The north is too cold for them, food is less abundant,
and leaving eggs to the care of nature is no longer
possible. Cold killed the reptilian monsters.

At the same time, naturally, we find an expansion
of the birds and mammals. Not only are their fierce
enemies removed, but the conditions for which they
are particualrly fitted — cold climate and brisk move-
ment— return to the earth. It is a good example of
what we mean by "survival of the fittest." In the
Mesozoic Age the reptiles were fitter than the birds
and mammals. The latter were far superior in brain
and organization, yet they were the less fit for those
particular conditions. When the cold returned, the
conditions of the struggle were reversed. The huge,
heavily armed, and armoured reptiles were the
** unfit." In spite of all their strength, they gave way
to tiny, rabbit-like creatures and birds.

70 THE BRONTOSAUR AND ITS COUSINS

There is a corresponding change in the earth's
vegetation. Up to this point it has been an evergreen
earth. There was no winter, no need to shed the
leaves once a year. Now, in the Chalk Period, we
find in America the traces of trees which shed their
leaves periodically. Winter has become an institution
of the northern hemisphere. Before the end of the
period we find the older types of trees giving way to
the willow and birch, the oak and mulberry, the
laurel and myrtle, the maple and elm, the walnut,
and dozens of other familiar trees. New flowers in
great variety appear. We will consider this opening
of our modem world in the next few chapters.

CHAPTER VII

THE EVOLUTION OF THE FLOWERS

The reader may now begin to understand the large
variety of living nature. But there are, as I know
from questions at the close of lectures on Evolution,
always a few who say that this variety is puzzling
from another point of view. Why do the older types
of animals and plants remain at all? One can under-
stand that in the beginning all animals and plants
were ** microbes" (single cells). One can follow the
story when the man of science says that life later
rose to the level of the ferns and mosses, the jelly-
fishes and corals; later again to that of reptiles and
cycads; still later to that of roses and eagles and
men. But why did not the whole world move on?
Why did not ferns and salamanders and lung-fishes,
etc., die out when they gave birth to higher forms?
Or why did they not all evolve ?

One has only to take a simple and important ex-
ample, and the answer is plain. The fishes gave birth
to the land animals, which are much higher. But it
would be obviously absurd to expect the fishes then
to die out, or all to leave the ocean. The waters re-
mained their natural and sufficient home, while the

71

^2 THE EVOLUTION OF THE FLOWERS

land provided a new home for the ''surplus popula-
tion." One might as well say that Englishmen ought
to have died out when they sent colonists to America
and Australia ! This is the principle to bear in mind :
The old or original environment remains good for the old
type. The new type may even live in the same region,
but it has new habits or a new diet. Nature really
provides half-a-million environments. So you get
half-a-million species in them. There is life wherever
there is an environment.

This is quite plain in the case of the plants, which
we are now going to consider. Omitting the micro-
scopic and other early types, there was a time when
none existed above the specimens of what you may
broadly call the '* sea-weed." Some of these invaded
the land, and were gradually transformed, in the new
conditions, into ferns and mosses. But this did not
make the least difference to the sea- weeds themselves.
The sea was as good a world as ever for them. In
course of time the ferns and mosses begot higher
types. But the particular sphere of ferns and mosses
remained. Your humble moss is still monarch of its
own environment; say, the moist, shaded hillside. It
is particularly fitted for that world, and thrives there
better than higher plants would. The pine and yew
were born of a remote Ice Age. But there are plenty
of cold and hardy regions for them, and they remain.

Thus, while the plant world has been marching on
through the ages, it has like the animal world, left

THE EVOLUTION OF THE FLOWERS 73

regiments behind at each station, as it were, and
these represent the stages of advance. A micro-
scopist will show you in a drop of pond-water the tiny
one-celled algcB which remain at the lowest level of
plant-life ; and he may then show you chains or clusters
of alg(E, representing the next great step, the forma-
tion of a many-celled body. The botanist would then
show you how, in the course of time, some of the cells
"specialize." Some make the stem, some the leaves,
some the roots, some the spores or seed.

But I have not space here to consider the very rich
evolution of the plant world. If I gave only a general
outline of it, the result would be a bewildering variety
of technical names. Some teachers think it real in-
struction to insist on a certain number of technical
names. It is not, unless a pupil is definitely learning
a particular branch of science. These names cause
brain-fog, unless they are thoroughly learned and
analysed. That is good in its place, but this is not
the place for it. We will rather make a general
survey of the evolution of flowers.

The various parts of a flower are leaves which have
been modified for their particular purposes in the
course of evolution. In a growing flower or a very
primitive flowering plant a botanist can clearly
demonstrate this. Here we will take it for granted.
The lower types of plants have spores, not seed, and
no flowers ; but it was found some years ago, on ex-
amining certain ferns which were beautifully pre-

74 THE EVOLUTION OF THE FLOWERS

served in the coal, that they had seed and seed organs
instead of the usual spores. They were branching,
as all living families do. One branch of the coal
forest plants was, under the stress of the Ice Age,
going to produce the pine and fir, the cones of which
are neither flowers nor spores. Another branch, the
seed-bearing ferns, was going to produce the flowering
plants. ^

The crude green "flowerets" of these seed-bearing
ferns are almost lost in the confusion of the Permian
Revolution, and it would be a sin against the purpose
of this little book to follow botanists in their learned
attempts to trace the evolution. It is enough that
the Ice Age closed the long reign of the lowly spore-
bearing plants, and opend the era of flowering plants
and conifers. We saw the Mesozoic plains were
covered with Cycads, palm-like plants with crude
types of flowers, or "fructifications." The colours we
can only estimate. Probably at first they were pre-
dominantly green, and, as time went on, yellow gained
upon the green. It is not thought that these were
the parents of our flowering plants. Probably some
hardy seed-bearing type of fern remained, during the
age of the great reptiles, on higher and cooler levels,
waiting, like the bird and mammal, for the return of
the cold.

^ See, for a short and authoritative account, D. H. Scott's Evolu-
tion of Plants (in the "Home University Library"). It is not
simple reading.

THE EVOLUTION OF THE FLOWERS 75

The cold of the Chalk Period gave them their oppor-
tunity. Then, as we saw, the flowering trees and
plants spread from eastern America, which seems to
have been higher than the west, and over the whole
northern hemisphere. There was still land across
the northern Atlantic, and in the very slow way of
forests they gradually reached and overran Europe.
Not only the trees I named, but the oleander and
magnolia, the palm and the grass, the lily and orchis
and iris, now came upon the stage. From green the
earth had turned partly yellow. From yellow it now
turns white.

As flowers are not fossilized, one is often asked how
we know that there were these successive waves of
colour. It is, of course, an inference; but it has good
grounds. If you arrange a large number of flowers
according to their degrees or stages of organization —
according to the complexity or simplicity of their
seed organs, petals, and sepals — you will find a pro-
nounced colour scheme. The simplest are predomi-
nantly yellow (green at first). Those of the next
stage of organization are mainly white, with some red.
The colour red predominates in the next group ; and
at the top you get blue and variegated flowers. As
this corresponds with their evolution in time, the sim-
plest naturally coming first, we gather the successive
appearances of the colours in nature.

It may also be asked how we can read the change
of climate from the appearance and trivimphant

76 THE EVOLUTION OF THE FLOWERS

spread of our higher flowering trees. This is simple
when one learns why a tree sheds its leaves in the
winter. The leaves are more or less the lungs of
the tree. Through them it gives off moisture. In the
winter, however, it receives little or no moisture from
its roots, according to the state of the ground, and
the leaves are sacrificed in order to preserve the
moisture in the tree. Here, again, one sees the last
term of a long evolution. The various steps of it
have been lost. It may have taken place on *'the
Lost Atlantis." ^ In any case, when we do find these
"deciduous" (leaf -shedding) trees appearing in the
Chalk Period, we know the meaning. The earth is
growing colder ; winter has begun.

But the great chill which killed the reptiles and
opened the reign of the birds, mammals, and flowering
plants melted away again like its predecessors. The
temperature of even the northern hemisphere rose so
high that magnolias, figs, and bamboos flourished in
Greenland, where men can now barely wrest their
remains from the frozen soil. Palms and aloes
flourished in France. Warm-loving animals wandered
as far north as Scotland. It was not so warm as it
had been in the earlier periods, and from this point
onward the earth becomes increasingly cooler; but

^ I use the name fancifully for the continent which so long did
exist across the North Atlantic. But it disappeared before the
coming of man, or at least long before civilization, and there is no
foundation for the Greek legend of a Lost Atlantis.

THE EVOLUTION OF THE FLOWERS 77

the genial climate of the whole earth lasted long
enough to permit a great expansion of the flowering
plants. The landscape slowly took on the features
which make it familiar to us to-day. But the world
was to pass through a mightier chill than ever before
its modern appearance would be finally reached.

At the time of the spread of the flowering plants
there was also a rapid evolution of the insect world.
Now the bees and wasps, ants and flies and butterflies,
came upon the scene. We saw that the coal forests
had had only primitive large flying insects, beetles,
and other lowly types. We saw that wings are
developed frequently in the course of evolution.
Wherever there is a great struggle for life, some of
the hunted will try to escape into the broad free at-
mosphere which floats above the teeming ground.
Even fishes, in the tropics, have developed a certain
power of flying, or rather "planing," away from their
enemies; and to see a flock of these ''flying fishes"
rise out of the water — if they are near the ship, you
can sometimes see the dark shade of a shark approach-
ing— gives one an idea of the beginning of the evolu-
tion of flight. You might almost say that the same
thing is happening under our eyes in England to-day.
Man is struggling to rise out of his congested roads
and travel in the free air. So insects, and reptiles
and birds, bats and ''flying foxes," have at different
times escaped from the struggle on the ground by
developing wings.

78 THE EVOLUTION OF THE FLOWERS

The active flying insects naturally developed very
richly when the earth became covered with iSowers.
One has only to watch the swarms of them hovering
about the flowers in the summer to realize how the
two worlds would grow simultaneously. Probably
everybody now knows that the insect is useful to the
flower in return for the food it gets. It is an advan-
tage when the pollen of one plant is taken to fertilize
the seed of another plant, instead of fertilizing its
own seed. The wind may perform this service, and
does in the case of some plants; but it is a clumsy
and wasteful process. It is far more effective when
the little bee, poking into the depths of the flower for
the honey which is prepared for it there, gets the
pollen on its body, by rubbing against the stamens,
and unconsciously carries it to the next flower.
This is "cross-fertilization," which is better than
self-fertilization.

It is generally believed that the colours of the
flowers are a sort of advertisement to the insects.
The yellow leaves of the buttercup — they are, like
all other parts of the flower, transformed leaves —
practically mean to the distant insect, "Free food
here." There has been some dispute in recent science
as to whether the insects really are attracted by
colours, but the experiments that have been made
seem to show that this is the case. Naturally, the
insects and the flowers must have developed together.
It takes ages to evolve any arrangement of this kind,

THE EVOLUTION OF THE FLOWERS 79

and it would be very unscientific to imagine first
the flower world slowly evolving its attractions,
and then imagine the insects discovering the
secret in some wonderful way. All through the
period of the great reptiles, flowers and insects
and their mutual service must have been developing
simultaneously.

But the mighty expansion of the flowers after the
severe chill of the Chalk Period would in turn lead to
a tremendous growth and rapid development of the
insects. We have so often seen the principle on
which the machinery of evolution works that it is
hardly necessary to repeat it here. It is absurd to
imagine a "vital force" pushing evolution in this or
that direction. That is merely playing with words.
It is equal to saying that "something or other did
it," and then imagining that you have explained the
matter.

You understand it much better when you remember
that the flowers which were cross-fertilized had the
best chance of growing the next generation, and that
those flowers had the best chance of cross-fertilization
which provided sweet food for insects and some
means of letting the insect know that the food was
there. Then imagine the broad sunny continents of
the Tertiary Era, which we have reached, teeming
with flowers. It was still so warm, remember, that
figs and bamboos grew in Greenland. There would
be an intense struggle among the seed, and the

80 THE EVOLUTION OF THE FLOWERS

cross-fertilized would have the advantage. Natural
selection would foster and increase every trick and
apparatus that led most surely to cross-fertilization.

To work out this principle in the world of flowers,
and explain the wonderful variety of flower structures,
would require a whole large volume, or series of
volumes. One must consult botanical works. Here
we can only consider broad features of the evolution
of nature. One of these is that the great outpouring
of the flowers came naturally after the severe chill
had removed the large imperfectly-flowering plants of
"the Middle Ages," along with the monstrous reptiles
and other mediaeval types; and that with the expan-
sion of the flowers came the spread of the bees and
wasps and butterflies.

You may think that flies and butterflies cannot be
fossilized, and so the man of science must be guessing
what happened millions of years ago. He often does
guess, though he is always careful to tell you that it
is only a guess, until he has found positive evidence
to prove that his guess was right. But here we have
direct evidence. Did you ever see a piece of amber
with a fly in it? There is a shop near the British
Museum in London where you can buy one at any
time. That fly may be two or three million years
old. Amber is more or less fossilized resin; and
ages ago the fly stuck on the resin, as it oozed from
the tree, and was covered over with fresh outpours of
resin. Then the tree died and the resin broke off;

THE EVOLUTION OF THE FLOWERS 8i

and it has beautifully preserved insects of three
million years ago for us to examine.

In other cases myriads of insects have fallen into
the mud at the bottom of lakes, and been preserved.
In some cases myriads have been buried in the fine
ash of a volcano. We have countless specimens, and
they help us to restore the scene after the reptiles
had gone. It now had large numbers of our familiar
trees and flowering plants. It began to have grass
on its plains. It had bees and wasps and butterflies
going from flower to flower. Next we have to bring
the birds on the scene, and then we will introduce
our familiar mammals and man.

6

CHAPTER VIII

THE COMING OF THE BIRDS

We seem to have neglected the birds for a long time.
They had really appeared several million years before
the age we are now considering, and it may be sup-
posed that such highly organized creatures, living in
the free air, would have prospered and spread con-
siderably diiring those millions of years. As a matter
of fact, we find very few remains of birds in the rocks
which represent that very long period. If the living
things of that age are buried in anything like the
proportion in which they lived, there must have been
extremely few birds.

A word of warning about these "fossil remains*'
may usefully be given here. Some people ask us
why, if the animals of the past are buried in our
rocks, we cannot find whole series of remains showing
the gradual transformation of, say, a reptile into
a bird or a mammal. Now, that is one of the
questions which ought not to be asked by any person
who makes a good use of his eyes. Just look round
a region that is teeming with animal life — say, a wood.
How many remains of those myriads of insects and
birds and other animals will there be left in a million

82

THE COMING OF THE BIRDS 83

years? Probably none whatever. The bodies must
be deposited in certain rare conditions to be preserved
and "fossilized." They must be put, as a rule, in the
mud at the bottom of stagnant water. As the vast
majority die on land, they are not preserved at all.
Only a tiny fraction of the things that have lived on
the earth are thus preserved.

So the story of evolution as it is written in the
rocks is very imperfect. Here and there it is almost
complete for a page or two. For instance, shell-fish
are easily preserved in lakes and there are cases
where we can trace gradual evolution for quite a long
distance. Sea-urchins are easily preserved in chalk-
ooze, and we can in many cases follow their gradual
evolution a long way in our chalk cliffs. But these
are exceptions. In other cases the bones are still
numerous enough to enable us to follow the gradual
evolution very fairly. We shall see this in the case
of the horse and the elephant. In most cases only
a specimen here and there in ages is preserved, by
some chance or other, and we are lucky to get these.

That is the situation as regards the evolution of the
bird. Only one specimen (or two specimens of the
same bird) has been preserved in the rocks from
the hundreds of thousands of years during which
a branch of the reptiles was being transformed into
birds. It was found in certain rocks in Bavaria.
Millions of years ago the bird flew in the atmosphere
of Europe, which was then mostly under water, as

84 THE COMING OF THE BIRDS

we saw, and its body was buried in a fine mud at the
bottom of a lake. Probably many were so buried,
but most of the rocks are still deep underground and
unexplored, while others have since been ground up
and used over agin. We were lucky to find this
petrified Archcuopteryx (Ancient Bird), as it is called.

It was about the size of a crow, and its various
parts have been so finely turned into stone that, as far
as external appearance goes, we might as well have
the actual body. It has the unmistakable feathers
and wings of a bird. But it is like no bird in the
world to-day. It is half a reptile. There is a long
tail, like that of a lizard; a clear continuation of the
backbone far beyond the back legs, with large feathers
sticking out on each side of the tail. It has two rows
of teeth in its jaws; and no bird in nature to-day has
teeth. It has also perfectly formed feet and claws
on its front limbs, its wings; and there are very few
birds in nature now which have such toes, though
the majority have, underneath the skin, stunted little
bones which represent them.

In the early days of evolution people used to talk
much about "missing links." In this case a very
important missing link was recovered. It is the link
between the reptile and the bird. If it were not for
the feathers, we should call it a flying reptile. It
perfectly illustrates the gradual conversion of a reptile
into a bird, as we sketched it in an earlier chapter.

We saw that this evolution was an outcome of the

THE COMING OF THE BIRDS 85

Ice Age. In the colder regions no ordinary reptile
could live. The animal itself was cold-blooded and
thinly clad, and it provided no warmth for its eggs or
food for its young. In the stress of the struggle that
must have followed in the overcrowded warm regions,
pioneers with favourable variations were able to
survive in more temperate localities. We must not
suppose an animal suddenly changing from a three-
chambered to a four-chambered heart. Even here
gradual development is not so difficult as may be
imagined. Some of our reptiles to-day have hearts
that are not strictly either three-chambered or four-
chambered. There is a sort of effort to get a fourth
chamber.

The feathers are less difficult to understand. They
are transformed scales. Look again at the next hen
you see, and you will notice that the scales which
cover its legs really bring it nearer to the reptile than
you had supposed. Examine a feather, and you will
see that it is composed of the same material. Feathers
are scales lengthened and "feathered," if one may
use the expression. The feather as we know it is the
outcome of millions of years of an evolution which
aimed at combining warmth with lightness. Even
the little ArchcEOpteryx, whose remains we have found,
does not belong to the Ice Age, but a very long time
afterwards. Its feathers are well formed. There
must have been myriads of earlier stages, with large
heavy scales becoming gradually more "feathery."

86 THE COMING OF THE BIRDS

As to the beginning of the care of the eggs, we
have, naturally, no positive knowledge whatever.
Nesting is very varied in nature to-day, and is in
some cases extremely simple. I would venture to
conjecture that for millions of years — possibly until
the last Ice Age — birds did not nest at all. But they
must have begun early to brood over the eggs. If
the mother needed feathers to keep her warm, the
eggs needed warmth to hatch. Here again there is
not a quite sudden leap from the reptile world. Some
of our living reptiles bury their eggs in a sort of
"nest."

These are merely general and superficial considera-
tions. I am only sketching the broad lines of develop-
ment. It is not possible or desirable here to go more
deeply into the matter. Special authorities on birds
must be consulted. I merely wish to make the bird
world broadly intelligible. Even children to-day
ought to know more than that there are birds because
there is air, and fishes because there is water, and
beasts because there is land. The doctrine of evolu-
tion, which throws such a wonderful light on nature,
is shockingly neglected in our schools. ** Nature
study " is a poor thing without evolution.

There are birds because once upon a time the earth
was for two or three hundred thousand years in the
grip of an Ice Age, and in some regions all the higher
animals (reptiles) would have perished if they had
not developed the "heating-apparatus" of the bird.

THE COMING OP THE BIRDS 87

The mammals came for the same reason, at the same
time, from the same reptile world. But the Ice Age
melted away, as we saw, and the birds and mammals
had no advantage in their higher organization. Fur
coats, that you could not get rid of, were not a good
equipment in an age of warm perpetual summer.
Brooding over eggs was unnecessary, and unnecessary
labour is not encouraged in nature. So we are not
surprised that bird-remains are very rare. In rocks
which represent several million years of the Mesozoic
Era we have found only these two specimens of one
bird.

Towards the end of the Age of Reptiles, in the
Chalk Period, we find a few others. They belong to
fully-formed birds of quite different types, and they
tell us that the bird world was now expanding. The
earth was cooling. Possibly the monstrous flying
reptiles, which would gulp down one of the early
birds like a dragon-fly, were being driven out of large
temperate regions, and making way for the birds.
As soon as they became lords of the air, they would,
like all new families, spread richly, and in different
directions.

In one feature the birds of the Chalk Period still
bear the trace of their earthly ancestry. They have
teeth, either separate real teeth or toothed jaws. It
was a matter of evolution and progress for these teeth
to disappear. They meant weight at one end of the
flying machine; and in the course of development

88 THE COMING OF THE BIRDS

the bird became able to grind its food in its crop, and
thus dispense with the teeth. One of these birds of
the Chalk Period seems to have lost the power of
flight, so that we are not surprised that it has teeth.
It was a swimming bird, like the diver, about four
feet high. The other is a small flying bird; though
it has distinct teeth, in sockets, in its jaws.

These belong, as I said, to the latter part of the
Age of Reptiles, when the climate was growing colder.
At the close of that period the flying reptiles perished
so completely that not a specimen is left in nature
to-day. The air was left to the birds and insects.
The warmth and abundance of food returned. The
outpouring of flowers fed the insects, and the vast
swarms of insects would feed the birds. The rocks
now show a great expansion and multiplication of
species, which we cannot follow here in any detail.
It is enough that our familiar birds begin to appear.
Ages before man came along there were owls and
parrots and many other types. There were still no
Arctic regions or Alps, remember; and warm-loving
birds could roam all over the earth.

In order to throw a little further light on the bird-
world I will anticipate a little. For two or three
million years after the birds had taken undisputed
possession of the air the climate of nearly the whole
earth remained more than temperate. Monkeys lived
in what we now call England. Elephants browsed on
the low hills which are now the Dogger Bank under

THE COMING OF THE BIRDS 89

the waters of the North Sea. Sea-serpents wandered
up the mouth of the Thames, and rhinoceroses and
hippopotami splashed in the rivers of Yorkshire.

But the earth was growing colder. I am not
satisfied that any good explanation has yet been
given of this progressive cooling of our globe, and
I will not speculate on it. Ice Ages we fairly under-
stand, as an effect of the rise of the land ; but general
cooling and the formation of permanent ice-caps
at the Poles have not yet been explained. We will
simply state the fact. The northern hemisphere
became more and more temperate. The warm-
loving plants and animals were slowly driven south.
The land was rising in very many parts of the earth.
The great masses of the Rocky Mountains and Andes,
the Alps and Atlas and Himalaya, were dtiring all
this time slowly rising towards the snow-line. A new
Ice Age was approaching. This, of course, explains
much of the cooling of the earth, but there is a
steady lowering of temperature which it does not
explain. After an Ice Age the earth never returns
quite to the degree of warmth which it had had
before.

However, the Ice Age at last set in. Seven million
square miles of northern Europe and America were
covered with permanent ice and snow. Glaciers,
immensely larger than those which now flow slowly
down the flanks of the higher Alps, flowed from the
hills of Scotland, Cumberland, and Wales. I will say

90 THE COMING OF THE BIRDS

more about this later. It had prodigious influence
on animal and plant life, as will be imagined after
our description of the Permian Revolution. This was
a far greater Ice Age.

Bamboos and magnolias had long ago retired south.
Now, as the ice-sheet spread south as far as the valley
of the Thames and the Danube, the whole population
fled before it. The change was, as ususal, extremely
slow, and the reader will not misunderstand when
I speak of even the plant-world retiring before it.
Only the south of Europe and Africa — they were then
connected by land — now bore the wealth of flowers on
which the insects lived, and the birds followed their
food. Hardy types, the birds of the Arctic and
Antarctic, were evolved, but the vast majority
retreated with the warmth and the insects.

Probably many features of our insects and birds
were developed during this long and severe trial. The
instinct of nesting would be fostered in the birds, and
probably it was then that the ants and bees developed
their elaborate ways of preparing against a "lean"
season. The migration of birds may also receive
much light from this geological event. It is known
that migrating birds do not simply fly "somewhere
south," where there are flowers and insects. Each
family has its winter resort, and they follow particular
and often curious routes to it. It is supposed that
they go back to their homes in the Ice Age, and they
follow routes which were at one time "all land"

THE COMING OF THE BIRDS 91

routes. There is really no such thing as "instinct."
The habits of the birds have been evolved under
pressure or guidance from without. So there is
nothing to "tell" them that land and water have
changed very much since the days of the Ice Age,
and year by year they follow the old routes, many of
which ought to have been altered long ago.

CHAPTER IX

THE TRIUMPH OF THE MAMMALS

The birds are our "sisters" in a way that poets do
not know. We, the mammals, and they were born
together of the Permian Revolution. We are the
common offspring of an Ice Age. That is the original
reason why we are ''warm-blooded." And warm
blood also means better blood, better nourished
brains, so that it was a great advance in organization.
Surely these things make nature more intelligible
than it was even to the more learned of our fore-
fathers? But we will now consider more closely the
origin and spread of the vast mammal family to which
we belong.

Mamma is the Latin word for breast. Our very
young children are not aware that they are speaking
a famous dead language when they address their
mothers by that word, but it is a fact that to the
Roman baby its mother was above all things a
mamma — a breast. The mammals are therefore the
animals with breasts; or, to take their leading differ-
ences from the other Vertebrates, with breasts, a
womb, a four-chambered heart, and a hairy coat.
You see at once that all these superiorities mean, first,

92

THE TRIUMPH OF THE MAMMALS 93

an adaptation to a colder climate. They mean warm
blood and care of the young.

We saw how the first mammals arose. One pro-
gressive branch of the reptiles, which passed safely
through the sieve of natural selection during the
Permian Ice Age, was capable of being adapted to the
colder climate. It is little use to give you its name
here, though scientific men are now fairly decided
which branch of the ancient reptiles it was that took
this fortunate turn. The heart became four-
chambered, and the blood warm. But again there
was no sudden leap; in fact, there is not in nature
to-day a perfectly clean distinction between the lowest
mammals and the higher reptiles. "Warm blood"
means, as I said before, that the blood system has the
power to keep the blood at a fairly even temperature
while the temperature outside may vary considerably.
In plain English, it means having warm blood in cold
weather. The blood of the reptile sinks with the
temperature of its surroundings. That is the chief
reason of the winter sleep of the tortoise or the snake.
But the lower mammals have not entirely "warm
blood." Their blood varies as much as 30° F. in
temperature. They live in Australia and New
Guinea, and are therefore not inconvenienced by
a severe winter. This imperfectness of their
machinery is quite a good illustration of evolution.

The fur coat, or coat of hair, is fully developed in
every mammal that we know, and we can only guess

94 THE TRIUMPH OF THE MAMMALS

how it was evolved. The reptiles' scales did not
evolve into hair, as those of the ancestor of the bird
were transfomred into feathers. Probably the hair
grew up out of the skin underneath the scales, and
eventually made the scales superfluous. When one
of the lower (not the lowest) mammals is developing
in the womb, and the hair begins to appear, it grows
in tufts or patches, as if each had originally grown
under a scale.

You notice that in this case I look for guidance
to one of the lower, but not lowest, mammals, and
this may surprise you. The fact is that the lowest
mammal in nature to-day — you will be introduced to
it in a moment — has no womb in which it bears its
young. It lays eggs, as snakes or turtles do. And
this throws a very interesting light on the evolution
of the third and greatest feature of our mammal
family, the nourishing of the young.

As we saw, the mothers which would carry on their
species through the stress of the Ice Age must, if they
lived in the temperate regions, care for their young.
The bird continued to lay eggs, but, unlike the reptile,
provided warmth for them with its own body. An
alternative way would be to hatch the eggs inside the
mother's body, and this line the mammals have fol-
lowed. Every animal that is bom comes of an Qgg\
though, to use a colloquialism, "there are eggs and
eggs." At first, however, the ancestor of the mammals
continued to lay eggs, like its reptile foremothers — I

THE TRIUMPH OF THE MAMMALS 95

nearly said forefathers. But when the eggs were laid,
the mother had a nest ready for them, perhaps
underground, to keep them warm.

This is the same as the birds, you may exclaim!
No; because when the little animals came from the
eggs the mother fed them from her own breast. The
flesh and skin of her breast were perforated, or had a
ntunber of large pores in them. When the young
licked this part of her breast, the fat-cells from her
blood oozed through, and the young were nourished.
It was the primitive milk. I need not point out the
great importance of this change, and the corresponding
change made by the bird. All animals had hitherto
been strict individualists. There were, it is true,
social groups of corals and sponges and a few others;
but these have no consciousness at all of their
"socialism." All parents among the higher animals
were purely selfish, and took no care of their eggs or
young. There was no need. Mother earth provided
everything. From this time onward there is at least
a link of mother and young, a beginning of social
emotion. You see what an Ice Age can do !

But how do we know all this if, as I said, the Per-
mian Ice Age was at least nine or ten million years
ago? Even if we had found a fossil, like that of the
"Early Bird," we could not possibly infer from it half
of what I have described. It is true that we could
not from the bones alone. Some writers credit men
of science with almost magical powers. There is a

96 THE TRIUMPH OF THE MAMMALS

story still in circulation that a distinguished man of
science once said that, if you gave him a single bone
of some dead animal, he could build up the whole
body. Scientific men are far more modest. A few
years ago they found the better part of a battered
himaan skiill in Sussex, but they are disputing to this
day how the missing parts of that skull ought to be
filled in.

Now, of the early mammals we have only a few
small bones in the rocks, and they would not tell us
much by themselves. But you remember how we
were able to describe, in the fourth chapter, the fishes
which ten millions of years ago left the water and
began to live on land. Remnants of that primitive
family, the lung-fishes, still survive in nature.
Animals of this kind are often called "living fossils."
They help us even more than fossils do. No speci-
mens of the earliest birds have survived in nature,
and we should know very little about them if we had
not been so lucky as to find the two fossil birds in
Bavaria. But with the mammals it is quite different.
Nature has preserved specimens of them alive for us.

We are fond of saying that nature "does" this or
the other. Of course, it is literally true, as all the
forces and causes or agencies that we know belong to
nature. But even children ought to be warned against
the practice of thinking that "nature" has intentions.
Take, for instance, this preservation of the early
mammals all through several millions of years. It

THE TRIUMPH OF THE MAMMALS 97

v/ill give another glimpse into the machinery of
nature if we describe it.

At the time when the earliest mammals appeared,
towards the end of tlie Permian Ice Age, South Africa
and Australia were, as we saw, connected by land. It
was in that part of the world that the little early
mammals lived. We find their bones in South Africa
and their living representatives in Australia and New
Guinea. They wandered from Africa to Australia;
or, as is more probable, they were evolved on the lost
continent, which is now beneath the waves of the
Indian Ocean, and travelled east and west. Anyhow,
they overran the country which we now call Australia.
But during the Age of Reptiles the land between
Africa and Australia foundered. One might almost
say that, when the early mammals reached Australia,
the gates were closed behind them. Australia became
an island. So when, in the course of time, lions and
tigers and other carnivorous mammals were evolved
in the rest of the world, they could not reach Australia,
and its very primitive population slumbered on until
early man and his dog came along to disturb them.

That is why we find primitive mammals in Aus-
tralia. The most primitive is a small furry creature,
about the size of a rabbit, which is often called in
English nature books the "Duckmole," because it
has a beak something like the duck's and it burrows
in the banks of the streams. Australians generally
call it the Platypus, or, if they have been to Melbourne

98 THE TRIUMPH OF THE MAMMALS

or Sydney University, they call It the Ornithorhyncus
("Bird Nose"). In describing the life of the early
mammals at the beginning of this chapter I described
the Platypus. It makes a nest in its burrow, and
lays eggs in the nest. When the young are born
they lick the mother's breast, and they are nourished
by the fat (milk) which oozes through the pores. So
the Duckmole is a reptile is so far as it lays eggs,
which no other mammal in the world does, but a true
mammal because it suckles its young.

There is a very different animal of the same family,
the Spiny Ant-Eater, in New Guinea; but we will
pass on to the next stage. As everybody knows, the
native animal population of Australia consists entirely
of pouched animals like the kangaroo. There is a
wild dog, or Dingo, that has puzzled naturalists a
good deal; but on the whole it seems to have been
introduced by early man, who must have been in
Australia a quarter of a million years ago. The na-
tive population are kangaroos, wallabies, and other
animals which are distinguished by the mother carry-
ing her young in a pouch in front of her belly.

The reason for this peculiar arrangement is very
interesting. Most people, even children, know that
the young of one of the ordinary mammals — a kitten,
puppy, whale, or human being — is formed in the
mother's womb, and built up on her blood. Certain
blood-vessels connect the little body in the womb
with the mother's blood-vessels. The child is "blood

THE TRIUMPH OF THE MAMMALS 99

of her blood." The kangaroo mother has not got
these blood-vessels. She cannot nourish the body of
her young with her blood. She goes a step beyond
the Platypus, it is true. She hatches the eggs inside
her own body; but when they are hatched — when all
the nourishment in the Qgg has been used up — she
can do no more in her womb. The very tiny and
imperfect young are born. Naturally, they would die
if left to themselves. She takes them in her mouth,
puts them in her pouch, and there they hang on to
her breasts (which are low down) until they are fully
formed.

Here is the next stage in the formation of a
mammal; and we are much obliged to Australia
for preserving these ancient curiosities for us. The
higher mammals are so much more perfect in their
arrangement for the birth of the young that these
primitive mammals would not be able to stand compe-
tition with them. The waters of Australia kept them
away. For science the Platypus and the kangaroo
are extremely interesting; and there is a third type
which is in some respects between the two. We do
not say that they are the ancestors of the mammals,
but they are precious remnants of the great family of
early mammals of the Age of Reptiles, and they beau-
tifully illustrate the evolution of the mammal body.

During the Age of Reptiles, as we saw, their higher
organization was of no service, and they lived an
obscure, hunted life and made little progress. Then

loo THE TRIUMPH OF THE MAMMALS

came the great chill of the Chalk period and the re-
moval of the giant reptiles. The African branch of
the family now began to go ahead, while the Australian
branch remained nearly stationary (as isolated popu-
lations generally do) . Towards the end of the Chalk
Period, and in the next geological period, we find so'
rapid and rich an expansion of the mammals that it
is impossible to give even a summary account of it
here. We must be content with a simple outline.

As I said, we do not regard the living duckmole
and kangaroo as ancestors of the mammals. The
kangaroo (and pouched animals, or ''Marsupials,"
generally) is clearly a side-line. The duckmole is
a better specimen of an early ancestor, if you omit
the "beak" and other features which were developed
later. From something like the duckmole, at all
events, a slightly higher type of mammal, building
up its young in its womb, developed in Africa, and
travelled north. These early mammals were probably
"arboreal and insectivorous"; they lived in trees and
fed on insects. When their Golden Age dawned they
multiplied rapidly, and, as we have seen so often,
soon experienced a heavy struggle for life, and evolved
in different directions. From eating insects some
developed a taste for larger game, and the familiar
contest of the vegetarian and the carnivore set in.

The development of the carnivores can be very
fairly traced by the rich fossil remains. Apart from
the seals and walruses, which retired to the ocean

THE TRIUMPH OF THE MAMMALS loi

from the grim struggle on land, the carnivores are
now mainly divided into a "dog" family and a "cat"
family. We have the common ancestors of these,
and can satisfactorily trace the evolution : the bears,
dogs, wolves, foxes, otters, jackals, badgers, etc., on
the one hand, and the lion, tiger, leopard, lynx,
hy^na, mongoose, etc., on the other. In the early
period we have carnivores with the general features
of the various types in one body, and, slowly, in the
course of two or three million years, the specific
types are shaped. There were at an early date even
fiiercer carnivores than now. At one time there was
a large lion-tiger (the "Sabre-Toothed Tiger," it is
often called), with canine teeth, of terrible strength,
seven or eight inches long.

These carnivores I take first because they help us
to understand the rest of the mammal family. They
proved to be the customary grisly machinery of
natural selection. Largely in the attempt to get
away from them, as well as to avoid competition for
food, the rest of our mammals spread in all directions.
Moles and rabbits found refuge underground. Hedge-
hogs and porcupines developed their barbed-wire
entanglements. Squirrels remained in the trees and
obtained their great agility. Shrews took to the
streams; porpoises and whales to the sea. Some
(lemurs, bats, etc.) adopted night life, instead of day
life. Some of the carnivores did the same, and new
and more wonderful devices had to be evolved.

102 THE TRIUMPH OF THE MAMMALS

The great order of the Ungulates (hoofed animals)
spread over the four continents, and generally de-
veloped speed. The hippopotamus relied on bulk,
and life in the water. The rhinoceros got bulk, a
good coat of mail, and a horn. The elephant also
had weight, a fair speed in case of need, and a pair
of very formidable canine teeth (tusks). But the
majority developed high speed and keen scent.

The ancestors of all these hoofed animals had five
toes on each foot. We have numbers of remains of
them; and there is a little animal in Africa to-day,
the Hyrax, which goes back a long way towards them,
as it had four toes on the front feet and three on the
hind feet. But you have only to count the toes of
your cat, and remember that carnivores and vege-
tarians had a common ancestor, to realize this.
Running tends to reduce the number of toes. If you
watch an athlete waiting for the pistol at the begin-
ning of a race, 3^ou see how he stands "on tiptoe."
In running the weight of the body is lifted as much
as possible off the soles of the feet and thrown on the
toes. And if the toes are like the human fingers,
longer in the centre and shorter at the sides, the
weight is thrown on the central toes, and the side toes
disappear. The horse became in time a three-toed
animal, as the rhinoceros is. But the ancestors of
the rhinoceros stopped there, and developed bulk and
armour. The ancestors of the horse continued to
rely on flight, two further toes disappeared, and the

THE TRIUMPH OF THE MAMMALS 103

modern horse with one toe and one toe-nail (hoof)
was born.

We can in the same way trace the evolution of
most of the mammals. We have found the bones of
the ancestors of the elephant for many generations,
and can say how its trunk was developed. We find
its canine teeth growing steadily longer. Perhaps
they were used for digging succulent roots. The
nose, to be of any use, had to keep pace with the
teeth in length, and the chin grew out to the same
length to bear the weight of the nose. When nose,
teeth, and chin became about a foot long, the nose
(or trunk) developed powerful muscles attaching it to
the skull. The chin again retired — we trace all this
in fossil elephants — and the elephant was left with
two very long teeth and a very long nose.

In much the same way, we can trace the evolution
of the camel, the bear, the seal, the dog, the cat, the
pig, and so on. We can follow the development of all
the bewildering varieties of teeth, of claws, of limbs,
of hairy coats, of horns, of eyes, of noses, of breasts,
etc. Food and safety are the keys to most of their
structures. Sexual selection — the choice of a mate
with certain features— explains other things: the
smooth face of some monkeys, the lion's mane, and
other features. Evolution is the great key. It puts
together the jig-saw puzzle of nature as no other
human thought ever did.

"Struggle" is only part of the mechanism. We

104 THE TRIUMPH OF THE MAMMALvS

have to keep our eyes wide open in studying evolu-
tion, as there are numbers of different influences at
work all the time. The changes of land and water
continued. All through the time of the evolution of
the mammals the land was rising. It made a great
difference to many of them. Vegetation also, as we
saw, was changing. The fruit-bearing trees were
coming in, and there were presently immense stores
of rich food, apart from insects, in the shape of nuts.
Until carnivores learned to climb trees, this was a
very safe and satisfactory world to live in. A very
large family of the primitive insect-eating and tree-
climbing mammals remained in the trees, and
prospered. While the horse was developing on the
plains of America, and the hippopotamus in the
swamps of Africa, the monkey family was evolving in
the trees, all unconscious of the remarkable destiny
of one of its branches. Here we naturally open a
new chapter.

CHAPTER X

THE ORIGIN OF MAN

Monkeys have always had a strange fascination for
men. More than one tribe that Hved among them
has puzzled over that queer suggestion of humanity
which they seem to have, and declared that they
must be human beings who had fallen from grace.
By the end of the eighteenth century it was openly
suggested in England that man had "descended"
from an animal of the kind. There were jeers and
jibes and hov^rls of laughter everywhere. Learned
men and unlearned scoffed. Now there is not a man
of science in the world who does not admit man's
descent from an ape-like form; and I do not think
that there is now a bishop in the world who would
oppose them. So let us not laugh too loudly at new

ideas.

It is usual to explain very carefully that man has
not been evolved from a monkey or an ape . Certainly
no existing monkeys or apes are in the line of man's
ancestry. There are in each case certain structural
differences which forbid us to suppose it. The Dutch
are not descended from either us or the Germans.
They are related to us and the Germans through a

105

io6 THE ORIGIN OF MAN

common ancestral tribe of some thousands of years
ago. They are remote cousins of ours. So the living
apes and monkeys are related to us only through a
common ancestral tribe of three or four million years
ago. They are remote cousins. Thoughtless people
sometimes ask why we cannot turn a man-like ape
into a man. They never ask whether we could turn
a negro or a Red Indian into a white European. Yet
the white and black and red men had a common
ancestor probably less than quarter of a million
years ago, whereas it is certainly much more than a
million years, possibly two or three million years,
since the common ancestor of the ape and the man
lived.

The difficulty that some people still have in
imagining the descent — it would be better to say
"ascent" — of man from an ape-like form of long ago
is caused by the foolish habit of contrasting themselves
with a gorilla or an orang. There is about themselves
a dignity, a wisdom, a virtue that are lamentably
absent from the gorilla. But if, instead of taking
that finished product of human evolution, ourselves,
we adopt the more sensible course of taking a lower
type of human being, the argument grows thinner.
After all, it is not we who descended from an ape-like
form; it is our remote ancestors. We descended from
them. So let us get as near as we can to our ancestors.
The Australian black takes us a long way. I have
seen Australian aboriginal "ladies" who would not

THE ORIGIN OF MAN 107

be so very disdainful of an orang. Yet these are not
half-way back to our ancestors. Some of the central
African natives take us still further. Take the ugliest
and most stupid of these that you can find, imagine
something far more ugly and stupid, and then you
have our human ancestor. We have various skulls
of him, and we know it. He goes very near the
higher ape-family.

But even we highly civilized and refined folk have
in our bodies — some day, perhaps, scholars will say
in our characters (wars, cruelties, etc.) also— many
traces of our brute ancestry. Why has the male
human being got breasts? He has real, though
stunted, milk-glands behind those little warts or teats
that you see. Why? Evolution alone gives the
answer. We come of a very ancient group of animals,
in which the male helped to suckle the young. Why
have we those shrivelled pieces of cartilage which we
call our ears ? They have no functions. They do not
help you to hear. Evolution, and evolution alone,
answers the question. We come of a remote animal
ancestor which had movable, pointed, useful ears like
those of the horse. There are about a hundred organs,
or parts or traces of organs, in the human body to-day
that can be explained only in this way.

We come of a remote animal ancestor. What was
it like, and how and why did it become man ? I have
said that it is now customary to explain very carefully
that our ancestor was not a monkey or an ape. 1 con-

io8 THE ORIGIN OF MAN

fess that I think this caution is overdone. It is a
concession to the spiritual police. If we had the re-
mains of man's ancestors before us, they would almost
certainly be classed as those of monkeys in the earlier
stage and apes in the later. Possibly some of them
are actually among the existing fossils.

On this point, however, there is some dispute among
men of science. There are those, possibly the ma-
jority, who would look for man's last pre-human
ancestor in some branch of the family of large man-
like apes which spread over the region of the Mediter-
ranean between a half-million and a million years
ago (to use a common scale). Certain branches of
this family became the gibbons, gorillas, orangs, and
chimpanzees. Other branches died out. One branch
became the human race.

Other scientific men would place the departure from
the ape-world much further back. Professor Keith
one of the most recent authorities, thinks that the
branch of the arboreal animals which was to become
man separated from the main stem before the man-
like apes were developed. He looks for a common
ancestor of the primitive htunans and the primitive
apes something like two million years ago.^ This
common ancestor was, however, of a monkey-type,
a branch of the very large simian world of the time.
But a more recent writer has maintained that the

^ See the excellent genealogical trees in his A ntiguity oj Man
(I9I5)»PP- 508 and 509.

THE ORIGIN OF MAN 109

whole family of lemurs, monkeys, and apes have such
differences of structure from man that they must be
regarded as separate developments. In other words,
man has a very remote common ancestor, of three or
four million years ago, with the lemurs, monkeys, and
apes; but our ancestor never passed through any of
those stages. These writers, of course, hold that man
was evolved from a primitive mammal, but that his
ancestors were not at any time so close to the monkeys
as to run the risk of being classified with them.

I am only mentioning these theories for the infor-
mation of the reader. The grounds of them do not
seem to me convincing, and I will follow the usual
view. This is, shortly, that a branch of the primitive
insect-eating mammals remained in the trees after
the Chalk Period, when most of the others descended
upon the freer earth. They developed in the direction
of the monkeys; whether through the lemur stage, or
whether the lemurs are (as seems probable) a side-
line, we need not inquire here. Tv/o or three million
years ago an enormous family of monkeys spread over
Europe (as far north as central England), Asia, and
Africa; and a branch passed into America. One
section of this family became the man-like apes, and
man's ancestors must have been so closely related to
these apes that, if one were produced to-day, we would
superficially pronounce it a man-like ape.

But how or why did our branch of the family get
that increase of brain which was the beginning of

no THE ORIGIN OF MAN

human development? Most people think that this
is a very difficult question, because they have a very
exaggerated idea of the increase of intelligence that
was necessary. They never ask us how or why the
man-like apes got their increase of intelligence over
the ordinary monkeys. Yet it is probable that the
earliest man did not surpass the chimpanzee in
brain-power more than the chimpanzee surpassed
the monkey. The earliest human skull that we have
may be 400,000 or 500,000 years old. But man had
then been developing for hundreds of thousands of
years. Unless you suppose that he was strangely
unprogressive during all that time, you are forced to
recognize earlier stages in which his brain was not
superior to that of a man-like ape; for the earliest
man we know, the product of ages of evolution, is
below the level of the lowest existing savage.

We will not, however, waste time on considerations
of this kind. The scientific authorities of the world,
belonging to the various branches of science which
touch this question, have long been quite unanimous
that man, body and mind, was evolved in this way.
If there are any persons who like to call into question
a statement on which all the scientific authorities in
the world are agreed, I can only say that England is
a free country; but I do not care to argue with such
people. Man, with an ape-like body, got some slight
increase of brain which natural selection began to
foster. How did he get it?

THE ORIGIN OF MAN in

It is generally agreed now among the experts that
leaving the trees and beginning to live on the ground
is enough to give our branch of the family an advan-
tage. Of the four man-like apes three live to some
extent on the ground, and some even use their hands
to help them along. The fourth, the gibbon, is much
more of an arboreal animal. It is very unlike man,
and not particularly intelligent, but it may interest
us here for two reasons: it can stand upright, and it
is extraordinarily active in the trees. Of course, it is
not in the line of our ancestry, but some of the best
authorities think that man's ancestor was probably
very active like the gibbon. If you have seen a gibbon
in its cage at the Zoological Gardens, you must have
noticed its prodigious leaps and untiring activity.

Now, it is supposed that our branch of the family
quitted the trees. It has been suggested that perhaps
our ancestors lived in forests in certain parts of Asia,
and that, owing to the rise of the land and increasing
dryness of the atmosphere, the forests disappeared.
Many reasons could be imagined. In any case, you
will have no difficulty in seeing that such a descent
from the trees would sharpen the wit. On the ground
a sharper watch must be kept for enemies. The hunt
for food is more exacting than among nut and fruit-
bearing trees. The back legs bear the weight of the
body more and more. The hands are used more and
more as hands. Physiologists work out the effect on
the brain of all these changes, and they tell us that

112 THE ORIGIN OF MAN

the new life would stimulate the brain. If you allow
at least half-a-million years to reach the level of the
lowest savage from the level of the chimpanzee, you
will realize that this suffices; and in spreading the
progress over that long period you are assuming a
rate of improvement of intelligence immeasurably
slower than we have actually witnessed in the last
hundred and fifty years.

It is really the slowness of man's early evolution
that puzzles us. I have on an earlier page mentioned
a prehistoric human skull that was found at Piltdown,
in Sussex, in 191 1. It must have been buried some-
thing like 400,000 years ago. There has been a great
deal of controversy about this skull, as parts are
missing, and it is possible, in reconstructing it, to
make the forehead slope back like that of a gorilla or
stand up like that of a modern man. From this
single skull, therefore, we will not draw any firm
conclusion. But the jaws were undoubtedly brutal
and retreating, the teeth bulging; and the majority
of the authorities concluded that it was the skull of a
man very low down in the scale of intelligence. As
all the other prehistoric skulls of early date are of the
same character, we have a fair idea of our ancestor of
between a quarter and half-a-million years ago. ^

' This is questioned by Professor Keith and those who make
the "Sussex man " highly developed in brain. They think that
there were two human races at the time, a higher and a lower, and
they put the real origin of man much further back, as I said.

THE ORIGIN OF MAN 113

And the stone implements, which we have recovered
in millions, confirms this. Whatever dispute there
may be about skulls, the stone implements tell a
plain story of gradual evolution. They are at first
so poor that experts could not agree for years whether
they had been touched by the hand of man or whether
their shape was purel}^ accidental. These are called
"Eoliths." The next and largest class of stone im-
plements, those which belong to the Old Stone Age,
begin with crudely chipped flints, and gradually
pass, in the course of perhaps a quarter-of-a-million
years, to rather skilfully shaped hand-axes, scrapers,
chisels, etc. They seem to make it impossible for us
to think that there were two races, a higher and a
lower, half-a-million years ago. Indeed, only a few
of the crudest flints (if any) go back to that remote
period, yet man had then already been on the earth
for ages. Thus from the stone implements we gather
that for ages man was too low in intelligence even to
shape stones for his use as tools and weapons. He
probably used sticks. Then for further hundreds of
thousands of years he was still too low to conceive
the idea of making handles for his implements, or
making the bow and arrow, and merely made such
progress as a poor type of savage might in the shaping
and finer touching of his stones. It is a story of most
extraordinarily slow progress in intelligence.

Putting together the bones and the stones, we can
fairly reconstruct the story of early man. For some

8

114 THE ORIGIN OF MAN

reason or other a branch of the ape-like tree-climbers,
as active as gibbons but as intelligent as orangs, left
the trees. The busier and more vigilant life on land
sharpened their wit a little, and they entered upon
the long, slow road of evolution of intelligence. They
lived in small family groups, as the man-like apes
do; not social groups. At first they may have helped
themselves along with their knuckles, as gorillas do;
but, if they were already as nearly erect as gibbons,
they would be able to use the hands more and more
for grasping purposes. Sticks would be their natural
weapons; but throwing stones, and eventually hitting
their enemy with large stones, would not be a very
advanced step to take. Various kinds of monkeys do
this. The human touch began when this primitive
creature first knocked two flints together to give one of
them a sharper edge. The age of "Eoliths" opened.
It seems probable that the cradle of the race was
in the region of the south-west of Asia. A great deal
of land foundered about that time in what is now the
Indian Ocean. Probably the region of man's evolu-
tion was part of this lost continent, the last remnant
of the continent which, we saw, at one time connected
Asia with Africa and Australia. It is significant that
we find our earliest human remains in the island of
Java. In the collection of prehistoric remains at
South Kensington you will find a skull marked the
Pithecanthropus," found in Java. The name means
Ape-Man," and the specimen is so labelled in every

<<

((

THE ORIGIN OF MAN 115

collection in the world. It tells its own sto^3^ These
bones belonged to a creature which was half ape and
half man, or midway between the higher apes and the
lowest savages. As a matter of fact, scientific men
at first disputed very warmly whether they were the
bones of an ape or a man. We now admit definitely
that they are human, and that they do not even repre-
sent the earliest human phase. Man had already
been evolving for hundreds of thousands of years.
But, of course, the Java branch of the family have re-
mained stationary, as isolated tribes do. The bones
in that case really represent a much earlier phase of
htunan evolution, and are most interesting. The
thigh bones are curved, the teeth projecting, and the
skull extremely low in the scale of intelligence.

We have a dozen skulls and jaws representing the
next chief phase — man of the Old Stone Age. The
Piltdown skull seems to belong to quite the earliest
part of it, and is very valuable. Other skulls found
in France, Belgium, and Germany show various
stages in the long journey upward. Man was still,
after half-a-million years development, below the
level of the Australian black. The skull of an Aus-
tralian black grimly watches me, in my study, as I
write this. It is quite respectable in comparison
with some of the prehistoric skulls I have examined.
The man of the Old Stone Age had a low, retreating
forehead, brutal jaws, and a robust but not tall frame.
He wore no clothes, but had still a thick coat of hair

ii6 THE ORIGIN OF MAN

over most of his body. All his implements were
carried and used in the hand, without handles, and
he had no bow and arrow. He had no home. The
climate was still so good that the rhinoceros and
hippopotamus and elephant wandered over Britain
with him. He lived in family groups, not social
groups. He was still subject only to the very slow
and cumbrous evolutionary method of natiiral selec-
tion— the struggle for food and life and survival of the
fittest. Had he remained subject only to this law of
progress, we might all to-day be at the level of the
Zulu. But natural selection now took on its grimmest
form, an Ice Age, and — something happened.

CHAPTER XI

SOCIAL EVOLUTION

Let us glance back for a moment at the course of our
story. During the first half of it, which we crushed
into a few pages, life had not got beyond the stage
of the worm, the shell-fish, and the star-fish. Twenty,
if not fifty, million years were used up in this poor
advance. Let us, for the sake of being clear, give a
definite number of years to the story of life — say,
fifty million years, though it was probably much more.
On that scale it took thirty million years for life to rise
to the level of the fern, the beetle, and the fish. Seven
or eight million years later life had advanced as far
as the first reptile.

Then a great Ice Age occurred, and the primitive
birds and mammals appeared. But there was a
reaction, and for seven or eight further million years
the reptile was the lord of the earth, and the mammal
Made hardly any progress. Forty-five million years
out of the fifty million were over when the mammals
began to spread. Four out of the five remaining
million years were over before the very lowly and
primitive thing that we can just call man came on

the scene.

117

ii8 SOCIAL EVOLUTION

But the pace of progress was still very slow. For
at least three quarters of a million years man made
inconceivably slow advance. For most of the time
he must have been stationary. Then the last Ice
Age occurred, and we shall see that it drove men
into social life. Dates are difficult, but we may put
this development of social life, roundly, about fifty
thousand years ago — to take the end of the Ice Age
and the full term of its influence. Man now reached
a level a little above that of the Eskimo. The pace
was now much faster. Ten thousand years ago the
foundation stones of civilization were laid in Egypt.
Five thousand years ago two great civilizations had
reached a high development. But there was still
something wrong with the machinery of evolution.
Man was nominally, but not thoroughl3^ social.
There was no social sentiment between groups of
men — tribes or nations — and horrible wars wasted
their resources and destroyed their lives. Seven
himdred years ago Europe was in most respects
lower than civilization had been five thousand years
before. A few centuries later the advance was
resumed. A hundred years ago we had got back to
the general level of ancient Rome and Greece. And
in the last hundred years, which have been especially
marked by the growth of social ideals, we have
passed every previous high-water mark of civilization,
and have made more progress than was made in any
five hundred years in the history of man !

SOCIAL EVOLUTION 119

This is what some writers on science and social
questions (like Mr. Benjamin Kidd) forget — or do
not know. "Darwinian" progress, or progress by
painful struggle and natural selection, is a great
fact. But it is a description of the past, not an ideal
of the present. It is the method of unintelligent
nature, costly and slow. Darwin himself — a very
gentle and humane man — drew a distinction between
"natural" and "artificial" selection. Natural selec-
tion we have seen plenty of. Artificial selection is
Vv^hen man breeds new species of pigeons or dogs or
sheep. It is intelligent, economical, and speedy. It
has been greatly developed in our time, when new
fruits and flowers are created speedily and cleanly, as
Luther Burbank does in California. Darwin would,
of course, have said, if you had asked him, that to
set up "nature's" way (that is to say, remember,
unintelligent nature's blind way) as a model for
intelligent man would be the height of absurdity.
But Darwin shrank very naturally from politics — all
social work was "politics" or "Radicalism" in his
time — and was concerned only with the past or with
non-human nature. Darwinism has not the slightest
bit of hostility to social idealism. It has nothing to

do with it.

What Darwin did not know as well as we do to-day
was the importance of social evolution. Dr. Russcl
Wallace tried to show this, but his work is rather
confused. I pointed out as we went along that dur-

120 SOCIAL EVOLUTION

ing the overwhelmingly greater part of the story of
life there was no social evolution at all. Social life
was found only among sponges and corals and other
unconscious or barely conscious types of animals,
and they made no progress during millions of years.
Social life proper began only in the last two or three
million years. There is no proof, in fact, that it
began earlier than within the last million years.
At all events, beavers, bees, ants, etc., began their
social ways in only quite recent geological time. So
the "Darwinian factor" has been the chief agency
of evolution during forty-eight out of fifty million
years.

In Darwin's time very little was known about pre-
historic man. Now we know his story very fairly.
I have described the early part of it: a period of
non-social life and extraordinarily slow progress.
Curiously enough, many advanced social writers
insist on regarding early man as social almost from
the start. They probably think, that this explains
his progress; and they would change their opinion,
which is a pure theory, if they knew how very little
progress man made for three-quarters-of-a-million
years. The facts are all the other way. The man-
like apes, early man's cousins, are not social. They
live generally in families. The lowest living human
groups to-day are imperfectly social. They live in
family groups, with strict monogamy, and have no
tribal organization. And, as far as we can gather

SOCIAL EVOLUTION 121

from the pre-historic remains, early man was not
social, and did not live in groups until the Ice Age.
So we may fairly infer that the clan or tribe, the
social group, was formed by the clinging together of
families, not the family evolved out of the social
group; and that this occurred late.

Now, the geological record throws a very important
light on this. During all that long period when early
man was merely creeping upward, so to say, the
climate of Europe was much warmer and better than
it is to-day. At first it was like the climate of Algeria ;
later like the climate of Australia. Men had plenty
of primitive food, and no need for fire, clothing, or
houses. But it was again growing steadily colder.
All the great mountain chains of our world were rising,
and when they reached their culmination a great
Ice Age set in. Five times in succession, with com-
paratively warm periods between, a sheet of ice and
snow spread from the mountains over Europe and
North America; and there were other sheets wherever
there were high mountains. At the fourth and great-
est spread of the ice-sheet Europe was glacial as far
south as the Thames and the Danube, and America
as far south as St. Louis and New York.

The pre-historic inhabitants of Europe were driven
south, and forced to live in caves. No doubt rock
shelters would be used at first, and men would gradu-
ally venture into the dark caverns. We find groups
huddling in the caves of Derbyshire, and very large

122 SOCIAL EVOLUTION

groups living in the caverns of the south of France and
the Pyrenees. We find that they now begin to make
clothes out of skins. You can see in the British
Museum to-day some of the bone needles they made
and used. They learn how to strike fire from flint.
They develop a skill in art; and towards the close of
this ''cave period" w^e find quite clever carvings in
ivory (tusks of miammoth), and drawings on stone,
bone, and ivory. In short, the pace of human
progress was enormously quickened dtuing the
coldest period of the Ice Age, and it was virtually a
new race that spread over Europe when the ice and
snow disappeared.

Social evolution had begun. Families were forced
to live together by the very nature of their new
homes. This would lead to greater and greater efforts
to communicate with each other. From the struc-
ture of the jaws of man before the Ice Age we can
fairly gather that he had no articulate speech. Lan-
guage of a crude kind seems to have been evolved
in the caverns. Men could exchange ideas, to some
extent; and the clash or contrast of different cultures
is the great secret of human progress. "Struggle" is
necessary. But those who think that it must be a
struggle of weapons and muscles, or of greed and
selfishness, are hopelessly unscientific. The struggle
of ideas and ideals in a perfectly harmonious group
is enough.

The main advantage of social life and communica-

SOCIAL EVOLUTION 123

tion is that it greatly helps the weaker in intellect to
rise. The man of poor mind can share the ideas and
discoveries of the genius. The race rises as a whole,
so that after the Ice Age we are not surprised to find
rapid progress. The stimulus to progress given by
social life would be checked, as long as the hard
conditions lasted, by the desperate struggle for food
and warmth. The new increase of intelligence helped,
because it created better weapons — the spear, bow
and arrow, hafted axe, etc. — but the severity of the
conditions would tend to distract and absorb energy.
When the last ice-sheet had melted, and Europe
recovered at least the degree of warmth it has to-day,
the new race, the men of the New Stone Age, spread
over it. In this the stimulus to progress was partly
checked. Tribes lost all communication with others,
and stagnated. Progress would be most in the south,
where groups were nearer each other.

I am, of course, neglecting the greater part of the
human family in this sketch. No doubt it had been
distributed over the earth before the Ice Age, but it
was chiefi}^ the branch of the family which turned
towards Europe that experienced the full stimulation
of the Ice Age. During the greatest extension of the
ice-sheet this branch of the race would, to a large
extent, retreat south, across the land bridges to
North Africa and Asia minor. There would be a
relatively thick population from the Persian Gulf to
Algeria, and this would be thickest from the Persian

124 SOCIAL EVOLUTION

Gulf to Egypt, where there was most depth of country.
Just about this time the valley of the Nile and the
valley which we call Mesopotamia were formed by the
rivers; and out of the turmoil and struggle of tribes
for the fertile valleys came the first beginnings of
civilization.

The story of evolution is a great aid to correct think-
ing. It may begin with stars which are a long way
off, but it leads to man and man's evolution. It
gives you a solid scientific ground for hope and trust
in man. No evolutionist can be a pessimist. The
human story is only just opening. Those million
years of early human development, of which I have
spoken, were only the prelude. Now we know more
or less where we are and what we are doing. Ac-
cording to the best estimates of mathematicians,
man will remain on this earth for something more
than ten million years yet. At the rate at which we
have gone for the last hundred years, this period of
time opens out a prospect of such happy developments
as are beyond the capacity of the liveliest imagina-
tion. We are the factors of evolution to-day. We
are the masters and the creators. Let us get the plan
right and forge ahead.

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What Is Man?

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chapters deal with the following subjects: — Man's
Pedigree, Primitive Man, the Evolution of the
Human Mind, Man as a Social Person, Human
Behavior and Conduct, Variability and Inertia,
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and Conflict of Races, Shadows and Disharmonies,
and Possibilities of further Evolution. It ends
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