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Broadcast Talks Published in Book Form by
Messrs. George Allen & Unwin Ltd
POINTS OF VIEW
By G. LOWES DICKINSON, DEAN INGE, H. G. WELLS, J. B. S.
HALDANE, SIR OLIVER LODGE, SIR WALFORD DAVIES
Edited with an Introduction by G. LOWES DICKINSON
"All these opinions are well worth reading." Contemporary Review
Second Impression
MORE POINTS OF VIEW
By the ARCHBISHOP OF YORK, VISCOUNT GREY OF FALLODEN,
SIR JAMES JEANS, DAME ETHEL SMYTH, SIR JOSIAH STAMP,
SIR HENRY NEWBOLT, HILAIRE BELLOC
"Even more interesting than the first volume." Education
ELECTRICITY IN OUR BODIES
By BRYAN H. C. MATTHEWS
"A fascinating book . . . which should appeal to a wide public."
Educational "Journal
THE MODERN STATE
By LEONARD WOOLF, LORD EUSTACE PERCY, MRS. SIDNEY WEBB,
PROFESSOR W. G. S. ADAMS, SIR ARTHUR SALTER
Edited by MARY ADAMS
"Perhaps one of the most immediately valuable books of collected
talks yet published." Enquirer
SCIENCE IN THE CHANGING WORLD
Edited by MRS. MARY ADAMS
An anthology of Science. The contributors are BERTRAND RUSSELL,
JULIAN HUXLEY, ALDOUS HUXLEY, HILAIRE BELLOC, J. B. S.
HALDANE, SIR OLIVER LODGE, SIR THOMAS HOLLAND, JOHN R.
BAKER, HUGH I'ANSON FAUSSET and H. LEVY
"Those with interest in modern scientific thought should not miss
this volume." Sphere
CHANGES IN FAMILY LIFE
By SIR WILLIAM BEVERIDGE and Others 3^. 6d.
"Offers abundant material for argument, a goodly stock of informa-
tion, and likewise food for thought." Time and Tide
BIOLOGY
IN
EVERYDAY LIFE
BIOLOGY
IN
EVERYDAY LIFE
BY
JOHN R. BAKER
AND
J. B. S. HALDANE
LONDON
GEORGE ALLEN Sf UNWIN LTD
MUSEUM STREET
FIRST PUBLISHED IN/ 1933
All rights reserved
PRINTED IN GREAT BRITAIN BY
UNWIN BROTHERS LTD., WOKING
PREFACE
THIS book comprises six talks broadcast in the
National programme in the Spring of 1933.
Conversational English differs markedly from the
written language, and it is essential to a good
broadcast that the language should be conversa-
tional. Indeed, it is almost a criterion of a good
broadcast that it should look queer when printed.
We have therefore made slight alterations, but
we have not rewritten the whole in the ordinary
language of print. Certain parts of the book, such
as the end of Chapter IV, were not actually
broadcast. We wish to express our gratitude to
the British Broadcasting Corporation for kindly
permitting publication in book form.
J. R. B.
J. B. S. H.
CONTENTS
CHAPTFR PAGE
PREFACE 7
By John R. Baker
I. A BIOLOGIST'S VIEW OF EVERYDAY LIFE 13
II. SOCIAL LIFE IN ANIMALS 29
III. THE DETERMINATION OF SEX 48
IV. THE QUALITY AND QUANTITY OF
MANKIND 64
V. WAR, DISEASE AND DEATH 83
By J. B. S. Haldane
VI. BIOLOGY AND STATESMANSHIP t o 3
By
JOHN R. BAKER
University Demonstrator in Zoology -, Oxford
CHAPTER I
A Biologist's View of Everyday Life
How much does each of us know about how the
world appears toother people? I confess I have not
the slightest idea how it appears to a Chinaman,
but I am not referring to people of other races.
I mean people of my own race who do different
things from me. It is often said that we have no
idea even how colours appear to anybody except
ourselves. Just think of the tremendous amount
we do not know about how all sorts of things
appear to other people, unless we happen to be
extraordinarily imaginative.
About sixteen years ago, when I was a boy
of sixteen, I was very keen on the microscopical
animals and plants that float about in the sea, and
I had an idea that I could invent a better net for
catching them than anybody else had invented.
To make this sort of thing you want very fine
silk netting. Now millers want very fine silk
netting, to use in sieves. They call it boulting
cloth. So I wrote to a large firm that makes
machinery for milling, and got a square yard of it.
That is the only object I have ever bought from
Mr. C., but every year since then Mr. C. has
13
Biology in Everyday Life
sent me a calendar; and every year since I have
had a study, it has hung in my study and told me
the date. It is not an ordinary calendar at all. On
each of its twelve pages are pictures of milling
machinery. Every April, amid a maze of com-
plicated machines, I search out and find a little
gadget called what do you think? a pritchel.
Sixteen years have gone by. I have grown from a
boy to a middle-aged man, and still to this day
I do not know what a pritchel is for. It looks
uncommonly like a flat-pointed pencil in the
picture. If a pritchel is a problem, what of the
other objects that Mr. C. shows to me each year?
What of this? "One harp or quarter of millstone
with ten qrs. running with the sun." I am out of
my depth here. The picture looks like a plan of
fortifications round a camp. And then a "round
bottom tin scoop"? How can one guess its
function? Or a "band sack hoist"? Or even a
"continuous worm"?
Here is a field of knowledge of which I know
nothing, absolutely nothing whatever. You have
your field of knowledge, on which you are an
expert. I calculate that the chances against your
field being biology are about fifty thousand to one,
so your outlook is almost certainly different from
mine. The point of this first chapter is just to
show you what it feels like to be a biologist.
A Biologists View of Everyday Life
Perhaps you will ask why I have let these
sixteen years go by and never found out what a
pritchel is. That is a perfectly good question and
I have a perfectly good answer to it. I have a
young friend. When I first met him I asked him
what he was interested in. His answer surprised
me. "Everything", he said; and so he is. I expect
he knows what a pritchel is. But if we try to
know about everything, then we can only have a
superficial knowledge of everything, and no deep
knowledge of anything. Some degree of specializa-
tion is absolutely necessary if we are going to find
out something new in any department of know-
ledge, and my object in life is to find out unknown
things about living organisms. Of course, it is
wrong to specialize too much. I know a man who
specializes on cockroaches, and not only on cock-
roaches, but on the cockroaches of a particular
group of islands! A friend of mine says that a
specialist is a man who wants to know more and
more about less and less. We shall not make any
world-shattering discoveries in that way. As in
most things in this life, the even mean between
the extremes is what we should aim at.
We are all of us rather apt to think that other
people's lives and outlooks are rather like our
own, until we begin to think seriously about it,
and then suddenly we find that we know nothing
15
Biology in Everyday Life
about other people's. Charles Darwin, the greatest
biologist of all time, spent many years of his life
studying barnacles. He had a room in his house
where, day after day, he studied his barnacles.
That probably seems extraordinary to you. But
did it seem extraordinary to his family? Let me
tell you. His family were one day shown round a
friend's house. We will call the friend Mr. A.
The hall, the dining-room, the drawing-room, and
no doubt the various domestic offices were re-
viewed in turn. One of Darwin's little boys was
there. The house would have seemed a very
ordinary house to an ordinary boy, but to Darwin's
boy it seemed an extraordinary house. When they
at last left to go home, he could contain himself
no longer. "But mother", he asked, "where does
Mr. A. do his barnacles ?" Darwin's son had
accepted the "doing" of barnacles as a natural
part of every grown man's existence.
I am not going to say what it is like to work at
barnacles, or even to work in a laboratory at all,
but I want to give you some idea of what it feels
like to be a biologist. Probably you think biologists
are very funny even extraordinary people ; and
probably you think that they are concerned with
things that don't matter a bit. Often things which
do not matter at all at the time they are discovered
become extraordinarily important a generation or
16
A Biologist's View of Everyday Life
so later. What about the man who was studying
the reproductive organs of grasshoppers and dis-
covered the secret of sex determination ? One day
fairly soon the world may be topsy-turvy as a
result of that discovery. Our newspapers are full
of politics, politics, politics. It cannot be very long
now before ordinary politicians take their proper
places in the background, and biologists begin
to control human life. Already this great revolu-
tion is beginning. I am reserving all that for
later chapters. In this first chapter I am asking you
to allow me to introduce myself and show you how
the biologist is alive to everything that is going
on around him, and alive in a special way.
Well, then, the biologist awakes in the
morning!
I am awakened by the pulling of blinds. I
am dimly conscious of my housemaid's movements
about the room. She has got up before me and
now she is doing things for me. Why? Is there
anything like that in the animal kingdom ?
Certainly there is. There is even the exact
counterpart of complete slavery. There is an ant
called Polyergus rufescens^ which is common in
parts of Switzerland. 1 The workers are very
ferocious and never look after their own young,
as the workers do in all ordinary kinds of ants.
See Wheeler.
B 17
Biology in Everyday Life
What is more, they are not even capable of
collecting their own food. How do they manage
to exist, if they cannot look after themselves?
They enslave other kinds of ants, especially one
called Formica fusca. Usually there are about six
times as many Formica as Polyergus in the nest.
Each Polyergus has half a dozen slaves to look
after it.
The slaves are workers, which do not breed,
In time they die off, and if they were not replaced,
the poor Polyergus would be as helpless as I
should be if my cook and housemaid and nurse
were suddenly to desert me. But there is just one
thing that Polyergus can do, and that is to get
more slaves from time to time. In the summer
small parties of Polyergus go off and look at the
Formica nests in the neighbourhood. Then one
afternoon in July or August all the Polyergus
ants in the nest march out together in a dense
column. They go straight to one of the Formica
nests. It is exactly like an Abyssinian slave raid.
It looks as though they had investigated all the
nests round about and for some reason chosen
this special one for attack. If the nest is defended,
they kill the defenders with their huge jaws. They
carry the pupae back to their own nest. In due
course the pupae change to adult ants, which
accept the Polyergus nest as their natural home,
18
A Biologist's View of Everyday Life
and spend their days slaving for their masters.
The architecture of the nest is exactly that of
the slave ants. Their masters cannot even excavate
a nest.
We have not got far with the day yet. I have
just woken up. From my bed I can see the basket
in which my dog. Merry, sleeps. I keep him just
as a pet, and because I like him. He is of no use
whatever. He is a cocker spaniel, but I do not
shoot. If a burglar were to come, he would be
almost certain to go up to him and lick him. I
keep him simply as a pet. I like patting him and
talking to him and taking him for walks. Do any
other kinds of animals keep pets ?
There is a minute beetle called Hetaerius that
lives in ants' nests in Europe and North America.
Hetaerius does nothing whatever to help in the
economy of the ants' nest. Yet the ants feed him:
in fact, he relies entirely on being fed by the
ants. Why do the ants tolerate him? Simply
because they like petting him. The ants lick him
all over the face, and appear to enjoy doing so.
When they start trying to lick his face, he pulls
his head back under his thorax, and the ant cannot
get at him properly. So the ant throws up some
of the contents of its stomach, which the beetle
likes to eat. Directly the beetle puts his head
forward to eat, the ant starts licking its face
Biology in Everyday Life
effusively. After a bit the beetle often pulls his
head back again, and the ant has to produce some
more food to induce it to allow itself to be fondled
again. The ants like carrying the beetles about
and also roll them over and over like barrels.
So it is not only human beings that like pets.
One of the first things I do is to put on my
spectacles, as I am shortsighted. That is to say,
the lenses of my eyes are of the wrong shape. It is
rather annoying to remember that they produce a
perfectly good image of everything, but in the
wrong place. Instead of producing the image on
the backs of my eyeballs, where the sensory cells
are that would convey the image to my brain,
they produce it in front of them, where there are
no sensory cells. If I put concave spectacles in
front of my eyes, the image is thrown back on to
the right place and I see clearly.
The frames of my spectacles are partly of what
is called tortoiseshell, but tortoiseshell is not
actually the shell of the tortoise. It comes from
the hawksbill turtle. Turtles, of course, have
paddles. Tortoises have separate fingers and toes.
The turtle that produces tortoiseshell is not the
same as the turtle which finds its way into soup.
The tortoiseshell turtle eats fish. Like most
carnivorous animals, it is not very good to eat.
The turtle which we eat eats seaweeds.
20
A Biologist's View of Everyday Life
I must get up and have a wash. Here is my
sponge. I propose to wash with the skeleton of a
marine animal. There is not any doubt the sponge
is an animal. Plants are living organisms which
can live on inorganic salts, or are obviously
related to ones which can. Animals are living
organisms which require organic matter ready
made for them. They either eat plants, or else
they eat animals that eat plants, or eat animals
that eat animals that eat plants, or at any rate
somehow or other get organic matter that was
made from inorganic salts by plants in the first
place. A sponge feeds on microscopic plants and
animals which float about in sea water. It is
really a sieve through which the water is passed
by the lashing of microscopic whips. The thing
we wash with is just the skeleton of it. There
are hundreds and hundreds of different kinds of
sponges, but only a few of them are any good for
washing. Most of them have masses of hard
pointed spicules in them, and they would be most
uncomfortable things to put against one's skin.
Then what a remarkable process shaving is!
To the biologist it presents all sorts of problems.
Why do hairs grow on my face ? One knows this
much. There exist certain glandular cells in the
reproductive organs of men, which make a
chemical substance and push it out into the
21
Biology in Everyday Life
blood. It circulates in every part of the body,
and makes the different parts grow in the male
way. The substance is what is called a hormone,
or chemical messenger. That is a partial explana-
tion, but it does not explain the use of a moustache
and beard. We call organs of this sort secondary
sexual characters. By that we mean that they are
not essential sexual characters in any obvious way.
The wattles of cocks are an example. They are
supposed to be an attraction to the female, and
Darwin thought that in the course of evolution
they gradually got bigger and bigger because the
hens tended to choose for mates the males with
the biggest wattles. But beards! Most men seem
to get chosen all right without them. They are a
bit of a mystery to the biologist. Perhaps they
were an attraction to the female of our pre-human
ancestor, and we have simply retained them,
while women have changed their opinion as a
result of education. If a modern English girl were
cast up as a baby on a desert island and managed
to survive, what would she think if she were
brought to England ? Would she fall for the first
bearded man she saw? I wonder.
Many men think the hair on their faces grows
more quickly if they shave than if they do not.
Recently a woman in America got four men to
send their shavings to her over a period of nine
22
A Biologist's View of Everyday Life
months, and she made elaborate measurements of
them. Sometimes they shaved every twelve hours,
sometimes they went four days without shaving.
It made no difference whatever. The hair went on
growing at the same speed whatever they did.
When I want to shave, I have got to have a
foam of bubbles to support the hairs while they
are being cut, and a slippery fluid to let the razor
slide along easily. Soap does the trick. It is an
extraordinary fact that for making this slippery
foam there is nothing so good as the hair of the
badger.
Have you ever seen a badger? One does not
often see one, because they are nocturnal. They
live in holes. Some people think it fun to pull
them out of their holes with specially made tongs
and then kill them. One must have an extra-
ordinary idea of the meaning of words if one calls
that sport. Badgers are most interesting animals
in several ways. Their long hair seems to be a
protection against attack as well as against cold.
Wherever one catches hold of a badger, he seems
able to bite. That is partly because his hair is so
long, and partly because his skin is so extra-
ordinarily loose. He can turn inside his skin, so
to speak. It seems rather extraordinary that a
structure that has evolved for the purpose of
protecting the badger and keeping him warm
23
Biology in Everyday Life
should be found to be the best possible instrument
for making a lather with soap.
People often think badgers are closely allied to
bears, but that is not so. They come in a group
with the stoats, weasels, otters and skunks. They
all agree in having very few molar teeth, that is,
teeth behind the ones that replace the milk teeth.
Bears have two above on each side, and three
below. The stoats and badgers never have more
than one molar tooth on each side in the upper
jaw, and only one or two below. We have three,
of course, both above and below, the last being
the so-called wisdom-tooth. Lots of animals have
three, but it is rather unusual for animals to have
only one, both above and below, like many of the
badger's relations.
Well, we have got on to teeth, and now that
I have shaved I must wash them. Is it not extra-
ordinary that we have to wash our teeth to keep
them in good condition? We seem to have the
worst teeth in the animal kingdom, and fossils of
our prehuman ancestors show that they too
suffered from dental decay. I wonder why it is.
One has the impression that our teeth are often
too crowded in our mouths. If only they were
better spaced, like most animals', food would not
get stuck between them, and then probably they
would not decay so fast. Why should our teeth
24
A Biologist's View of Everyday Life
be so crowded? I wonder if it can be that they
did not get proportionally smaller while our jaws
were decreasing in size. There is no doubt that
our ancestors had much bigger jaws than we.
They stuck forward something like a gorilla's or
chimpanzee's. Nearly all the fossil skulls of our
remote ancestors show that. (Actually I should say
the relations of our remote ancestors, because of
course there is no evidence that any of the fossil
skulls really represent actual ancestors of modern
man.) The aborigines of Australia still retain
the large jaw, but it is not nearly so prominent as
those of the fossil skulls, and theirs are not so
prominent as the gorilla's.
Let us get dressed. Do any animals dress?
That all depends on what one calls dressing. By
dressing, I mean putting a bit of the environment
on oneself for protection. Certainly there are
animals that do that. The caddis-worm is an
obvious example. You have probably seen him.
He lives at the bottom of ponds. He is the
larva of the caddis-fly, but you do not often see
caddis-flies. That is because caddis-flies are dull-
coloured and do not often fly about. They prefer
to remain hidden. The larva or caddis-worm
takes tiny bits of vegetable matter or grains of sand
and makes a little tube out of them in which he
lives.
25
Biology in Everyday Life
My clothes are sewn together. The caddis-worm
does not exactly sew, but there is a tropical ant
called Oecophylla which practically sews. I really
think that Oecophylla is one of the most wonderful
animals in the whole of nature. It does not sew
to make clothes, but to make its nest. It makes its
nest of leaves sewn together at the edges with
silk. Now no adult insect 1 makes silk, though
insect larvae that is caterpillars often do. The
larvae of Oecophylla make silk. They make it in
two glands in the abdomen and it oozes along a
tube in a sticky condition and finds its way out
by a pore on the lower lip. Ant larvae are abso-
lutely unable to move about and could not possibly
sew with this silk. What is the use of it ? What I
am going to tell you is practically unbelievable,
but it is true nevertheless. To make a nest, a row
of ants holds the edges of two leaves together.
Then other ants line up on the other side of the
leaves at their junction. They actually sew them
together, holding the leaves in their jaws and
passing the larvae to and fro across the gap. They
use the larvae as living reels of silk. The silk sticks
to the leaves where it touches them.
Now brushing the hair. My hair is quite short.
That is because I get it cut every now and then.
Does any animal besides man have the habit of
1 Except the fly Hilara.
26
A Biologist's View of Everyday Life
cutting bits off itself? The Motmot is a bird
something like a kingfisher. He lives in Central
America. He has an extraordinary habit. 1 He
nibbles off the barbs of his middle pair of tail
feathers all the way along except just at the tip,
where he leaves a racket-shaped end. All along
the rest of the feather he leaves nothing but the
bare quill. I say "he", but actually both sexes do it.
I do not only brush my hair; I also comb it.
Animals, too, sometimes have combs. The middle
toe of the nightjar is like a comb, and he is
thought to arrange his feathers with it. Gannets
and herons have a similar arrangement. Then
there is a curious Malayan mammal called
Galeopithecus. He seems to be allied to the
insectivores, the mole and shrew and their allies,
but he is bigger than these, and he has got a
membrane stretched on each side between his
arms and his legs, so that he can glide about from
tree to tree. Galeopithecus has a comb. His lower
front teeth are comb-like. They are really very
extraordinary to look at. Perhaps you could see
them in a museum, if you happen to live in a
big town.
Combs are sometimes made of tortoiseshell, and
sometimes they are synthetic, but often they are
made of whalebone. What is whalebone ? First of
1 O. Salvin, Proceedings of Zoological Society of London, 1873 (p. 429).
27
Biology in Everyday Life
all whalebone is not bone. It is a horny substance.
It is produced by the toothless whales only. It
hangs from the roof of the mouth in ridges. The
lower edges of the ridges are frayed. The whale
fills his mouth with water, and then raises his
tongue. In big specimens his tongue may weigh a
ton. When he raises it, the water is squeezed out
between the frayed ends of the whalebone. The
minute floating animals in the water are held back
by the whalebone, which is really a sort of filter.
He licks them off and swallows them. It seems
extraordinary that such a huge animal should feed
on almost microscopic food, and perhaps even
more extraordinary that the substance which has
evolved to act as a filter for the whale's food
should have been found to be one of the best
substances for preventing human hair from getting
tangled.
If I were to go right through my day, it would
take many chapters, but we have more serious
business to which to attend. This is really just an
introductory chapter, to give an idea of a biologist's
outlook on things in general. In the next chapter
we shall discuss social animals. Man is essentially
a social animal. We must study social animals in
some detail first, so that even the second chapter
will be to some extent introductory.
28
CHAPTER II
Social Life in Animals
WHAT is the greatest feat of heroism that you
have ever heard of? I suppose that heroism usually
consists in disobeying a strong instinct for some
worth-while object. Usually it is the self-preser-
vation instinct, I suppose, to which the hero is
superior. What do you yourself regard as the
greatest act of heroism ? I know what I think, and
the ordinary self-preservation instinct was not
concerned. My hero rose superior to the herd
instinct. Mr. Courtauld went into the interior of
Greenland with a party, and then remained there
when the party returned to the coast. He remained
there throughout the black Arctic winter abso-
lutely by himself, with not a single human being
within 1 20 miles. He completely disobeyed one
of the strongest instincts we have, for the sake
of making observations on the weather in a place
where practically nothing was known before. 1
Have you ever been alone? How far is the
farthest you have ever been from any other human
being? And how long did you remain at this
distance ?
1 The Polar Record, No. 4, July 1932.
29
Biology in Everyday Life
We are so obviously social animals that we do
not often bother to think about it, or to ask our-
selves whether many animals are like ourselves
in that respect, or whether perhaps it is rather an
unusual phenomenon in the animal kingdom.
Let us look at the minutest animals of all first,
the little very simple beasts that swim about in
ponds and which we have to use a microscope to
see at all. Most of them are not social : I mean they
do not depend on others of the same sort as them-
selves. They multiply by dividing into two. Each
soon grows the missing part. They are so simple
that that is not difficult. In the higher animals
that would be obviously impossible, because
neither half could get on for a moment without
the other. Even if each had the power of growing
the missing bit, it would not be able to, because
it would be dead from loss of blood before it had
time. Each of these little beasts is only a speck
of living matter, with nothing like blood and no
complicated organs, so things are easy for it.
After dividing, the two new individuals separate
and swim away and go about their own businesses
and pay no attention to one another. There was
one individual, and now there are two : that is all.
Now some species do not behave like that.
When one divides into two, the two do not
separate, but stick together. Each of them
30
Social Life in Animals
divides, so now there are 4, and when they
divide again there are 8, and they still stick
together and go on dividing. Soon we have 16,
and then 32 and 64 and 128 and 256 and 512
and 1,024 and 2,048. We are into thousands at
the tenth division. The little beasts are growing
all the time. Well, you will say, we shall be able to
see it soon. Why have we not all seen one of these
creatures? Wait a moment. Perhaps you have.
Fifty divisions give us countless millions of little
beasts, and even if they are very small, the total
size must be quite great. Do all the little beasts
look exactly the same ? They do not. The ones on
the outside become flattened and horny. The ones
right in the middle form themselves into a tube,
and they are the ones that are the best at eating.
They do enough eating for all the other ones put
together. They are protected from harm by the
horny ones on the outside, and in exchange they
give up some of their food to the horny ones.
The two sorts help one another. Another sort
makes a hard substance which gives the whole
collection of them a certain amount of strength ;
and others are especially good at contracting,
and they enable the whole collection to move
about and get food and escape from enemies.
What a wonderful collection of little beasts, all
being so self-sacrificing! Not one is working
31
Biology in Everyday Life
just for itself. They all work for the common
good.
Are these wonderful collections of little beasts
very rare ? If we hunt for them, shall we be able
to find one and study it ? Where shall we look ?
Do not bother to look. You are one yourself.
That is all you are nothing else. If you did not
mind me hacking you about, I could take a little
bit of any part of you and show it you under the
microscope, and you would see the tiny beasts
which compose you.
So you see, in a sense you are not an individual,
but a mass of millions of individuals and nothing
else. We may call you an individual of the second
grade, made up of millions of individuals of the
first grade. Nearly always all the tiny individuals
work together for the common good of the second
grade individual, but just sometimes some of them
in one part begin multiplying indefinitely, and
will not stop, and these ones do nothing for the
common good. On the contrary, they poison it.
Then we have cancer. Luckily the rays given off
by radium check their multiplication.
We have studied two grades of individuality.
Are there any more grades ?
Take the sea anemone. It is an animal that
lives in rock pools round our coasts. There is a
circle of tentacles round the mouth and often they
32
Social Life in Animals
are of bright colours. These are individuals of the
second grade like you and me, but in the tropics
there are anemones that divide into two, and the
two into four and so on, until there are hundreds
or thousands. They do not separate from one
another. They remain attached like super-Siamese-
twins. Their insides are connected, too, and so one
cannot starve while another has food. They all
together make a single solid rock-like skeleton.
We call the whole mass a coral. It may be yards
across. It is an individual of the third grade.
We can extend that term a bit. Supposing the
anemones separated from one another, but still
remained in a group and helped one another in
some way. Should we be able to talk about the
third grade still ? I do not see why not, so long as
the whole group worked together for the common
good. This sort of third grade individual is not
rare in the animal kingdom. A hive of bees is an
example. An ants* nest is an even better example,
perhaps, because ants have carried the thing
farther than bees. In a hive of bees you find males,
females and workers, but in an ants' nest you may
find males, females and more than one sort of
worker. When I say more than one sort, I do not
mean simply that some of them specialize at one
thing and some at another. It is not just that.
Their bodies are specially constructed for the
c 33
Biology in Everyday Life
particular work they have to do. Among many
kinds of ants there are ordinary workers and also
soldiers. The ordinary workers do the ordinary
work of the nest, such as carrying pupae about
and getting food. They are ordinary looking ants.
The soldiers are most extraordinary looking ants.
They are much bigger than the ordinary workers,
with a head that is disproportionately enormous,
with huge savage jaws in front. The soldiers'
job is to guard the nest from attack.
That is interesting; but here is something ever
so much more so. In the honey ants the ordinary
workers do all the ordinary work of the nest,
and also collect a sugary fluid that exudes from
oak galls, and another sweet fluid called honey
dew, which is produced by plant lice. The ants
stroke the plant lice with their feelers till they
exude it from the hind end of their body. The
workers then eat it. Many sorts of ants do that,
but the honey ants now behave in a most extra-
ordinary way. They go home, and enter special
chambers in the nest, where an extraordinary
spectacle presents itself. These special chambers
have smooth floors and walls, but the ceilings are
rough, and to the ceilings a large number of ants
are attached. Ants, I say, but you certainly would
not call them ants unless you knew, because they
look much more like little footballs. Their abdo-
34
Social Life in Animals
mens are tremendously swollen, and the thorax
and head look like little after-thoughts attached at
one side. Those repulsive abdomens are stuffed
full of the sweet fluid that the ordinary workers
bring back. When they come back, they approach
the living jam-jars and vomit, and the living jam-
jars eat the vomit and grow even fatter still. They
can move a little about the ceiling, but if they
lose hold and fall to the floor, they are so fat that
they cannot get up to the ceiling again. There they
stay, some hundreds of them in a big nest. They
may live there for years. If there is a period of
food-shortage, all the ants of the nest come and
cause them to vomit in their turn. That is the
use of them to the nest as a whole: they are
living food-stores. It is not certain whether all
the worker ants in the nest have the capacity to
swell and become food-stores, or whether some
of them are from the beginning different from
the rest.
Among the backboned animals there are plenty
of social kinds, but there are not any cases of
different types within a single kind, except so far
as the male is different from the female. There is
nothing corresponding to a soldier ant, which is
structurally adapted to its special job.
Among the mammals the most obviously social
are the marmots, beavers, vizcachas, horses, deer,
35
Biology in Everyday Life
oxen, antelopes, sheep, goats, porpoises, dogs and
wolves, seals and sea-lions, fruit-bats, many
monkeys and man. What advantage do they get
from being social ? In the great majority of cases
the advantage is simply protection from flesh-
eating enemies. Often they have ways of warning
one another of the approach of danger. You have
probably heard rabbits stamping with their hind
feet for that purpose. Among antelopes definite
sentries are set. While the herd as a whole is
feeding in the open, one or two individuals mount
guard on any suitable little hillocks and keep a
look-out.
In social animals an instinct to keep with the
herd is absolutely necessary. The way sheep
follow one another unquestioningly is proverbial.
We are social animals ourselves, and in crowds
we are extraordinarily easily led to follow one
another, to do things which we would not think
of doing if we were by ourselves. In America
whole crowds go off to prisons and drag out
negroes who have not been tried for any offence
and hang them. We see here the herd instinct at
its worst. If you took those lynchers separately,
you would find that nearly every one of them
wanted the negro to have a proper trial. Yet in
a crowd they all are raving mad to kill him.
The herd instinct has both its bad and its good
36
Social Life in Animals
side. Altruism only occurs in social animals.
Altruism is an action for the benefit of other
members of the same herd, and morality is, or
should be, based on it. Altruism satisfies our herd
instinct, and therefore makes us happy, just as the
satisfaction of other instincts does. Some people
have scarcely any of this instinct, and are abso-
lutely selfish. These people sometimes argue that
no one ever does an unselfish act. They say that
every apparently unselfish act is done so as to
get some benefit in a roundabout way. That is just
nonsense and ignorance: a certain amount of
altruism is instinctive in normal people.
The herd instinct makes us like to be in
crowds. Probably television will one day enable
us to have cinema shows broadcast to us in our
houses, but I am sure most people will still
flock to cinemas, for the sake of the satisfaction
they get from being in a crowd which is swayed
by the same emotions.
I have said that the advantage of being social
is usually protection against enemies, but of course
that is not so with the dogs and wolves. With these
carnivorous animals the advantage is that they
can attack animals which are far too big for one
of them to attack alone. It is rather curious that
societies for the sake of offence are rare. Also it is
curious that such a close relative of the dog as
37
Biology in Everyday Life
the fox should be completely non-social. The
advantage of the dog as a pet is simply due to its
herd instinct. It attaches itself to its master as it
would to the pack in the wild state.
A large herd cannot act together for the common
good unless there is some leader to follow. Among
wild dogs and wolves the leader is always an old
male. The younger males want to be leaders also,
and fight him for the leadership. He holds on as
leader so long as he is the strongest; but when
he gets old, he is beaten in a fight, and a younger
male takes his place. This is probably quite an
effective system, because a dog that is good at
fighting will probably also be good at hunting
the animals on which the pack feeds.
Now let us look at a few other social animals.
Let us look at the vizcacha first. This is a rodent
which lives in South America. It is not absolutely
unlike a rabbit with short ears and a bushy tail.
It lives in villages of twenty or thirty members.
There are about a dozen burrows in the village,
and all the burrows intercommunicate under-
ground. Like most social animals, vizcachas talk
to one another a good deal. Of course, they have
not got a proper language, with words denoting
definite things, but they make a great variety of
sounds. No doubt this helps to keep the herd
together. A sudden change in the sound would
38
Social Life in Animals
indicate alarm, and all could escape into the
burrows before most of the members of the
village had any idea what the danger was. Like
other social animals, the vizcacha is altruistic. If
one of the community is carried off by a peccary
(a sort of pig-like animal that lives in South
America), its friends try to rescue it.
Occasionally a new village is formed. Hudson 1
says that the vizcacha that founds a new village is
always a male. He goes and digs his burrow in a
new place, away from any other village, and later
gets a female to live there with him. As the
family grows, a new community is gradually
built up.
We have seen that a male is the leader of the
pack of wild dogs and the founder of a new village
among the vizcachas. Is the male always the
leader among social animals? Certainly not.
Among red deer the herd is led by an old female.
The old males lead a non-social life. In the
mating season the herd breaks up. The males
fight for the possession of the females, but there
is no fighting for the leadership of the herd.
The female often has duties that one might
not expect of her. People often imagine that it is
a sort of law of nature that the female is the weaker
and more timid sex. That is absolutely untrue. It
1 W. H. Hudson, The Naturalist in La Plata, Dent, 1903.
39
Biology in Everyday Life
is the female lion that teaches the young to hunt.
In spiders the female is often the larger sex, and
in many species it is the rule that directly after
courtship she kills and eats the male. It is not at
all an uncommon thing for the female to be the
larger sex. This is especially so among the savage
birds of prey, for instance, the kestrel and golden
eagle. The female sparrow-hawk is much larger
than the male. It is said that if a pair of goshawks
is caught and put in a cage, they always fight, and
the female always kills the male. 1 The phalarope
is a northern wading-bird. The female is both
larger and more brightly coloured than the male,
and takes the more active part in courtship. It is
the male that sits on the eggs.
In the most diverse groups of the animal
kingdom we come upon species in which the
male is minute compared with the female, and
parasitic on her. There is a marine worm in which
the female is about the size and shape of a plum,
while the male is about a twentieth of an inch long
and lives inside her kidney. Then there are the
oceanic angler fishes. If you live in London you
can see splendid models of them in the main hall
of the Natural History Museum at South Ken-
sington. The male is a tiny little object which
R. Lydekker, Wild Life of the World, Vol. I, Warne, London
(no date).
40
Social Life in Animals
attaches itself to the skin of the female by its
mouth and never lets go. It actually fuses with
the flesh of the female, and is nourished by the
foodstuffs circulating in her blood.
Perhaps it is not beside the point to mention
the otter. The young are not instinctively aquatic
at all. They are forced into the water and taught
to swim and catch fish by the female. The male
takes no part in their education.
Now we must get back to our social animals
again. I only wanted to make it clear that the
superiority of the male sex is by no means a
law of nature, and we must not be surprised
when we find a female leading the herd in a social
species.
Social animals can work together and make
things that solitary species never could. The beaver
is the best example. The beaver is a gnawing
animal a rodent rather more than three feet
long, counting his tail. His tail is flat when looked
at from above. He has thick brown fur. He eats
the bark of trees. He is very clumsy on land. He
always likes to be near a stream, because he is
extremely agile in the water, and can easily
escape from his enemies, the bear and wolverene.
Now, streams have a way of drying up in North
America, where he lives. So what does he do?
He helps to do something that he could never do
Biology in Everyday Life
by himself. The whole community works together
and builds a dam across the river, to keep the
water permanently at a high level. They cut down
trees by gnawing through them near the base, and
then cut off the branches and cut the trunks up
into convenient logs. If the trees are close to the
river, it is easy for them to transport the logs to
the site of the dam. If there are no trees close to
the river, they make a canal from the river to
where the trees are, and float the logs down it. 1
They build the dam of logs and mud, weighting
it down with heavy stones.
There is one special reason why they want to
have deep water always, and that is to keep their
front doors under water, so that no land animal
can enter their houses. Their houses are great
rounded domes, about eight feet high and as
much across. They are generally on the river
bank, sometimes partly submerged. They are
made of branches plastered together with mud,
and the walls are so thick that the space inside is
quite small. The passage from the house to the
submerged front door may be thirty feet long.
When a beaver is alarmed, it does something
which is not of any use to itself, but which helps
the other members of the community. It gives the
1 V. Bailey, United States Department of Agriculture, Bulletin
No. 1078.
42
Social Life in Animals
water a resounding slap with its flat tail, and the
noise warns all the others to dive for safety. Its
instincts are designed for the preservation of the
community of beavers as a whole.
Let us now take an animal that is interesting
in quite a different way. It has no remarkable
social instincts, but it is necessarily social from its
abundance in the places where it lives. Probably
you have never seen a lemming, but if you live
in the country you have no doubt seen a short-
tailed field mouse, and the lemming is like that,
only a good deal bigger and much fatter in
proportion. He lives in the high plateaux, up
above the limit of the coniferous trees, in grass-
land with birch and willow. He eats grass chiefly,
and the people who live down by the coast do not
see him. But he multiplies and multiplies, and he
gets too numerous for the amount of grass that
there is on those mountain wastes. If only he
would reproduce more slowly, all would be well,
but he does not: he breeds as hard as ever when
he is already getting too numerous. Indeed there
is some evidence that he breeds harder than ever
at that time. Poor fool, he does not realize what
is in store for him. If lemmings could moralize
like human beings, I dare say there would be
many good old-fashioned ones who would say they
liked to see lemmings with a good quiver-full,
43
Biology in Everyday Life
whatever that may mean. Perhaps if they could
take photographs, a signed photograph of il Duce
among lemmings would be awarded to the mothers
of more than a certain number of young. Anyway,
they act as though they had some such stimulus to
fertility.
At last there is no more grass left nothing
whatever to eat. This timid, secretive, mountain
animal is forced by hunger to forsake its home
and emigrate. In countless thousands they swarm
down the valleys, ever westward to the lowlands
and the sea. Their emigration is useless, but they
are driven to it by hunger. They swarm across
rivers and through villages, and all timidity is
lost. Though excessive breeding is the cause of
their trouble, they breed as they go. Infectious
disease is rife in the overcrowded swarm. Foxes^
hawks and owls congregate round the emigrating
hordes and feed upon them. Onward they go,
farther and farther from the mountain plateaux
above, the only region where they can live per-
manently. At last they come to the sea. Plunging
into it, they swim out to their death. As though the
water were not enough punishment for their folly,
the gulls attack them. A ship may steam for a
quarter of an hour through an army of millions of
lemmings. They may reach an island and gain
temporary respite, but on they go into the sea
44
Social Life in Animals
beyond. Not one returns. Every emigrating lem-
ming dies. The offspring of those which breed on
the way die also. The whole venture is useless. 1
It is caused by over-population. If breeding had
been slower, there would always have been plenty
of food for all.
Up in the mountains there remains a minute
number of lemmings which have never emigrated.
What they find to feed upon is not known.
Presumably they must be near starvation until the
grass has had time to grow after the great exodus.
Next year the number of lemmings increases. Four
years after the year of the great exodus the
numbers are once more enormous. Rapid breeding
continues and the emigration is re-enacted. The
interval between one emigration and the next is
not always exactly four years, but it approximates
to that. 2 It is not always a huge emigration: the
size of it varies. But three times every dozen years
the lemming gives us a practical demonstration of
the folly of unregulated reproduction.
Why do not all animals have the same trouble
as the lemming? If no house-sparrow died except
from old age, in a quarter of a century we should
not be able to see the ground anywhere. It would
be completely carpeted with house-sparrows, and
* W. Heape, Emigration , Migration and Nomadism, Heffer, 1931.
C. Elton, Animal Ecology t Sidgwick and Jackson, 1927.
45
Biology in Everyday Life
we should not be able to take a step without
walking on them.Yet on the average their numbers
remain the same from year to year. It is clear that
they are dying off in great numbers all the time,
and that their rate of reproduction just suffices to
balance the loss. What would happen if we started
a Sparrow Protection Society, and made sure that
none died from cold or from the attacks of
enemies ? The number of sparrows would increase
and increase until it became so great that suddenly
the food supply would be insufficient. Suddenly
there would be starvation on an appalling scale,
and sparrows would stand a good chance of being
nearly exterminated by misplaced kindness. If
we really wanted to protect sparrows, our Pro-
tection Society would have other functions beyond
applying electric warmers to their sleeping places
and exterminating their enemies. I fancy that an
army of birds' nesters would also have to be
engaged to remove an egg or two from every
sparrow's nest.
This is not just wild speculation. In the old days
deer lived and maintained a normal population in
North America, They were eaten by the mountain
lion, and their natural rate of increase was suffi-
cient to make good the loss. In one of the American
national parks the mountain lion has been practi-
cally exterminated by man. That must be nice for
46
Social Life in Animals
the deer, you will say. The deer multiplied till
there were about 30,000 of them in the park.
Every scrap of grass was eaten. The trees were
everywhere browsed upon as high as the deer
could reach. Then starvation. 1
So far as man is concerned, can we draw any
conclusions from our study of social animals?
Firstly, we will do well to recognize the herd
instinct. We should allow ourselves the full
satisfaction of obeying it whenever our reason
tells us that it prompts us to act for the benefit
of the community as a whole. We can see, though,
that in animals the instinct is sometimes perverted
in an extraordinary way. Sometimes it is a harm-
less perversion, as when a whole flock follows its
leader to do a stupid thing. If we think, reason
will tell us not always to follow stupid leadership.
But sometimes, in animals, the perversions of the
herd instinct are ugly. A wounded cow is often
attacked by one of its own herd, and then the
others join in, and the wretched beast is gored
to death. We see the same hideous sight in the
lynching of down-and-out negroes in the United
States of America, and in the travesties of justice
such as the Scottsboro' case.
Can we learn any lesson from the lemming?
We can, but shall we ?
1 M. A. C. Hinton, Proceedings of the Linnean Society of London,
i44th Session, 1931-2 (p. in).
47
CHAPTER III
The Determination of Sex
IT'S not much fun being a biologist! The trouble
is that everyone else knows better. I wonder why
poor biologists have been singled out in this way.
Why not chemists for a change? Chemists are
absolutely immune. No one thinks he knows better
than a chemist. If a chemist says that rosaniline
is made by the reaction of one molecule of aniline
with one of orthotoluidine and one of parato-
luidine, he is not contradicted. No one writes to
the newspapers and says he can make rosaniline
out of ink and sawdust. It just does not happen.
Perhaps it is partly because chemistry is written
in awful symbols which frighten people off the
subject. If so, I almost wish we had as many signs
and barbarous words in biology, because it gives
one rather a pain to see well-meaning people writ-
ing pure nonsense about biology in newspapers.
They even write books on the subject that are a
living advertisement of ignorance from beginning
to end. Of course everyone must be ignorant of
whole fields of knowledge, but it is a mistake to
lay down the law on subjects of which one knows
nothing.
48
The Determination of Sex
There are branches of biology that are immune.
No one writes to the newspapers about the devel-
opment of the chondrocranium in elasmobranchs.
But there are large departments of biology that
are considered fair game. Evolution is one. There
is one subject that ignorant people have fastened
on to more than all the others put together, and
that is the determination of sex.
People often say, " Everyone is entitled to his
opinion, " and so he is so far as insoluble prob-
lems are concerned. But I have never been able
to see why anyone is entitled to a demonstrably
false opinion. I once saw a perfectly unconcerned
gentleman walking about the streets of London
with a large biscuit-box stuck on his head in place
of a hat. On the box was written in large letters,
"The day of judgment is at hand/' Well, more
power to him ! That is all I can say. He is entitled
to that opinion. No one can deny the possibility
that he may be right. But why is anybody entitled
to a demonstrably false opinion as to how sex is
determined ?
A lot of the misunderstanding comes from
people not taking account of the laws of chance.
About the same number of boys are born as girls.
Actually about 105 boys are born to 100 girls
in most European countries. For the moment let
us assume equality (we shall discuss the reasons
D 49
Biology in Everyday Life
for the departure from absolute equality later).
Now suppose that sex is just a matter of chance,
like tossing a coin. What do we mean by chance?
We simply mean that a very large number of
independent factors are influencing the result.
In tossing coins and catching them we have an
example of pure chance. What does the result
depend on? It depends on many independent
factors. That is the point. It depends on which
way the coin happens to be up to start with,
whether it is level or at an angle, how hard I
flick it round, exactly what part of it I flick, how
far I throw it up in the air, whether there are any
air currents in the room, how far it has fallen
when I catch it, and whether it does or does not
complete a turn when it reaches my hand, which
itself depends on what part of my hand it touches
first, and in what direction my hand is moving.
If all those things were absolutely exactly the same
every time, I should get the same result every
time. But they all vary, and they vary inde-
pendently of one another. That is what makes
what we call chance. The more independent
variables, the closer the approximation to pure
chance.
The more times I toss, the closer will the
approximation be likely to be to one head to one
tail. If I were to toss a million times, I should get
The Determination of Sex
something very close to 500,000 heads to 500,000
tails. But I may toss six times and get four heads
to two tails. If so, what will happen if I toss six
times again ? What are the chances ?
This is where many people go wrong. The
chances are that I shall get three heads and three
tails, not that I shall "make up" for what has
happened, so to speak, by getting four tails and
two heads. There is no making up for past events
in pure chance. How could there be ? Past tosses
do not influence any of the many factors affecting
the flight of the coin in the next toss.
I have got four heads to two tails. Suppose I
am determined to toss a total of a million tosses
altogether. IVe got 999,994 tosses to come.
Half of that is 499,997. The final figures which
are now more likely than any others on pure
chance are 499,999 tails and 500,001 heads.
That is a very close approximation to equality, is
it not ? A good deal closer than 4 to 2 ! But the
4 to 2 at the beginning cannot influence what is
coming later.
Suppose we toss a coin six times and write
down the result, and then toss it six times again
and write down the result, and spend the whole
day doing that and nothing else. What should
we find ? We should find that more of our results
were three heads and three tails than any other
Biology in Everyday Life
combination. Next would come four heads to
two tails, and two tails to four heads. There
would be fewer still of the combination five heads
to one tail, and one head to five tails. There would
be least of all of the combinations six heads to no
tails, and no heads to six tails. Try it, if you do
not believe me. You must spend hours at it if
you decide to try. Actually one can calculate
mathematically how many of each combination
one may expect.
So far we have dealt with pure chance. If you
let the coin fall and roll on the floor till it drops,
it is no longer pure chance. The head side is
ever so slightly heavier, and tends to fall down-
wards rather more often than the tail side. It
only makes a very small difference to the result,
because in most cases the other factors influence
the result much more. But just occasionally the
coin runs levelly along the floor, and then it falls
tails up, because the head side is slightly heavier.
So in a very large number of throws we shall get
rather more tails than heads. There is a slight
bias in the tails direction.
Now at last we come to the point. The deter-
mination of sex depends on chance, with a bias
towards the male sex. The questions are: What
are all the factors which influence the chance ?
Can we direct them ? And what causes the bias ?
The Determination of Sex
The sexual cells produced by men are called
spermatozoa, or better, sperms. I spend most of
my time studying sperms, because I am interested
in birth control, and I want to invent ways of
preventing them from fertilizing eggs. Sperms
are microscopic little things looking rather like
tadpoles. Of course one can only see them under
the microscope. It is fascinating to watch hundreds
or thousands of them all swimming aimlessly but
rapidly in the field of the microscope, and still
more fascinating to get just one in the field of
view of the highest power lens and consider that
in that microscopic speck there lies the whole
inheritance from the father, the factors that
would affect the development of every part of the
offspring if it were allowed to fertilize an egg.
The eggs produced by women and nearly all
mammals are minute, but not so small as the
sperms. They contain the inheritance from the
mother. The first sperm to reach the egg fuses
with it, and the single cell formed by their fusion
grows into the embryo. Directly the sperm has
fused with the egg, changes take place in the egg,
which make it impossible for the other sperms to
fuse with it. All the other sperms die.
There are two sorts of sperms, male-producing
and female-producing. That is not a theory: it is
a fact. It is a fact which is totally ignored by the
53
Biology in Everyday Life
ignorant people who pretend that they know how
to control sex. The female-producing one has got
a rod-shaped body in it called an X chromosome.
You can see it in the developing sperm. The male-
producing sperm has no X chromosome. If you
are a woman, you have got an X chromosome
derived from your father in every cell in your
body. If you are a man, you have not got a single
X chromosome derived from your father in your
body. The X chromosome derived from the
father makes the embryo grow in the female
way. In its absence the embryo grows in the male
way. It all depends on which sort of sperm
happened to fertilize the egg from which you
grew. And what decided that ? Mainly chance.
About five million sperms compete for one
egg. They all swim about at random until one
reaches it. If you let a mixed flock of a hundred
black sheep and a hundred white sheep loose in
a field and left the gate open, the chances would
be equal whether a white sheep or a black sheep
would wander out first. But if white sheep hap-
pened on the average to be a little more active
than black sheep, the chances would be slightly
in favour of a white sheep getting out first. Make
the assumption that the white sheep are on the
average a little more active. Then, if you tried the
experiment repeatedly, perhaps a black sheep
54
The Determination of Sex
would get out first in 100 cases and a white sheep
in 1 10 cases.
That seems to be analogous to what happens
with sperms. We know for certain that male-
producing sperms are produced in exactly the
same number as female-producing sperms, yet
more boys are conceived than girls. We do not
yet know what the advantage is that male-produc-
ing sperms have.
You have to imagine the sperms all swimming
about in a tube inside the body of the woman.
They start at one end; the egg is up at the other
end. They do not swim in any particular direc-
tion. Someone has shown that if you artificially
put the sperms in at the wrong end, near the eggs,
some of them find their way down to where they
ought to have started; and they find their way
down just as fast as they ordinarily find their way
up. What factors decide which sperm shall be
the one that gets to the egg first? It depends on
where each sperm happens to be at the start;
what direction it happens to be pointing in ; how
thick the fluid is through which it happens to
have to swim at each part of its course ; how many
times it happens to bump into another sperm and
into the wall of the tube; in what direction its
course is deflected when it does so ; what currents
it meets in the fluid in which it swims; exactly
55
Biology in Everyday Life
where the egg happens to be placed in the tube;
and so on. There are so many independent factors
that it is nearly a case of pure chance, but not
quite, because male-producing ones do have some
slight advantage, and do get to the egg first
rather more often than the female-producing
ones.
You must notice that the egg has not the least
tendency to grow into one sex rather than the
other. It is absolutely indifferent. That again is
not a theory: it is a fact. It applies to man and all
hairy animals, but funnily enough in birds things
are the other way round. In birds every egg is
determined as either a male-producer or a female-
producer. In birds there are not two sorts of
sperms: they are all the same. But in mankind
and in all other mammals that have been studied,
the egg has nothing to do with sex determination.
The sperm decides it.
One odd guess that turns up from time to time
is that one ovary produces male-producing eggs
and the other one female-producing eggs. It is
possible to say quite definitely that that is not so.
You can completely remove one ovary, but the
sex of the young ones produced is still mixed.
The egg has nothing whatever to do with the
matter in mammals.
Another guess is that the time of conception
56
The Determination of Sex
makes a difference. That is an old midwives' tale.
The whole question has been most carefully
analysed, and it has been shown that in man the
time of conception does not influence the sex
ratio. In cattle the matter has been investigated
on a huge scale, and it has been proved statistically
that the time of service does not make the least
difference to the proportion of the sexes.
How can these erroneous ideas have gained
ground ? That is not difficult to answer. Someone
gets a "hunch" about the matter. Perhaps it is
someone who has had several boys running. So
she tells a lot of people how she thinks she has
managed it, and they do likewise. Possibly a
book is written about it. Some of the people who
hear about it have a boy straight off, or two boys,
or even three boys, and they think it is a case of
cause and effect. They write and tell her, and she
is confirmed in her opinion. The people who do
not get what they want do not generally bother
to write. You see, we expect on pure chance that
a certain proportion of couples will have three
boys running. You remember that we discussed
all that when we were talking of tossing coins.
One can calculate mathematically what propor-
tion of families of three may be expected to
consist of three boys, when the sex ratio at birth
of the whole population is 105 boys to 100 girls.
57
Biology in Everyday Life
The calculated proportion of all-boy families is
what you would expect on the assumption of
chance coupled with the slight bias in favour of
the male-producing sperm that we have spoken of
already.
If you happen to have six girls and no boys,
you are very likely to think that there is some-
thing peculiar about you that makes you especially
prone to have girls. It is not so. It is exactly
analogous to getting six heads running when you
toss coins. It happens with coins approximately
as often as it happens with babies. If you have
six girls, the chances are still about even what
the sex of your next child will be. Of course, it
may be a girl again. On pure chance we should
expect a minute number of families of a dozen
girls and no boys, if people had families as big as
that nowadays. The unfortunate parents would be
unable to imagine it as a case of chance, but it is
chance all the same.
I can say quite definitely and certainly that
there is at the moment no known method by which
people can influence the sex of the children they
conceive. I repeat that there are all sorts of
superstitions that one can follow, and pure
chance will give the desired result to a certain
calculable proportion of the people who follow
the superstition. The people who get the desired
58
The Determination of Sex
effect will naturally make the mistake of imagining
that it is a case of cause and effect.
Now suppose I said this: "Wear a brass ring
round your little finger, and you will have only
boys." If I said it sufficiently forcibly, probably
lots of people would go off and do it. The next
child would be a boy in about half the cases
rather more than half really, because of the bias
in favour of the male-producing sperms. The ones
who got boys would be very much pleased and
would think me very clever. Roughly half of the
lucky ones would have a boy again at the next
birth, and roughly half of these would go ahead
and have a third boy, unless they stopped having
children. Well, these extra lucky ones would
probably think me a perfect genius, but actually,
of course, chance would have brought about the
result, not the brass ring.
Shall we ever be able to control the sex of our
children ? Of course, I cannot say. I can only give
my opinion, to which I am as much entitled as
the gentleman with the unusual headgear. My
opinion is that it is very probable that we shall.
Someone has got to think out a way of separating
male-producing from female-producing sperms:
that is all. It sounds easy, and it is a thrilling
problem that has attracted a lot of people, but no
one has solved it yet.
59
Biology in Everyday Life
If the female-producing sperms were larger
than the male-producing (and there is some evi-
dence they are), we might one day be able to
make some sort of a filter to separate them. I
have got a large glass tube in my laboratory
reaching from the floor to the ceiling. I fill it with
fluid and put sperms in at the top and wait. Their
weight causes them gradually to sink to the
bottom. I hoped that the female-producing sperms
would sink more quickly than the others, but
nothing came of it. Professor Huxley and I also
tried racing them along horizontal tubes. We
made them all swim towards the same direction
by sending a weak electric current through the
fluid in the tube. Sperms tend to swim towards
the positive pole. We fondly imagined that they
might conveniently sort themselves out into two
groups. The group that got to the pole first would
be the male-producing ones, we thought. But
they did not sort themselves out at all. On the
contrary, they remained in a single group. So that
was no good.
You see, we know how sex is determined by
the sort of sperm that chances to reach the egg
first. But we cannot control it yet. We cannot give
one sort of sperm an advantage over the other. It
is tantalizing to think of two and a half million
male-producing sperms and two and a half million
60
The Determination of Sex
female-producing sperms all swimming about at
random, and the decision being left almost to
chance. It is tantalizing because many people are
desperately anxious to have a child of a certain
sex, and there are millions of the right sort of
sperms there, but we cannot control them. If only
we could find out the nature of the advantage the
male-producing sperms have, we might be able
to give them an even greater advantage artificially.
But that is one of the many unsolved problems
of biology.
Only a few months before the publication of
this book two workers in Moscow published a
preliminary note on a method by which they
claim to be able to separate the two sorts of
sperms. They use an electric current, but in quite
a different way from Professor Huxley and me.
I remain sceptical until much larger figures are
available. The results as they stand might be due
to chance. Whether this will really be found to be
a dependable way of separating the two sorts of
sperms or not, I do not know, but I do think it
very probable that one day we shall be able to
separate them. Then what ?
People have often said to me that if we could
decide the sex of our children, nearly everyone
would have boys, and the race would almost die
out. Certainly there would be a chance of every-
61
Biology in Everyday Life
thing being topsy-turvy at first, and for a year or
two we might get some extraordinary sex ratios.
But I don't think it would go on. When Mrs.
Jones and Mrs. Smith and Mrs. Williams and
Mrs. Robinson had all had a succession of boys,
just think what excitement there would be when
Mrs. Johnson went and produced a girl! Girls
would have quite a rarity value. Also I have found
that people in genera] do not really want to have
boys only. Most people prefer a mixed family.
I consider myself lucky because I have got a
girl and a boy. You must not think that I arranged
it. It was chance, as in the case of every human
family that has ever been conceived.
The people who would benefit chiefly from the
power to control the determination of sex would
be people who by chance have had several children
of one sex and none of the other. The nation as a
whole might benefit also, because it is generally
best to have about the same number of men as
women in any non-polygamous country. Although
more boys are born than girls, boys are more
delicate on the average, and men tend to be killed
in accidents more than women and also to die
younger without accidents, so we always have
more women than men, and many women can
never marry. At every age above 1 9 there are more
females than males. In 1921 there were 118
62
The Determination of Sex
women aged 20-24 to every 100 men, and 120
women aged 2529 to 100 men of the same age,
Here are the figures for each of the succeeding
five-year groups: 119, 116, 113, 107, 107, 109,
113, 119. The next group is the age-group 70-74.
Look how the preponderance of women increases
rapidly at these ages: 134, 148, 168, and finally
at ages of 85 and more, 205 women to every
100 men. 1
The State could easily keep the sexes about equal
if it wanted to, if we could control the sex ratio.
It would not be difficult to think out some way
of encouraging people to have children of the
required sex. Control of things that previously
were not controllable is one of the applications of
science. Control of the sex ratio would be just
one example of it. Pure science aims simply at a
description of the universe, but one of the effects
of science is to give us control over nature. We
must think quickly, so as always to be prepared
to use our control in the way that gives the greatest
benefit to the greatest number. 2
1 A. M. Carr-Saunders and D. Caradog Jones, The Social Structure
of England and Wales, Oxford, 1927.
* For a more detailed account of the determination of sex, see J. R.
Baker, Sex in Man and Animals, Routledge, 1926. See also F. Okland,
Is it a Boy?, Allen and Unwin, 1932.
CHAPTER IV
The Quality and Quantity of Mankind
THERE is no evidence that our inborn nature,
bodily or mental, has evolved since the beginning
of civilization. There is no reason why it
should have evolved. Evolution is supposed to
happen in wild life because the ones that chance
to be the fittest to survive are the ones that do
survive. We know that vastly more young are
born in every species than grow up and reproduce
their kind. On the average it will be the ones that
happen to be well equipped for the battle of life
that will survive. The young ones may inherit
the advantages that ensured their parents'
survival.
In social animals this survival of the fittest does
not act so much on the individual as on the herd.
When a herd is attacked, the strong and brave
members of it are more likely to be killed than
the weaklings. An individual which would not be
capable of finding its own food for itself might
easily survive in herds. It would rely on the
leaders to bring it to good pastures. Survival of
the fittest would apply rather to the fittest herd
than to the fittest individual. Weaklings could be
64
The Quality and Quantity of Mankind
tolerated until they seriously undermined the
efficiency of the herd as a whole: then the herd
would tend to get wiped out as a whole, from
attacks of enemies or inability to find food.
I think that if we remember this, we may find
a clue to the meaning of polygamy. In many social
animals the males have several wives. The sexes
are about equal in numbers, so of course many
males get no wives. That seems a bad arrange-
ment, but is it really bad ? The males fight together
for the possession of the females. You see that in
many sorts of social animals deer, for instance,
or seals. It is only the brave and strong ones that
can mate and have young. The weaklings in the
herd are tolerated, but in the polygamous species
they do not have any young, and so they do not
transmit their weakness to offspring. I think that
that must be partly why polygamy is much
commoner in animals that live in herds than in
animals that do not. But there are exceptions to
everything in biology, and the wild-duck is
strictly monogamous when living a wild life,
although it is a social animal, and the lion is
sometimes polygamous, although it does not live
in herds. We must take full account of these
exceptions, but nevertheless we can see that social
janimals would gain a certain advantage from
'polygamy. It would help them to avoid the one
E 6 S
Biology in Everyday Life
great disadvantage of social life to the species,
the preservation of the unfit.
What is the primitive condition of mankind
as regards marriage ? Was he polygamous, or did
he stick to one wife in prehistoric times, when he
was just emerging from his ape-like ancestry? I
do not know and nobody else knows, but there
are many anthropologists who think there was
what is called "group marriage", the mating of
several people of one sex with several of the other.
There is a good deal of evidence for it, mostly
derived from a study of primitive people living
in various parts of the world to-day. It is largely
based on their having no special word for
"mother". They call their mothers by the same
name as they call all the other women whom
their fathers would have been allowed to marry.
And it is the same with their fathers: they have
no special word for them. The evidence is most
ingenious, but I doubt whether it is conclusive.
I think I am right in saying that no animal
practises group-marriage. Now polygamy is very
widespread in social animals, and man is a social
animal, and many races of man are to this cfay
polygamous. It may be the natural condition.
When reason replaces custom, the habits of
mankind are changed ; and in the highest civiliza-
tions monogamy has replaced polygamy, probably
66
The Quality and Quantity of Mankind
because of the trouble that is caused if there are
a lot of unmarried men about. Civilized men do
not want to be fighting all the time, and the
natural tendency of polygamy is to make men
want to fight for wives, and the ones who do not
get any will be discontented. Also polygamy puts
women into an undeserved position of inferiority,
so that there are good reasons for encouraging
monogamy. But there is one evil result. Since all
males may marry and have children, the one great
disadvantage of social life is encouraged: the
weakling, who is preserved by the herd as a whole,
may reproduce and transmit his undesirable
qualities to his offspring; and the herd will take
care of those too.
It is instinctive in social animals to look
after and protect feeble members of the herd.
It is primarily an instinct to protect the young
and the females, I suppose, but anyhow there
must be this general altruistic defensive instinct
in any herd, and it may extend to any member
of the herd who is in difficulties. I used
to have a cocker spaniel who had an extra-
ordinarily strong instinct to protect my wife
from strangers, and often he was very much
worried if I played at all roughly with her. He
thought she was being attacked, and he was on
the defensive for her.
67
Biology in Everyday Life
Among ourselves we call this instinctive
altruism "humanitarianism". It is quite neces-
sary for our life as social animals. People differ
extraordinarily in the amount of sex instinct and
self-preservation instinct that they have got, and
it is the same with the humanitarian instinct.
Some people suffer nearly as much from seeing or
thinking of other people suffering as from suffer-
ing themselves. Other people seem scarcely
affected by other people's sufferings. Obviously
some sort of mean between the two is desirable.
The anti-humanitarian the person who does not
feel for others at all cannot help it any more
than a man who is devoid of sex instinct: but he
is quite unsuited to social life. The person at the
other extreme lacks the amount of hardness that
is often necessary for decisive, courageous action,
and also he is not necessarily the person who
actually does most to prevent suffering.
This is the whole burden of what I want to say:
normal people instinctively want to help the weak
members of the community, but the result of this
is that the weak members of the community
survive and transmit their weakness to their
children. So we are in a dilemma: what shall
we do ?
First of all, let us find out who are the weak.
There are quite a lot of people who think that if
68
The Quality and Quantity of Mankind
only all the people who call themselves "upper-
class" it really means just the rich people
were to have lots and lots of children, and if only
all the poor people were to have very few, we
should be all right as a nation. Now that pre-
supposes that the rich people are rich because
they possess some inborn superiority over poor
people. Well, do they? That is the first problem.
So far as physical characters are concerned,
there is a big average difference between rich
and poor people. Rich people are on the average
considerably taller (though, of course, there are
plenty of tall poor people and short rich people).
Someone measured the schoolboys aged 14 in
Liverpool. 1 The average measurement at a second-
ary school was 5 feet 2 inches ; at a council school
in a poor district it was only 4 feet 7 inches. Pro-
bably these physical differences between the
classes are caused largely by differences in the
food of the growing child.
What about intelligence? That is a much
harder problem. Is there any difference between
the various classes in their inborn intelligence?
How shall we find out? Obviously it would not
be any good to test people in Latin to find out.
The children of the professional classes usually
learn Latin, and the children of labourers usually
1 A. M. Carr-Saunders, Eugenics, Williams and Norgate, 1926.
6 9
Biology in Everyday Life
do not, so we could not find out anything about
intelligence in that way. Obviously our tests must
not deal with subjects which are taught to one
class and not to another. So far as possible they
must not give an advantage to any special class.
For instance, it would not be fair to ask, "How
can one live on 155. q.d. a week?" because a rich
person would not have the slightest idea, however
intelligent he might be.
The best tests are not perfect, but they do try
so far as possible to avoid giving any benefit to
people with special environments. There are tests
for every age from 3 to 1 6. It has been found
experimentally how hard each test must be for
the average person of each age to be able to pass
it, but not to be able to pass the test for the next
higher age. The tests do not generally go farther
than 1 6, because our intelligence does not seem
to increase after 16. Of course, we go on getting
more and more experience, but we do not get any
more intelligent. I must admit, though, that some
experience of life is quite essential to doing most
of the tests.
Here are a few examples from Terman's tests. 1
Here is one for age 16. "Define the difference
between character and reputation." I hope I
1 R. Pintner, Imclligence Testing Methods and Results, University
of London Press, 1924.
70
The Quality and Quantity of Mankind
agree with Mr. Terman on that. Here's one for
age 12. "What similarities are there between
wool, cotton and leather ?" Here is one for age 10.
"Why should we judge a person more by his
actions than his words?" One feels glad that one
is not 10! Now age 3. "Repeat six or seven
syllables, such as: 'I have a little dog'." Each test
consists of a number of most varied questions.
Idiots are people who never arrive at the
mental age of 3. Imbeciles are grown-up people
who pass the test for the mental age of 3 with
flying colours, but fail at the test for 8. The
Americans have a special word for people who
can do tests for children of 8, but cannot do tests
for children of 11. They call them "morons".
The word "feeble-minded" is a general one for
people whose intelligence fails to develop, so that
their mental age is that of a child.
A couple of investigators gave tests to 548
children in American schools. They found the
average marks obtained by the whole group. Then
they grouped the children according to the class
their parents belonged to professional, executive,
artisan or labourer. They found that 85 per cent,
of the children of the professional classes got
more than the average marks; 68 per cent, of the
children of the executive class got more than the
average marks; only 41 per cent, of the artisans'
Biology in Everyday Life
children and 39 per cent, of the labourers'
children got more than the average. A good many
other people have made similar tests elsewhere.
Someone found that 60 per cent, of the profes-
sional class children got more than average marks.
The figure for labourers' children was 47 per
cent.
The general conclusion to be reached from a
study of the results of these intelligence tests is
this. High and low intelligences are distributed
among every class of the community, but there is
a tendency for people of high intelligence to be
rather more abundant in the professional class
than in the labouring class. Of course, the feeble-
minded will usually tend to find their way into
the poorest classes, and thus bring down the
average of the intelligence of the poorest classes,
however intelligent the people may be whose
poorness is due to accident of birth.
The general conclusion which I reach is that
it does not matter very much, in the present
circumstances, from what class of the community
the next generation is chiefly derived, but the
average innate intelligence would probably be
somewhat higher if it were derived largely from
the professional classes and somewhat lower if
derived largely from the labourer class. But in
any class we could find an abundance of people
72
The Quality and Quantity of Mankind
of the highest inborn intelligence who would be
the most suitable parents of the next generation.
Any class could provide such people, but there
would be a somewhat higher proportion of them
in the professional class than elsewhere.
At the present time the professional classes
have, on the average, considerably fewer children
than the poorest people, and this is probably not
in the best interests of the country. If the pro-
fessional classes consisted simply of the people of
the highest inborn intelligence, then it would be
a tragedy for the nation for them to reproduce
most slowly of all: but it is not so. It could only
become so if everyone were given an equal chance
of becoming a member of the professional class.
It is possible for the children of very poor
parents to get the best possible education, if they
are lucky and intelligent and precocious, but it is
difficult. Think how easy it is for the children of
rich parents ! They can get a University education
without any effort unless they are fools, and then
they can pass on to a profession, Think what
thousands of others are equally well equipped
mentally, but have no possible chance of making
the fullest use of their brains 1 What chance has
the child of a poor man to become a doctor or a
lawyer ?
So long as we make it very difficult to pass from
73
Biology in Everyday Life
one class to another, it does not matter very much
which class reproduces most rapidly. Now we
must revert to a matter we have discussed before,
the herd instinct. The normal herd instinct in
animals acts for the benefit of the herd as a
whole, but among men an extraordinary per-
version of the herd instinct has arisen. People's
sympathies tend to be for those other people who
have about as much money as they have them-
selves, and they transfer their herd instinct just
to that group or class, and tend to be suspicious
of other classes. People often pretend to a great
patriotism, but (except perhaps in times of national
emergency) the class feeling is a much more real
thing than the unperverted instinct, which is a
feeling of sympathy with other people of one's
own race as a whole. It is this strong class feeling,
which I regard as a perversion of the herd instinct,
which prevents the best brains from getting
surely to the top.
If we really wanted above everything else that
our race should flourish, we should give everyone
a really equal chance to succeed, and should see
to it that the people who had the highest inborn
intelligence and energy were the ones who were
actually doing the work requiring the most brains.
Having found those people, we should encourage
them to have as many children as would be con-
74
The Quality and Quantity of Mankind
sistent with the mothers' and children's health
and welfare. The people who were inferior we
would encourage to have few children. That
would be true patriotism, something very different
from the flag-waving and anti-foreign propaganda
which now flourish under that name.
I have mentioned that people of the professional
classes have on the average considerably fewer
children than poorer people. On the whole there
is a tendency in England and many countries for
people to have fewer children the richer they are.
Why is this? It was not so a century ago. There
seems to be little doubt that it is due to their
using birth-control methods. It seems probable
that the majority of couples among the rich and
in the professional classes who are not sterile use
some form of birth control. Poor people have less
money to buy books about the subject, and in
various ways their poverty disqualifies them from
making use of the information.
To understand problems of birth control it is
essential to remember that our inborn instincts
and natural fecundity are unlikely to have changed
since the times of our ape-man ancestor. Evolu-
tion probably only occurs as a result of the
survival of the fit, not as a result of the survival
of the offspring of those who have less sex instinct
and less natural fecundity than their neighbours.
75
Biology in Everyday Life
We are therefore still adapted physiologically to
the production of vastly more children than is
now necessary. We have lowered our death-rate
since those ancient times, and it is still falling.
If we were to keep our birth-rate at the old figure,
we should become seriously overpopulated. There
is some likelihood that Great Britain is already
overpopulated: I mean that we should have a
higher average standard of living if we had fewer
people. Economists generally fail to take sufficient
interest in population problems. They would like
to be clever enough to arrange a policy that would
result in everyone having sufficient of the good
things of life, whatever the population. As a
biologist, I look at the matter differently. I should
like to see our birth-rate controlled so as to give
the highest possible average standard of living.
Most people who use birth-control methods
probably do so without any particular thought of
the State as a whole. They are concerned with the
health and happiness of the mothers and children
concerned. A mother's life may be rendered
almost intolerable by pregnancies following one
another in quick succession, and there is evidence
that children tend to be healthier when they are
not born in quick succession. In poor families the
birth of each child reduces the standard of living
of the others.
76
The Quality and Quantity of Mankind
It is questionable whether very poor people,
who cannot support large families, should be
encouraged to have them. Every living man,
woman and child has a right to work or full
maintenance in any civilized state, and in the
same way it may be argued that people have a
duty to the State not to produce children which
the State has to support, if the State is already
overpopulated.
Perhaps in the distant future we shall have a
Ministry of Population. Its job will be to
estimate the best population for the conditions,
and to devise means of securing a decrease or
increase of the birth-rate as required. If the
politicians make the conditions different, the
Ministry of Population will have to adjust the
population.
At the present moment there is no Ministry of
Population, but the Ministry of Health allows
Local Authorities to run birth-control clinics.
Forty-one local authorities either have already
established special clinics, or give birth-control
information at gynaecological clinics, or refer
cases to voluntary clinics or to private doctors,
or authorize their medical officers to give advice.
Nine others have decided to give birth-control
advice, but have not started yet. Three others
have lent premises to the National Birth Control
77
Biology in Everyday Life
Association for use as voluntary clinics. These
figures come from the secretary of the Association.
Voluntary clinics are run by this Association and
also by the Constructive Birth Control Associa-
tion and by the Society for the Provision of Birth
Control Clinics.
It is important to realize that in this country
birth control is perfectly legal. It is legal to make,
advertise, sell and use contraceptives.
So far there has been little laboratory research
on the subject, but things are moving forward.
The Birth Control Investigation Committee is the
body that organizes the laboratory research, and
I am one of the workers under it. At present the
birth-control methods are not absolutely reliable.
No method can be countenanced that is harmful.
The possibility of harmful effects is being investi-
gated under the auspices of the Committee. The
harmfulness of contraceptives has been made
much of by people who could not tell a damaged
tissue from a normal one, if provided with a
perfectly good microscope and a perfectly good
microscopical section of the tissue. Certain methods
have been found to be quite harmless.
We have seen that it probably does not matter
tremendously what class of people reproduces
most, so long as we go on making it difficult for
people to rise from one class to another. But,
78
The Quality and Quantity of Mankind
apart from classes, is there any sort of person who
ought not to reproduce ?
To that I answer, " There certainly is." The
congenitally feeble-minded person should not have
children. If a normal person becomes feeble-
minded as a result of a blow on the head, it does
not matter if he or she reproduces, because the
children will not inherit the defect; but if a
person inherits feeble-mindedness, he or she will
transmit it to descendants. We must distinguish
between inherited and non-inherited feeble-
mindedness. Goddard found that 54 per cent,
of the feeble-minded people he studied had
feeble-minded relations. Whole families of people
have been studied in detail by Lidbetter, showing
this feeble-mindedness in generation after genera-
tion. There are notorious families in America in
which feeble-mindedness has been passed on
unceasingly. People sometimes argue that one
cannot define the symptoms of inherited feeble-
mindedness in such a way as to distinguish it
from accidental feeble-mindedness, and there-
fore there is no such thing as inherited feeble-
mindedness. That seems to me a poor argument.
It fails to take account of something that is
common knowledge to biologists that a character
may be affected in the same way by inheritance
as by environment,
79
Biology in Everyday Life
The inheritance of congenital feeble-mindedness
is not absolutely understood, but one form of it
behaves like what is called a Mendelian recessive.
That means that a person can suffer from it
although neither of his parents did, and he can
transmit it to his descendants, though not neces-
sarily to his sons or daughters. Also it means that
it is particularly likely to appear among the
children of cousin marriages. If two feeble-
minded people marry, all the children are likely
to be feeble-minded. Sometimes all the children
are not feeble-minded, and then people with a
little knowledge of biology think that we really
know nothing about the inheritance of it, because
it does not fit in with simple Mendelian schemes.
A little learning is a dangerous thing. It is not
difficult to account for such cases, if one has an
adequate knowledge of the laws of inheritance.
There is a good deal of evidence that the
feeble-minded are increasing in numbers in this
country. They are careless of the consequences of
their actions, and they reproduce rapidly. They
appear to be a real danger to the State. They are
the weak members of the herd. So now we are
really back at what we were talking about at the
beginning. The weak members of the herd in a
polygamous species are protected and led to good
pastures, but the weak males do not reproduce.
80
The Quality and Quantity of Mankind
Polygamy sees to that. We are not polygamous,
so we must take other steps to prevent the repro-
duction of the congenitally unfit. Men may be
sterilized quite simply. This is a small and simple
operation. A general anaesthetic is not required.
A local one suffices. It is a fact that most people
have not the slightest idea what the sterilizing
operation is. They imagine it to be the same as
castration, the operation carried out on male farm
animals which are not required for breeding. It
has nothing to do with that operation. That
operation removes the sex instinct and changes
the bodily growth of young animals. The steriliz-
ing operation has no such effect. If a man were
to be sterilized without being told what was being
done to him, he would continue with his ordinary
married life without the slightest idea that any-
thing had happened to him. He would be sur-
prised to find that he had no children.
It should be made legal for any congenitally
feeble-minded man to be sterilized if he agrees to
it himself, if his wife agrees to it, and if the Board
of Control gives consent. It is not proposed that
anyone should be sterilized against his will, if he
is sufficiently intelligent to express his will.
For women the sterilizing operation is a major
abdominal operation, and I am doubtful whether
we should be justified in encouraging anyone to
F 81
Biology in Everyday Life
undergo that except for reasons of personal
health. What is wanted is some more research
into simple ways of sterilizing women. The
trouble with feeble-minded people is that they
are too careless to use birth-control methods.
Some people think that those who ask for the
legalization of sterilization are anti-humanitarians,
who want to attack the weakest members of the
community. It is not so. The legalization of
sterilization would be most humane, because it
would prevent the birth of people who cannot
hope to live really happy and useful lives.
The newspapers are filled with politics, politics,
politics: chiefly flag-waving and class war! Just
occasionally a little paragraph is hidden away
somewhere dealing with the really live issues
that we have discussed in this chapter. We could
cut out class war. We could make sure that talent
always rose to the top. We could encourage the
reproduction of the best stocks and prevent the
reproduction of the unfit. We could make sure
that the population of the country was adapted
to its needs, and that mothers could always space
births to the greatest advantage of their children
and themselves. Any nation which decided on that
course of action would rise supreme.
Shall we continue just to muddle along anyhow?
Probably we shall.
82
CHAPTER V
War, Disease and Death
"WAR is a biological necessity/' We have all
heard that. At least, I confess I have not ever
heard a biologist say it, but it is pretty generally
accepted by lots of people, and it sounds learned.
Let us examine it. What is at the back of people's
minds ?
I think it all comes from the struggle for
existence and the survival of the fittest. We know,
of course, that even the slowest breeding animals
produce far more young than can ever grow up
and themselves reproduce. There must be a con-
tinual struggle to obtain a sufficiency of food and
to avoid carnivorous enemies. Only the larger
carnivores are free from any obvious attack. There
is no animal that attacks them offensively, though,
of course, the larger vegetarian animals will use
all their strength in defending themselves against
them. I say they are free from obvious attack,
because of course they are not free from the
attacks of parasites.
Almost every animal one sees has its parasites.
A favourite question in examinations for zoology
students is the removal of the parasites from a
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Biology in Everyday Life
frog. One need not bother to ask oneself whether
the frogs one supplies to the candidates have got
any parasites. They are all stuffed with them, in
lungs, intestine and bladder. I have never come
across an earthworm in which I could not find
parasites. Wild mice are usually parasitized by
fleas, and ticks are found on the skin of all sorts
of beasts. Bats are often crawling with curious
parasites. Birds have special insects living beneath
their feathers.
Obviously or not obviously, a great struggle
for existence goes on in nature. Carnivorous and
parasitic animals are utterly ruthless as to the
suffering they cause (although, as we shall see
later, it is generally not to the advantage of
parasites actually to kill).
The struggle goes on everywhere, but is it war ?
What is war ? I think it is impossible to speak of
war except in a social kind of animal. It is a fight
between one herd and another herd of the same
kind or a closely allied kind.
Now let us review the whole animal kingdom
and describe all the wars the different social
animals have. Let us go right through all the
different social mammals first of all, the ones I
mentioned in the second chapter: the marmots,
beavers, vizcachas, horses, deer, oxen, antelopes,
sheep, goats, porpoises, dogs and wolves, seals,
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War, Disease and Death
fruit-bats and social monkeys. Let us describe the
different sort of war each kind goes in for how
they fight herd against herd amongst the same
kind the weapons and tactics they use, the
biological significance of the whole thing. Shall
we go right through that ? All right.
It is a simple task, I am glad to say. War, as I
have defined it, is simply non-existent in the
animal kingdom, except possibly in the slave-
making ants. Elsewhere, throughout the whole
animal kingdom, 1 there is nothing remotely
resembling war: and even in ants it is not really
war according to our definition, because there are
not fights between different nests of the same
species or of closely allied species. So far is war
from being a biological necessity that it is practi-
cally biologically unknown except among human
beings.
We must regard all races of man as being
of the same kind or species, because a person
of any race can marry one of any other race
and have children who are themselves perfectly
fertile, so far as is known. That is the only
criterion of a single kind or species that we
have that is of any value, though I admit it is
not perfect.
In social animals, each herd has its own
1 One hive of bees sometimes attacks another.
85
Biology in Everyday Life
territory, and it never invades the territory of
other herds. The territory instinct is extra-
ordinarily strongly implanted in animals.
Take the antelopes, just as a random example.
The feeding-ground of each herd is sharply
marked off. A herd never invades another herd's
territory. Occasionally a few individuals may
trespass across the boundary, but they are at once
driven away, and they give the appearance of
knowing that they are in the wrong, for they will
not fight to maintain their position, as they would
unhesitatingly if they were on their own ground.
The dog is an example familiar to everyone. For
the domestic dog his master's house and garden,
if he has got one, represent the territory of the
pack of his ancestors. A dog that never fights
in the street (that is neutral territory) will fight
ferociously if another dog happens to stroll in
through the open gate. The dog that strolls in
knows that he is in the wrong, and generally
escapes as soon as possible, even if he is a bigger
dog and ordinarily more ferocious.
There is one antelope in particular that gives
a splendid example of respect for the territory of
others. 1 The springbuck of Bushmanland is a
little yellow-coloured antelope similar to a gazelle,
but differing in having a white stripe along the
1 See Heape, quoted in footnote to p. 45.
86
War, Disease and Death
middle of the back over the haunches. Males are
about thirty inches high at the shoulder. The
springbuck lives in almost desert country. Like the
lemming, it has periods of increased population
during which starvation is threatened. At these
periods, like the lemming, it emigrates. There are
fertile areas all round except to the west, but they
are occupied by another race of springbuck and
by other kinds of antelopes. The springbuck of
Bushmanland, although starving, does not go
north or east or south. He could find plenty to
eat there, but the ingrained instinct not to invade
occupied territory is too much for him. He goes
west in every sense of the term. He loses all his
natural timidity and marches in enormous herds
over country in which he cannot live towards the
sea. If he comes to a village, he sweeps through
it as though no longer afraid of man. The
advancing army may be several miles wide and
over forty miles long. It streams onwards, some-
times crossing rivers. At last, after a march of
about two hundred miles, it reaches the sea. All
plunge in and are drowned. None return. To the
springbuck this mad useless emigration is pre-
ferable to an invasion of occupied territory.
We reach this conclusion: herds of social
animals have their own territories, and never start
aggressive wars against other social animals of
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Biology in Everyday Life
the same or closely allied species. If there is
any individual trespassing, there is a strong
defensive instinct which causes the trespasser
to be ejected.
I speak purely from the biological and not in
the least from the military point of view when I
say that to resist trespassing on one's own territory
is probably instinctive and natural, while there is
no biological basis for aggressive warfare. Mili-
tarists sometimes think it necessary to carry out
operations outside the home country in order to
defend the home country, but in so doing they
cannot rely on instinctive support from the people
of their country; but when their country is
actually invaded, then instinct probably prompts
resistance.
When we consider man's nearest allies among
animals, we find that the male is commonly larger
than the female, and the significance of this greater
size is that he has an instinct to protect his wife
and family. It would be useless to be bigger and
stronger if there were no such instinct. The
difference in size is not great in the orang-utan
and chimpanzee, but it is very great in the gorilla.
There is of course a considerable average dif-
ference in size between the sexes in mankind,
and one cannot fail to appreciate its significance.
Men are almost certainly more innately ferocious
War, Disease and Death
than women. Women seldom really like having a
good row with one another. However much they
may like making what are called "catty" remarks
in the absence of the person they dislike, they
very seldom show their dislike openly to the
person concerned. Now that is just what many
men do like doing. I have often thought what a
lucky thing it is that the differences between the
sexes in mankind are so small compared with the
differences one finds in many kinds of animals.
Think what life would be like if men were as
innately ferocious as bulls or male mandrills ! We
are spared that, but it is nonsense to pretend
that the two sexes are exactly equivalent as regards
the instinct to fight when annoyed.
I conclude that most men would find themselves
almost driven by instinct to fight if their own
territory were invaded by hostile foreigners, how-
ever much opposed to war their reason might
tell them to be. Even the Oxford Union would
be less pacifist in the presence of an invading
army.
I have enormous sympathy with pacifists, but I
think they tend to overlook men's innate instinct
to protect their own territory. I am not saying
whether it is a good instinct or a bad instinct:
I am only saying that the instinct probably exists.
When people try to overcome instincts, they
Biology in Everyday Life
generally have no success with the great majority
of normal people. The medieval Church tried to
overcome the sex instinct, and a few people still
leave the world for monasteries and nunneries:
but the race continues to exist. I often find that
pacifists regard non-pacifists with something like
horror. They would get a much more sympathetic
hearing if they were more sympathetic themselves,
and realized that the man who is prepared to fight
for his own territory is probably only obeying his
instincts in the same way as he does when he
marries and has a family or refrains from walking
about in woods alone at night.
As for the aggressive militarist the man who
wants his countrymen to fight abroad to increase
his territory he cannot pretend that it is likely
that there is any innate instinct to do that, as
no animal does it, and we have no knowledge of
any human instincts which do not occur also in
animals.
That is enough about war. We have still two
equally cheerful subjects ahead of us, disease and
death.
Obviously I am not going to look at disease
in the ordinary way. You would have to get a
medical man to do that. I want to look at disease
from a biological point of view. We have seen
that carnivores and parasites are absolutely ruth-
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War, Disease and Death
less : it is all part of the never-ending struggle for
existence. It does not matter to a parasite whether
it makes the animal it lives on ill or not: its own
survival is all that matters to it. Parasitic life has
its obvious advantages: the parasite has not got
to go searching for food. A flea can eat whenever
it wants to. Nevertheless parasites are up against
one big difficulty. It does not matter to them
how much illness or pain they cause : but if they
kill the animal they live on, then there is trouble.
It usually means the death of them also.
Suppose a man has got malaria. That means
he has got some little single-celled animals inside
his red blood-corpuscles. So long as he goes on
living, these malaria germs are all right. Every
now and then he may be bitten by a malaria
mosquito. The mosquito sucks up some of the
germs and infects somebody else with them later
on. That is all right for the malaria germs. But
suppose the malaria germs go and kill the man.
What advantage do they get out of that? None
at all. On the contrary, the result is that they all
die themselves. That is why the vast majority of
parasites do not kill the animals they live on:
it would be death to themselves. In the course of
evolution they will become better and better
adapted to the animals they live on. They will
avoid the most vital organs, and will not produce
9 1
Biology in Everyday Life
any deadly waste products. It is generally only
the maladjusted parasites that kill, the ones that
have not yet become adapted to their hosts nor
their hosts to them. Also death of both often
occurs if a parasite happens to get into the wrong
animal, because then neither is adapted to the
other. In continental countries men are to some
extent adapted to the influenza germ, and influenza
is not usually a very serious illness ; but influenza
is not a disease that occurs naturally in the western
Pacific Islands, and the Melanesians are not
adapted to it. The result is that if someone goes
to those islands with influenza, the natives catch
it and die off like flies.
Sometimes it does not matter to a parasite if it
kills its host in the end. There are animals called
ichneumon flies that lay their eggs in or on the
caterpillars of other insects. The eggs develop into
caterpillars which live inside the other caterpillars
and gradually eat them up. If they started eating
the brain, their hosts would die, and they would
die too as a result: so at first they only eat the
less essential organs. Later on they do kill their
hosts, but only when they are just ready to come
out and change to the chrysalis stage. They do
not eat in the chrysalis stage, so it does not
matter that they have killed their hosts.
There are just a few parasites that must kill
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War, Disease and Death
their hosts for their own good. 1 These are
microscopic animals that live in the muscles of
fishes. They cannot get out through any of the
apertures of the body, so they have only one way
of getting from one fish to another, and that is
by the death and disintegration of the one they
are living in. They multiply enormously in the
muscles, and the muscles are used up and the fish
dies. Other fishes accidentally infect themselves
when they come across disintegrated bits of the
dead fish. Nothing of this sort happens with land
animals. With them, death of the host usually
means the death of all internal parasites.
Thus it is not to the advantage of parasites to
kill their hosts in the vast majority of cases. Never-
theless they certainly do often kill them. A tre-
mendous amount of human death does occur from
diseases caused by parasites. What would happen
if we prevented all disease caused by germs or
parasties of every sort ?
Suppose a very rich man in good health thought
that the most worth-while thing in the world
would be just to go on living. Well, he could get
a special room made for himself, and have it
sterilized so that it did not contain any germs.
He could go through a course of treatment to
1 E. A. Minchin, An Introduction to the Study of the Protozoa, Arnold,
1912.
93
Biology in Everyday Life
make sure he was free from all parasitic disease.
Then one day he could have the surface of his
body sterilized and with all the necessary pre-
cautions he could enter his room. Only sterilized
air would be allowed to enter the room. Nearly
all his food would have to be cooked to prevent
germs from getting in with it. Special precautions
would have to be taken in introducing those
vitamins that are destroyed by cooking. Double
doors would have to be used for introducing any-
thing into his room or removing anything from
it; and when things were being introduced, it
would be necessary to leave them for a bit between
the double doors and meantime have the air
between the doors sterilized. The man could only
open his inner door when that had happened.
With some such arrangement as this it would
be possible for a man to make sure that he
did not die of infectious disease. Would he live
for ever, or is there such a thing as natural death ?
In the young embryo, the cells that compose
the body are not specialized for their various
jobs. As the body grows up, they become special-
ized in various ways, some as nerve cells in the
brain, others as digestive cells in the intestine,
and so on. As they become specialized, they lose
their power of living. Irreversible changes tend to
occur in them, which finally result in their death.
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War, Disease and Death
Now this is the interesting thing: if you can
change them back to their embryonic, unspecial-
ized condition, you can give them a new lease
of life. The length of time they have existed does
not matter, if you can do that.
With flat-worms you can do that. If you put
some meat in an open bottle and leave the bottle
in a pond for a few days, you will probable find
some flat-worms in it. An ordinary sort is about
an inch long when fully grown. In time it would
die in the ordinary course of events, but if you
put it in perfectly clean water and do not feed it,
a very remarkable thing happens. 1 It uses up its
own substance as food, and gets gradually smaller
and smaller, until it is only a quarter of an inch
long, and narrow in proportion. This is the
interesting thing: the cells have become un-
specialized, almost embryonic, the cells of a
young animal. Of course, you could starve it to
death : but if you now start feeding it, it grows
and develops like a normal young flat-worm.
You have given it a new lease of life. When it is
full-grown, you can do the same thing again,
and so on repeatedly.
There is another way in which you can make
cells become embryonic and so give them a new
1 Child, Senescence and Rejuvenescence, University of Chicago Press,
95
Biology in Everyday Life
lease of life. If you cut the hinder four-fifths off
a flat-worm, and keep just the head end, some of
the cells of the head end become embryonic and
start dividing and give rise to the whole of the
missing part. When that has happened, you can
do the same thing all over again, and again and
again. It has been done thirteen times, and then
the animals were only killed accidentally. One
can certainly rejuvenate the cells of flat-worms.
The trouble with the higher animals is that
you cannot rejuvenate the nerve cells, the cells of
the brain and spinal cord. When a nerve cell has
once been fully formed in one of the higher
animals, it never divides again. If it were to
divide, there would be a chance, because cells
commonly get a bit embryonic when they divide.
In other tissues occasional cell divisions occur;
but the cells in my brain are the self-same ones
that will be there when I am an old man, except
for those that have died off before I am old, and
that is a thing that has probably started already,
as I am thirty-two. So far, no one has thought
of any way of rejuvenating old brain cells, or
preventing them from gradually dying off. One
can rejuvenate the rest of the body to some extent
sometimes by giving gland extracts, or by stimu-
lating certain ductless glands to do their work;
but the brain goes on growing old. It is conceiv-
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War, Disease and Death
able that one day someone might find a way of
making nerve cells grow embryonic again.
Natural death in man is probably death from
old age of the nerve cells. Other parts of the
body cannot go on long without the brain,
though the skin does not die instantaneously at
the moment of what we call death, and hair may
continue growing for a bit after heart and lungs
have ceased to act.
Is natural death in the animal kingdom always
the result of the death of nerve cells from old
age? Certainly not. The Mayflies provide an
obvious example.
The nymphs of Mayflies live for one to three
years under water in ponds and streams. One
day, often in May, they come out of the water,
cast their skin twice in rapid succession, and
emerge as finished Mayflies. The finished Mayfly
has only rudimentary jaws, inherited from an
ancestor which used to eat: but they are useless.
It has a mouth, but it is not used for eating. It
has a digestive tube, but it is not used for digest-
ing. It fills its stomach with air and can take in
more or let part of it out. This process seems
to have something to do in an obscure way with
balancing, but it is difficult to see exactly how it
works. Anyhow, it does not eat. It mates, lays
its eggs if it is a female, and dies of simple
c 97
Biology in Everyday Life
starvation of all its tissues. That is natural death
for a Mayfly. Sometimes its natural life in the
adult form is less than a day.
Every law in biology has its exceptions, and
the salmon seems to provide exceptions at every
stage in its career, so I do not pretend to be able
to lay down the law. I shall try to present the
life-history of an average salmon very shortly, to
illustrate this talk about death. There are dif-
ferences of possible behaviour at almost every
stage. 1
Suppose some eggs were laid in gravel in
shallow water in a river last November (1932).
They will have hatched into tiny fishes, what are
called "fry'* by now (spring), and by autumn
they will be two or three inches long and they
will have dark bands and spots on them. These
"parr'* will live this winter and next winter in
the river, but in the spring of 1934 they will
lose their markings and become silvery, and their
tail fins will become more pointed and they
will migrate as "smolts" to the sea during the
early summer. They will then live an entirely
marine life for a bit. The following summer
(1935) they may return to the river as "grilse",
but others will wait until the summer of 1936,
* P. D. Malloch, Life-History and Habits of the Salmon . . ." Black,
1910.
War, Disease and Death
or till the winter ; but perhaps still more of them
will remain in the sea till the spring of 1937.
Then they will come up from the sea to the rivers
to breed, and when they come to a waterfall they
will jump it. They can jump up to as much as
ten feet at a time. Now the whole point is that
from the moment they leave the sea they cease
to feed. Meanwhile their reproductive organs are
growing at the expense of their muscles. In
November or later the females lay their eggs and
the males pour the milt over it. The spent fish
are called "kelts", and thousands of them may
float helplessly downstream with the current and
die. It is usually said that they have died of
starvation, because they have not fed in the
river; but I think the cause of death must really
be largely the sudden change in bodily functions
when the spawn and milt are discharged. The
body is already enfeebled by lack of nourishment,
and now this shock to its system usually kills it,
though some return to the sea and eventually
breed again in the river.
Thus, different animals have different natural
deaths. To keep a salmon alive unnaturally long,
we might try to prevent it from allowing its
reproductive organs to grow. To keep a Mayfly
alive, we should have to devise means of nourish-
ing it. To prolong human life, we should have
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Biology in Everyday Life
to find out how to make the nerve cells embryonic
once more. We have seen, from our study of the
flat-worm, that that is not theoretically impossible.
Lastly, the llama. I should say the huanaco,
because I mean the wild beast, not the tame
variety. He is a sort of humpless camel, and he
lives in the desolate stony plains of Patagonia
in South America. He lives his life in herds, far
from any cover or concealment. When he is
going to die, a strange instinct comes over him.
He makes for a special spot at the southern
extremity of Patagonia. There, on the banks of
a river, are thickets of small twisted trees. This
lover of open plains squeezes himself in under
the branches and deposits his bones with those
of generations of his ancestors. Hudson 1 thinks
it is an instinct inherited from the time when his
ancestors were forest animals which always
retreated to cover when in danger or difficulty.
If so, it is a retained useless instinct like our own
instinct of clinging on tightly with our hands and
even with our toes when we are frightened, which
is quite useless to us now that we no longer live
in trees.
1 See footnote to p. 39.
IOO
By
J. B. S. HALDANE
F.R.S.
Professor of Genetics, University of London
Head of Genetical Department, John Innes Horticultural Institution
CHAPTER VI
Biology and Statesmanship
I LIKE controversy, and I confess I had rather
hoped that Dr. Baker would have given me an
opportunity of smiting him hip and thigh.
Unfortunately I agree with almost everything he
has written. But not quite everything. This is
largely because we have been engaged on different
branches of biology. He knows a lot more than
I do about animals; I know more than he does
about human physiology and about statistics.
Now how can the biologist help the statesman ?
He cannot dictate a policy to him. However, he
can tell him whether certain statements are true
or not; and he can tell him what will be the
consequences of certain actions. But the better
biologist he is the more often he will say "I don't
know". Above all, he can draw the statesman's
attention to certain facts and say, "What are you
going to do about them?", and he can make him
look at old facts from a new angle.
Let me give you an example of what I mean.
What is a successful man? Some people mean a
man who makes a lot of money; others would
say a man who earns the esteem of his fellows,
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Biology in Everyday Life
and is honoured by them. But the biologically
successful man is the man who lives a long and
healthy life, and leaves behind him a number of
healthy children. Now in our society social
success and biological success do not go together.
The well-to-do classes in the towns live longer
than the poor, but they do not have so many
children; and even the richest groups in the
towns do not live anything like so long as the
poor agricultural labourers in the country. That
simple fact shows that there is something pretty
badly wrong with our society. The ambitious and
intelligent men and women deliberately seek an
environment which condemns them to premature
death and sterility. Don't get away with the idea
that our society is peculiar in this respect. In the
Middle Ages the human qualities most admired
were holiness and chivalry. They condemned
their holy men and women to celibacy, and
killed off their knights in war. Of course, sanctity
and chivalry are not strongly inherited, but
heredity probably counts for something in both,
and we can see now that our ancestors did their
best to breed out these qualities. In the same
way we are breeding out the hereditary qualities
which we admire.
The same sort of thing is quite frequent in
nature. Most of our British beetles can fly they
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Biology and Statesmanship
do not fly a great deal, but it is worth their while
to have wings to take them to suitable environ-
ments from time to time. In the island of Madeira
about a third of the beetles are wingless. It would
seem that the advantages of flight are more than
outweighed by the danger of being blown out to
sea. In the same way there is reason to believe
that in our society the feeble-minded are breed-
ing quicker than the rest of the population. What
ought we to do about it? A number of people
consider that the feeble-minded, who are said to
number three or four hundred thousand in
England and Wales, should be sterilized and
prevented from breeding. Sterilization is not, of
course, castration, but in the case of men at least
a trivial operation. Nevertheless it is an interesting
fact that few, if any, of the biologists who have
made important contributions to our knowledge
of heredity have so far supported this programme.
Let us see why not. In the first place feeble-
mindedness is a very difficult thing to define, and
is not strongly inherited. There are cases where I
believe that sterilization would be justifiable. There
is a peculiar and terrible form of cancer called
glioma which attacks the eyes of children in the
first year of their life. Unless one or both eyes
are removed they invariably die, after great
suffering, before the age of six. When patients
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Biology in Everyday Life
who have been saved from death by removing
their eyes have children, the majority of such
children suffer like their parents. Here, I believe,
is a case where sterilization would be justifiable.
So it would in the case of certain other well-
defined diseases affecting perhaps a few thousand
people in the country.
But feeble-mindedness is nothing so definite.
The law defines feeble-minded persons as those
who "require care, supervision, or control, for
their own protection and that of others". I
strongly suspect that I am feeble-minded myself
according to this definition. I never can manage
to pack all the things I need into a suitcase if
I am going away. It may be my collar, my
pyjamas, or my toothbrush that I forget, but
fortunately I have a legally appointed guardian
in the shape of my wife, who supervises my
actions. At present anyone can be certified as a
mental defective on the words of two doctors and
a magistrate, and, since doctors and magistrates
are human, they sometimes make mistakes.
You cannot draw a sharp line, as you can in
the case of some other inborn defects; nor was
Dr. Baker quite correct in suggesting that
feeble-mindedness is incurable. I could give
examples to the contrary, but I would sooner
tell you about my friend Professor X ? who is a
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Biology and Statesmanship
very distinguished Fellow of the Royal Society.
Up to the age of ten he did not learn to talk,
and would have been classified as an imbecile or
an idiot. Then an aunt spent a year or so in
teaching him to talk, and was quite successful.
Or perhaps not quite. He still does not talk as
clearly as he might. He will never get a job as a
B.B.C. announcer. But he can design apparatus
that will solve problems which no amount of
talking would solve. I am glad to say that he
has two fine children.
Again, though feeble-mindedness runs in
families, it is not strongly inherited. Dr. Baker
quoted a statement of a certain Dr. Goddard on
this subject. I feel sure that he has not read
Dr. Goddard's books. Here is a quotation from
one of them, about the parents of a feeble-minded
child: "Both parents are feeble-minded. The
father is very high grade, so that for a considerable
time we were much in doubt as to how to classify
him. His feeble-mindedness takes the form which
makes him noted as being peculiar. He is ignorant,
lives alone, but is a good workman, sober, honest
and industrious. " A good workman, sober, honest,
and industrious, but not good enough for Dr,
Goddard. It seems to me perfectly monstrous that
we should be asked to interfere with our fellows
on evidence of this kind. There are no satisfactory
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statistics about the inheritance of mental defect.
Those which exist seem 1 to show that if we could
prevent all mental defectives from breeding it
would take some centuries to halve the present
proportion of them in our population.
There is another grave objection to a policy of
wholesale sterilization. It would certainly not be
applied impartially as between different social
classes. Let us see how such laws actually work.
John Hill was a labourer with five children in
the American State of Washington. As the
children were half-starved, he stole a number of
hams. He was sentenced to imprisonment for not
less than six months or more than fifteen years,
but the sentence was suspended during his good
behaviour. The judge concluded that the family
was mentally sub-normal, and suggested that
he be sterilized, to which he consented. This may
have been an excellent thing for the human race,
but does anyone suggest that the same thing
would have happened had Mr. Hill been the son
of a millionaire ?
The programme of the party now in power
in Germany includes a number of so-called
eugenic measures, intended to check the breed-
ing of various types of defectives, and of
1 I hope that further research may demonstrate that such
measures would be more effective.
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Biology and Statesmanship
persons who are not of "German race". As
they describe people who do not share their
political opinions as defective "minderwertig" is
the word it would seem that a large proportion
of the German people is regarded as biologically
undesirable. In England self-styled eugenists have
attacked poor relief, and transitional benefit for
the unemployed, on the ground that this class is
on the whole congenitally inferior. Now it seems
to me that the danger of multiplication of the
mentally defective is a real one; but there is a
much more pressing and immediate danger. And
that is that people of whom Governments do not
approve should, on eugenic grounds, be sterilized,
segregated or starved. To my mind the attempt
to justify such measures on biological grounds is
a prostitution of science, far more serious than
the manufacture of high explosives, bombing
aeroplanes or poisonous gases. We biologists
cannot prevent statesmen from doing these things,
but we can most emphatically protest against
their being done in the name of biology, and
in countries where speech is still free we
can warn the public against this misuse of our
science.
The same sort of pseudo-scientific propaganda
goes on about race. It may be that negroes are
congenitally inferior to whites, or Italians to
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Swedes, but there is no scientific evidence for this.
If you could suddenly exchange all the babies in
a Kentish village and a South African kraal it is
quite likely that the standard of civilization in the
village would go down, and that in the kraal
would go up. But I don't know; nor does anyone
else. Studies of whites and negroes living side by
side under like conditions on a West Indian
island showed no great differences in intellectual
endowment between the two. In most countries
the negroes enjoy far worse social and educational
advantages than the whites, and no fair com-
parison can be made. If you want to see which of
two cows gives most milk you put them both in
the same field; you don't put one in an English
meadow and the other on the African veldt. So
with men and women.
There is one more reason why a eugenic pro-
paganda which seeks to check the breeding of
certain classes is a little misleading. The popula-
tion in this country is still rising, but fertility
has fallen so greatly that it will soon begin to
diminish. If you take a hundred new-born English
girls and assume that fertility does not fall any
farther (which it almost certainly will), you find
that, on the average, they will only have about
eighty daughters, twenty less than are needed
to keep the population steady. Even if medicine
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Biology and Statesmanship
were so perfected as to abolish all deaths under
thirty, the population would still diminish.
Now it may be that this country would be
better off with a somewhat smaller population,
but it is fairly clear that the immediate problem
is rather to encourage the propagation of the
desirable majority of the nation rather than to
discourage that of the undesirable minority. The
drop in fertility is not wholly, perhaps not mainly,
due to birth control by contraceptives. It has
occurred in Italy where contraceptives are effectu-
ally forbidden by law, and in Bavarian villages
where they are forbidden by religion, as well as
in England. Too many of our supposedly advanced
thinkers are still thinking in terms of twenty years
ago, when fertility was very much higher.
Now this does not mean that nothing should
be done to deal with mental defect. The first
thing needed is a proper study of it. Think of
eye defects causing weak sight. Some are con-
genital, some acquired; some can be remedied,
some cannot. But because short-sight is hereditary
in some families we do not suggest that short-
sighted people should be sterilized. We realize
that they should wear the right kind of spectacles.
A proper study of mental defect would perhaps
show that some kinds are incurable and strongly
hereditary. If so, there would be a case for
in
Biology in Everyday Life
sterilization of sufferers from those particular
kinds. But it is as unscientific to lump all sorts
of feeble-mindedness together, and treat them
alike, as it would be to lump together all kinds of
weak sight.
What more general eugenic measures could a
statesman take ? Beyond question the most imme-
diately important eugenic measure is to avoid
another war. There may be ethically justifiable
wars I personally think there are but there
are assuredly no biologically justifiable wars. In a
modern war the heathiest young men in each
fighting nation are killed off. The unhealthy
remain behind and beget the next generation.
War is a far more serious evil from the eugenic
point of view than the multiplication of mental
defectives.
Secondly, a eugenical statesman would take
steps to raise the birth-rate among all classes
except the mentally or physically defective. One
main reason for the falling birth-rate is probably
that children are felt as an economic burden.
This is inevitable under our present economic
system. An institution such as hereditary wealth
is clearly unsound biologically. For the fewer
children you have the more you can leave to
each. Moreover, childlessness is rewarded by a
rise in the social scale. A man with no children
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Biology and Statesmanship
or one is likely to save money; a man with ten
cannot do so. Apart from luck, there are two keys
to economic success, namely ability and sterility.
So long as this is so, ability will tend to marry
sterility; and able people to have fewer children
than simpletons. The only cure for this state of
affairs is some form of endowment of motherhood.
I welcome the coming fall in our population
because it will probably force the Government
to do something concrete for mothers of large
families the most exploited and least politically
vocal group in our whole population.
There is a tendency among people who have
thought superficially on biology to support our
existing social inequalities by analogy with the
Darwinian struggle for existence and survival of
the fittest. This is a mistake due to the confusion
between social and biological success. If able men
who became rich usually had large families, and
failures who drifted into the slums had small ones,
then our economic system would be biologically
sound. Actually the opposite is the case. The
biologist must welcome economic measures which
tend, either to equalize incomes as between
different social classes, or to equalize the standard
of living as between members of large and small
families in the same social class.
I have been dealing with eugenics because
H 113
Biology in Everyday Life
Dr. Baker raised this issue, not because I think
that it is the most immediately important applica-
tion of biology to politics. No eugenic measures
could have much effect for a generation. What
about the forty million people who are here now ?
If you are looking after animals the first thing
you must think about is their food. A diet which
will keep them alive is not good enough to keep
them healthy. If you want a stock of rats to grow
as well as possible you must feed them properly.
But that is not enough. Even though they have
the best possible diet from the moment of birth
you will not get the best results unless their
mothers have been well fed too. It takes two
generations before you can wipe out the results
of bad feeding. The same is probably true of man,
though the evidence is not so complete. You must
be very careful of putting down physical defects
in a child to bad heredity unless both it and its
mother have had an adequate diet.
Do English people get as good a diet as a
biologist would prescribe for them ? Let us take a
family of a man, a wife and three children. Recent
calculations 1 show that an adequate diet for them
would cost about 1 is. per week in London.
This diet does not include such luxuries as tea
and jam, let alone beer, but it is fully adequate
1 Week-end Review, April i, 1933.
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Biology and Statesmanship
as regards essential dietary constituents. Now it
is obvious enough that some million English
families have not got a guinea a week to spend on
food. I need not quote rates of wages or of unem-
ployment benefit to prove this. If you get less
food than this physiological standard, or the same
gross amount, but with less of certain desirable
constituents such as fruit, greens and liver, you
will not die of it. But you will not grow as fully
as you might, and you will be more liable to
various infections.
A biologically minded Government would re-
gard proper feeding as an important branch of
national defence, which it is. For we have had
wars with the Dutch, French, Russians, Germans
and other nations. But these have been matters of
a few years. We are all of us always at war with
disease. Even between 1914 and 1918 a great
many more English people were killed by the
germs of infectious diseases than by our human
enemies.
I expect some of you think I am misusing my
position as a biologist to make propaganda against
our present Government; so to prove that I am
trying to be scientific, I am going to talk about
some social reforms of which I happen to be in
favour, but which cannot be supported on bio-
logical grounds. I should like to see agricultural
Biology in Everyday Life
labourers' wages raised. But this would not make
them any healthier. They live about as long as
the farmers who employ them. From the merely
animal standpoint they are pretty well off. The
poor in our towns are not even as well off as well-
cared-for animals.
Again, I should personally like to see the school-
leaving age raised. But as a biologist I must at
once admit that by the time they reach the age
of 14 a good many children seem to be pretty
incapable of learning anything more. There are
large innate inequalities of intelligence, but neither
cleverness nor stupidity is confined to any one
social group. An educational system designed
by a biologist would recognize that inequality.
If you have very bright and very dull children
in the same class you are being unfair to both.
You keep back the bright, and go too fast for the
dull. A proper educational system would greatly
increase the number of free places and scholarships
now available. Even in London there are not
enough; almost everywhere else far too few. And
such a system would also recognize the fact that
not only does the level of intelligence which is
finally reached vary, but so does the rate of
getting there. The child whose intelligence
matures quickest does not always get farthest in
the long run. Our existing scholarship system
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Biology and Statesmanship
seems to be designed to pick out precocious
children. The hollyhock grows in height ten or
twenty times as fast as the oak, but it does not
get so far in the long run. We need an educational
system that will encourage human oaks as well
as human hollyhocks.
Let me put the same point of view rather
differently. In any community there must be
inequality. We need skilled and unskilled workers,
and there must be a few men and women in
positions of authority. If everyone were born
equal, it would not much matter how the various
posts in society were allotted. But we are not
born equal, far from it. The best community is
that which contains fewest square pegs in round
holes, bricklayers who might have been musicians,
company directors who, by their own abilities,
would never have risen above the rank of clerk.
If ability was strictly hereditary, a rigid class
system would be biologically justified. But we
all know that wise parents may have foolish sons,
and conversely. So a system of hereditary classes
is not only unjust but inefficient. The greater the
equality of opportunity, the greater the likelihood
that the right man or woman will be found for
any given post. Our society to-day is so complicated
that we simply cannot afford to let much of our
best human material go to waste, as it does to-day.
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Biology in Everyday Life
But equality of opportunity does not mean
equality for those who seize the opportunity and
those who miss it. The biologist would demand
so much equalization of incomes that no child
should be born of a half-starved mother, itself
inadequately housed and fed, and denied opportu-
nities because its father had been a failure. He
would not demand equal pay for the worker and
the slacker, the genius and the dunce. If our
society were organized to employ the productive
resources which science has given it, there would
be enough goods available to secure a satisfactory
minimum for all, and a reasonable degree of
luxury for those who had succeeded on their own
merits. Under such a social system we might
perhaps begin to think of restricting the breeding
of social failures. To do so under our present
system would in many cases merely be to add one
injustice to another.
The biologist is not merely concerned with
men, but with other animals and plants. Some
of these are our friends, some our enemies. Five
hundred years ago we still had large-scale enemies,
even in England. The last English wolves were
killed in the reign of Henry VII. Wolves and
wolf-hunting impressed themselves on the people's
mind, so that the wolf left its name in such places
as Wolverhampton, Wolverton, and Wolvercote.
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Biology and Statesmanship
We still have non-human enemies, but they are
smaller. Some, like the louse and the bed-bug,
we can see with the naked eye. Others, like the
bacteria which cause diphtheria and tuberculosis,
we can only see with a microscope. Still others,
for example, the causes of measles and smallpox,
we cannot see even with a microscope. Now these
are our real enemies. The flea, which carries
plague, and the louse, which conveys typhus
fever, have killed far more men than ever were
killed by wolves. But we have never organized
against them as we have against wolves, because
they have never struck the people's imagination
as enemies of man. If they had, we might have
towns called Louserhampton and Disinfecton.
The biologist realizes that there is a war on
a very real war of man against disease. Un-
fortunately, except for the doctors, nurses, research
workers, and sanitary workers, such as the muni-
cipal dustmen and sewermen, we are mostly non-
combatants in this war. We wait till we have been
attacked by bacteria, and then call in the doctor.
Let us try to imagine what the world would be
like if we had biologically educated statesmen
backed by a biologically educated public. Do not
think that we should all go about in fear and
trembling. I do not go about in mortal terror
because there are bacteria about, any more than
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Biology in Everyday Life
I did in India because there were tigers and
cobras there. But we would no more tolerate lice
than we do man-eating tigers. We should say
that the proper place for lice was in the Zoo, and
we should organize a campaign to make them as
extinct in England as the wolf is to-day. It would
mean a pretty thorough overhaul of our slums,
and about time too! We should no more tolerate
a house that harboured bed-bugs than a forest
full of tigers.
And the same with infectious diseases. When
the virus of smallpox lands on our shores we hunt
it down as we should hunt down a foreign invader
or a lion. But we do not take the same measures
about measles. There are three reasons for this,
We have not woken up to the fact that measles
kills a great many more people than smallpox or
tigers. The effort needed would be very con-
siderable. And above all the effort would have to
be international. It would be little use abolishing
measles in England if nothing were done about it
in France. But just imagine what an international
war on disease and parasites would be like. Sup-
pose the peoples and Governments of our own
country and the Dominions, Europe, the United
States and Japan, agreed to make a real effort to
abolish the principal infectious diseases and
parasites. We should have to clean ourselves up
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Biology and Statesmanship
and impose a medical inspection and three
weeks' quarantine on visitors from outside. We
should have our setbacks. A case of diphtheria in
Liverpool, and we should rush over armies of
experts from the Continent to examine all possible
contacts, and throw a ring round the area of
infection. An outbreak of measles in Marseilles,
and doctors from England and Germany would
be flying south to help the French in their fight.
You can say that this is a Utopian idea. But the
spirit is there already in international medical and
scientific congresses. They cut across the bound-
aries of international hatred. The last two inter-
national physiological congresses were in Boston
and Rome. The next is to be in Moscow. There
is international rivalry at such congresses; but it
is a friendly rivalry. The English try to show
the Germans that we have something new to tell
them about the nervous system; the Germans
show us what they have discovered about diges-
tion. There are no secrets. We are all working
for the same ends. And why? Because a discovery
in medical science can only be used for the com-
mon good. A sick foreigner is of no advantage
to this country on the contrary, he is a possible
source of infection. The more we realize the
existence of these common enemies of all man-
kind, the more we shall forget the enmities
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Biology in Everyday Life
between men. That is why the inclusion of
biology in our education and our common think-
ing is one of the most powerful weapons that
exist against international hatred.
Some of you think that I should like to hand
the world over to an international tyranny of
doctors. But wait a bit. Is your doctor really a
tyrant? Remember that the world to-day is
largely run by business men, that is to say, men
who work with a view to getting rich. They may,
or may not, enrich others in the process. But
the doctors cannot try to corner health. They
have a very low death-rate from chronic ailments
like cancer and heart disease, which can be tackled
in their early stages ; but they die in large numbers
of acute infections caught from their patients. The
pursuit of wealth is generally competitive; that
of health must be co-operative. My wealth is not
your wealth, but my health is your health, because
if I fall ill you are likely to contract the same
illness.
You see then that biology can do two things
for statesmanship. It can urge the statesman to
certain definite reforms. But, still more important,
it can deflect his mind from issues where one
man's good is another man's harm, issues of
military and economic rivalry, to issues of health
where the interests of different classes and dif-
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Biology and Statesmanship
ferent nations are one. There are higher points
of view than the biological. Man is not merely an
animal; but he is an animal, and in our political
and economic thought we are apt to treat him as
a machine for making commodities or a unit in
an army. We may desire to educate him or to
save his soul; but we differ very sharply about
education and salvation. We are all agreed about
the difference between a live and a dead man, and
mostly about the difference between sickness and
health. And the carrying out of biologically
desirable reforms would be a wholetime job which
would keep statesmen busy for a century. During
that century they would have learned to treat their
fellow-men not as rivals, but as colleagues. The
human race would have become civilized.
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