CuM'^

READINGS IN

BIOLOGICAL SCIENCE

READINGS IN

BIOLOGICAL SCIENCE

Edited by
IRVING WILLIAM KNOBLOCH, Ph.D.

Associate Professor of Biological Science
Basic College, Michigan State College

New York and London
APPLETON-CENTURY-CROFTS, INC.

Copyright, 1948, by
APPLETON-CENTURY-CROFTS, JNC.

AH rights reserved. This book, or parts
thereof, must not be reproduced in any
for?fi without permission of the publisher.

438

PRINTED IN THE UNITED STATES OF AMERICA

DEDICATED TO

MY GOOD COUNSELORS

PROFESSOR W. P. ALEXANDER
MY WIFE

AND

MY MOTHER

Preface

Since general education calls for a fulfilment of the aim of teaching
students how to think as well as ivhat to think, it would appear that read-
ing material designed to stimulate and develop the thought processes is
important and necessary. Primarily this volume is intended to be read in
conjunction with a textbook, and used in this way, it should accomplish
much in achieving the goals of a basic biology course. In certain situa-
tions, however, instructors may desire to use this book independently as
background for a lecture or laboratory course.

The book follows a general plan, but the instructor may not choose
to assign the readings in consecutive order. It is organized to start with
material on life and the cell and then follow a general scheme of watching
the green plant make organic food, of animal nutrition, circulation, and
so on. Finally, there are several articles of a philosophical nature which,
for the most part, seem to integrate the various divisions of biological
study.

It will be evident to the instructor that an attempt has been made to
focus on articles that are readable and inspiring rather than those of a
classic nature. This idea is in accord with the fast, modern tempo of
teaching. When once the student has developed a firm interest in the
science, he will wish to examine the classic papers in detail. In reproduc-
ing the articles herein presented, a certain amount of abridgment was
thought to be desirable to enhance readabiHty.

Many famous biologists have contributed to the development of this
book, and the warm thanks of the editor go to them as well as to the
various publishers who granted permission to reprint. The source of each
article and the author are indicated in a footnote on the first page of each
article. Short biographical sketches which give an idea of the caliber of
the individual contributors will be found at the end of the book. I am
grateful especially to Howard Rather, Dean of the Basic College of
Michigan State College for suggestions contained in the introduction and
to Dr. Chester A. Lawson, Head of the Department of Biological Sci-
ence, Michigan State College, for valuable criticisms on the selection of
articles destined for inclusion.

I. W. K.

vii

Introduction

The college curriculum is experiencing the most extensive face-lifting
in its entire career. The early American college was characterized, in one
respect, by an odiously rigid set of course requirements, the general idea
being that students were entirely devoid of judgment and value-sense.
Later this gave way, before the onslaughts of hberals, to a type of cur-
riculum in which the student was hemmed in with few required subjects
and overwhelmed with a tempting array of streamlined electives. This
change was probably predicated upon the belief, equally erroneous, that
students, now that they were in college, were mature adults and had some-
how mysteriously gained all the mature attributes of responsible citizen-
ship.

At the present time the pattern is being set for a healthy compromise
between these two extreme viewpoints, a compromise which assures the
student of the basic, broad, general principles of education and at the
same time allows a reasonable amount of free choice of subject-matter. In
addition, the general education program cocks a realistic eye at the major-
ity of college students who benefit most by two years of college and who
leave school at the end of that time. The program smooths off the rough
edges, gathers up the threads, and attempts to assure that a great deal of
worth-while integration will have been accomplished both for those who
leave and for those who stay.

World War II has shown us the important fact that the human mind
is capable of performing astonishing feats when put under pressure. It has
demonstrated the value of the scientific mind in producing and harness-
ing basic research. For example, the atom bomb was not something e7i-
tirely new but was actually the careful mixing of previously ascertained
knowledge with some new material. Many of the ingredients and steps
in the bomb's manufacture had been thought out by scientists who had no
idea that such knowledge would be used to usher in an atomic age.

This lesson of the power of the trained mind was not lost upon the
business man or the industrialist. Evidently the better positions will now
be made available to those who can initiate and carry out fundamental
research on basic problems in industry and business and also to those who
can fulfil the requirements of the modern, alert employee in general.
Many college professors and college graduates are being recruited into
positions of opportunity where their keen thinking ability is appreciated.

ix

X INTRODUCTION

The old sequence of ridicule, endure and embrace is now being repeated
with v^ehemence.

In many general education programs, and the list is growing by the
semester, the improvement of the student's thinking ability is a major
goal. Some of the advantages of the new trend are that broader view-
points are possible, relationships become more evident, dormant interests
are aroused, motivation for further inquiry is provided, a personal phi-
losophy of life can be attained and a healthy attitude for the examination
of ancient superstitions, provincialisms and intolerances is maintained.

It cannot be too strongly emphasized that the general improvement in
the thinking of the great mass of people will determine largely the quality
of government that we have. If we allow the dictates of our reveries and
our emotions to govern our actions, or if we stop thinking and rely en-
tirely upon recognized authority we shall see a people ridden with race
riots, hatreds, crime waves, and dociUty. These are, among others, the
natural fruits of such thinking or lack of it.

Biology, with its great wealth of material and its use of the scientific
method has a fundamental role to play "in helping students understand
the forces that have reshaped our civilization and which now threaten to
destroy it. At this of all times it should be clear that understanding the
social implications of the sciences is an imperative in general education." ^

1 "Higher Education for American Democracy," Vol. I, A Report of the Presi-
dent's Commission on Higher Education (U.S. Government Printing Office, 1947),
p. 52.

Contents

PAGE

I'REFACE Vii

INTRODUCTION ix

I. Biological Beginnings i

Excerpts from "Nature of Man, Humours, Aphorisms and

Regimen" . . Hippocrates 2

Excerpts from "De Generatione Animalium" Aristotle 6

Excerpts from "Enquiry into Plants" . . Theophrastiis 9

Excerpts from "Natural History" Pliny 12

Excerpts from "The First Observations on 'Little Animals'

Protozoa and and Bacteria in Waters"

Antoiiy Van Leeiiwenhoek 14
The Evidence of the Descent of Man from Some Lower

Form Charles Darwin 20

On the Relations of Man to the Lower Animals .

Thofnas H. Huxley 29

IL Life and the Cell : . 40

"Whence Cometh Life?" Willis R. Hunt 41

The Lens Turned on Life . . Donald Ciilross Peattie 46

How Life Becomes Complex S. J. Holvies 50

The Quest for the Mystery of Life

H. GordoJi Garbediaji 59

in. The Structure and Function of Higher Plants . . 64

A Tour of a Tree Henshaw Ward 6^

The Finest Show on Earth . . . Edwin B. Matzke 76

"Supernatural" Plants Karl C. Haviner 83

IV. Nutrition 86

Food and Fitness A. ]. Carlson 86

Why We Eat What We Eat . . Warren T. Vaughan 92

Fads, Fancies and Fallacies in Adult Diets

Russell M. Wilder loi
xi

Xll CONTENTS

PAGE

V. Circulation no

The Heart and Circulation

A. J. Carlson mid V. Johnson no

Your Heart . .

Metropolitan Life Insurance Compafiy and American

Heart Association 123

VI. Nervous and Endocrine Control of the Body . , , . 134

The Background of Human Mentality Ralph Linton 135

The Endocrine Control of the Body . Michael F. Giiyer 141

VII. Reproduction 154

Reproduction Emanuel Rddl 155

Sex Michael F . Guy er 159

VIII. Embryology 168

Embryology Leslie Brainerd Arey 168

Embryology and Genetics . . Thomas Hunt Morgan 172
Old Problems and New in Experimental Embryology .

E. G. Butler 178

IX. Heredity 188

Gregor A4endel and His Work .... Hugo litis 189

Human Heritage Carroll Lane Fe?it07i 195

The Study of Human Heredity . Laurence H. Snyder 199

What Will Your Child Look Like? . Amraju Scheinfeld 206

What Blood Tells David C. Rife 211

The Inheritance of Disease .... Paul A. Lewis 215

X. Eugenics 227

Some Bearings of Genetics on Human Affairs ....

Otto L. Mohr 228

The Role of Eugenics .... Ed-win Gratit Conklin 232

XI. Evolution 237

The Age of Homo sapiens . . . . W. W. Howells 237

Man's Long Story Lewis G. Westgate 243

What We Do Not Know About Race

Wilto?! Marion Krogman 255

XII. Ecology 267

Interdependence of Plants and Animals . . A. S. Pearse 268

CONTENTS xill

PACF

Some Adaptations to the Environment

Horatio Hackett Neirman i-j-^

Bees Raise Questions ... Henry S. Conard i-j-j

How Dangerous Is the Jungle . . C. Snydam Cutting 287

XIII. Health and Disease 297

Enter Louis Pasteur E. C. Large 298

Pestilences and Moralists . . . Hotvard W. Haggard 304

Animal Parasites Transmissible to Man

Benjamin Schivartz 309

Defrenerative Disease Karl B. Mickey 322

Walter Reed and Yellow Fever

Grace T. Hallock and C. E. Turner 331

A'lental Disease — A Challenge Winfred Overholser 340

Mental Diseases ... Bernard ]affe 348
The Significance of Plant Disease in Agriculture .

K. Starr Chester 353

Pollen and Hay Fever Margate Kienast 360

XIV. Economic Biology 367

Man and Nature R.T. Young 368

Wonder Plants of Commerce and Industry . .

A. Hyatt V err ill ^jz

The Vandals Angela Patri 378

The Conservation of Wildlife .... Seth Gordon 379

Finishing the Mammals Rosalie Edge 382

The Itinerant Eel Paul Bulla 392

XV. Biological Philosophy 39^

The Living Machine R. T. Young 399

Teleological Arguments Archie J. Bahm 407

To What Extent Is a Science of Man Possible? ...

Frederick Osborn 416

Science Versus Life A.J.Carlson 423

The Biologist Looks at Man . . . Julian S. Huxley 43 1

MEET THE AUTHORS 44°

GOOD BROWSING 44^

2 READINGS IN BIOLOGICAL SCIENCE

relativity and while it may be hard to believe, our present science will
probably look quite amateurish to those men and women who follow us.
Many important problems in biology remain to be solved and who can
say what transformations their solutions will make in our present-day
ideas?

EXCERPTS FROM Nature of Man, Humours, Aphorisms

and Regmien *

HIPPOCRATES
NATURE OF MAN

He who is accustomed to hear speakers discuss the nature of man beyond
its relations to medicine will not find the present account of any interest.
For I do not say at all that a man is air, or fire, or water, or earth, or any-
thing else that is not an obvious constituent of a man; such accounts I
leave to those who care to give them. Those, however, who give them
have not in my opinion correct knowledge. . . .

Now about these men I have said enough, and I will turn to physicians.
Some of them say that a man is blood, others that he is bile, a few that
he is phlegm. . . . The body of man has in itself blood, phlegm, yellow
bile and black bile; these make up the nature of his body, and through these
he feels pain or enjoys health. Now he enjoys the most perfect health
when these elements are duly proportioned to one another in respect of
compounding, power, bulk, and when they are perfectly mingled. Pain is
felt when one of these elements is in defect or excess, or is isolated in the
body without being compounded with all the others. For when an ele-
ment is isolated and stands by itself, not only must the place where it left
become diseased, but the place where it stands in a fiood must, because of
the excess, cause pain and distress. In fact when more of an element flows
out of the body than is necessary to get rid of superfluity, the emptying
causes pain.

Now I promised to show that what are according to me the constituents
of man remain always the same, according to both convention and nature.
These constituents are, I hold, phlegm, blood, black bile, and yellow bile.
First I assert that the names of these according to convention are separated,
and that none of them has the same name as the others; furthermore, that
according to nature their essential forms are separated, phlegm being quite
unlike blood, blood being quite unlike bile, bile being quite unlike phlegm.
How could they be like one another, when their colours appear not alike

* Reprinted by permission of the publishers from the Loeb Classical Library, Hip-
pocrates, Volume IV, translated by W. H. S. Jones. Cambridge, Mass.: Harvard Uni-
versity Press, 1 93 1.

BIOLOGICAL BEGINNINGS 3

to the sight nor does their touch seem ahke to the hand? From the follow-
ing evidence you may know that these elements are not all one, but that
each of them has its own power and its own nature. If you were to give a
man a medicine which withdraws phlegm, he will vomit you phlegm; if
you give him one which withdraws bile, he will vomit you bile. Similarly
too black bile is purged away if you give a medicine which withdraws
black bile. And if you wound a man's body so as to cause a wound, blood
will flow from him. So long as a man lives he manifestly has all these ele-
ments always in him.

Phlegm increases in a man in winter; for phlegm, being the coldest con-
stituent of the body, is closest akin to winter. It is in winter that the
sputum and nasal discharge of men is fullest of phlegm; at this season mostly
swellings become white, and diseases generally phlegmatic. And in spring
too phlegm still remains strong in the body while the blood increases. And
in summer blood is still strong, and bile rises in the body and extends until
autumn. In the summer phlegm is at its weakest. But in autumn, blood
becomes least in man, for autumn is dry and begins from this point to chill
him. It is black bile which in autumn is greatest and strongest. All these
elements are then always comprised in the body of a man, but as the
year goes round they become now greater and now less, each in turn and
according to its nature.

Now, as these things are so, such diseases as increase in the winter ought
to cease in the summer, and such as increase in the summer ought to cease
in the winter, with the exception of those which do not depart in a period
of days. When diseases arise in the spring, expect their departure in
autumn. Such diseases as arise in autumn must have their departure in
spring. Whenever a disease passes these limits, you may know that it will
last a year.

HUMOURS

The fashions of diseases. Some are congenital and may be learned by
inquiry, as also may those that are due to the district, for most people are
permanent residents there, so that those who know are numerous. Some
are the result of the physical constitution, others of regimen, of the con-
stitution of the disease, of the seasons. Countries badly situated with respect
to the seasons engender diseases analogous to the seasons.

If the seasons proceed normally and regularly, they produce diseases that
come easily to a crisis. If the summer proves bilious, and if the increased
bile be left behind, there will also be diseases of the spleen. So when spring
too has had a bilious constitution, there occur cases of jaundice in spring
also. When summer turns out hke to spring, sweats occur in fevers. When
the spring turns out wintry, with after-winter storms, the diseases too are
wintry, with coughs, pneumonia or angina. For seasons, too, suffer from
relapses, and so cause diseases,

4 «• READINGS IN BIOLOGICAL SCIENCE

South winds cause deafness, dimness of vision, headaches, heaviness,
and are relaxing. A north wind causes coughs, sore throats, constipation,
difficult micturition accompanied by shivering, pains in the side and chest.
Droughts accompany both south winds and north winds.

It is changes that are chiefly responsible for diseases, especially the
greatest changes, the violent alterations both in the seasons and in other
things. But seasons which come on gradually are the safest, as are gradual
changes of regimen and temperature and gradual changes from one period
of life to another.

Sufferers from hemorrhoids are attacked neither by pleurisy, nor by
pneumonia, nor by spreading ulcer, nor by boils, nor by swellings, nor per-
haps by skin-eruptions and skin-diseases. Blood-spitting may be caused
by the season, by pleurisy, or by bile. When swellings by the ear do not
suppurate at a crisis, a relapse occurs when the swelling softens; when the
relapse follows the normal course of relapses, the swelling rises again and
remains, following the same periods as occur when fevers relapse.

APHORISMS

Old men endure fasting most easily, then men of middle age, youths
very badly, and worst of all children, especially those of a liveliness greater
than the ordinary.

In summer and in autumn food is most difficult to assimilate, easiest in
winter, next easiest in spring.

Do not disturb a patient either during or just after a crisis, and try no
experiments, neither with purges nor with other irritants, but leave him
alone.

In acute disease use purgatives sparingly and at the onset, and then only
after a thorough examination.

When sleep puts an end to delirium, it is a good sign.

Spontaneous weariness indicates disease.

It is easier to replenish with drink than with food.

When on a starvation diet, a patient should not be fatigued.

In the case of acute diseases to predict either death or recovery is not
quite safe.

Strong drink dispels hunger.

At the beginning of diseases, if strong medicines seem called for, use
them; when they are at their height it is better to let the patient rest.

In every disease it is a good sign when the patient's intellect is sound and
he enjoys his food; the opposite is a bad sign.

Those who are constitutionally very fat are more apt to die quickly
than those who are thin.

Size of body in youth is noble and not unpleasing; in old age it is in-
convenient and less desirable than a smaller stature.

Autumn is bad for consumptives.

BIOLOGICAL BEGINNINGS 5

Cold sweats, occurring with high fever, indicate death; with a milder
fever they indicate a protracted disease.

And on whatever part of the body there is sweat, it means that the
disease has settled there.

Those who are attacked by tetanus either die in four days or, if they
survive these, recover.

Consumption occurs chiefly between the ages of eighteen and thirtv-five.

When unnaturally fat women cannot conceive, it is because the fat
presses the mouth of the womb, and conception is impossible until they
grow thinner.

Kidney troubles, and affections of the bladder, are cured with difficulty
when the patient is aged.

If one of the small intestines be severed it does not unite.

It is better to give no treatment in cases of hidden cancer; treatment
causes speedy death, but to omit treatment is to prolong life.

Both sleep and sleeplessness, when beyond due measure, constitute dis-
ease.

Those diseases that medicines do not cure are cured by the knife. Those
that the knife does not cure are cured by fire. Those that fire does not cure
must be considered incurable.

REGIMEN

I maintain that he who aspires to treat correctly of human regimen must
first acquire knowledge and discernment of the nature of man in general
— knowledge of its primary constituents and discernment of the com-
ponents by which it is controlled.

Now all animals, including man, are composed of two things, different
in power but working together in their use, namely, fire and water. Both
together these are sufficient for one another and for everything else, but
each by itself suffices neither for itself nor for anything else. Now the
power that each of them possesses is this. Fire can move all things always,
while water can nourish all things always; but in turn each masters or is
mastered to the greatest maximum or the least minimum possible. Neither
of them can gain the complete mastery for the following reason. The
fire, as it advances to the limit of the water, lacks nourishment, and so turns
to where it is likely to be nourished; the water, as it advances to the limit of
the fire, finds its motions fail, and so stops at this point. When it stops
its force ceases, and hereafter is consumed to nourish the fire which assails
it.

Males and females would be formed, so far as possible, in the following
manner. Females, inclined more to water, grow from foods, drinks, and
pursuits that are cold, moist, and gentle. Males, inclined to fire, grow from
foods and regimen that are dry and warm. So if a man would beget a girl,
he must use a regimen inclined to water. If he wants a boy, he must live

6 READINGS IN BIOLOGICAL SCIENCE

according to a regimen inclined to fire. And not only must the man do
this, but also the woman. For growth belongs, not only to the man's
secretions, but also to that of the woman, for the following reason. Either
part alone has not motion enough, owing to the bulk of its moisture and
the weakness of its fire, to consume and to solidify the oncoming water.
But when it happens that both are emitted together to one place, they
conjoin, the fire to the fire and the water likewise. Now if all the fire fall
in a dry place, it is set in motion, if it also master the water emitted with
it, and therefrom it grows, so that it is not quenched by the onrushing
flood, but receives the advancing water and solidifies it on to what is there
already. But if it fall into a moist place, immediately from the first it is
quenched and dissolves into the lesser rank. On one day in each month it
can solidify, and master the advancing parts, and that only if it happen
that parts are emitted from both parents together in one place.

EXCERPTS FROM Dc Generatioiie Ajiimalium *
(on the generation of animals)

ARISTOTLE

Now some animals come into being from the union of male and female,
i. e. all those kinds of animals which possess the two sexes. This is not the
case with all of them; though in the sanguinea t with few exceptions the
creature, when its growth is complete, is either male or female, and though
some bloodless animals have sexes so that they generate offspring of the
same kind, yet other bloodless animals generate indeed, but not offspring
of the same kind; such are all that come into being not from a union of
the sexes, but from decaying earth and excrements. To speak generally, if
we take all animals which change their locaHty, some by swimming, others
by flying, others by walking, we find in these the two sexes, not only in
the sanguinea but also in some of the bloodless animals; and this applies
in the case of the latter sometimes to the whole class, as in the cephalopoda
and Crustacea, but in the case of insects only to the majority. Of these,
all which are produced by union of animals of the same kind generate also
after their own kind, but all of which are not produced by animals, but
from decaying matter, generate indeed, but produce another kind, and
the ofl^spring is neither male nor female; such are some of the insects.

But all those creatures which do not move, as the testacea and animals

* From The Basic Works of Aristotle, edited by Richard McKeon, section trans-
lated by Arthur Piatt, by permission of Oxford University Press, New York. Copy-
right 1 94 1.

t Animals with blood. — Ed.

BIOLOGICAL BEGINNINGS 7

that live by clinging to something else, inasmuch as their nature resembles
that of plants, have no sex any more than plants have, but as applied to
them the word is only used in virtue of a similarity and analogy. For there
is a slight distinction of this sort, since even in plants we find in the same
kind some trees which bear fruit and others which, while bearing none
themselves, yet contribute to the ripening of the fruits of those which do,
as in the case of the fig-tree and the caprifig.

The same holds good also in plants, some coming into being from seed
and others, as it were, by the spontaneous action of Nature, arising
either from decomposition of the earth or of some parts in other plants,
for some are not formed by themselves separately but are produced upon
other trees, as the mistletoe.

Some animals manifestly emit semen, as all the sanguinea, but whether
the insects and cephalopoda do so is uncertain. Therefore this is a question
to be considered, whether all males do so, or not all; and if not all, why
some do and some not; and whether the female also contributes any semen
or not; and, if not semen, whether she does not contribute anything else
either, or whether she contributes something else which is not se-
men.

Now it is thought that all animals are generated out of semen, and that
the semen comes from the parents. In this investigation and those which
follow from it, the first thing to do is to understand what semen is, for
then it will be easier to inquire into its operation and the phenomena con-
nected with it. Now the object of semen is to be of such a nature that from
it as their origin come into being those things which are naturally formed,
not because there is any agent which makes them from it . . . but simply
because this is the semen.

Now the offspring comes from the semen and it is plainly in one of the
two following senses that it does so — either the semen is the material from
which it is made, or it is the first efficient cause. Now that which comes
from the generating parents is called the seminal fluid, being that which
first has in it a principle of generation, in the case of all animals whose
nature is to unite; semen is that which has in it the principles from both
united parents, as the first mixture which arises from the union of male
and female, be it a foetus or an ovum, for these already have in them that
which comes from both.

Semen, then, is part of a useful secretion. So we must say the opposite
of what the ancients said. For whereas they said that semen is that which
comes from all the body, we shall say it is that whose nature is to go to
all of it, and what they thought a waste product seems rather to be a secre^
tion.

A further proof that it is not a waste product, but rather a secretion is the
fact that the large animals have few young, the small many. For the
large must have more waste and less secretion, since the great size of

8 READINGS IN BIOLOGICAL SCIENCE

the body causes most of the nutriment to be used up, so that the residue or
secretion is small.

Again, no place has been set apart by Nature for waste-products but
they flow wherever they can find an easy passage in the body, but a place
has been set apart for all the natural secretions; thus the lower intestine
serves for the excretion of the solid nutriment, the bladder for that of the
liquid; for the useful part of the nutriment we have the upper intestine,
for the spermatic secretions the uterus and pudenda and breasts, for it is
collected and flows together into them. The male stands for the effec-
tive and active and the female, considered as female, for the passive and
it follows that what the female would contribute to the semen of the male
would not be semen but material for the semen to work upon.

So much for the discussion of this question. How is it that the male
contributes to generation and how is it that the semen from the male is
the cause of the offspring? Does it exist in the body of the embryo as a
part of it from the first, mingling with the material which comes from
the female? Or does the semen communicate nothing to the material body
of the embryo but only the power and movement in it? Now the latter
alternative appears to be the right one both a priori and in view of the
facts. For, if we consider the question on general grounds, we find that,
whenever one thing is made from two of which one is active and the
other passive, the active agent does not exist in that which is made, and,
still more generally, the same applies when one thing moves and another is
moved. It is plain then that it is not necessary that anything at all should
come away from the male, and if anything does come away it does not
follow that this gives rise to the embryo as being in the embryo, but only
as that which imparts the motion and as the form; so the medical art cures
the patient.

What occurs in birds and oviparous fishes is the greatest proof that
neither does the semen come from all parts of the male nor does he emit
anything of such a nature as to exist within that which is generated, as
part of the material embryo, but that he only makes a living creature by
the power which resides in the semen. For if a hen-bird is in process of
producing wind-eggs and is trodden by the cock before the tgg has
begun to whiten and while it is all still yellow, then they become fertile
instead of being wind-eggs. And if while it is still yellow she be trodden by
another cock, the whole brood of chicks turn out hke the second cock.

The same conclusion is to be drawn from the generation of oviparous
fishes. When the female has laid her eggs, the male sprinkles the milt over
them, and those eggs are fertilized which it reaches, but not the others;
this shows that the male does not contribute anything to the quantity but
only to the quality of the embryo.

In all animals that can move about, the sexes are separate, one individual
being male and one female, though both are the same in species, as with

BIOLOGICAL BEGINNINGS 9

man and horse. But in plants these powers are mingled, female not being
separated from male. Wherefore they generate out of themselves, and do
not emit semen, but produce an embryo, what is called the seed. For as
the tgg is an embryo, a certain part of it giving rise to the animal and the
rest being nutriment, so also from a part of the seed springs the growing
plant, and the rest is nutriment for the shoot and the first root.

It is the nature of those creatures which do not emit semen to remain
united a long time until the male element has formed the embryo, as with
those insects which copulate. The others remain so only until the male has
discharged from the parts of himself, introduced something which will
form the embryo in a longer time, as among the sanguinea. For the former
remain paired some part of a day, while the semen forms the embryo in
several days. And after emitting this they cease their union.

In all this Nature acts like an intelligent workman. For to the essence
of plants belongs no other function or business than the production of
seed; since, then, this is brought about by the union of male and female,
Nature has mixed these and set them together in plants, so that the sexes
are not divided in them. But the function of the animal is not only to
generate (which is common to all living things) but they all of them par-
ticipate also in a kind of knowledge, some more and some less, and some
very little indeed. For they have sense-perception, and this is a kind of
knowledge. Now it is by sense-perception that an animal differs from
those organisms which have only hfe. But since, if it is a hving animal, it
must also live; therefore, when it is necessary for it to accomplish the
function of that which has life, it unites and copulates, becoming like a
plant, as we have said before.

EXCERPTS FROM Enquiry into Plants *

THEOPHRASTUS

DEFINITIONS OF THE VARIOUS CLASSES INTO WHICH

PLANTS MAY BE DIVIDED

Now since our study becomes more illuminating if we distinguish dif-
ferent kinds, it is well to follow this plan where it is possible. The first
and most important classes, those which comprise all or nearly all plants,
are tree, shrub, under-shrub, herb.

A tree is a thing which springs from the root with a single stem, having
knots and several branches, and it cannot easily be uprooted; for instance,

* Reprinted by permission of the publishers from the Loeb Classical Library,
Theophrastus: Enquiry into Plants and Minor Works on Odours and Weather Signs,
translated by Sir Arthur Hort, 2 volumes. Cambridge, Mass.: Harvard University
Press, 1916.

10 READINGS IN BIOLOGICAL SCIENCE

olive fig vine. A shrub is a thing which arises from the root with many
branches; for instance, bramble Christ's thorn. An under-shrub is a thing
which arises from the root with many stems as well as many branches; for
instance, savory rue. A herb is a thing which comes up from the root
with its leaves and has no main stem, and the seed is borne on the stem; for
instance, corn and pot-herbs.

These definitions however must be taken and accepted as applying gen-
erally and on the whole. For in the case of some plants it might seem that
our definitions overlap; and some under cultivation appear to become dif-
ferent and depart from their essential nature, for instance, mallow when
it grows tall and becomes tree-like. For this comes to pass in no long
time, not more than six or seven months, so that in length and thickness the
plant becomes as great as a spear, and men accordingly use it as a walking-
stick, and after a longer period the result of cultivation is proportionately
greater. So too is it with the beets; they also increase in stature under cul-
tivation, and still more do chaste-tree Christ's thorn ivy, so that, as is
generally admitted, these become trees, and yet they belong to the class
of shrubs. On the other hand the myrtle, unless it is pruned, turns into a
shrub, and so does filbert: indeed this latter appears to bear better and
more abundant fruit if one leaves a good many of its branches untouched,
since it is by nature hke a shrub. Again neither the apple nor the pome-
granate nor the pear would seem to be a tree of a single stem, nor indeed
any of the trees which have side stems from the roots, but they acquire the
character of a tree when the other stems are removed. However, some
trees men even leave with their numerous stems because of their slender-
ness, for instance, the pomegranate and the apple, and they leave the stems
of the olive and the fig cut short.

OF 'male' and 'female' in trees

Taking all trees according to their kinds, we find a number of differ-
ences. Common to them all is that by which men distinguish the 'male'
and the 'female,' the latter being fruit-bearing, the former barren in some
kinds. In those kinds in which both forms are fruit-bearing, the 'female'
has fairer and more abundant fruit; however some call these the male
trees — for there are those who actually invert the names. This difference
is of the same character which distinguishes the cultivated from the wild
tree, while other differences distinguish different forms of the same kind,

OF THE MEDICINAL USES OF DIVERS PARTS OF PLANTS

As was said, of some plants the root, fruit and juice are all serviceable,
as of all-heal among others; of some the root and the juice, as of scammony
cyclamen thapsia and others, such as mandrake; for the leaf of this, they
say, used with meal, is useful for wounds, and the root for erysipelas, when
scrapped and steeped in vinegar, and also for gout, for sleeplessness, and

BIOLOGICAL BEGINNINGS I I

for love potions. It is administered in wine or vinegar; they cut little balls
of it, as of radishes, and making a string of them hang them up in the
smoke over must.

Of hellebore both root a'nd fruit are useful for the same purposes, — if
it is true, as is said, that the people of Anticyra use the fruit as a purge:
this fruit contains the well-known drug called sesamodes.

Various parts of all-heal are also useful, and not all for the same pur-
poses; the fruit is used in cases of miscarriage and for disorders of the
bladder, while the juice is used in cases of miscarriage and also for sprains
and such-like troubles; also for the ears, and to strengthen the voice. The
root is used in childbirth, for diseases of women, and for flatulence in beasts
of burden.

Of cyclamen the root is used for suppurating boils; also as a pessary for
women and, mixed with honey, for dressing wounds; the juice for purgings
of the head. They say also that the root is a good charm for inducing rapid
delivery and as a love potion.

Of 'wild cucumber' (squirting cucumber) the root is used for white
leprosy and for mange in sheep.

Of germander the leaves pounded up in olive-oil are used for fractures
and wounds and for spreading sores; the fruit purges bile, and is good
also for the eyes; for ulcers in the eye they pound up the leaf in olive-oil
before applying it.

OF ROOTS POSSESSING REMARKABLE TASTE OR SMELL

The differences between roots are shown in their tastes and in their
smells: some are pungent, some bitter, some sweet: some again have a
pleasant, others a disagreeable smell. The plant called yellow water-lily is
sweet: it grows in lakes and marshy places. It has a large leaf which lies
on the water: and it is said that it acts as a styptic if it is pounded up and
put on the wound: it is also serviceable in the form of a draught for
dysentery.

Liquorice is also sweet; some indeed simply call it 'sweet root.' It is use-
ful against asthma or a dry cough and in general for troubles in the chest:
also, administered in honey, for wounds: also it has the property of quench-
ing thirst, if one holds it in the mouth.

These then are sweet: other roots are bitter, and some unpleasant to
the taste.

Aladder has a leaf like ivy, but it is rounder: it grows along the ground
like dog's-tooth grass and loves shady spots. It has diuretic properties,
wherefore it is used for pains in the loins or hip disease.

The root of polypody is rough and has suckers like the tentacles of the
polyp. It purges downward: and, if one wears it as an amulet, they say
that one does not get a polypus.

12 READINGS IN BIOLOGICAL SCIENCE

OF PLANTS POSSESSING PROPERTIES WHICH AFFECT

THE MENTAL POWERS

As to those that affect the mind, strykhnos is said to upset the mental
powers and make one mad; while the root of onotheras (oleander) ad-
ministered in wine makes the temper gentler and more cheerful. This
plant has a leaf like the almond, but smaller, and the flower is red like a
rose. The plant itself forms a large bush; the root is red and large and, if
this is dried, it gives off a fragrance like wine.

EXCERPTS FROM Natural History *

PLINY

The birth of triplets is attested by the case of Horatii and Curiatii:
above that number is considered portentous, except in Egypt, where drink-
ing the water of the Nile causes fecundity. Recently on the day of the
obsequies of his late Majesty Augustus a certain woman of the lower
orders named Fausta at Ostia was delivered of two male and two female
infants, which unquestionably portended the food shortage that followed.
We also find the case of a woman in the Peloponnese who four times pro-
duced quintuplets, the greater number of each birth surviving. In Egypt
also Trogus alleges cases of seven infants born at a single birth.

Persons are also born of both sexes combined — what we call Hermaph-
rodites, formerly called androgyni and considered as portents, but now
as entertainments. We read of Eutychis who at Realles was carried to her
funeral pyre by twenty children and who had given birth thirty times,
and Alcippe who gave birth to an elephant.

Transformation of females into males is not an idle story. A girl at
Casinum was changed into a boy, under the observation of the parents and
at the order of the augurs was conveyed away to a desert island. I myself
saw in Africa a person who had turned into a male on the day of marriage
to a husband. (It is said that) at the birth of twins neither the mother nor
more than one of the two children usually lives, but that if twins are born
that are of different sex it is even more unusual for either to be saved: that
females are born more quickly than males, just as they grow older more
quickly: and that movement in the womb is more frequent in the case of
males, and males are usually carried on the right side, females on the
left.

All the other animals have a fixed season for copulation and for bear-

* Reprinted by permission of the publishers from the Loeb Classical Library, Pliny:
Natural History, Volume II, translated by H. Rackham. Cambridge, Mass.: Har-
vard University Press, 1942.

BIOLOGICAL BEGINNINGS I 3

ing offspring, but human reproduction takes place all the year round
and the period of gestation varies — in one case it may exceed six months,
in another seven, and it may even exceed ten: a child born before the
seventh month is usually still-born. Only those conceived the day before
or the day after the full moon, or when there is no moon, are bom in the
seventh month.

On the tenth day from conception pains in the head, giddiness and dim
sight, distaste for food, and vomiting are symptoms of the formation of the
embryo. If the child is a male, the mother has a better colour and an easier
delivery; there is movement in the womb on the fortieth day. In the case
of the other sex, all the symptoms are the opposite: the burden is hard to
carry, there is a slight swelling of the legs and groin, but the first movement
is on the ninetieth day. But the greatest amount of faintness occurs when
the embryo begins to grow hair; and also at the full moon, which period
is also specially inimical to infants after birth. The gait in walking and
everything that can be mentioned are so important during pregnancy that
mothers eating food that is too salt bear children lacking nails, and that not
holding the breath makes the delivery more difficult; indeed, to gape dur-
ing delivery may cause death, just as a sneeze following copulation causes
abortion.

It is against nature to be born feet foremost. It is Nature's method for a
human being to be born head first, and it is the custom for him to be carried
to burial feet first.

It is also well known that sound parents may have deformed children
and deformed parents sound children or children with the same deformity,
as the case may be; that some marks and moles and even scars reappear in
the offspring, in some cases a birthmark on the forearm reappearing in the
fourth generation.

Cases of likeness are indeed an extremely wide subject, and one which
includes the belief that a great many accidental circumstances are in-
fluential— recollections of sights and sounds and actual sense — impressions
received at the time of conception. Also a thought flitting across the mind
of either parent is supposed to produce likeness or to cause a combination
of features, and the reason why there are more differences in man than in
all the other animals is that his swiftness of thought and quickness of mind
and variety of mental character impress a great diversity of mental pat-
terns, whereas the minds of the other animals are sluggish and are alike for
all and sundry, each in their own kind.

Particular individuals may have a certain physical incongruity be-
tween them, and persons whose union is infertile may have children when
they form other connexions. Also some women have only female or only
male children, though usually the sexes come alternately; some women are
childless in youth; on some parentage is bestowed once in a lifetime; cer-
tain women are always delivered prematurely, and those of this class, if

i4 READINGS IN BIOLOGICAL SCIENCE

ever they succeed in overcoming this tendency by the use of drugs, usually
bear a female child.

A woman does not bear children after the age of fifty, and with the
majority menstruation ceases at forty. Woman is, however, the only animal
that has monthly periods; consequently she alone has what arc called moles
in the womb. This mole is a shapeless and inanimate mass of flesh that re-
sists the point and the edge of a knife; it moves about and it checks menstru-
ation, as it also checks births: in some cases causing death, in others grow-
ing old with the patient, sometimes when the bowels are violently moved
being ejected. A similar object is also formed in the stomach of males,
called a tumour. . . .

The latter (women who do not menstruate), however, do not have chil-
dren, since the substance in question (menstrual fluid) is the material for
human generation, as the semen from the males acting like rennet col-
lects this substance within it, which thereupon immediately is inspired
with life and endowed with body. Hence when this flux occurs with
women heavy with child, the offspring is sickly or still-born or sanious,
according to Nigidius. (The same writer holds that a woman's milk does
not go bad while she is suckling a baby if she has become pregnant again
from the same male.) It is stated, however, that the easiest conceptions are
when this condition is beginning or ceasing. We have it recorded as a sure
sign of fertility in w^omen if when the eyes have been anointed with a drug
the saliva contains traces of it.

■>>><<<■

EXCERPTS FROM The FiTst Observations on
^^Little AimnaW Protozoa and Bacteria hi Waters *

ANTONY VAN LEEUWENHOEK
1ST OBSERVATION ON RAIN-WATER

In the year 1675, about half-way through September (being busy with
studying air, when I had much compressed it by means of water), I dis-
covered living creatures in rain, which had stood but a few days in a new
tub, that was painted blue within. This observation provoked me to in-
vestigate this water more narrowly; and especially because these little
animals were, to my eye, more than ten thousand times smaller than the
animacule which Swammerdam has portrayed, and called bv the name of
Water-flea, or Water-louse, which you can see alive and moving in water
with the bare eye.

Of the first sort, that I discovered in the said water, I saw, after divers

• From Aritony Van Leeuwenhoek and His ''Little Ani^nals'' by Clifford Dobell.
Reprinted by permission of Harcourt, Brace and Company, Inc.

BIOLOGICAL BEGINNINGS I 5

observations, that the bodies consisted of 5, 6, 7 or 8 very clear globules,
but without being able to discern any membrane or skin that held these
globules together, or in which they were enclosed. When these animacules
bestirred 'emselves, they sometimes stuck out two little horns, which were
continually moved, after the fashion of a horse's ears. The part between
these little horns was flat, their body else being roundish, save only that it
ran somewhat to a point at the hind end; at which pointed end it had a
tail, near four times as long as the whole body, and looking as thick, when
viewed through my microscope, as a spider's web. At the end of this tail
there was a pellet, of the bigness of one of the globules of the body; and
this tail I could not perceive to be used by them for their movements in very
clear water. These little animals were the most wretched creatures that I
have ever seen; for when, with the pellet, they did but hit on any particles or
little filaments (of which there were many in water, especially if it hath
but stood some days), they stuck entangled in them; and then pulled their
body out into an oval, and did struggle, by strongly stretching them-
selves, to get their tail loose; whereby their whole body then sprang back
towards the pellet of the tail, and their tails then coiled up serpent-wise,
after the fashion of a copper or iron wire that, having been wound close
about a round stick, and then taken off, kept all its windings. This motion,
of stretching out and pulling together the tail, continued; and I have seen
several hundred animacules, caught fast by one another in a few filaments,
lying within the compass of a coarse grain of sand.

I also discovered a second sort of animacules, whose figure was oval; and
I imagined that their head was placed at the pointed end. These were a
little bit bigger than the animacules first mentioned. Their belly is flat,
provided with divers incredibly thin Httle feet, or little legs, which were
moved very nimbly, and which I was able to discover only after sundry
great efforts, and wherewith they brought off incredibly quick motions.
The upper part of their body was round, and furnished inside with 8, 10
or 12 globules: otherwise these animacules were very clear. These little
animals would change their body into a perfect round, but mostly when
they came to lie high and dry. Their body was also very yielding: for if
they so much as brushed against a tiny filament, their body bent in, which
bend also presently sprang out again; just as if you stuck your finger into
a bladder full of water, and then, on removing the finger, the inpitting went
away. Yet the greatest marvel was when I brought any of these animacules
on a dry place, for I then saw them change themselves at last into a round,
and then the upper part of the body rose up pyramid-like, with a point
jutting out in the middle; and after having thus lain moving with their feet
for a httle while, they burst asunder, and the globules and a watery humour
flowed away on all sides, without my being able to discern even the least
sign of any skin wherein these globules and the hquid had, to all appear-
ance, been inclosed; and at such time I could discern more globules than

1 6 READINGS IN BIOLOGICAL SCIENCE

when they were aHve. This bursting asunder I figure to myself to happen
thus: imagine, for example, that you have a sheep's bladder filled with shot,
peas, and water; then, if you were to dash it apieces on the ground, the shot,
peas, and water would scatter themselves all over the place.

Furthermore, I discovered a third sort of little animals, that were about
twice as long as broad, and to my eye quite eight times smaller than the
animacules first mentioned: and I imagined, although they were so small,
that I could yet make out their little legs, or little fins. Their motion was
very quick, both roundabout and in a straight line.

The fourth sort of animacules, which I also saw amoving, were so small,
that for my part I can't assign any figure to 'em. These little animals were
more than a thousand times less than the eye of a full-grown louse (for I
judge the diameter of the louse's eye to be more than ten times as long as
that of the said creature), and they surpassed in quickness the animacules
already spoken of. I have divers times seen them standing still, as 'twere,
in one spot, and twirhng themselves round with a swiftness such as you see
in a whip-top a-spinning before your eye; and then again they had a cir-
cular motion, the circumference whereof was no bigger than that of a
small sand-grain; and anon they would go straight ahead, or their course
would be crooked.

Furthermore I also discovered sundry other sorts of little animals; but
these were very big, some as large as the little mites on the rind of cheese,
others bigger and very monstrous. But I intend not to specify them; and
will only say, that they were for the most part made up of such soft parts,
that they burst asunder whenever the water happened to run off them.

THE 2ND OBSERVATION. RAIN-WATER

The 26th of May it rained very hard. The rain abating somewhat, I
took a clean glass and got rain-water, that came off a slate roof, fetched me
in it, after the glass had first been swilled out two or three times with the
rain-water. I then examined it, and therein discovered some few very
little animals; and seeing them, I bethought me whether they might not
have been bred in the leaden gutters, in any water that might ersru^hile have
been standing in them,

THE 3RD OBSERVATION. RAIN-WATER

On the same date, the rain continuing nearly the whole day, I took a
big procelain dish, and put it in my court-yard, in the open air, upon a
wooden tub about a foot and a half high: considering that thus no earthy
particles would be splashed into the said dish by the falling of the rain
at that spot. With the water first caught, I swilled out the dish, and the
glass in which I meant to preserve the water, and then flung this water
away: then, collecting water anew in the same dish, I kept it; but upon

BIOLOGICAL BEGINNINGS 1 7

examining it, I could discover therein no living creatures, but merely a
lot of irregular earthy particles.

The 30th of May, after I -had, since the 26th, observed this water every
day, twice or thrice daily, I now first discovered some (though very few)
exceeding little animacules, which were very clear.

On the 31st ditto, I discovered more little animals in the water, as well
as a few that were a bit bigger; and I imagine that ten hundred thousand of
these little animacules are not so big as an ordinary sand-grain. Compar-
ing these animacules with the little mites in cheese (which you can see
amoving with the bare eye), I would put the proportion thus: As the
size of a small animacule in the water is to that of a mite, so is the size of
a honey bee to that of a horse; for the circumference of one of these same
little animacules is not so great as the thickness of a hair on a mite.

THE 4TH OBSERVATION. RAIN-WATER

On June 9th, collected rain-water betimes in a dish, as aforesaid, and
put it at about 8 o'clock in the morning in a clean wine glass, and exposed
it to the air at about the height of the third storey of my house, wondering
whether the little animals would appear sooner in water thus standing in
the air.

The loth ditto, observing this water, I fancied that I discovered living
creatures; but they were so few, and not so plainly discernible, I could not
accept this for the truth.

On the nth ditto, seeing this water, with the naked eye, stirred in the
glass by a stiff gale of wind (which had now blown from the same
quarter for 36 hours; the weather being very cold withal, that it did not
irk me to wear my winter clothes), I had no thought of finding any living
creatures in it; but upon examining it, I saw with wonder quite 1000 living
creatures in one drop of water. These animacules were of the smallest sort
that I had yet seen.

The 1 2th of June, in the morning (the wind being west, with both sun-
shine and an overcast sky), observing again, I saw the aforesaid animacules
in such great numbers in the water which I took from the surface, that now
they did not amount to merely one or two thousand in one drop.

The 13th ditto, in the morning, examining the water again, I discovered,
beside the aforesaid animacules, a sort of little animals that were fully
eight times as big as the first; and whereas the small animacules swam gently
among one another, and moved after the fashion of gnats in the air, these
larger animacules had a much swifter motion; and as they turned and
tumbled all around and about, they would make a quick dart. These
animacules were almost round.

On the 14th of June I did perceive the very little animacules in no less
number.

1 8 READINGS IN BIOLOGICAL SCIENCE

On the 1 6th ditto, the animacules seen as before; and the water (which
had been, in all, about % of a pint) being now more than half dried out,
I flung it away.

5TH OBSERVATION. RAIN-WATER

The 9th of June, I put some of the last-collected water, likewise in a
clean wine-glass, in my closet; and on examining it, I described no anima-
cules.

The loth of June, observing this foresaid rain-water, which had now
stood about 24 hours in my closet, I perceived some few very little living
creatures, to which, because of their littleness, no figure can be ascribed;
and among others, I discovered a little animal that was a bit bigger, and that
I could perceive to be oval.

The I ith ditto, observing this water again, I saw the foresaid small an-
imacules, though very few in number.

The 1 2th ditto, I saw the very small animacules, as yesterday; and be-
sides these, a small animal that had nearly the figure of a mussel-shell, lying
with its hollow side downwards. 'Twas of the length anigh of a louse's
eye.

The 13th ditto, I also saw one bigger animacule, like that just spoken of.
Aloreover I discovered animacules which were somewhat longer than an
oval. These were about 6 times as long as the foresaid very small animacules;
and their head, which was somewhat long drawn out, they oft-times pulled
in, and then looked to be almost round. There were also animacules which
appeared perfectly round, their diameter being twice as long as that of
smallest animacules of all. These two large sorts were very yielding, so
that their body did bend before the least little filament which they chanced
to brush against in the water.

The 16th ditto, I perceived the oval animacules in yet greater numbers;
and they were flat beneath, and round above: and besides these, there were
very small animacules that were three times as long as broad, together
with divers other sorts which it would take all too long to specify. In the
evening of the same day, I discovered little paws on the foresaid oval anima-
cules, which were many in number, in proportion to the animacule. And
at this point, I stopped my observations upon this water.

OBSERVATIONS ON WELL-WATER

I have in my yard, standing in the open air, a well, which is about 15-
foot deep before you come to the water. It standeth at the south, but so
encompassed with high walls, that even when the sun is on the sign of
Cancer, the coping of the wall is not shown upon. This water cometh out
of the ground, which is well-sand, with such force, that whenever I have
tried to empty the well there was always about a foot of water still left in.
On a summer's day this water is so cold that 'tis not feasible to keep your

BIOLOGICAL BEGINNINGS 1 9

hand in it for long. Having no thought that there would be living creatures
in it (for 'tis very palatable and clear), I examined it in September of last
year, and discovered therein a great number of very small animacules,
which were very clear, and a bit bigger than the very smallest animacules
that I've ever seen. And I imagine (having aforetime weighed a grain of
water), that there were commonly more than 500 living creatures in one
grain of this water. These animacules were very sedate, moving without
any jerks.

In the winter I perceived no little animals, nor did I see any of them this
year before the month of July, and then not in such great plenty; but in
the month of August, their number was much increased.

OBSERVATIONS ON SEA- WATER

The 27th of July, 1676, 1 betook myself to the seaside, hard by the village
of Schevelinge. Finding myself upon the shore, and observing the sea-water
as well as I could, I discovered in it divers little animacules. I gave to a
certain person who went into the sea, to bathe himself, a new glass vial
and besought him that, when he was in the sea, he would rinse it out twice
or thrice and then fill it up with water. This having been carried out ac-
cording to my orders, I tied the vial up tight with a clean bit of bladder:
and on reaching home and examining the water, I perceived therein a little
animal that was blackish, having a shape as if 'twere made up of two glo-
bules. This little animal had a peculiar motion, after the manner of a very
little flea, when seen, by the naked eye, jumping on a white paper; yet
'twas only displaced, at every jump, within the compass of a coarse sand-
grain, or thereabouts. It might right well be called a water flea; but 'twas
not so big, by a long way, as the eye of that little animal which Swammer-
dam calls the water-flea.

The 31st ditto, having examined this water every day since the 27th,
and perceived no little animals in it; upon this date I did now see a good
hundred of 'em where at first I had seen but one; but they were now of
another figure, and not only smaller, but also very clear. They were like
an oblong oval, only with this difference, that they tapered somewhat more
sharply to a point at what I imagined to be the head end. And although
these were at least a thousand times smaller than a very small sand-grain,
I saw, notwithstanding, that whenever they lay high and dry out of the
water they burst asunder, and flowed apart or scattered into three or
four very small globules and some watery matter, without my being able
to discern any other parts.

The 8th of August, I again discovered a very few of the foresaid anima-
cules; and I now saw a few so exceeding small that, even through my
microscope, they well-nigh escaped the sight. And here I stopped my
observations.

■>>> <<<

20 READINGS IN BIOLOGICAL SCIENCE

THE EVIDENCE OF THE DESCENT OF MAN FROM
SOME LOWER FORM *

CHARLES DARWIN

He who wishes to decide whether man is the modified descendant of
some pre-existing form, would probably first enquire whether man varies,
however slightly, in bodily structure and in mental faculties; and if so,
whether the variations are transmitted to his offspring in accordance with
the laws which prevail with the lower animals. Again, are the variations
the result, as far as our ignorance permits us to judge, of the same general
causes, and are they governed by the same general laws, as in the case of
other organisms; for instance, by correlation, the inherited effects of use
and disuse, etc? Is man subject to similar malconformations, the result of
arrested development, of reduplication of parts, &c., and does he display in
any of his anomalies reversion to some former and ancient type of struc-
ture? It might also naturally be enquired whether man, like so many other
animals, has given rise to varieties and sub-races, differing but sHghtly from
each other, or to races differing so much that they must be classed as doubt-
ful species? How are such races distributed over the world; and how,
when crossed, do they react on each other in the first and succeeding
generations? And so with many other points.

The enquirer would next come to the important point whether man tends
to increase at so rapid a rate, as to lead to occasional severe struggles for
existence; and consequently to beneficial variations, whether in body or
mind, being preserved, and injurious ones ehminated. Do the races or
species of men, whichever term may be applied, encroach on and replace
one another, so that some finally become extinct? We shall see that all
these questions, as indeed is obvious in respect to most of them, must be
answered in the affirmative, in the same manner as with the lower animals.
But the several considerations just referred to may be conveniently de-
ferred for a time: and we will first see how far the bodily structure of
man shows traces, more or less plain, of his descent from some lower
form.

THE BODILY STRUCTURE OF MAN

It is notorious that man is constructed on the same general type or model
as other mammals. All the bones in his skeleton can be compared with cor-
responding bones in a monkey, bat, or seal. So it is with his muscles, nerves,
blood-vessels and internal viscera. The brain, the most important of all the
organs, follows the same law, as shewn by Huxley and other anatomists.
Bischoff, who is a hostile witness, admits that every chief fissure and fold

• From The Descent of Man and Selection in Relation to Sex by Charles Darwin.
D. Appleton and Co., New York. 1886.

BIOLOGICAL BEGINNINGS 21

in the brain of man has its analogy in that of the orang; but he adds that
at no period of development do their brains perfectly agree; nor could
perfect agreement be expected, for otherwise their mental powers would
have been the same.

It may, however, be worth while to specify a few points, not directly
or obviously connected with structure, by which this correspondence or
relationship is well shewn.

A-Ian is liable to receive from the lower animals, and to communicate to
them, certain diseases, as hydrophobia, variola, the glanders, syphilis,
cholera, herpes, &c.; and this fact proves the close similarity of their tissues
and blood, both in minute structure and composition, far more plainly
than does their comparison under the best microscope, or by the aid of
the best chemical analysis. A4onkeys are liable to many of the same non-
contagious diseases as we are; thus Rengger, who carefully observed for
a long time the Cebus Azarae in its native land, found it liable to catarrh,
with the usual symptoms, and which, when often recurrent, led to con-
sumption. These monkeys suffered also from apoplexy, inflammation of
the bowels, and cataract in the eye. The younger ones when shedding
their milk-teeth often died from fever. Medicines produced the same effect
on them as on us. Many kinds of monkeys have a strong taste for tea, coffee,
and spirituous liquors: they will also, as I have myself seen, smoke tobacco
with pleasure, Brehm asserts that the natives of north-eastern Africa catch
the wild baboons by exposing vessels with strong beer, by which they are
made drunk. He has seen some of these animals, which he kept in con-
finement, in this state; and he gives a laughable account of their behaviour
and strange grimaces. On the following morning they were very cross
and dismal; they held their aching heads with both hands, and wore a most
pitiable expression: when beer or wine was offered them, they turned away
with disgust, but relished the juice of lemons. An American monkey, an
Ateles, after getting drunk on brandy, would never touch it again, and
thus was wiser than many men. These trifling facts prove how similar the
nerves of taste must be in monkeys and man, and how similarly their whole
nervous system is affected.

Man is infested with internal parasites, sometimes causing fatal effects;
and is plagued by external parasites, all of which belong to the same genera
or families as those infesting other mammals, and in the case of scabies to
the same species. Man is subject, like other mammals, birds, and even in-
sects, to that mysterious law, which causes certain normal processes, such
as gestation, as well as the maturation and duration of various diseases, to
follow lunar periods. His wounds are repaired by the same process of
healing; and the stumps left after the amputation of his limbs, especially
during an early embryonic period, occasionally possess some power of
regeneration, as in the lowest animals.

The whole process of that most important function, the reproduction of

2 2 READINGS IN BIOLOGICAL SCIENCE

the species, is strikingly the same in all mammals, from the first act of
courtship by the male, co the birth and nurturing of the young. Monkeys
are born in almost as helpless a condition as our own infants; and in certain
genera the young differ fully as much in appearance from the adults, as do
our children from their full-grown parents. It has been urged by some
writers, as an important distinction, that with man the young arrive at
maturity at a much later age than with any other animal: but if we look
to the races of mankind which inhabit tropical countries the difference
is not great, for the orang is believed not to be adult till the age of from
ten to fifteen years. Man differs from woman in size, bodily strength,
hairiness, &c., as well as in mind, in the same manner as do the two sexes
of many mammals. So that the correspondence in general structure, in
the minute structure of the tissues, in chemical composition and in con-
stitution, between man and the higher animals, especially the anthropomor-
phous apes, is extremely close.

EMBRYONIC DEVELOPMENT

Man is developed from an ovule, about the 125th of an inch in diameter,
which differs in no respect from the ovules of other animals. The embryo
itself at a very early period can hardly be distinguished from that of other
members of the vertebrate kingdom. At this period the arteries run in
arch-like branches, as if to carry the blood to branchiae which are not
present in the higher vertebrata, though the slits on the sides of the neck
still remain, marking their former position. At a somewhat later period,
when the extremities are developed, "the feet of lizards and mammals,"
as the illustrious Von Baer remarks, "the wings and feet of birds, no less
than the hands and feet of man, all arise from the same fundamental
form." It is, says Prof. Huxley, "quite in the later stages of development
that the young human being presents marked differences from the young
ape, while the latter departs as much from the dog in its developments,
as the man does. Startling as this last assertion may appear to be, it is de-
monstrably true."

After the foregoing statements made by such high authorities, it would
be superfluous on my part to give a number of borrowed details, shewing
that the embryo of man closely resembles that of other mammals. It may,
however, be added, that the human embryo likewise resembles certain
low forms when adult in various points of structure. For instance, the
heart at first exists as a simple pulsating vessel; the excreta are voided
through a cloacal passage; and the os coccyx projects like a true tail, "ex-
tending considerably beyond the rudimentary legs." In the embryos of
all air-breathing vertebrates, certain glands, called the corpora Wolffiana,
correspond with and act like the kidneys of mature fishes. Even at a
later embryonic period, some striking resemblances between man and the
lower animals may be observed. Bischoff says that the convolutions of the

BIOLOGICAL BEGINNINGS 23

brain in a human foetus at the end of the seventh month reach about the
same stage of development as in a baboon when adult. The great toe, as
Prof. Owen remarks, "which forms the fulcrum when standing or walking,
is "perhaps the most characteristic peculiarity in the human structure;" but
in an embryo, about an inch in length. Prof. Wyman found "that the great
toe was shorter than the others; and, instead of being parallel to them, pro-
jected at an angle from the side of the foot, thus corresponding with the
permanent condition of this part in the quadrumana." I will conclude with
a quotation from Huxley, who after asking, does man originate in a dif-
ferent way from a dog, bird, frog or fish? says, "the reply is not doubtful
for a moment; without question, the mode of origin, and the early stages
of the development of man, are identical with those of the animals imme-
diately below him in the scale: without a doubt in these respects, he is far
nearer to apes than the apes are to the dog."

RUDIMENTS

This subject, though not intrinsically more important than the two
last, will for several reasons be treated here more fully. Not one of the
higher animals can be named which does not bear some part in a rudi-
mentary condition; and man forms no exception to the rule. Rudimentary
organs must be distinguished from those that are nascent; though in some
cases the distinction is not easy. The former are either absolutely useless,
such as the mammae of male quadrupeds, or the incisor teeth of ruminants
which never cut through the gums; or they are of such slight service to
their present possessors, that we can hardly suppose that they were devel-
oped under the conditions which now exist. Organs in this latter state are
not strictly rudimentary, but they are tending in this direction. Nascent or-
gans, on the other hand, though not fully developed, are of high service to
their possessors, and are capable of further development. Rudimentary or-
gans are eminently variable; and this is partly intelligible, as they are useless,
or nearly useless, and consequently are no longer subjected to natural selec-
tion. They often become wholly suppressed. When this occurs, they are
nevertheless liable to occasional reappearance through reversion — a cir-
cumstance well worthy of attention.

The chief agents in causing organs to become rudimentary seem to have
been disuse at that period of life when the organ is chiefly used (and this
is generally during maturity), and also inheritance at a corresponding
period of life. The term "disuse" does not relate merely to the lessened
action of muscles, but includes a diminished flow of blood to a part or or-
gan, from being subjected to fewer alternations of pressure, or from be-
coming in any way less habitually active. Rudiments, however, may occur
in one sex of those parts which are normally present in the other sex; and
such rudiments, as we shall hereafter see, have often originated in a way dis-
tinct from those here referred to. In some cases, organs have been reduced

24 READINGS IN BIOLOGICAL SCIENCE

by means of natural selection, from having become injurious to the species
under changed habits of life. The process of reduction is probably often
aided through the two principles of compensation and economy of growth;
but the later stages of reduction, after disuse has done all that can fairly
be attributed to it, and when the saving to be effected by the economy of
growth would be very small, are difficult to understand. The final and com-
plete suppression of a part, already useless and much reduced in size, in
which case neither compensation nor economy can come into play, is per-
haps intelligible by the aid of the hypothesis of pangenesis. But as the whole
subject of rudimentary organs has been discussed and illustrated in my
former works, I need here say no more on this head.

Rudiments of various muscles have been observed in many parts of the
human body; and not a few muscles, which are regularly present in some
of the lower animals can occasionally be detected in man in a greatly re-
duced condition. Every one must have noticed the power which many
animals, especially horses, possess of moving or twitching their skin; and
this is effected by the pamiiciihis carnosiis. Remnants of this muscle in an
efficient state are found in various parts of our bodies; for instance, the
muscle on the forehead, by which the eyebrows are raised.

The extrinsic muscles which serve to move the external ear, and the in-
trinsic muscles which move the different parts, are in a rudimentary con-
dition in man, and they all belong to the system of the pamiiciihis; they are
also variable in development, or at least in function. I have seen one man
who could draw the whole ear forwards; other men can draw it upwards;
another who could draw it backwards; and from what one of these persons
told me, it is probable that most of us, by often touching our ears, and thus
directing our attention towards them, could recover some power of move-
ment by repeated trials. The power of erecting and directing the shell of
the ears to the various points of the compass, is no doubt of the highest serv-
ice to many animals, as they thus perceive the direction of danger; but I
have never heard on sufficient evidence, of a man who possessed this power,
the one which might be of use to him. Some authors, however, suppose that
the cartilage of the shell serves to transmit vibrations to the acoustic nerve;
but Mr. Toynbee, after collecting all the known evidence on this head,
concludes that the external shell is of no distinct use. The ears of the chim-
panzee and orang are curiously like those of man, and the proper muscles
are likewise but very slightly developed. I am also assured by the keepers
in the Zoological Gardens that these animals never move or erect their
ears; so that they are in an equally rudimentary condition with those of
man, as far as function is concerned. Why these animals, as well as the pro-
genitors of man, should have lost the power of erecting their ears, we can-
not say. It may be, though I am not satisfied with this view, that owing to
their arboreal habits and great strength they were but little exposed to dan-
ger, and so during a lengthened period moved their ears but little, and thus

BIOLOGICAL BEGINNINGS 25

gradually lost the power of moving them. This would be a parallel case
with that of those large and heavy birds, which from inhabiting oceanic
islands, have not been exposed to the attacks of beasts of prey, and have
consequently lost the power of using their wings for flight. The inabihty
to move the ears in man and several apes is, however, partly compensated
by the freedom with which they can move the head in a horizontal plane,
so as to catch sounds from all directions.

The nictitating membrane, or third eyelid, with its accessory muscles
and other structures, is especially well developed in birds, and is of much
functional importance to them, as it can be rapidly drawn across the whole
eye-ball. It is found in some reptiles and amphibians, and in certain fishes,
as in sharks. It is fairly well developed in the two lower divisions of the
mammalian series, namely, in the monotremata and marsupials, and in
some few of the higher mammals, as in the walrus. But in man, the quad-
rumana, and most other mammals, it exists, as is admitted by all anatomists,
as a mere rudiment, called the semilunar fold.

The sense of smell is of the highest importance to the greater number
of mammals — to some, as the ruminants, in warning them of danger; to
others, as the carnivora, in finding their prey; to others, again, as the wild
boar, for both purposes combined. But the sense of smell is of extremely
slight service, if any, even to the dark coloured races of men, in whom it
is much more highly developed than in the white and civilized races. Never-
theless it does not warn them of danger, nor guide them to their food; nor
does it prevent the Esquimaux from sleeping in the most fetid atmosphere,
nor many savages from eating half-putrid meat. In Europeans the power
differs greatly in different individuals, as I am assured by an eminent na-
turalist who possesses this sense highly developed, and who has attended to
the subject. Those who believe in the principle of gradual evolution, will
not readily admit that the sense of smell in its present state was originally
acquired by man, as he now exists. He inherits the power in an enfeebled
and so far rudimentary condition, from some early progenitor, to whom
it was highly serviceable, and by whom it was continually used. In those
animals which have this sense highly developed, such as dogs and horses, the
recollection of persons and of places is strongly associated with their odour;
and we can thus perhaps understand how it is, as Dr. Maudsley has truly
remarked, that the sense of smell in man "is singularly effective in recalling
vividly the ideas and images of forgotten scenes and places."

Man differs conspicuously from all the other Primates in being almost
naked. But a few short straggling hairs are found over the greater part
of the body in the man, and fine down on that of the woman. The different
races differ much in hairiness; and in the individuals of the same race the
hairs are highly variable, not only in abundance, but likewise in position;
thus in some Europeans the shoulders are quite naked, whilst in others they
bear thick tufts of hair. There can be Httle doubt that the hairs thus scat-

26 READINGS IN BIOLOGICAL SCIENCE

tered over the body are the rudiments of the uniform hairy coat of the
lower animals. This view is rendered all the more probable, as it is known
that fine, short, and pale-coloured hairs on the limbs and other parts of the
body, occasionally become developed into "thickset, long and rather coarse
dark hairs," when abnormally nourished near old-standing inflamed sur-
faces.

The fine wool-like hair, or so-called lanugo, with which the human
foetus during the sixth month, is thickly covered, offers a more curious
case. It is first developed, during the fifth month, on the eyebrows and
face, and especially round the mouth, where it is much longer than that
on the head. A moustache of this kind was observed by Eschricht on a
female foetus; but this is not so surprising a circumstance as it may at first
appear, for the two sexes generally resemble each other in all external char-
acters during an early period of growth. The direction and arrangement of
the hairs on all parts of the foetal body are the same as in the adult, but are
subject to much variability. The whole surface, including even the fore-
head and ears, is thus thickly clothed; but it is a significant fact that the
palms of the hands and the soles of the feet are quite naked, like the inferior
surfaces of all four extremities in most of the lower animals. As this can
hardly be an accidental coincidence, the woolly covering of the foetus
probably represents the first permanent coat of hair in those mammals
which are born hairy. Three or four cases have been recorded of persons
born with their whole bodies and faces thickly covered with fine long
hairs; and this strange condition is strongly inherited, and is correlated with
an abnormal condition of the teeth. Prof. Alex. Brandt informs me that he
has compared the hair from the face of a man thus characterised, aged
thirty-five, with the lanugo of a foetus, and finds it quite similar in texture;
therefore, as he remarks, the case may be attributed to an arrest of develop-
ment in the hair, together with its continued growth.

It appears as if the posterior molar or wisdom-teeth were tending to
become rudimentary in the more civilised races of man. These teeth are
rather smaller than the other molars, as is likewise the case with the corres-
ponding teeth in the chimpanzee and orang; and they have only two sep-
arate fangs. They do not cut through the gums till about the seventeenth
year, and I have been assured that they are much more liable to decay, and
are earlier lost than the other teeth; but this is denied by some eminent
dentists. They are also much more liable to vary, both in structure and in
the period of their development, than the other teeth. In the Melanian
races, on the other hand, the wisdom-teeth are usually furnished with three
separate fangs, and are generally sound; they also differ from the other
molars in size, less than in the Caucasian races. Prof. Schaaffhausen accounts
for this difference between the races by "the posterior dental portion of
the jaw being always shortened" in those that are civilised, and this short-

SlOLOGICAL BEGINNINGS 2^

ening may, I presume, be attributed to civilised men habitually feeding on
soft, cooked food, and thus using their jaws less.

With respect to the alimentary canal, I have met with an account of only
a single rudiment, namely the vermiform appendage of the caecum. The
caecum is a branch or diverticulum of the intestine, ending in a cul-de-sac,
and is extremely long in many of the lower vegetable-feeding mammals.
In the marsupial koala it is actually more than thrice as long as the whole
body. It is sometimes produced into a long gradually-tapering point, and
is sometimes constricted in parts. It appears as if, in consequence of changed
diet or habits, the caecum had become much shortened in various animals,
the vermiform appendage being left as a rudiment of the shortened part.
That this appendage is a rudiment, we may infer from its small size, and
from the evidence which Prof. Canestrini has collected of its variability
in man. It is occasionally quite absent, or again is largely developed. The
passage is sometimes completely closed for half or two-thirds of its length,
with the terminal part consisting of a flattened solid expansion. In the orang
this appendage is long and convoluted: in man it arises from the end of
the short caecum, and is commonly from four to five inches in length,
being only about the third of an inch in diameter. Not only is it useless,
but it is sometimes the cause of death, of which fact I have lately heard two
instances: this is due to small hard bodies, such as seeds, entering the pas-
sage, and causing inflammation.

In man, the os coccyx, together with certain other vertebrae hereafter to
be described, though functionless as a tail, plainly represent this part in
other vertebrate animals. At an early embryonic period it is free, and pro-
jects beyond the lower extremities of a human embryo. Even after birth it
has been known, in certain rare and anomalous cases, to form a small ex-
ternal rudiment of a tail. The os coccyx is short, usually including only
four vertebrae, all anchylosed together: and these are in a rudimentary
condition, for they consist, Vv'ith the exception of the basal one, of the
centrum alone. They are furnished with some small muscles; one of which,
as I am informed by Prof. Turner, has been expressly described by Theile
as a rudimentary repetition of the extensor of the tail, a muscle which is
so largely developed in many mammals.

The spinal cord in man extends only as far downwards as the last dorsal
or first lumbar vertebra; but a thread-Hke structure (the filum terminale)
runs down the axis of the sacral part of the spinal canal, and even along
the back of the coccygeal bones. The upper part of this filament, as Prof.
Turner informs me, is undoubtedly homologous with the spinal cord, but
the lower part apparently consists merely of the pia mater, or vascular in-
vesting membrane. Even in this case the os coccyx may be said to possess
a vestige of so important a structure as the spinal cord, though no longer
enclosed within a bony canal.

2 8 READINGS IN BIOLOGICAL SCIENCE

The reproductive system offers various rudimentary structures; but these
differ in one important respect from the foregoing cases. Here we are
not concerned with the vestige of a part which does not belong to the
species in an efficient state, but with a part efficient in the one sex, and
represented in the other by a mere rudiment. Nevertheless, the occurrence
of such rudiments is as difficult to explain, on the belief of the separate
creation of each species, as in the foregoing cases. Hereafter I shall have
to recur to these rudiments, and shall shew that their presence generally
depends merely on inheritance, that is, on parts acquired by one sex having
been partially transmitted to the other. I will in this place only give some
instances of such rudiments. It is well known that in the males of all
mammals, including man, rudimentary mammae exist. These in several
instances have become well developed, and have yielded a copious supply
of milk. Their essential identity in the two sexes is likewise shewn by their
occasional sympathetic enlargement in both during an attack of the mea-
sles. The vesiciila prostatica, which has been observed in many male mam-
mals, is now universally acknowledged to be the homologue of the female
uterus, together with the connected passage. It is impossible to read Leuck-
art's able description of this organ, and his reasoning, without admitting
the justness of his conclusion. This is especially clear in the case of those
mammals in which the true female uterus bifurcates, for in the males of
these the vesicula likewise bifurcates.

The bearing of the three great classes of facts now given is unmistak-
able. But it would be superfluous fully to recapitulate the line of argument
given in detail in my Origin of Species. The homological construction of
the whole frame in the members of the same class is intelHgible, if we admit
their descent from a common progenitor, together with their subsequent
adaptation to diversified conditions. On any other view, the similarity of
pattern between the hand of a man or monkey, the foot of a horse, the
flipper of a seal, the wing of a bat, &c., is utterly inexplicable. It is no scien-
tific explanation to assert that they have all been formed on the same ideal
plan. With respect to development, we can clearly understand, on the
principle of variations supervening at a rather late embryonic period, and
being inherited at a corresponding period, how it is that the embryos of
wonderfully different forms should still retain, more or less perfectly, the
structure of their common progenitor. No other explanation has ever been
given of the marvellous fact that the embryos of a man, dog, seal, bat, rep-
tile, etc., can at first hardly be distinguished from each other. In order to
understand the existence of rudimentary organs, we have only to suppose
that a former progenitor possessed the parts in question in a perfect state,
and that under changed habits of life they became greatly reduced, either
from simple disuse, or through the natural selection of those individuals
which were least encumbered with a superfluous part, aided by the other
means previously indicated.

BIOLOGICAL BEGINNINGS 29

Thus we can understand how it has come to pass that man and all other
vertebrate animals have been constructed on the same general model, why
they pass through the same early stages of development, and why they
retain certain rudiments in -common. Consequently we ought frankly to
admit their community of descent; to take any other view, is to admit that
our own structure, and that of all the animals around us, is a mere snare
laid to entrap our judgment. This conclusion is greatly strengthened, if
we look to the members of the whole animal series, and consider the evi-
dence derived from their affinities or classification, their geographical
distribution and geological succession. It is only our natural prejudice, and
that arrogance which made our forefathers declare that they were de-
scended from demi-gods, which leads us to demur to the conclusion. But
the time will before long come, when it will be thought wonderful that
naturalists, who were well acquainted with the comparative structure
and development of man, and other mammals, should have believed that
each was the work of a separate act of creation.

ON THE RELATIONS OF MAN TO THE
LOWER ANLMALS *

THOMAS H. HUXLEY

The question of questions for mankind — the problem which underlies
all others, and is more deeply interesting than any other — is the ascer-
tainment of the place which Man occupies in nature and of his relations to
the universe of things. Whence our race has come; what are the limits
of our power over nature, and of nature's power over us; to what goal we
are tending; are the problems which present themselves anew and with
undiminished interest to every man born into the world. Most of us
shrinking from the difficulties and dangers which beset the seeker after
original answers to these riddles, are contented to ignore them altogether,
or to smother the investigating spirit under the featherbed of respected
and respectable tradition. But, in every age, one or two restless spirits,
blessed with that constructive genius, which can only build on a secure
foundation, or cursed with the mere spirit of scepticism, are unable to
follow in the well-worn and comfortable trace of their forefathers and
contemporaries, and unmindful of thorns and stumbling-blocks, strike
out into paths of their own. The sceptics end in the infidelity which asserts
the problem to be insoluble, or in the atheism which denies the existence
of any orderly progress and governance of things: the men of genius pro-

• From Evidence as to Man's Place in Nature by Thomas H. Huxley. D. Appleton
Co., New York. 1871,

30 READINGS IN BIOLOGICAL SCIENCE

pound solutions which grow into systems of Theology or of Philosophy,
or veiled in musical language which suggests more than it asserts, take the
shape of the Poetry of an epoch.

Each such answer to the great question, invariably asserted by the fol-
lowers of its propounder, if not by himself, to be complete and final, re-
mains in high authority and esteem, it may be for one century, or it may
be for twenty: but, as invariably. Time proves each reply to have been a
mere approximation to the truth — tolerable chiefly on account of the igno-
rance of those by whom it was accepted, and wholly intolerable when tested
by the larger knowledge of their successors.

In a well-worn metaphor, a parallel is drawn between the life of man
and the metamorphosis of the caterpillar into the butterfly; but the com-
parison may be more just as well as more novel, if for its former term we
take the mental progress of the race. History shows that the human mind,
fed by constant accessions of knowledge, periodically grows too large for
its theoretical coverings, and bursts them asunder to appear in new habili-
ments, as the feeding and growing grub, at intervals, casts its too narrow
skin and assumes another, itself by temporary. Truly the imago state of
Man seems to be terribly distant, but every moult is a step gained, and of
such there have been many.

Since the revival of learning, whereby the Western races of Europe
were enabled to enter upon that progress towards true knowledge, which
was commenced by the philosophers of Greece, but was almost arrested
in subsequent long ages of intellectual stagnation, or, at most, gyration,
the human larva has been feeding vigorously and moulting in proportion.
A skin of some dimension was cast in the i6th century, and another towards
the end of the i8th, while, within the last fifty years, the extraordinary
growth of every department of physical science has spread among us
mental food of so nutritious and stimulating a character that a new ecdysis
seems imminent. But this is a process not unusually accompanied by many
throes and some sickness and debility, or, it may be, by graver disturbances;
so that every good citizen must feel bound to facilitate the process, and
even if he have nothing but a scalpel to work withal, to ease the cracking
integument to the best of his ability.

The importance of such an inquiry is indeed intuitively manifest.
Brought face to face with these blurred copies of himself, the least thouqht-
ful of men is conscious of a certain shock, due, perhaps, not so much to
disgust at the aspect of what looks like an insulting caricature, as to the
awakening of a sudden and profound mistrust of time-honoured theories
and strongly-rooted prejudices regarding his own position in nature, and
his relations to the under-world of life; while that which remains a dim
suspicion for the unthinking, becomes a vast argument fraught with the
deepest consequences, for all who are acquainted with the recent progress
of the anatomical and physiological sciences.

BIOLOGICAL BEGINNINGS 3 I

I now propose briefly to unfold that argument, and to set forth, in a
form intelligible to those who possess no special acquaintance with ana-
tomical science, the chief facts upon which all conclusions respecting the
nature and the extent of the bonds which connect man with the brute
world must be based: I shall then indicate the one immediate conclusion
which, in my judgment, is justified by those facts, and I shall finally dis-
cuss the bearing of that conclusion upon the hypotheses which have been
entertained respecting the Origin of Man.

The facts to which I would first direct the reader's attention, though
ignored by many of the professed instructors of the public mind, are easy
of demonstration and are universally agreed to by men of science; while
their significance is so great, that whoso has duly pondered over them
will, I think, find little to startle him in the other revelations of Biology. I
refer to those facts which have been made known by the study of De-
velopment.

It is a truth of very wide, if not of universal application, that every
living creature commences its existence under a form different from, and
simpler than, that which it eventually attains.

The oak is a more complex thing than the little rudimentary plant con-
tained in the acorn; the caterpillar is more complex than the egg; the
butterfly than the caterpillar; and each of these beings, in passing from its
rudimentary to its perfect condition, runs through a series of changes, the
sum of which is called its Development. In the higher animals these changes
are extremely complicated; but, within the last century, the labours of
such men as Von Baer, Rathke, Reichert, Bischof, and Remak, have almost
completely unravelled them, so that the successive states of development
which are exhibited by a Dog, for example, are now as well known to the
embryologist as are the steps of the metamorphosis of the silk-worm moth
to the school-boy. It will be useful to consider with attention the nature
and the order of the stages of canine development, as an example of the
process in the higher animals generally.

The Dog, like all animals, save the very lowest (and further inquiries
may not improbably remove the apparent exception), commences its
existence as an egg: as a body which is, in every sense, as much an egg as
that of a hen, but is devoid of that accumulation of nutritive matter which
confers upon the bird's egg its exceptional size and domestic utility;
and wants the shell, which would not only be useless to an animal in-
cubated within the body of its parent, but would cut it off from access
to the source of that nutriment which the young creature requires,
but which the minute egg of the mammal does not contain within it-
self.

The Dog's egg is, in fact, a little spheroidal bag, formed of a delicate
transparent membrane called the vitelline mejiihrane^ and about Ksoth to

Jl READINGS IN BIOLOGICAL SCIENCE

M2oth of an inch in diameter. It contains a mass of viscid nutritive matter
— the yelk — within which is inclosed a second much more dehcate sphe-
roidal bag, called the gemiinal vesicle. In this, lastly, lies a more solid
rounded body, termed the germinal spot.

The egg or Ovum, is originally formed within a gland, from which, in
due season, it becomes detached, and passes into the living chamber fitted
for its protection and maintenance during the protracted process of gesta-
tion. Here, when subjected to the required conditions, this minute and
apparently insignificant particle of living matter, becomes animated by a
new and mysterious activity. The germinal vesicle and spot cease to be
discernible (their precise fate being one of the yet unsolved problems of
embryology), but the yelk becomes circumferentially indented, as if an
invisible knife had been drawn round it, and thus appears divided into two
hemispheres.

By the repetition of this process in various planes, these hemispheres be-
come subdivided, so that four segments are produced; and these, in like
manner, divide and subdivide again, until the whole yelk is converted into
a mass of granules, each of which consists of a minute spheroid of yelk-
substance, inclosing a central particle, the so-called juicleiis. Nature, by
this process, has attained much the same result as that at which a human
artificer arrives by his operations in a brick field. She takes the rough
plastic material of the yelk and breaks it up into well-shaped tolerably
even-sized masses — handy for building up into any part of the living
edifice.

Next, the mass of organic bricks, or cells as they are technically called,
thus formed, acquires an orderly arrangement, becoming converted into
a hollow spheroid with double walls. Then, upon one side of this spheroid,
appears a thickening, and, bv and by, in the centre of the area of thicken-
ing, a straight shallow groove marks the central line of the edifice which is
to be raised, or, in other words, indicates the position of the middle line
of the body of the future dog. The substance bounding the groove on
each side next rises up into a fold, the rudiment of the side wall of that
long cavity, which will eventually lodge the spinal marrow and the brain;
and in the floor of this chamber appears a solid cellular cord, the so-called
notochord. One end of the inclosed cavity dilates to form the head, the
other remains narrow, and eventually becomes the tail; the side walls of
the body are fashioned out of the downward continuation of the walls of
the groove; and from them, by and by, grow out little buds which, by
degrees, assume the shape of limbs. Watching the fashioning process stage
by stage, one is forcibly reminded of the modeller in clay. Every part, every
organ, is at first, as it were, pinched up rudely, and sketched out in the
rough; then shaped more accurately, and only, at last, receives the touches
which stamp its final character.

Thus, at length, the young puppy assumes such a form. In this condi-

BIOLOGICAL BEGINNINGS 33

tion it has a disproportionately large head, as dissimilar to that of a dog
as the bud-like limbs are unlike his legs.

The remains of the yelk, which have not yet been applied to the nutri-
tion and growth of the young animal, are contained in a sac attached to
the rudimentary intestine, and termed the yelk sac, or umbilical vesicle.
Two membranous bags, intended to subserve respectively the protection
and nutrition of the young creature, have been developed from the skin
and from the under and hinder surface of the body, the former, the so-
called amnion, is a sac filled with fluid, which invests the whole body of
the embryo, and plays the part of a sort of water-bed for it; the other,
termed the allantois, grows out, loaded with blood-vessels, from the
ventral region, and eventually applying itself to the walls of the cavity,
in which the developing organism is contained, enables these vessels to
become the channel by which the stream of nutriment, required to supply
the wants of the offspring, is furnished to it by the parent.

The structure which is developed by the interlacement of the vessels
of the offspring with those of the parent, and by means of which the
former is enabled to receive nourishment and to get rid of effete matters, is
termed the placenta.

It would be tedious, and it is unnecessary for my present purpose, to
trace the process of development further; sufKce it to say, that, by a long
and gradual series of changes, the rudiment here depicted and described,
becomes a puppy, is born, and then, by still slower and less perceptible
steps passes into the adult Dog.

There is not much apparent resemblance between a barn-door Fowl
and the Dog who protects the farm-yard. Nevertheless the student of
development finds, not only that the chick commences its existence as an
egg, primarily identical, in all essential respects, with that of the Dog, but
that the yelk of this egg undergoes division — that the primitive groove
arises, and that the contiguous parts of the germ are fashioned, by pre-
cisely similar methods, into a young chick, which, at one stage of its
existence, is so like the nascent Dog, that ordinary inspection would
hardly distinguish the two.

The history of the development of any other vertebrate animal. Lizard,
Snake, Frog, or Fish, tells the same story. There is always, to begin with,
an egg having the same essential structure as that of the Dog: — the yelk
of that egg always undergoes division, or segmentation as it is often
called: the ultimate products of that segmentation constitute the building
materials for the body of the young animial; and this is built up round a
primitive groove, in the floor of which a notochord is developed. Further-
more, there is a period in which the young of all these animals resemble
one another, not merely in outward form, but in all essentials of structure,
so closely, that the differences between them are inconsiderable, while^

34 READINGS IN BIOLOGICAL SCIENCE

in their subsequent course, they diverge more and more widely from one
another. And it is a general law, that, the more closely any animals re-
semble one another in adult structure, the longer and the more intimately
do their embryos resemble one another; so that, for example, the embryos
of a Snake and of a Lizard remain like one another longer than do those
of a Snake and of a Bird; and the embryo of a Dog and of a Cat remain
like one another for a far longer period than do those of a Dog and a
Bird; or of a Dog and an Opossum; or even than those of a Dog and a
Monkey.

Thus the study of development affords a clear test of closeness of struc-
tural affinity, and one turns with impatience to inquire what results are
yielded by the study of the development of Man. Is he something apart?
Does he originate in a totally different way from Dog, Bird, Frog, and
Fish, this justifying those who assert him to have no place in nature and
no real affinity with the lower world of animal life? Or does he originate
in a similar germ, pass through the same slow and gradually progressive
modifications, — depend on the same contrivances for protection and nutri-
tion, and finally enter the world by the help of the same mechanism? The
reply is not doubtful for a moment, and has not been doubtful any time
these thirty years. Without question, the mode of origin and the early
stages of the development of man are identical with those of the animals
immediately below him in the scale: — without a doubt, in these respects,
he is far nearer the Apes, than the Apes are to the Dog.

The Human ovum is about ^25 of an inch in diameter, and might be
described in the same terms as that of the Dog. It leaves the organ in which
it is formed in a similar fashion and enters the organic chamber prepared
for its reception in the same way, the conditions of its development being
in all respects the same. It has not yet been possible (and only by some
rare chance can it ever be possible) to study the human ovum in so early
a developmental stage as that of yelk division, but there is every reason
to conclude that the changes it undergoes are identical with those ex-
hibited by the ova of other vertebrated animals; for the formative ma-
terials of which the rudimentary human body is composed, in the earliest
conditions in which it has been observed, are the same as those of other
animals.

Indeed, it is very long before the body of the young human being can
be readily discriminated from that of the young puppy; but, at a tolerably
early period, the two become distinguishable by the different form of their
adjuncts, the yelk-sac and the allantois. The former, in the Dog, becomes
long and spindle-shaped, while in Man it remains spherical: the latter, in
the Dog, attains an extremely large size, and the vascular processes M^hich
are developed from it and eventually give rise to the formation of the
placenta (taking root, as it were, in the parental organism, so as to draw
nourishment therefrom, as the root of a tree extracts it from the soil)

BIOLOGICAL BEGINNINGS 35

are arranged in an encircling zone, while in iMan, the allantois remains
comparatively small, and its vascular rootlets are eventually restricted
to one disk-like spot. Hence, while the placenta of the Dog is like a girdle,
that of Man has the cake-lil^e form, indicated by the name of the organ.

But, exactly in those respects in which the developing Man differs from
the Dog, he resembles the Ape, which, like man, has a spheroidal yelk-sac
and a discoidal — sometimes partially lobed-placenta.

So that it is only quite in the later stages of development that the young
human being presents marked differences from the young ape, while the
latter departs as much from the dog in its development as the man does.

Startling as the last assertion may appear to be, it is demonstrably true,
and it alone appears to me sufficient to place beyond all doubt the struc-
tural unity of man with the rest of the animal world, and more particularly
and closely with the apes.

Thus, identical in the physical processes by which he originates — identical
in the early stages of his formation — identical in the mode of his nutrition
before and after birth, with the animals which lie immediately below him
in the scale — Man, if his adult and perfect structure be compared with
theirs, exhibits, as might be expected, a marvellous likeness of organiza-
tion. He resembles them as they resemble one another — he differs from
them as they differ from one another. And, though these differences and
resemblances cannot be weighed and measured, their value may be readily
estimated; the scale or standard of judgment, touching that value, being
afforded and expressed by the system of classification of animals now cur-
rent among zoologists.

It is quite certain that the Ape which most nearly approaches man, in the
totaUty of its organization, is either the Chimpanzee or the Gorilla; and
as it makes no practical difference, for the purposes of my present argu-
ment, which is selected for comparison, on the one hand, with Man, and
on the other hand, with the rest of the Primates,^ I shall select the latter (so
far as its organization is known) — as a brute now so celebrated in prose
and verse, that all must have heard of him, and have formed some con-
ception of his appearance. I shall take up as many of the most important
points of difference between man and this remarkable creature, as the
space at my disposal will allow me to discuss, and the necessities of the argu-
ment demand; and I shall inquire into the value and magnitude of these
differences, when placed side by side with those which separate the Gorilla
from other animals of the same order.

In the general proportions of the body and limbs there is a remarkable
difference between the Gorilla and Man, which at once strikes the eye.

1 We are not at present thoroughly acquainted with the brain of the Gorilla, and
therefore, in discussing cerebral characters, I shall take that of the Chimpanzee as my
highest term among the Apes.

36 READINGS IN BIOLOGICAL SCIENCE

The Gorilla's brain-case is smaller, its trunk larger, its lower limbs shorter,
its upper limbs longer in proportion than those of Alan.

I find that the vertebral column of a full grown Gorilla, in the Museum
of the Royal College of Surgeons, measures 27 inches along its anterior
curvature, from the upper edge of the atlas, or first vertebra of the neck,
to the lower extremity of the sacrum; that the arm, without the hand, is
3 1 1/2 inches long; that the leg, without the foot, is 26V2 inches long; that
the hand is ()% inches long; the foot 1 1^ inches long.

In other words, taking the length of the spinal column as 100, the arm
equals 1 15, the leg 96, the hand 36, and the foot 41.

In the skeleton of a male Bosjesman, in the same collection, the propor-
tions, by the same measurement, to the spinal column, taken as 100, are
— the arm 78, the leg 1 10, the hand 26, and the foot 32. In a woman of the
same race the arm is 83, and the leg 120, the hand and foot remaining the
same. In a European skeleton I find the arm to be 80, the leg 1 17, the hand
26, the foot 35.

Thus the leg is not so different as it looks at first sight, in its proportions
to the spine in the Gorilla and in the Man — being very slightly shorter
than the spine in the former, and between Yk, and % longer than the spine
in the latter. The foot is longer and the hand much longer in the Gorilla;
but the great difference is caused by the arms, which are very much longer
than the spine in the Gorilla, very much shorter than the spine in the Man.

The question now arises how are the other Apes related to the Gorilla
in these respects — taking the length of the spine, measured in the same
way, at 100. In an adult Chimpanzee, the arm is only 96, the leg 90, the
hand 43, the foot 39 — so that the hand and the leg depart more from the
human proportion and the arm less, while the foot is about the same as in
the Gorilla.

In the Orang, the arms are very much longer than in the Gorilla (122),
while the legs are shorter (88); the foot is longer than the hand (52 and
48), and both are much longer in proportion to the spine.

In the other man-like Apes again, the Gibbons, these proportions are
still further altered; the length of the arms being to that of the spinal
column as 19 to 11; while the legs are also a third longer than the spinal
column, so as to be longer than in Man, instead of shorter. The hand is
half as long as the spinal column, and the foot, shorter than the hand, is
about %iths of the length of the spinal column.

Thus Hylobates is as much longer in the arms than the Gorilla, as the
Gorilla is longer in the arms than Man; while, on the other hand, it is as
much longer in the legs than the Man, as the Man is longer in the legs than
the Gorilla, so that it contains within itself the extremest deviations from
the average length of both pairs of limbs.

The Mandrill presents a middle condition, the arms and legs being nearly
equal in length, and both being shorter than the spinal column; while hand

BIOLOGICAL BEGINNINGS 37

and foot have nearly the same proportions to one another and to the spine,
as in Man.

In the Spider monkey (AteJes) the leg is longer than the spine, and the
arm than the leg; and, finally, in that remarkable Lemurine form, the Indri,
{Lichanoms) the leg is about as long as the spinal column, while the arm is
not more than ^Msths of its length; the hand having rather less and the
foot rather more, than one third the length of the spinal column.

These examples might be greatly multiplied, but they suffice to show
that, in whatever proportion of its limbs the Gorilla differs from Alan, the
other Apes depart still more widely from the Gorilla and that, consequently,
such differences of proportion can have no ordinal value.

But now let us turn to a nobler and more characteristic organ — that by
which the human frame seems to be and indeed is, so strongly distinguished
from all others, — I mean the skull. The differences between a Gorilla's
skull and a Man's are truly immense. In the former, the face, formed largely
by the massive jaw-bones, predominates over the brain case, or cranium
proper: in the latter, the proportions of the two are reversed. In the Man,
the occipital foramen, through which passes the great nervous cord con-
necting the brain with the nerves of the body, is placed just behind the
centre of the base of the skull, which thus becomes evenly balanced in the
erect posture; in the Gorilla it lies in the posterior third of that base. In
the Man, the surface of the skull is comparatively smooth, and the supra-
ciliary ridges or brow prominences usually project but little — while, in
the Gorilla, vast crests are developed upon the skull, and the brow ridges
overhang the cavernous orbits, like great penthouses.

Sections of the skulls, however, show that some of the apparent defects
of the Gorilla's cranium arise, in fact, not so much from deficiency of
brain case as from excessive development of the parts of the face. The
cranial cavity is not ill-shaped, and the forehead is not truly flattened or
very retreating, its really well-formed curve being simply disguised by
the mass of bone which is built up against it.

But the roofs of the orbits rise more obliquely into the cranial cavity,
thus diminishing the space for the lower part of the anterior lobes of the
brain, and the absolute capacity of the cranium is far less than that of Man.
So far as I am aware, no human cranium belonging to an adult man has
yet been observed with a less cubical capacity than 61 cubic inches, the
smallest cranium observed in any race of men by Morton, measuring 63
cubic inches: while, on the other hand, the most capacious Gorilla skull
yet measured has a content of not more than 34^/4 cubic inches. Let us
assume, for simpHcity's sake, that the lowest Man's skull has twice the
capacity of the highest Gorilla.

No doubt, this is a very striking difference, but it loses much of its ap-
parent systematic value, when viewed by the light of certain other equally
indubitable facts respecting cranial capacities.

38 READINGS IN BIOLOGICAL SCIENCE

The first of these is, that the difference in the volume of the cranial cavity
of different races of mankind is far greater, absolutely, than that between
the lowest Man and the highest Ape, while relatively, it is about the same.
For the largest human skull measured by Morton contained 114 cubic
inches, that is to say, had very nearly double the capacity of the smallest;
while its absolute preponderance, of 52 cubic inches — is far greater than that
by which the lowest adult male human cranium surpasses the largest of the
Gorillas (62 — 34^ = 27%)- Secondly, the adult crania of Gorillas which
have as yet been measured differ among themselves by nearly one-third,
the maximum capacity being 34.5 cubic inches, the minimum 24 cubic
inches; and, thirdly, after making all due allowance for difference of size,
the cranial capacities of some of the lower Apes fall nearly as much, rela-
tively, below those of the higher Apes as the latter fall below Man.

Thus, even in the important matter of cranial capacity. Men differ more
widely from one another than they do from the Apes; while the lowest
Apes differ as much, in proportion, from the highest, as the latter does
from Man. The last proposition is still better illustrated by the study of
the modifications which other parts of the cranium undergo in the Simian
series.

It is the large proportional size of the facial bones and the great projec-
tion of the jaws which confers upon the Gorilla's skull its small facial
angle and brutal character.

But if we consider the proportional size of the facial bones to the skull
proper only, the little Chrysothrix * differs very widely from the Gorilla,
and in the same way as Man does; while the Baboons (Cynocephahis) exag-
gerate the gross proportions of the muzzle of the great Anthropoid, so
that its visage looks mild and human by comparison with theirs. The differ-
ence between the Gorilla and the Baboon is even greater than it appears at
first sight; for the great facial mass of the former is largely due to a down-
ward development of the jaws; an essentially human character, super-
added upon that almost purely forward, essentially brutal, development
of the same parts which characterizes the Baboon, and yet more remark-
ably distinguishes the Lemur.

Similarly the occipital foramen of the Lemurs is situated completely in
the posterior face of the skull, or as much further back than that of the
Gorilla, as that of the Gorilla is further back than that of Man; while, as if
to render patent the futility of the attempt to base any broad classificatory
distinction on such a character, the same group of Platyrrhine, or American
monkeys, contains the Chrysothrix, whose occipital foramen is situated far
more forward than in any other ape, and nearly approaches the position it
holds in Man.

Again, the Orang's skull is as devoid of excessively developed supra-
ciliary prominences as a Man's, though some varieties exhibit great crests

• Squirrel monkey. — Ed.

BIOLOGICAL BEGINNINGS 39

elsewhere and in some of the Cebine apes and in the Chrysothrix, the
cranium is as smooth and rounded as that of Man himself.

What is true of these leading characteristics of the skull, holds good,
as may be imagined, of all minor features; so that for every constant differ-
ence between the Gorilla's skull and the Man's, a similar constant differ-
ence of the same order (that is to say, consisting in excess or defect of the
same quality) may be found between the Gorilla's skull and that of some
other ape. So that, for the skull, no less than for the skeleton in general,
the proposition holds good, that the differences between Man and the
Gorilla are of smaller value than those between the Gorilla and some other
Apes.

Whatever part of the animal fabric — whatever series of muscles, what-
ever viscera might be selected for comparison — the result would be the
same — the lower Apes and the Gorilla would differ more than the Gorilla
and the Man. I cannot attempt in this place to follow out all these com-
parisons in detail, and indeed it is unnecessary I should do so. But certain
real, or supposed, structural distinctions between man and the apes remain,
upon which so much stress has been laid, that they require careful con-
sideration, in order that the true value may be assigned to those which are
real, and the emptiness of those which are fictitious may be exposed. I
refer to the characters of the hand, the foot, and the brain.

Alan has been defined as the only animal possessed of two hands terminat-
ing his fore limbs, and of two feet ending his hind limbs, while it has been
said that all the apes possess four hands; and he has been affirmed to differ
fundamentally from all the apes in the characters of his brain, which alone,
it has been strangely asserted and reasserted, exhibits the structures known
to anatomists as the posterior lobe, the posterior cornu of the lateral
ventricle and the hippocampus minor.

That the former proposition should have gained general acceptance is
not surprising — indeed, at first sight, appearances are much in its favour:
but, as for the second, one can only admire the surpassing courage of its
enunciator, seeing that it is an innovation which is not only opposed to
generally and justly accepted doctrines, but which is directly negatived
by the testimony of all original inquirers, who have specially investigated
the matter: and that it neither has been, nor can be, supported by a single
anatomical preparation. It would, in fact, be unworthy of serious refutation,
except for the general and natural belief that deliberate and reiterated asser-
tions must have some foundation.

Thus, whatever system of organs be studied, the comparison of their
modifications in the ape series leads to one and the same result — that the
structural differences which separate Man from the Gorilla and the Chim-
panzee are not so great as those which separate the Gorilla from the lower
apes.

>>>>>>>>>>>>>>>>>>>>>>>>>>■><<<<<<<<<<<<< <<<<< <<<<<< <■<<•

II

T-^ife a?id the Cell

FOR thousands of years mankind was unaware of the intricate detail
existing in the organic world. No doubt, thoughtful scientists sensed,
in a very real way, the unexplored universe to be revealed later by the
microscope and chaffed at the optical limitations of the human eye.

Our entire concepts regarding the continuity of life, of function, of
reproduction and other topics are bound up with and verified by the
tremendous wealth of data revealed by the specially-shaped disks of glass
in our light microscopes and, lately, by the streams of electrons loosed
by the sensational electron microscope.

When Hooke and Leeuwenhoek first saw the cells of cork and the
bacterial cell respectively, in the seventeenth century, the great search for
the constitution of matter and, indeed, for the mystery of hfe, had begun
in earnest. It was two hundred years later, however, before enough evi-
dence had been collected to warrant the theory that all organisms were
composed of cells. Once this theory was accepted, progress seemed to
come faster. The nucleus, the chromosomes, the cytoplasm, the other cell
bodies were examined and the wonderful stories connected with cell
division and later reduction division were pieced together. These studies
in turn made possible an understanding of the importance of the chromo-
somes in carrying factors for inheritance, the assortment of genes, chromo-
some changes resulting in mutations and other fundamental concepts.

Man has always been interested in his origin and numerous theories have
been set forth, some with rather unconvincing assurance. It seems impos-
sible to many that such a highly organized structure as the cell could
have evolved from inorganic materials. Man's many futile attempts to
duplicate life are a subject of ridicule to the uninitiated. The layman must
always realize that the hardest riddles take the longest time to solve and,
in terms of biological history, we have scarcely started grappling with
the problem. Most scientists feel confident that some generation, in the not-
too-distant future, w ill have all the necessary factors at hand to answer the
riddle of life itself. We also feel confident that once this is solved, several
other as-yet unknown problems will arise to perplex them. The true
scientists are never perturbed at the thought that their contributions are
but bricks in the foundation. Science grows by insistent curiosity and
incessant hopefulness.

40

LIFE AND THE CELL 4 1

"whence COMETH LIFE?" *
WILLIS R. HUNT

Philosophers have for ages attempted to explain life and death and to
determine where one leaves off and the other begins. Present-day scientists
are continuing to investigate this burning question.

Maybe the turning point is where the protein-building catalyst or
enzyme first appears. Although it is non-living itself, it no doubt is the
precursor of life, that is, it precedes and gives intimation of the coming
of life. Possibly the most primitive living unit may be the gene. Have any
of you ever seen a gene? No! It can not be seen even by the ultra micro-
scope, but if we are to account for the hereditary behavior of protoplasm
we must postulate invisible genes. Genes, as you remember, are the units
or atoms of heredity. Other assumptions are that the viruses or bacteri-
ophages may be the most elementary predator or form of life.

It will not be possible to say just where or how life first appears, but some
evidence can now be given that the genes and the viruses are at the
boundary or border line of Hfe.

Like life the origin of disease has been subject to many theories and
much speculation down through the ages. Primitive peoples believed that
evil spirits caused disease. In the Middle Ages invisible particles were
thought to be the cause. Bacteria were not even seen until the middle of
the seventeenth century, and were only proven to be the cause of disease
about sixty years ago.

It has been estimated that there are seven hundred and forty-two living
agents causing disease in man. Thirty-one are ascribed to a something, called
a virus. There are some forty more viruses causing disease in the lower
animals, fowls, insects, fishes and plants. Examples of some virus diseases,
to mention a few, are smallpox, rabies, parrot fever, yellow fever, herpes,
mumps, measles, infantile paralysis, warts, epidemic influenza and the
common cold. Distemper of dogs, foulpox, cowpox, swinepox, jaundice
of silkworms and the so-called mosaic diseases of the tobacco, potato and
the tomato plants are examples of virus diseases in other groups of or-
ganisms.

Just what the nature and properties of these "mysterious purveyors of
disease" are has been one of medicine's and bacteriology's greatest prob-
lems. Up to recently the following three questions had not been answered:
(i) Are viruses animate or inanimate? (2) Are they ultramicroscopic
entities related to bacteria? (3) Do they represent inanimate chemical prin-
ciples like catalysts or enzymes, for example, pepsin, an organic enzyme,
which stimulates digestive changes in the stomach?

• Reprinted by permission of the Scientific Monthly, American Association for the
Advancement of Science. Copyright 1938.

42 READINGS IN BIOLOGICAL SCIENCE

We may define a virus as an infective agent below the size limit of
microscopic determination which passes through the finest made filters.
They are obligate parasites: no saprophytic forms are known. This is not
surprising, is it, since symptoms are the only means of recognizing them?
They can not grow and multiply in artificial culture media, but in tissue
culture, specific for the virus, the infective agent has been developed. For
immunization viruses are propagated by serial injection of animals. Their
behavior is very much like that of a living organism.

An open mind is necessary in regard to the nature of viruses. One of
the smallest known viruses causes foot and mouth disease. It is only large
enough to hold a few dozen protein molecules. Is this consistent with life?
Would it be consistent if smaller viruses were discovered? Does not their
minute size preclude their being alive? It must be remembered that no
virus has a characteristic form or the ability to assimilate Hfeless matter.
Are not form and assimilation two of the chief attributes of life? These
questions can not be answered, for we do not know whether there is a
definite boundary line between the living and the non-living.

As a virus is dependent on living cells for its development, does not this
suggest that they may be derivatives of those cells, an enzyme or catalyst,
for example? Catalysts effect a chemical change. The viruses then may have
the peculiar property of stimulating healthy normal cells to reproduce
more virus substance. The living characteristics that are possessed by a
virus are shown only when the virus is associated with living tissue, namely,
metabolic assimilation of heterogeneous substances, adaptation and re-
production.

On the other hand, the principles of proof that a particular species of
living organism is the cause of a specific disease is stated in Koch's postu-
lates. First, the causal organism must be found in all cases of the disease;
secondarily, it must be grown in successive pure cultures outside the
body; thirdly, the cultures must be able to reproduce the disease in sus-
ceptible laboratory animals or plants, and lastly, the organism must be
recovered from the artificially infected host in pure culture. No doubt if
viruses were living they would follow these postulates. They do not
satisfy number two, namely, cultivation outside the tissue of the host.

Most of the knowledge about viruses has been gained through the study
of tobacco mosaic virus. It is the oldest known. It was first described in
1857, but its filterability was not discovered until 1892. It was then dis-
covered that the extracted juice of a tobacco plant affected with mosaic
would infect a healthy plant if placed into its tissues or rubbed onto the
leaf hairs, even after it had been filtered through a Chamberland filter.

Tobacco mosaic is the most infectious of all virus diseases. Even when
dried and ground into a powder, diseased leaves will still have the property
of infectability after months of desiccation. The virus may be extracted
by ether, chloroform, carbon tetrachloride, toluene or acetone without

LIFE AND THE CELL 43

any destruction of its infective properties. An infinitive amount of the
virus will increase many times over when inoculated into a normal plant.
The symptoms of a diseased plant are the mottling of the leaves due to
alternating patches or spots of light green or yellow, and dark green, but
under certain conditions the mottling may be masked.

In 192 1 a new concept of the nature of the tobacco mosaic was sug-
gested. The substance of this concept was that it was a product of the host
cell, a gene, perhaps, that has revolted from the shackles of coordination,
and having the property of reproduction, continued to produce disease
only in the living plant cells.

As tobacco mosaic virus is the most outstanding in having properties
which are easily worked with, as stated above, and as it is typical and
representative of all viruses it has been experimented with extensively.
Countless numbers of tobacco plants have been grown and infected
artificially. The diseased plants after a certain time were ground up, pressed
and the tobacco juice containing the virus extracted. Protoplasm, in gen-
eral, contains proteins, fats and carbohydrates. Certain enzymes are pro-
tein splitters or digesters. Proteolytic pepsin, as noted before, is an organic
protein digester. This enzyme was added to some of the plant juices in a
test-tube and kept under suitable conditions to see if it would act on the
virus. After a certain length of time a small amount of the solution was
rubbed on the leaves of some healthy plants. No infection resulted after
repeated tests, as the protein causing the disease had been digested. Pepsin
is specific in its action; it will not act on fats, carbohydrates, hydrocarbons
or salts. Therefore a sound conclusion that the virus is protein in nature
can be made.

Certain chemicals such as ammonium sulfate or dilute alcohol will precipi-
tate proteins. They were added to some of the diseased tobacco juice to
which pepsin had not been added. A solid precipitate was thrown down.
A bit of the supernatant fluid was rubbed on healthy leaves. No infection
resulted. A different picture was represented when a neutral liquid, as
water, was added to the precipitate and it was dissolved and then rubbed
on normal leaves. Diseased plants resulted. These two experiments proved
without doubt that the infective agent resided in the protein molecules.

To further prove the nature of the virus, the precipitate was again dis-
solved in a neutral liquid and ammonium sulfate compound was added.
Crystals were formed from the solution. These crystals were refined by
ten successive fractionations and recrystallizations. By this technique all
impurities as well as all living matter was separated out. Why do we say
that living matter was ehminated? Because no protoplasm is known to pos-
sess the property of crystallization. Did you ever see a crystalline gonococ-
cus, amoeba or a "crystalline chicken" either in a coop or walking down
Fifth Avenue on Easter Sunday or any other day for that matter?

Now if these crystals infect healthy plants far-reaching results can be

44 READINGS IN BIOLOGICAL SCIENCE

expected in regard to their nature. A few crystals were dissolved in a
neutral liquid a hundred million or more times their bulk. Healthy leaves
were again inoculated, and all the symptoms of the mosaic virus disease
resulted. The conclusion of this experiment was that the crystals were
made of many protein molecules, and each molecule of this cluster of
crystals is a single virus of the tobacco mosaic disease.

Chemical analysis proves that the virus molecule is very large, a macro-
molecule. Carbon, nitrogen, hydrogen and chlorine have been found in
these molecules, but how many atoms of each and their arrangement is
not known. That is, there is no chemical formula for a virus as yet.

In addition to the above chemical methods the ultracentrifuge clarifies
the evidence as to the nature of these macro-molecules. The ultracentri-
fuge gives us a knowledge of the protein itself, degree of purity and the
extent of its concentration at each step in its isolation. A pure protein in
true solution is made up of molecules of the same size and shape, and it
will sediment at a constant rate in an intense uniform centrifugal field. The
heavier the molecule the greater the rate of sedimentation. The sedimentary
boundaries that arise between protein and solvent are determined by
photographing. The molecular weight of the mosaic virus was found to
be seventeen million times as heavy as a hydrogen atom. We may now
think of this virus as a "macro-molecule" with a structure that must con-
sist of hundreds of thousands of atoms, and may be more.

Is this virus living or non-living? Remember that it can't be cultivated
in a test-tube, but bacteria which seem to be their nearest living relatives
can assimilate, grow and reproduce in this non-living medium. Yet the
only way this virus can grow and reproduce itself is when it is stimulated
by contact with the tobacco plant tissues. An infinitesimal particle will
infect a normal plant and in a few days the whole tobacco crop will be
diseased and producing the original amount of virus a million times over,
is not this ability to propagate itself a property of living things?

Maybe this virus lives a Dr. Jekyll and Air. Hyde sort of life, a dual
personality, alive in certain phases of its existence and raising havoc in a
tobacco field, and under another set of conditions not alive and harmless
as sterile water. It is alive and has the attributes of living things when in
the presence of tobacco protoplasm and non-living in other environments.

This crystalline protein causing tobacco mosaic has many points in com-
mon with a gene. They are about the same size. They both reproduce
under certain specific conditions and can refrain from reproducing for
long periods of time without losing this property when favorable condi-
tions exist. Quite a human characteristic! This characteristic can be il-
lustrated by the inactiveness of the genes in an unfertilized egg of a hu-
man, thank goodness, or in the resting seed of a daisy or the inactiveness of
a virus in dried tobacco leaves or in a spittoon.

Furthermore, the gene and the virus have another similarity in common

LIFE AND THE CELL 45

namely, that of unstability. A gene can and does mutate. The virus may
suddenly change or mutate to a "masked" form showing no mottling, and
this form in turn change into another strain showing a yellow mottling in
place of the original light green. The size of the virus molecule increases
with these mutations.

The gene to be effective must associate with other genes. It doesn't work
alone. A virus must be in contact with living protoplasm to be effective. Is
this single gene or virus molecule alive? The evidence points to the
answer, "No."

Azotobacter is a heterotrophic genus of nitrogen-fixing bacteria which
is able to use free uncombined nitrogen of the atmosphere. It grows in
well-aerated arable soils; it is a strict aerobe. Azotobacter is about the size
of a yeast plant cell. It obtains its energy from the oxidation of carbohy-
drates in the soil, and takes in free nitrogen from the air for the synthesis
of protoplasm. Is not this a property of living organisms?

Some Russian chemists recently carried out a very interesting experi-
ment. A culture of these bacteria were grown. They were then crushed
and their juices filtered off. There were no traces of the cell present. To
this filtrate a carbohydrate was added, oxygen and nitrogen gas were bub-
bled through the liquid. This filtrate then produced ammonia like the
culture of hving bacteria in the flask of nutrient broth. What was pro-
duciuQ" the same chemical reaction in the lifeless fluid that was carried out
by the living bacteria in their metabolic activities? Enzymes were no doubt
responsible in both chemical reactions. More ammonia was produced in
the test-tube than in the living culture. May not this be explained by the
fact that in vitro the enzymies were not shackled with the extra burden of
producing the characteristics of life?

We are still at the starting line of life, and much more work will of
necessity have to be done before we can answer all the questions in regard
to the nature of genes and viruses. Can't we make the assumption that
the organization of matter is just a step in the production of life? Isn't it
a matter of complexity of organization from these simple bacteria through
the protozoa and metazoa to ourselves? Doesn't matter itself start from
protons, neutrons and electrons, combine to form atoms, and atoms to
form molecules, and aggregates of molecules to form crystals?

Is not the phenomenon which we call hfe the chief difference between
these organizations? Somewhere and somehow in the general mixup in
the formation of carbohydrates, fats and proteins from simpler substances,
the catalyst or enzyme makes its appearance. The first catalysts may make
amino acids, other catalysts simple proteins from these amines, and then
other catalysts more complex proteins. The association of many proteins
to form large molecules may be the first genes. These genes arranged
themselves in strings to form chromosomes, specialization developed and
the attributes of life were exhibited. From the evidence which has been

46 READINGS IN BIOLOGICAL SCIENCE

given there seem to be two possibilities as to where life first appears,
either as macro-molecules in the form of genes or macro-molecules as
viruses. Both genes and viruses fit in part into the Mechanistic and the
Vitalistic theories of life. But whatever the first form of life was, we may
well assume that the enzyme is the precursor of life, and whenever it finds
itself in a favorable environment it becomes active and Ufe begins.

THE LENS TURNED ON LIFE *
DONALD CULROSS PEATTIE

It is Sunday, with a Sabbath meekness on the face of things. Across the
roll and dip of the great plain I saw, as I went walking with my black-
thorn, the distant woods as blue-black, rainy-looking islands upon the im-
mense watery prairie, and near at hand the young yellow of the willow
whips, first brilliance of the year. Now this was a scene a midlander could
love, but I went thinking, thinking, wagging that human tail my cane, how
all that I saw came to me thus only because of a specified convexity in the
cornea of my eye.

The trouble with our human concepts is that we are so pitifully small
when it comes to the great, and so unbearably gross when it comes to the
small. We occupy a position in the scale of things that is somewhat on the
trivial side of total mediocrity. Little wonder if our ideas are mediocre
too.

One comes at last to feel that the invention of the microscope by Janssen
of Holland in the seventeenth century was the beginning of modern natural
history, for the lens added a new dimension to our eyes and enabled us
literally to see to the heart of many a problem. The sentence I have just
written sounds good enough to pass unchallenged. But it sounds better
than it is, for it seems to assert that one man invented the microscope, and
it leaves us to infer that, once it was invented, men, peering through it,
saw truth at last. In fact, however, having seventeenth-century minds,
they did not in the least make of what they saw what we would. Except for
a few larger minds, the early microscopists were largely engaged in
watching the antics of fleas.

And the revolution in biological thought consequent on the use of the
microscope did not take place in the seventeenth century but in the un-
finished century, 1850 to our times. It is the modern technical improve-
ments, coupled with the forward march of allied sciences, that have created
the merciful triumphs of bacteriology, carried us into a deep perspective
of atomic structure and brought light into the dark mystery of protoplasm

* Reprinted from Green Laurels by permission of Simon and Schuster, Inc. Copy-
right 1936, by Donald Culross Peattie.

LIFE AND THE CELL 47

itself. The seventeenth-century microscopy was necessarily limited by
the imperfections of the early instruments, and still more by the state of
the allied sciences at the time. But it was, none the less, an era of high
adventure in natural history, for the lens, however faulty, gave to all
greatly inquisitive minds the first rapturous look at the wonderworld of
structure. Without that glimpse, steriHty would have fallen upon further
inquiry, so that the microscope seems to have come not a moment too soon
in the history of natural science.

If I were writing the history of biology, I would tell how the century
had been electrified at its opening by Harvey's announcement of the cir-
culation of the blood, and how others applied themselves to the great un-
finished business of measuring that mortal tide. When Malpighi turned
his lens upon the structure of the lung, he saw for the first time why it is
that man draws breath. When Leeuwenhoek peered through his home-
contrived microscope, he found the corpuscles of the life stream, that no
eye had seen before — and was tickled in his bourgeois soul to set Swam-
merdam right about them. The heart, the brain, the glands, the nerves,
every organ of the human and his fellow vertebrates, became subject to
intensive scrutiny. And that scrutiny for the first time revealed the func-
tions of the organs. It is almost impossible for me to believe it, but it is
true that not so long ago men did not know that the brain was the seat of
thought; some believed that it cooled the blood. No one ever thought
more nobly than Plato, but he never guessed what he was thinking with.
He had no idea that whatever else thought may be, it is also a physical
process, like digestion. So biology was at last founded upon the structure
of life itself, and natural history, which is the outdoor view of biology,
was tethered at last to physical realities.

Young Jan Jacobz Swammerdam impresses us now as the greatest bi-
ologist of his age, and once more I am going to slight many accomplish-
ments and tell my story in terms of what Swammerdam learned of the
cryptic, multiplex and jfantastical insect world.

For the insects constitute an exception to almost everything you can
say about the rest of the animal kingdom. You no sooner think that you
have established a law, discovered a fundamental plan of animal architec-
ture, or learned a secret of function, than you find some long-faced grass-
hopper sneering denial at you. The very stuff of which the insects are
made is not like ours. They are not built of bones, but encased in chitin.
Chitin is the horn of the rhinoceros beetle, the wing of the dragonfly, the
sting, the eye, the armor, the hairs, the antennae, the very thread on which
the spider escapes you. Nothing will so permanently revise your biological
outlook as to discover how different an animal may be from yourself and
still in its own environment be a king. The insect, for instance, has what
may be called a brain, but how differently constituted. Its sensory receiv-
ing organs are scattered, not concentrated into a federal government, so

48 READINGS IN BIOLOGICAL SCIENCE

that some ants seem to smell with their feet and even in utter blackness so
find their way upon a beaten track, whether by smell or touch, that that
thought which is memory seems practically to reside in their six wire-like
legs. Whereas our sense of balance is located above the Eustachian tubes near
the ear, it appears in some insects in a particular joint of the antenna. This
sort of topsyturvydom could be developed at length, but it is obvious that
the first man who with a clean strong lens and a cool head broke into the
hitherto locked world of insect anatomy found himself in an Aladdin's
cave of new truths. Of what he saw, Swammerdam made drawings that
in three centuries have not, I think, been surpassed.

Throwing health and honor to the winds, Swammerdam achieved a
work that was epochal. Singlehanded he discovered half the secrets of the
hive. Where Aristotle had seen a king bee as the ruler of the apian com-
munity, Sw ammerdam detected the matriarchy, and proved that the queen
is the only effective female of the hive. He unmasked the infinitely effete
drones as the true males, and the workers as neuters. He put forth deHcate
skill, such as the world had never seen, to reveal the anatomy of the eyes
and sting and proboscis — that marvelous tongue that dips in the deepest
nectaries of the flowers. Of the bee eye nothing escaped him; he saw the
many-faceted eyes which are largest in the drone, and the three other
eyes that no one else had ever noticed, simple eyes like ours. He alone knew
that the compound eye was not a collection of such cameras as our eyes
that have pupil and iris, but that it is rather a window, admitting almost
all the light that falls on it. As for the sting, he knew that it is curved in the
queen, straight in the worker, and wanting in the drone. He experimented
with its venom, thrusting the darts into his arm, swallowing the poison,
rolling it on the sensitive tip of his tongue. With such a knowledge of
bee anatomy as this, science was now for the first time in a position to
generalize upon the economy, politics and behavior of the hive. Greatest
of the Dutchman's triumphs was his discovery of the metamorphosis of
insects. The egg, the caterpillar, the pupa and the butterfly are all, he
proved to an astonished Europe, one and the same individual in different
growth stages.

I am come now to the last of the three great microscopists of the age,
Antony van Leeuwenhoek. Wealthy, but self-made, an expert lens grinder
who increased magnification up to two hundred and seventy diameters
before he realized that more median lenses give the best results, unwilling
to part with the secret of his art, shrewd with a sort of magnified common
sense, gossipy, stubborn, ignorant of any language but Dutch and con-
temptuously proud of it, Leeuwenhoek of Delft was one of the most
eccentric personalities of the scientific age, and you may be sure that his
English friends in the Royal Society did not miss a wrinkle in his character.

He had, boylike, discovered the sheer rapture of looking at the whole

LIFE AND THE CELL 49

world through a lens. Not only were his lenses more sensational than any-
thing that had yet been produced, but the eye at the objective was
shrewder, brighter, more restless. There was only oile trouble, and that
was that the mind behind the lens was not the equal of the crystal or the
cornea.

The inveterate Peeping Tom of Delft called his opus Secrets of Nature,
and some of the secrets he revealed were the human male's spermatozoa,
the bacteria he found in his mouth by scraping his back teeth, the genera-
tion of fleas, the eggs of tadpoles, and the true nature of the red corpuscles
of the blood. His minor discoveries are almost endless, though he never
had the patience to tunnel through until fact met fact in a significant pene-
tration. There was even a moment when he made an absurd pretension —
he declared that he saw in the spermatozoon a whole tiny man, body and
limbs and head.

He drove nails in the coffin of the spontaneous generation theory by his
discovery that vermin are not bred out of filth but come from eggs laid
there by their predecessors. He revolutionized our view of sex, diminish-
ing the importance of the male, when he showed that plant aphids re-
produce parthenogenetically, by a sort of virgin birth of endless fatherless
generations. He found the true egg of ants, and revealed that what are
called and still sold as ant eggs are in reality ant pupae in their chrysalids.
One day he discovered the striated nature of muscles, and another he dug
out of his rain gutter those fascinating dervish animalculae, the rotifers.
He started enough lines of inquiry to found a whole school of biology —
and yet he was so jealous of his knowledge that he never took a pupil.

It was in this era, too, that man first worked on the fascinating problem
of the irritability and motions of plants, stimulated to it by the arrival
from the tropics of a mere botanical curiosity, the sensitive plant. It was
an era when men began to suspect and assert — though they risked the rack
for it — the animate nature of fossils.

So it may seem to us that the colorful seventeenth century was almost
within sight of our own, as it pursued the nature of the cell and attacked
the paralyzing myth of spontaneous generation, penetrated close to the
heart of sex and unwrapped the mystery that clings around the seed. We
have the feeling that the men of that age were coasting along golden shores
that were hidden from them in thin mists, and that with a little more per-
severance, vision and daring, they would have had a landfall of twentieth-
century discovery.

■>>><<<

50 READINGS IN BIOLOGICAL SCIENCE

HOW LIFE BECOMES COMPLEX *
S. J. HOLMES

Lest the reader be led to expect a discussion of the distractions of living
in our modern society, I may explain at the outset that this is a purely bi-
ological article. It deals with the complexities of the life processes in plants
and, especially, in animals, and how these complexities came about.

Life presents an enormous range in complexity from that of the human
body down to the bacteria or organisms even simpler, such as the filter-
able viruses, if they are organisms at all. An amoeba carries on the same
fundamental Hfe processes as a man, with almost no organs. It moves with-
out muscles, transmits stimuli without nerves, digests without stomach
or intestine, respires without lungs or gills, and reproduces its kind by
pinching itself in two. An amoeba, which is by no means the simplest form
of life, is the product of long series of evolutionary changes. It occupies
a niche in nature in which it has persisted with little change for millions
of years, during which other animals have forged ahead and acquired
structural organizations of great complexity and almost endless variety.
If we compare the structure of a frog, an insect, a clam, a starfish or an
earthworm, we find remarkable differences of form and internal organiza-
tion but the diverse organs of these animals are devoted to the discharge of
the same essential functions. All of them have organs of digestion, ab-
sorption, respiration, excretion and reproduction. The varied structures
of these animals represent so many different w^ays of solving essentially
the same physiological problems. Why all this bewildering variety of
structure and pattern?

Obviously, life as it has become more complex has followed many dif-
ferent paths. For the most part we can not say that one animal solves its
problems better than another. The amoeba gets along very well in its way,
and so does the starfish, the spider, the squid, the porpoise and all the rest
of our animal relatives. They persist and perpetuate their kind, and pos-
sibly enjoy life after their fashion, and this is about all a hving creature can
reasonably expect. As Aristotle observed, the activities of all organisms
center about two ends — the preservation of the individual and the perpetua-
tion of its kind. These are the two great problems that face every living
creature. Death to the individual or its kind is the penalty for failure to
discover the correct solution. Organisms have tried different ways — mil-
lions of different ways — of finding an answer to these Sphinx riddles, and
the number of right answers that have been hit upon is indicated by the
multitudinous diverse types of plant and animal life. A higher type of
organization would be of no advantage to a creature in certain situations.

* Reprinted by permission of the Scientific Mo7ithly, American Association for the
Advancement of Science. Copyright 1941.

LIFE AND THE CELL 5 I

If an animal or plant occupies a niche to which it is well adapted, it may-
persist almost unchanged for an indefinite period of time. The lamp shell
Lingula has changed very slightly since the Cambrian period. For animals
that bury themselves in the sea beach, life some hundreds of millions of
years ago was probably much the same as it is to-day. All along the course
of organic evolution there are forms that have found their niche and have
stayed there, while others that were more adventurous explored new fields
and acquired profound changes in adaptation to different kinds of environ-
ment.

There are some types of environment that favor an advance of or-
ganization, and life, which is ever ready to take advantage of opportunities
for its own increase, has developed there into higher forms. Nature ap-
parently strives to fill all kinds of situations with living inhabitants. What
she seems to be interested in is having as many children as possible. Whether
they are high or low in the scale is a quite secondary matter. Certainly,
Nature has been remarkably successful in producing offspring of the most
compHcated structure along many different lines, and we may now con-
sider some of the ways in which she has achieved this end.

One important influence is an indirect result of mere increase in size.
Every student of elementary geometry has learned that as a body increases
in size its surface increases as the square of its diameter, while its volume in-
creases as the cube. When a body grows, therefore, its volume increases
disproportionately to its surface. This fact has very important conse-
quences for living organisms. In a spherical organism of i, 2, 3 or 4 inches
in diameter, for instance, the surface areas would be as i, 4, 9 and 16, while
the volumes would be as i, 8, 27, and 64. But if the Hfe processes went on
at the same rate in these organisms, there would be a more rapid exchange
through a given area of surface in the large organisms than in the small
ones. As size increases, absorption of nutriment, the elimination of waste
and exchange of gases in respiration will have to be carried on so much
faster through a given area of surface that further growth would be auto-
matically checked. Perfectly spherical organisms of homogeneous struc-
ture, therefore, could not attain a very large size; they never do. Where
any considerable size is reached in a plant or animal, it is always attended
with structural devices for increasing surface in relation to volume.

A good deal of the complicated anatomy of higher animals is a result
of extending surfaces devoted to the fundamental vital processes of absorp-
tion, excretion, digestion and respiration. Small animals can obtain suf-
ficient free oxygen by absorbing it through the body-wall. But where
size increases, relatively more surface is required for respiratory exchange.
Aquatic animals quite generally meet the situation by pushing out the integ-
ument to form gills. Among terrestrial animals gills, unless protected by
structures by which they are kept moist, are usually replaced by organs
that ramify within the body and thus keep respiratory surfaces protected

52 READINGS IN BIOLOGICAL SCIENCE

from desiccation. Our lungs, for instance, are outgrowths of the anterior
part of our digestive tube. The finer subdivisions of the bronchial tubes
lead to very thin-walled air cells through which respiratory exchange
readily occurs between the air and the blood in the capillaries with which
the air cells are richly supplied. If our lungs were ironed out, so to speak,
the total area of their surface in intimate association with the blood would
be about equal to the wall space of a fair-sized room.

In organs devoted to absorbing food the same principle is abundantly
illustrated. Consider the surface of a large tree with its numerous leaves
having expanse which may be more than an acre in area. In this expanse of
leaves the carbon dioxide of the air is absorbed and, together with water, is
built up into carbohydrates under the influence of sunlight. And in the
root system with its millions of root hairs there is a great expanse of sur-
face through which water and salts are absorbed from the soil. Organs
of excretion, such as our kidneys and their numerous coiled tubules, are
devices for bringing a large area of excretory cells into close relationship
with the blood. The same statement applies to glands of all sorts, whether
devoted to the elaboration of digestive juices or the production of other
substances. If we survey our own bodily structure or that of any other
complex animal and consider how much of its make-up consists of exten-
sions of surfaces involved in absorption, secretion, excretion and respira-
tion, we will find that we have included no small part of its structural com-
plexity.

But the story by no means ends here. In order to live at all every organ-
ism, even the simplest, must perform the basic functions of absorption,
assimilation, respiration, excretion, conduction and reproduction. But in
order that these basic functions can be discharged in a more highly de-
veloped organism, other activities subservient to them have been super-
added. Let me illustrate. All organisms must take in nutriment from the
outside. In animals the food usually requires to be digested before it can
be absorbed and gain access to the living protoplasm. The essential feature
of digestion is splitting up food substances by means of enzymes, or fer-
ments until they are rendered capable of solution and diffusion through
living membranes. Digestion is a process subsidiary to absorption. The
amoeba performs this function in little vacuoles in its protoplasm formed
by the secretion of fluid around engulfed particles of food. These vacuoles
disappear after their work is accomplished, and the undigested residue of
the food is expelled to the outside. They are little stomachs improvised for
the occasion. In a hydra we have permanent specialized organs set apart
for the function of digestion, but the structures involved are of a very
simple and primitive kind. In striking contrast with this is our own diges-
tive machinery with its comphcated stomach and intestine and the highly
developed glands of liver and pancreas, to say nothing of numerous small
glands elaborating their specific kinds of digestive ferments. But where

LIFE AND THE CELL 53

SO much apparatus is devoted to digestion and absorption, still more ap-
paratus is required in order that the parts can carry on their work. We have
muscle fibers in the walls of the alimentary canal which in the esophagus
aid in swallowing, and in the stomach bring about the churning motions
that facilitate the chemical part of the digestive process, while in the in-
testine they effect the discharge of food along its course. All these parts are
equipped with blood vessels which supply oxygen, remove waste and carry
away absorbed food materials to be distributed to other parts of the body.
And, again, the movements of the muscular coats of the alimentary canal,
the secretions of glands and the regulation of the blood supply are co-
ordinated through the agency of the nervous system and also by special
kinds of hormones or internal secretions. These agencies are required to
make it possible for the parts more immediately concerned in digestion
and absorption to function in an adequate manner.

But in addition to the organs that are directly accessory to the digestive
apparatus, animals are equipped with tentacles, teeth and various other
organs for the capture of prey. The sharp claws of the cat, the poison
glands of the spider and the tentacles of the octopus are all devices to en-
able their possessor to capture prey upon which the digestive juices of these
animals may act. But further complications arise by the development of
organs and instincts subsidiary to these activities of capturing and over-
coming prey. A striking instance is furnished by the common orb-weaving
spiders. Toward evening in summer time one may often witness the mar-
velous performance of spinning an orb web. The making of the frame of
the orb, the placing of the rays, the spinning of the spiral of sticky web
and the formation of the central disc, or hub, are carried out with a nicety
and precision that have excited the admiration of all observers. The web
finished, the spider takes up its position head downward in the center, with
its feet on the rays where they readily feel the agitation conveyed by the
struggles of an entangled insect. Following the signal, the spider rushes out
upon its prey, often employing more web in the endeavor to impede the
movements of its victim. Then comes the sudden rush, the burial of the
fangs and afterward the leisurely meal. Here we have a complex series of
acts in preparation for capturing prey, which in turn is a preparation to the
acts of overcoming and feeding upon it, and these activities in turn are
more directly subservient to the various acts involved in digesting and
absorbing food.

We might take another illustration from the industry of the hive bees,
among which there is not only food collecting, but food storing, and, in
preparation for food storing, the construction of the beautifully regular
six-sided cells of the honeycomb. Or, again, we might cite the grain gather-
ing and storing of the agricultural ants and the peculiar fungus-growing
industry of certain species of ants and termites. These activities, indirectly
accessory to nutrition, often involve the evolution of highly specialized

54 READINGS IN BIOLOGICAL SCIENCE

organs for their performance. Among such are the pollen basket on the
hind legs of the hive bee, the pollen combs, the wax glands on the under-
side of the abdomen, and the peculiar wax pincers by which the scales of
wax are removed. The whole structure and instinctive behavior of the
worker bee have been profoundly modified in relation to the accessory
nutritive activities upon which she unselfishly spends so much of her en-
ergies. We thus see how, in relation to the primitive function of nutrition,
one complication leads on to another, and this again to a third, and so on.
The basic vital process of (A) absorption becomes associated with the
preliminary and preparatory activities of (B) digestion. These may finally
involve. elaborate mechanisms for their discharge, but subsidiary to these
there are worked in (C) specialized modifications of the muscular and
nervous systems, to say nothing of other parts. Subsidiary activities of
collecting food, involve often, complicated structures and modes of be-
havior, and subsidiary to these, again, we have (E) such acts as web spin-
ning and comb making, and many others, each entailing more or less ex-
tensive changes of structure and behavior. In this way life becomes more
and more complex.

We see much the same sort of thing exemplified in the development of
industry. One may manufacture such articles as cigarettes with a very
simple layout. A few girls with very simple apparatus could turn out a
goodly number of these articles in a day. But if a primitive plant should
grow into a large factory, we would find the installation of more complex
machinery and no end of accessory activities. There would be janitors,
bookkeepers, stenographers, business managers, traveling salesmen, special
buyers, pay clerks, advertisers, night watchmen, and perhaps attorneys
and plain clothes detectives, all of whom would be engaged in work sub-
sidiary, directly or indirectly, to the fundamental function of the factory.
Although the basic function of nutrition may be a more complicated proc-
ess than making cigarettes, it comes to require in special cases a vast deal
of machinery to carry out the subordinate activities and the activities sub-
sidiary to these, and so on to the spinning of the spider's web and the build-
ing of the comb of the hive bee.

It would be instructive to consider another illustration of how compli-
cations pile up in the evolution of life, and this time I will select the process
of reproduction, which is certainly a basic vital function characteristic of
all species of living organisms. Its simplest manifestation is in the fission
of a very primitive form of life, such as a bacterium. The propagation of
all but the simplest of the one-celled organisms commonly involves in
some part of the life cycle the intervention of sex. So far as is known, the
bacteria, the blue-green algae and some other groups are primarily sex-
less. Doubtless, life existed on the globe for many millions of years before
sex entered upon the scene, but it is a significant fact that it never evolved
very far. One might indulge in flights of fancy as to what plants and animals

LIFE AND THE CELL ^^

might be like if evolution had continued to go on without the development
of sex. Certainly, the higher animals, if there were any, would be very
different from what they now are structurally, physiologically, emotion-
ally and intellectually. The reader may try to imagine what sort of crea-
tures they would be. His guess would be as good as that of the professional
biologist.

We shall not discuss the problem of the biological significance of sex
further than to state that its great importance in evolution is attested by the
fact that only very primitive organisms were evolved until the advent
of sexual reproduction. Then evolution took a spurt upward. The most
primitive manifestation of sexual reproduction is the conjugation of two
similar simple organisms. Both the nuclei and the surrounding protoplasm
of the conjugants fuse to become one flesh, after which often following a
resting stage, multiplication by fission goes on as before. At first there is no
clear distinction of male and female, but in many one-celled organisms,
plants as well as animals, the conjugating individuals are differentiated into
a large, relatively immobile female cell and a much smaller, actively swim-
ming male cell. This differentiation parallels the differences between the
ovum, or egg cell, and the spermatozoon of the higher animals.

In all the multicellular animals the sex cells are sharply differentiated
into eggs and sperm, but in more primitive groups, such as sponges, corals,
jelly fish and many worms and molluscs, sexual reproduction is usually
accomplished quite simply by discharging the eggs and sperm into the
water and leaving their union to chance. In all but the simplest of the multi-
cellular animals the sex cells are produced in specialized organs, often pro-
vided with ducts for their transfer to the outside. But sexual reproduction
does not involve elaborate behavior or many accessory structures until
the development of internal fertilization. This step is one of tremendous
importance for further evolution. We see it foreshadowed, as it were, in
certain groups of animals in which the fertilization of eggs still occurs
outside the body, by the development of instincts that bring about a close
association of the sexes during the breeding season. During the period of
egg laying in fishes, for instance, the female is closely followed by the
male, who frequently rubs against her body and discharges his milt, or
sperm, over the eggs as soon as they are extruded. In the breeding season
the males of many species develop brighter colors and, sometimes, small
bodily protuberances and other structures associated directly or indirectly
with the function of mating. These modifications are not, as a rule, exten-
sive. In frogs, toads and some other amphibians a closer association of the
sexes is secured by the clasping instinct of the male. As in fishes, the dis-
charge of the eggs from the female prompts the simultaneous discharge
of the sperm from her male companion, the eggs being fertilized in the
water by the sperm which penetrate their jelly-hke covering. That such
mating habits probably led to internal fertilization is indicated by the fact

56 READINGS IN BIOLOGICAL SCIENCE

that among both fishes and amphibians there are species in which the eggs
are fertilized within the body of the female, as they are in all the higher
classes of vertebrate animals. But, however fertilization of eggs within
the body may have been originally accomplished, the process once started
has entailed most elaborate developments; it has led to the evolution of
diverse structures for the transfer of sperm cells, organs for clasping the
female, and the perfection of organs of sight, smell and hearing which en-
able the males to discover the whereabouts of the other sex. The enormous
eyes of the drone honeybee and the elaborately developed antennae which
are the olfactory sense organs of male moths are among the many evidences
of the influence of the function of mating upon the evolution of organs of
sense. When internal fertilization is once evolved, the male is confronted
with the problem of distinguishing the female of his own species from all
other kinds of living creatures. Here is one of life's hurdles which must
be surmounted if the species continues to exist. Consider, for instance, the
nuptial flight of the queen bee. When the young queen makes her first
flight into the air, a number of the big-eyed drones immediately start in
pursuit. Their course is directed not only by sight but by odor, which they
detect by their well-developed antennae, which are much more richly
supplied with sense organs than those of the queen or worker. Mating takes
place in the air and the process is usually fatal to the male. The sperms are
stored in a special receptacle in which they may Hve for years. Apparently,
the queen controls the outlet of this organ because eggs laid in drone cells
are not fertilized and hence develop into drones, while those which are
fertilized develop into queens or workers. In this case internal fertihzation
involves not only specialization of the reproductive apparatus of both sexes,
but the elaboration of organs in the male useful in distinguishing and fol-
lowing the female. The function of mating has, so to speak, put a premium
upon the development of activity, acuity of sense, powers of discrimina-
tion and special aptitudes of various kinds. It has thus been a potent factor
in the evolution of mind, as well as bodily organization. This is indicated
especially by the frequently elaborate behavior of many animals prepar-
atory to the act of fertilization. In birds especially, but also in certain in-
sects and spiders, the male performs various antics while courting the
female, as Darwin has described in much detail in his writings on sexual
selection. Courtship is obviously an activity subsidiary to the union of
the sexes and it has led to the development of many structural features and
special instincts for display. The brilliant ornamentations of male birds, so
wonderfully manifested in the peacock's tail and the plumage of the birds
of paradise, is associated with instincts for the efl:'ective exhibition of these
attractions. A large part of the courtship of male birds involves also the
employment of song. Doubtless, few people have ever reflected that the
voice owes its origin and at least the early stages of its evolution to its use
as an aid to mating. The power of making sounds is possessed in greater

LIFE AND THE CELL 57

or less degree by many kinds of insects, but where it is conspicuously
manifested, as in crickets, katydids and cicadas, it is employed in courtship.
In the vertebrates, although there are a few fishes that make noises of un-
certain function, the voice proper first appears in amphibians. The breed-
ing season in the spring is the time in which the croaking of male frogs is
most vociferous, and it has been observed that the females go to the local-
ities from which the croaking proceeds. In both the birds and the mammals
the voice has acquired other sexual functions, but it still retains its primi-
tive employment as a sex call, a function which has received perhaps its
acme of perfection in the song of the nightingale. To a certain extent vocal
sounds are made in connection with the battles of the males for the posses-
sion of the females, as is exemplified by the nocturnal encounters of tom
cats and the challenge uttered by the bull moose as he goes on the war
path against possible rivals. But in these cases also the use of the vocal
apparatus is closely associated with the function of mating.

With the evolution of parental care the voice comes to be extended be-
yond its original sexual function and is employed in different ways in
fostering and protecting the domestic group. The danger chirr of the
mother quail sends her flock under cover; the cluck of the hen keeps her
brood closer around her, and her peculiar call indicative of the discovery
of food brings the young chicks to share the prize. And the cry of the
young mammal causes the mother to rush to the defense of her offspring
or to supply its nutrient wants. Crying, by the way, plays a very impor-
tant biological function which human beings share with their humbler
mammalian relatives. It is the part of human language which rests upon
a basis of pure instinct. It is a call for help prompted by hunger, distress,
fear or perhaps merely the desire for attention, as it may come to be in
spoiled babies. On the other hand, the response of the mother to the cry
of her infant is doubtless prompted by a strong instinctive impulse even
in human beings, as it clearly is in lower mammals.

As social groups came to be evolved, the voice comes to be employed as
a means of integrating the activities of the members. Warning cries, grunts
of satisfaction in comradeship, cries of distress that bring others to the
defense of an animal that is attacked and many other utterances which are
instinctively made and instinctively responded to are wide-spread among
the higher social and gregarious animals. Finally in man the voice comes to
be employed in articulate speech with all that this implies for the further
evolution and cultural development of mankind.

We have already commented on our inability to predict what kind of
organic world would have been evolved had it not been for the advent of
sex. Very probably its highest products would have been voiceless, and
since organs of hearing tend to go along with organs for the production of
sound, the creatures would have probably also been deaf.

I must point out also another line of development which has grown out

58 READINGS IN BIOLOGICAL SCIENCE

of activity associated with, and subsidiary to, the function of reproduction.
This is the evolution of parental care. Maternal affection does not enter
upon the scene until comparatively late in the evolution of animal life.
The whole vast groups of worms, molluscs, echinoderms and Crustacea
do not manifest the least solicitude for the welfare of their offspring.
The same statement is true for the great majority of insects, spiders, fishes
and amphibians. Among the lower invertebrate animals the discharge of
the sex cells into the water fulfills all responsibility for the perpetuation
of the species. In the higher invertebrates the simple physiological func-
tions of producing and discharging sex cells are accompanied by accessory
activities of various kinds. Aiany species of insects devote much care to
laying eggs in situations that provide food for the future larvae. One might
write a whole treatise on the varied and highly specialized modifications
of egg laying. The cabbage butterfly is careful to deposit her eggs upon
cabbages, mustard or some other member of the natural order of Cruciferae.
The mother blowfly chooses meat, if tainted so much the better. The
solitary wasp, according to its kind, hunts out a narrowly restricted group
of beetles, grasshoppers or insect larvae, stings her victim so as to paralyze
but not to kill it, lays an egg upon it, buries it in a hole, carefully fills the
hole with dirt, then leaves her progeny to its fate. No maternal affection
here. In fact, the mothers do not recognize their offspring as any kin of
theirs, if they see them. The whole elaborate and highly specialized per-
formance is gone through blindly and instinctively. There are many
kinds of insects which spends much effort in making receptacles for eggs
and in storing food for their progeny. Numerous species of solitary bees
provision their nests with pollen and honey which the larva feeds upon.
Only in a few species do the mother bees remain with the nest and supply-
food directly to the larvae after they have hatched from the eggs. Care
for eggs long antedates care for what comes out of the eggs. But when the
association between the parents and their living offspring was once estab-
lished, a hne of evolution was started which has led to the most momentous
consequences for the further development of animal life.

I shall pass over the manifestations of care for offspring as it has devel-
oped in ants, bees and termites among social insects, and its temporary
appearance in a few groups of fishes in which the parents may accompany
the young for a short time until the school becomes scattered. In birds
one may find various stages from types in which the parents foster and
protect the young for a short time and then leave them to shift for them-
selves, to the domestic behavior of the higher song birds which raise their
broods in carefully constructed nests and spend much of their time in keep-
ing the nests clean, brooding their offspring and finding food to fill their
hungry mouths. The more care is expended on offspring the more help-
less they become, and the more dependent they are upon the ministrations
of their parents. Successive generations become more closely tied together.

LIFE AND THE CELL 59

In solitary wasps they are completely separated. Neither knows the other.
In the robin they are intimately united for a prolonged period. One may
often see a nearly full-grown robin soliciting and receiving food from its
indulgent parents after it is perfectly able to forage for itself.

Among the mammals, the care of offspring has become part and parcel
of the perpetuation of life. In fact, the possession of mammary glands, the
unique structural feature to which the class of Mammalia owes its name,
would be valueless in the absence of the maternal instinct to foster and
nourish the young, and the correlated instinct of the young to obtain its
food from the maternal fount. As in birds, parental care increases, as a
rule, as we pass from lower to higher forms. In the apes it is exhibited in
many ways that appear quite human. We may regard it as the source of
social sympathy and affection. It is the earliest form of true altruism. With-
out it man would probably never have become a "normal animal," as he
was said to be by Herbert Spencer.

Parental care, as I have attempted to show (although lack of space for-
bids producing sufficient evidence for this conclusion), is an outgrowth
of accessory reproductive activities which have been superadded to the
more primary reproductive functions. If it has afforded the evolutionary
basis for altruistic behavior it is because reproduction is fundamentally
and essentially an altruistic function. It is concerned not with the individ-
ual per se but with others. We can not say that altruism evolved out of
egoism. Both are present in the simplest organism that divides by fission.
Both are coeval with life itself.

THE QUEST FOR THE MYSTERY OF LIFE *
H. GORDON GARBEDIAN

Why do we fall sick? Why do we grow old.^ And why do we die? We
would have the answers to those great riddles if we could find the answer
to the more fundamental problem: Why do we live?

To explain the life process has become the great quest of modern science.
That search is already yielding surprising results and unusual benefits to
mankind, and if it succeeds in giving us an understanding of the complex
phenomena of Hfe it would be the crowning glory of man.

Artificial life created out of non-living stuff in the laboratory is a dream
as old as the alchemists' ambition to make gold out of lead. Present-day
investigators have obtained results which tend to show that it is possible
to make artificial "cells" which contain the spark of life and which are

* Copyright 1933 by H. Gordon Garbedian. Reprinted by permission of Crown
Publishers.

6o READINGS IN BIOLOGICAL SCIENCE

wonderfully suggestive of the possible future realization of the ancient
dream of man-made Hfe. These studies have led some biologists to surren-
der the idea of natural death and to reach instead the daring conclusion that
death is "accidental."

,Most biologists today prefer the definition given by G. H. Lewes, that
"life is a series of definite and successive changes both in structure and in
composition, which take place in an individual without destroying its
identity."

In his eager desire to find the key that will unlock the mystery of the
life process, the scientist has speculated about the awe-inspiring theme
of the origin of life. Tracing backward the history of man's evolution, we
come to a point beyond which we can go no farther. Through mammals
we go back to the age of reptiles; from reptiles to mollusks; from mollusks
to seaworms, and from seaworms to slime and single-celled creatures.
Beyond that there seems to be a "No Trespassing" sign over a gate which
hides from us the greatest mystery of all.

Where did life come from? How did it start? Why has it ascended the
evolutionary ladder that it has and where is it going next?

For thousands of years mankind adhered to the notion known as spon-
taneous generation, according to which hving creatures arose spontane-
ously out of the air or the sea, or out of the mud. There are various schools
of thought today which differ sharply in their speculations about life's
beginning. There are some scientists who support the theory of Panspermia,
according to which hfe is as old and as fundamental as inanimate matter.
Its sperms or spores, according to this view, are supposed to be scattered
through the vast universe and to have reached our planet quite acciden-
tally. Lord Kelvin has suggested that they were carried here via those
brilliantly illuminated meteorites which constantly bombard our earth
from outer space.

The image of Aphrodite rising from the sea has a scientific justification
in the view of those biologists who believe that the living has risen on this
planet from what we regard as the non-living. These men of science pro-
claim that it is fairly certain that life originated in the primeval ocean,
since the inorganic salts present in the circulating fluids of animals corres-
pond in nature and relative amounts to what we have good reason to
believe was the composition of the ocean hundreds of millions of years ago.
A new approach to the problem of the origin of life on earth was recently
suggested by Dr. Assar Hadding, the noted Swedish geologist, who con-
tends the hfe began here in warm water puddles after the world's first
rains.

Life, according to Dr. Hadding, was impossible until our globe had
cooled sufficiently to allow the condensation of water. This first happened,
he believes, in the Winter seasons of the two poles. Before that, the sur-
face of the globe must have been covered with loose, hot volcanic ash.

LIFE AND THE CELL 6 1

With the chemical action of water on. this ash, he holds, the complicated
composition of protoplasm became possible.

The tide of life may have begun flowing in any of these ways. Whatever
form animated life may have taken at the start, living beings — plants and
animals — did appear when this.planet's surface cooled sufficiently to invite
organic existence. Life has developed from small and lowly creatures to
highly complex creatures. This development culminates in the strangest
and most wonderful organization we know of in the universe, the mind
of man.

Let us suppose that you are strolling through a park. On a near-by bench
sits a man, reading the morning paper under the shade of a giant oak tree
which lifts its leafy arms to blue heaven. A flower bed is afire with brilliant
hues, while bumble bees murmur among the roses.

Unless you happen to be a biologist, you see little similarity between
the man, the tree, the flowers and the bees. But science has revealed that
all living organisms within both the plant and animal kingdom — including
man — are built of the same chemical stuff. All life is based on an innocent
looking jelly-like, semi-fluid substance, called protoplasm after the two
Greek words, "protos," meaning "first," and "plasma," meaning "to form"
— or, therefore, "to form first." Thomas Huxley, the great British biologist,
coined the best definition of protoplasm that we have when he termed it
"the physical basis of life."

Protoplasm is contained in the cell, which is the basic unit of all forms
of life. The simplest living organisms consist of single celled animals, of
which there are about 10,000 species. The common, undistinguished
amoeba, a hundredth of an inch in diameter and a great lover of stagnant,
muddy waters, belongs to this classification. Other living creatures con-
sist of aggregations of cells, the number varying upon the complexity
of the organism. In the human being, millions upon million of these cells,
or factories of life, are in combination.

A living cell consists merely of a droplet of protoplasm, surrounded by
a wall. The mass within this wall or membrane is called the cytosome.
Within this cytosome is a concentrated, mysterious mass called the nucleus.

Nobody knows what the chemical formula for protoplasm is. Very
likely it is not a single formula, but a whole series of formulas, each one
very complex in itself, with the complexity vastly increased by their
interrelations. A correct chemical picture of living protoplasm would
probably give us the secret of life.

Carbon is one of its fundamental components. Three types of carbon
compounds unite to form protoplasm: the carbohydrates, which are vari-
ous combinations of carbon, hydrogen and oxygen; fats, a more compli-
cated structure of the same chemical elements; and proteins, the most com-
plicated compounds in protoplasm, which include in addition to carbon,
hydrogen and oxygen, combinations of nitrogen, phosphorus, sulphur and

6l READINGS IN BIOLOGICAL SCIENCE

iron. More than half of the bulk of protoplasm consists of water, while
salts including sodium, potassium, calcium, magnesium, iron and man-
ganese, are also present in small quantities.

Constant activity is one of the most important characteristics of proto-
plasm, as it is in all life. Protoplasm has an energy content which inspires
constant interaction between it and the outside environment. Like the
engine of your automobile, protoplasm absorbs fuel in the form of food
and then burns it to provide the energy necessary for its varied activities.
The biologist has named this process metabolism. Protoplasm has as its
distinguishing characteristics the powers of growth, reproduction and a
keen sensitiveness to environment. The living cells, therefore, feed, breathe,
grow and reproduce. During these activities, the carbohydrates, fats and
proteins in the cell, through oxidation and other processes, undergo
changes by virtue of which their chemical structure is transformed, en-
ergy meanwhile being absorbed from them to the cell. To keep the life
process going, it is necessary that a new supply of carbohydrates, fats and
proteins be continually fed into the living cells and that the waste prod-
ucts produced by the various processes be carried away.

The modern discovery that all life is based on a stuff called protoplasm
is one of the greatest in the history of science, and it has led to an eager
school of scientists who are striving toward the creation of life in the
laboratory. Consequently, scientists have achieved some stirring results
which hold the promise that we may be on the threshold of exciting events.

After a person is dead, many parts of the body, it has been proved,
remain alive for hours or days. Hair and nails, for example, grow longer
after death because the cells from which they grow are still living. In
Russia, Dr. S. J. Tchenchulin apparently kept the severed head of a dog
alive for more than three hours, while his colleague. Dr. A. Kubliako,
kept a human heart functioning for at least thirty hours outside the body
that once had owned it.

Professor Woodruff of Yale has further demonstrated that there need
be no termination to the continued existence of pure-lived protozoa, or
uni-cellular animals. He found no natural death in a culture of Farainecmm
in 8,500 generations equal to 250,000 years of human Hfe, and the culture
was going as well at the end as at the beginning. Morgan of Columbia found
that ^5oth part of a worm will regenerate and be "younger" than the
original. These tests pointed to the sensational conclusion that life cells
and tissues are potentially immortal, a conclusion which now seems to have
received definite confirmation at the hands of Dr. Alexis Carrel, world
famous surgeon of the Rockefeller Institute.

Twenty years ago. Dr. Carrel set out to determine just what life power
was inherent in the tiny myriad cells known to make up our bodies. He
posed several questions and set out to find answers for them: When man
or any other animal died, did he die completely in all parts of the body, or

LIFE AND THE CELL 63

did some of the infinitesimal cells go on living for a while on their own
initiative? If a cell could be removed from a dead person, could it be made
to go on "living" after the rest of the body was dead and buried? Was there
eternal life in any part of the human anatomy, and, if there was, would
it give us the key to eternal life for the human being as a whole?

The average life of a chicken is only about five years. Dr. Carrel* has
in his laboratory, still alive and hearty, some cells taken from the heart of
a chicken embryo more than twenty years ago. He has also kept tissue
cells from rats, mice, guinea pigs and human bodies growing in his labora-
tory in favorable culture conditions for many years. Cells taken from
brains live only a short time at best, but most of the other cells do very
well — as well as the chick's heart.

Dr. Carrel concludes from these results that the human cells are poten-
tially immortal; detached, they might, under the right conditions, go on
living and having descendants forever! Combined by nature into bodies,
into a system so marvelous and intricate as to produce our brains, they
produce also decay and death. The explanation? The best theory that Dr.
Carrel can offer is that a single cell in a semi-liquid state is able to discharge
its poisons — necessary by-products of life — directly and entirely into this
liquid outside itself, while in the body these poisons cannot escape and
therefore pile up an inevitable burden of decay and death.

The discovery of biologists that living cells are exempt from oblivion
has led many noted scientists to speculate about immortality. Evolutionary
biology does not preclude the belief of an endless soul in Nature, in the
opinion of some scientists, including Dr. Arthur H. Compton, Nobel
Prize winner in physics, who holds: "Biologically speaking, life is essen-
tially immortal. The apple may decay, but the seed grows into a new tree
which flowers and begets new seeds. It is because we concentrate our
attention upon the tree that we say the end of life is death. Life, whether
it be of an apple seed or the germ cells of man, is essentially continuous
and eternal.

"The reply is heard, however, 'Though my body may be merely the
hull that surrounds the living germ, I want to know what will happen
to me when the hull decays.' To this question science has no straightfor-
ward answer to give. For when you ask. What will happen to me? you are
concerned not with your body, but with your consciousness, mind or
soul, which is not material, and regarding which science does not directly
concern itself."

* Dr. Carrel is now dead. — Ed.

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III

The Structure and Function of Higher Plants

Man's primary interest is, understandingly enough, in man. As the world
draws closer together, as food problems change from national to
international problems, science has turned more and more attention to
plant life, for it is upon the carbohydrate and oxygen-producing capacity
of the chlorophyll-bearing plant that animal life depends. The layman
may well be forgiven his astonishment when he learns that some 80,000
botanists are engaged in solving the riddles of the plant world and thus con-
tributing, directly or indirectly, to human welfare. The botanist stands
not only at the core of the food, clothing and shelter problem but fre-
quently is found fighting the front line battles against plant diseases.

Like animals, plants range from single-celled to many-celled structures.
Simplest of the plants are the viruses, bacteria, yeasts, and certain algae.
They are called simple because they are single-celled and lack root, stem
and leaf. One of the interesting things about the bacteria and the simple
algae is that they have been found in the oldest rocks and so are extremely
old phylogenetically. The fact that many of these simple forms reproduce
by binary fission or splitting means that the present individuals are cyto-
plasmic and in some cases nuclear descendants of the first cells to appear
on this earth. This might be termed immortality.

Leaving the single-celled plants, we note more complex arrangements —
some are mere aggregations of independent cells stuck together, others
show slight differences in form of cells and indicate a type of speciahzation,
a division of labor. Many of the fungi and algae are tremendously com-
plex, as for example the huge puffball and the giant brown algae, the latter
growing in the oceans to a length of several hundred feet, with root-like and
leaf-like structures. From the one-celled green alga to the billion-celled
redwood tree, towering three hundred feet or more, is quite a contrast.

Plant physiology is the science which deals with the functions of plants,
their growth, metabolism and kindred subjects. These scientists have been
studying for years the formation of sugar, of starches, of rubber, of chicle,
of oils in plants. Lately this study has taken a very interesting and vital turn.
Botanists are now studying the formation of anti-bacteria, anti-spirochaete,
and anti-protozoan substances by plants. Some of these important products
are already known to you as penicillin, streptomycin, tyrothrycin and
gramicidin. Again plants are furnishing man with life-saving substances

64

THE STRUCTURE AND FUNCTION OF HIGHER PLANTS 65

as they have in the past. We should always be conscious of our debt to
the Flemings, the Floreys, and the Waksmans who labor to make hfe
safer and more healthful to their fellow men.

A TOUR OF A TREE *

HENSHAW WARD

I am standing on a lawn in Carpinteria, near the Coast Highway of
Southern California. Above me is a Torrey pine that carries its foliage a
hundred feet above the base and spreads it on stout, sprangling arms over
a diameter as great as its height. Seen from underneath it is a galaxy of eight-
inch needles; from a distance it is a delicate cloud of soft gray-green color.
Occasionally some one whizzing by in a car remarks, "There's a big
tree." For thirty-six years I have known it, watching it grow from sprig to
giant, without making any better comment.

This morning I begin to notice what a pine tree is. Its trunk, almost
four feet in diameter, is a notable piece of architecture, for it bears the
strain of a wide-stretched load, through the hardest gales. Its branches are
contrived for spreading tens of thousands of needles to the sun and air, so
that they may make sugar to feed new twigs which will spread new
needles.t Underground there are thousands of regiments of rootlets that
forage for water and mineral food, which must be transported to the sugar
factories. All these industrious armies of roots and leaves are engaged in
one common purpose — nourishing the seeds in the cones. Such a purpose
can not be carried out by haphazard. What generalship directs these
myriad forces in orderly cooperation?

If you accompany me on a tour of this tree, viewing the sights that any
ordinary microscope shows, you will need no help in making your own
speculations about the powers which lie beyond vision.

Squinting through a microscope is hard work; even for a man of long
experience it is a tricky task. The only way to go sightseeing comfortably
in a tree would be to reduce ourselves to microscopic size, carrying with
us a corresponding increase in power of vision. If, for instance, a man
nearly six feet tall could reduce himself to one-tenth of his size, his height
would be seven inches. In this tree trip he would see a pineneedle as a red-
tipped stake taller than himself, three-sided, with sharp corners; he could
see that two of the sides are concave and decorated with seven rows of
glistening white spots, while the third is convex and has twice as many
rows of spots. He would feel of the saw-teeth on the corners and would

* From Explor'mg the Universe by Henshaw Ward. Copyright 1927. Used by
special permission of the pubHshers, The Bobbs-Merrill Company.

t Mr. Ward does not mean to imply that plants function for a purpose here or
elsewhere in this article. — Ed.

66 READINGS IN BIOLOGICAL SCIENCE

wonder about the sticky, brownish stuff that smears part of one side.
A needle would be a curiosity which he would often tell about.

Hence a tour of a pine tree by a seven-inch person would be ten times
as interesting as if he kept his normal height. But even then he would see
no more than a pocket lens reveals. Suppose he were reduced to a hun-
dredth of his size, so that the needle was nearly seventy feet long and each
small saw-tooth became a spine growing from a lump. The whole tree
would be nearly two miles high. Then the idea of a "tour" of its roots and
branches would not seem a figure of speech.

But even if the sights in a tree appeared a hundred times as large as they
now do, a tourist would not see much. The secrets of structure would still
be hidden. If we wish to get any proper view of them, we shall have to
reduce ourselves to a tenth of the hundredth of our actual height. This
needle, upon which you have rashly ventured with me, though it hung
only ten feet from the ground, is now nearly two miles above ground and
is long enough for a two-hundred-and-twenty-yard dash; the top of the
tree is seventeen miles above us.

Here you are, two miles above the earth, swinging in the light wind
through an arc of five hundred feet. I will make you ten times smaller
still, and give you ten times more power of seeing. Now the ground has
become a vague, cloudy area twenty miles away; the needle is a mile and
a quarter long, and you are sitting on an edge of it that is more rugged than
the ridge of the Santa Ynex Mountains.

Perhaps you think we are now prepared for the journey, but I assure
you that you will be disappointed if you set out in your present condition.
You can not see much. Look down ten feet to the nearest one of the gray
mounds that run in a row parallel to the edge where we are perched. It
is one of the spots that dot all the surface of the needle. Even in your present
smallness you see it as only two feet wide, and you can only make out a
mass of pulp and dirt and resin. Nothing is clearly defined. I will make
you ten times smaller still. Then, just for the sake of convenient arithmetic,
I will reduce you by a factor of 2.1. You are now one three-thousandth
of an inch tall. Twenty such creatures as you standing on each other's heads
in a column would reach as high as the thickness of the sheet of paper on
which you are reading. Do you think I overdo in making you ready to
see a tree? You will shortly be complaining that you are too big.

Hold fast to this gummy hillock while I explain the scenery. We are
near the base of a needle, one of a cluster of five, and are facing toward the
base. Behind us is the tip of the needle, twenty-seven miles away. We are
on a resinous mountain ridge that is composed of the water-proof coating
of the needle. On our right is the wide, convex side of the needle, which is
three hundred fifty yards across; but we see only half of the width because
the other side is hidden below the slope. In color it is like a wilted lawn.
Its expanse is covered with gray hummocks that heave and gently writhe

THE STRUCTURE AND FUNCTION OF HIGHER PLANTS 67

like pulpy craters. On our left is the perpendicular cliff of one of the nar-
row sides of the needle. It is covered with the same sort of palpitating hum-
mocks and is plastered with brownish lumps of resin in which are stuck
white and brown boulders — things that mortals call "dust grains blown by
the wind." The ridge on which we sit, between these two sides, looks as
if it has been formed out of gray gelatine that had hardened with a trans-
lucent, glistening surface in a maze of mounds and hollo\^'s. Behind us
the ridge slopes up sharply to a height of fifty feet. A hundred yards ahead
of us is a queer thing.

As we clamber toward it, bracing our feet in the rough surfaces of the
hollows and gripping the knobs on the mounds, we see that we are con-
fronting a cone of gleaming gray. It is embedded in a hill fifty feet high
and is pointed toward us, elevated at an angle, like a threatening coast-
defense cannon, as if it were set to impale anything that rushed against it.
If we clamber to its top and look forward, we see another sharp cone,
mounted and pointed toward us in the same way. Back of us along all the
miles to the tip, at intervals of from two hundred to six hundred feet,
stretches a continuous row of similar cones — three hundred of them. They
are the spines that a mortal can feel as a slight roughness when he rubs
his thumb down the edge of a needle.

Of course each spine was constructed by a cell. It was formed by proto-
plasm that was pushed out to a sharp point and hardened there. It was
created by an organism that was born with this special power, an organ-
ism which was one of the dozen of kinds provided for, to the last nicety
of detail, in the swarming multitude of growths in the embryo of a cluster
of pine needles. And this endlessly complex multitude was at first all pro-
vided for in one small part of a single cell. And that cell had been born from
another which, within its single self, contained provision for all the sorts
of cells that were to form wood and cones on a whole branch. And all the
provisions for the branch were just part of an earlier cell that became a
pine-cone. There can not be any chance or miracle about the birth of a
single spine. It had to be exactly provided for in the ancestor of a line of
cells.

Nor could the individual spines be left to grow as they liked. The number
and placement of them had to be governed by some precise apparatus, so
that they should grow only on the three edges, that there should be about
thirty or fort^^ to the inch, and that all of them should point one way. If
we ask why they exist, we shall receive no answer but guesses. Perhaps the
young trees were once less likely to be eaten if there were spines to rasp
the tongue of some Mesozoic herb-eater. Perhaps — but nobody knows.
There they grow, exactly as the seeds of this species have ordained that
they should grow for unknown million of years. So stable and enduring is
the mechanism of heredity in each of its small details.

Excuse the lecture while you are clinging for dear life to a mountainous

68 READINGS IN BIOLOGICAL SCIENCE

ridge which swoops through the air thirty miles a second when the wind
freshens, and which is so far from the other clusters of needles that you
can not see them. VVe are alone in the wide sea of air — no place for reflect-
ing on an abstraction of biology. Doubtless you wish to get under cover.

Hold fast while we crawl up the slope to one of the white spots that
extend in straight rows from base to tip of the needle. It is a hundred feet
away. We can reach it if we carefully watch our foothold and grip the
sticky knobs that dot the surface.

So — here we are at the border of a pulpy square, forty feet wide, rising
five feet above the level of the surface of the leaf. It is heaving like a
breathing body. Follow me up the side of it and across it to the dirty look-
ing center. This one of the forty-eight thousand breathing-holes on the
needle. (Don't be astonished at that number; it is small because the pine
is adapted to a dry hfe. Some leaves have millions of breathing-holes.) This
hole is by no means a safe place, for the passage down through it will close
at any time when the leaf grows too dry; we might be caught and suffo-
cated. However, on this foggy morning the chances are good that the hole
will remain open. The diameter is more than a yard at the top. As we crane
our necks over the edge and peer down, we can see that the passage grows
more restricted below, but it looks wide enough for us to wriggle through.
Now you begin to realize that you were not made small enough for a
comfortable trip through a pine tree. I am going down head first, because
there is no fear of dropping into any deep cavern — the space in the needle
is close-packed with equipment. You may go feet first if you will feel
safer.

For five feet I make a plunge, staying myself with outspread arms and
legs; then I squirm five feet more between the soft pulsing walls of the
funnel — and drop ten feet, as if I had broken through the ceiling of a room,
to a cushiony floor that feels like a rubber mattress filled with water.

Of course this floor is a cell. Every place you can touch in all the height
and breadth of a tree is part of a cell. The floor is a breathing, hard-
working, intricate individual. In shape it is an irregular oblong, some fifteen
feet in width. VVe are sitting on the end of it — as if on the end of a great
sack of water that extends fifty feet in length toward the axis of the needle.

As our eyes become accustomed to the dim light, we realize that we
are in a chamber about ten feet in diameter, formed by the ends of a dozen
or more cells. These are pressed tightly together — in fact they are prac-
tically grown together; for there are ducts communicating between them,
and they work as an organized whole. Here and there you can see that
between the cells there are passages wide enough for us to creep through,
but nowhere wide enough for comfortable walking. You should have al-
lowed me to make you smaller.

If we gaze about a few minutes, taking in one feature after another of
this chamber under a breathing-hole, we begin to realize that we are in the

THE STRUCTURE AND FUNCTION OF HIGHER PLANTS 69

midst of manifold operations; every square foot of the walls is at work,
pulsing, circulating fluids, moving globes and disks about bewilderingly.
We feel the vibrations of .industry, as if we were in the midst of hard-
working machinery where all the noises have been muffled to a low roar.
Even the chamber is not mere space between the units of the factory. It
is full of activity. You can feel the currents of gas circulating — not in
happy-go-lucky drafts, but with orderly purpose. If you had only con-
sented to be made a thousand times smaller than your present lumbering
self of one three-thousandth of an inch, you could now see what is hap-
pening. As it is, there is no way to show you except by coloring the cur-
rents artificially. Hold your hands close over your eyes for a minute while
I release the necromantic dyes and let them diffuse themselves throughout
the room . . . No, not quite yet, another minute, please . . . Now you
may look.

The red wisps that seep from the cells and come blowing out of the
passages between cells, making straight for the funnel above us and passing
to the outer air, are oxygen. The bits of gray haze, which float gently from
the cells toward the funnel and disappear upward through it, are water-
vapor. The dark-green strands which steal in toward us from the breathing-
hole, drifting toward the cells and disappearing into them, are carbon
dioxide. As we watch these currents they seem gentle and aimless; there
is nothing exciting in their appearance. But if we had super-eyes which
could penetrate to all that is taking place, we should know that we are ob-
serving the most fundamental mystery in all the course of nature. We are
seeing the inorganic world made organic. Be polite for the space of a para-
graph while I tell what this means.

A leaf — whether of palm or geranium or cactus or pine — is a factory for
converting water and carbon dioxide into organic food. Nowhere else in
nature can this miracle be performed. Each of the cells that surround us is
an organism which receives a supply of water from the ground and a
supply of carbon dioxide from a breathing-hole. Its energy is supplied by
the sunlight, from which it extracts certain rays and apphes them to the
water and the gas. By a process too elaborate and profound for the in-
vestigation of chemists it turns the energy of light waves upon these simple
molecules, mingling six of each in a massive and unstable molecule of
grape sugar — CeHjaOg. This is easily and quickly converted to starch; it
is altered to protein by the addition of elements brought from the ground;
it is the basis of all animal hfe — for no animal could exist but for the food
that is manufactured in leaves. The animal kingdom is a parasite upon the
industry of the sugar-making disks.

If the cell were a perfectly efficient laboratory, it would build sugar
molecules without wasting any water. For water is precious; it must be
pursued by millions of industrious rootlets that fight their way through
harsh masses of dry soil to wring from it the moisture that it grudges to

yo READINGS IN BIOLOGICAL SCIENCE

yield. All this hard-won booty must be transported through the roots, up
the trunk, along the branches, into the twigs, by leaf ducts, to the thirsty
cells. Water is costly, the plant's greatest treasure. Yet it leaks away from
the cells, out through their walls, and escapes from the funnels of the
breathing-holes. Why should there be such waste? Simply because the
needle is an imperfect apparatus. It works well enough to maintain a hardy
tree in soil that is not too poor. But it is far from perfect. Here is a text for
a long essay on evolution as a process of adjustment. All the adaptations
of plants and animals are of that sort — fairly good, sometimes astonishingly
good, but never complete. Evolution has been a series of makeshift con-
trivances.

Still this chamber of gases is by no means so illfitted for its purpose as you
might imagine. The cells which open and close the outlet are automatically
influenced by the supply of water in the cells; as the supply is depleted,
the cells stretch out and make the hole smaller; they will close completely
if a hot, dry atmosphere is robbing the leaf of too much water. Further-
more, the chamber keeps the gases well distributed. Carbon dioxide is
brought alongside the cell walls, where they can absorb it, oxygen is car-
ried out.

Look through the wall of this cell which forms the right-hand side of
the chamber. The wall is thin and almost transparent. Behind it you can
see the streams of protoplasm winding up and down and across, engaged
in transactions too subtle to be even guessed at. Far along the side you
can make out a globe, the nucleus, in which — if only our eyesight were
more acute — we could see the chromosomes that lie ready to procreate if
the signal comes. The central portion of the cell is full of sap, which is
under pressure, keeping the walls taut. Many "organs" of the cell are
vaguely visible — the technical names for which are confessions of igno-
rance about their function — chondriosomes, Golgibodies, cytoplasmic
granules, microsomes. Be at ease. I am not going to discourse on the un-
known. I merely wish it understood that you are gazing, not at specks of
stuff, but at the "organs" of a life which is far, far beyond comprehension.

Most prominent among the contents of this cell are the green disks, two
or three feet in diameter, which float in the protoplasm. These are the
places where some red and blue rays of sunlight are set to work for the com-
pounding of water and carbon dioxide into sugar. If you were not so large,
you would not be blind to what goes on within the disks. You can see
nothing. Science has not yet been able to see anything. We might as well
move on.

On to what? When you have clamped this gas-mask over your head and
wormed your way two hundred feet toward the axis of the needle (only
a third of the distance), you have passed a confusing array of cells of many
sorts and of all shapes, jammed together Hke a medley of elastic factory
rooms under hydraulic pressure, flattened here, bulged there, now almost

THE STRUCTURE AND FUNCTION OF HIGHER PLANTS 7 1

spherical, again shaped like a narrow chest. If some botanist were here to
lecture as we pass the various factory units, he could tell of cells which
combine sugar with substances brought up from the roots, thus forming
material from which to biiild protoplasm; of cells which make resin; of
several sorts of cells which form channels for carrying sugar and starch
and proteins and water and carbon dioxide. Further information he could
not furnish. Which cells govern the repairs of an injured bit of the water-
proof coat of a leaf? Whence issue the orders for sending to the stem more
sugar, or for receiving more nitrogen and sulphur to increase the stock of
proteins? What cells direct the ducts of a given area to furnish more water
or to clear away more oxygen? In short, where reside the instincts that
direct the cooperation of the two or three million organisms which live
between base and tip of one needle? When science can answer, it will have
made the first step toward understanding a tree.

We can not linger for any more speculations of this sort, because a
long journey lies ahead. Slip into this tunnel which carries a stream of
sugar solution to the base of the cluster of needles. What! You are afraid
of drowning? But there is no way to move about in a tree except through
these ducts that carry water up and dissolved food down. Be courageous.
You have now entered into the life of the tree and will find that you can
breathe in its sap. Have no fear. Dive in.

The current is swift enough to be rather terrifying, but you will grow
accustomed to the speed. It feels Hke ten miles an hour, and it is that fast
if you measure by the sort of standard you used in your human state. Then
you had a unit of length called a "mile," which was about nineteen hundred
times your height; when you traveled nineteen thousand times your height
in sixty minutes you said you were going "ten miles an hour." You are
now moving at a rate about nineteen hundred times your height in one
hour. The rate will increase somewhat after we reach a large branch. Just
what the speed of currents is in this pine I can not learn, but in some fleshy
plants the movement of sap is, at times, as fast as five hundred and fifty
miles an hour. So we are guessing our present rate very conservatively.
As human beings measure distance, we are about ru'o inches from the base
of the cluster of needles; as that distance is measured by tree tourists, it
is seven miles; hence we shall be forty minutes in reaching the stem.

Perhaps I had best remind you once more, at the risk of repeating too
much, that this smooth, round tunnel through which we pass is not an
excavation. It is not even a space left vacant by the architects of the needle.
No, each section of the tunnel was originally a cell, which removed all of
of itself except the sheath, broke down its end walls, and joined itself to the
sheaths at either end, thus forming a continuous duct. All space in a tree,
everything in a tree, was designed and made by cells.

As we swirl along and you grow accustomed to the fish-like way of
breathing, you notice that there are fewer factory cells and that we are

72 READINGS IN BIOLOGICAL SCIENCE

passing to a region of transportation and storage. Here a duct from another
needle comes alongside ours; our tunnel will soon be one of a bundle of
tunnels. Gradually, with the utmost nicety, the passages of the five needles
are merged into one trunk system. We arrive at the stem.

Here is the junction point for half a dozen bunches of needles. The
traffic is as congested and complicated as in a Chicago freight-yard. A
hardened botanist may feel assured that all the transfer of water and starch
and solids and proteins is managed automatically. Perhaps it is. But if we
should try to map the maze of tunnels and the control-points of dis-
tribution, we should find that human wit was only dodging the issue when
it uses the word "automatic." It would seem just as wise to call the day's
work of Chicago automatic. Consider one slight sample — the disposal of
some particles of the nitrogen which has been transported all the way from
a remote tip of a root. It is very valuable; more of it is required for some
needles than for others, and all the needles desire it. Nitrogen has no in-
telligence for dividing itself into five unequal portions and going where it
is needed. A nitrogen compound is very sluggish and must be handled
and shipped by some sort of supervision. What forces apportion it in this
labyrinth of busy highways? I am not hinting that there must be intelligence
at work; indeed the required skill seems of a higher order than intelligence.
I am only protesting that when we say "automatically" we say nothing.
The imagination of man has never conceived any term for describing the
way in which consignments of sulphur and phosphorus are handled in the
node of a twig.

We return down the twig in a sugar stream, and continue on beyond to
the branch from which it grows, a hundred-mile trip. You can read of the
layers of which the twig is composed — the bark and cork, the cambium and
wood and pith — in any text book. You might while away the hours by
speculating on how a twig can increase its diameter each season. Three
years hence it will be twice as large; its bark must reach twice as far; yet
every minute of the time the bark must remain water-tight. For deadly ene-
mies of the tree are always drifting through the air and will invade it if the
least spot is left unguarded. Spores of fungi much smaller than the cells
would enter the wood and feed upon its stores of food as certainly as
bacteria always enter any broken skin of an apple and cause decay. So
the bark must always be sealed. How does it increase its circumference
without permitting any microscopical gap at any moment?

We enter the branch at a node where three other twigs converge with
ours. We are to travel the length of it to where it joins a larger branch —
somewhat more than the distance betu^een New York and Chicago. Here
the branch is only seven miles in diameter, and at its base is only ten miles
in diameter. Somehow this seems impossible architecture. We can conceive
a cable of those dimensions, but we can not conceive how the cable could
be transformed into a stiff, staunch girder, bent through three ungainly

THE STRUCTURE AND FUNCTION OF HIGHER PLANTS 73

angles, that would withstand any storm, though carrying a load of sails,
and never be twisted or snapped in two. Human engineers will
never devise the struts for such a truss. We marvel when we are small-
sized tourists, but we never give a branch a moment's thought when we
are sixty-nine inches tall.

If we should stop off midway of the branch, and if we had axes, and if
we had enough time and a supply of food, we might cut our way out of
this sap tunnel and hack a passage to the spongy heart of the branch. There
we should find some open spaces. We could walk all the way to the trunk
of the tree. But in order to reach such a passage we should have to chop for
nearly a mile. I suppose you would prefer to ride. You may as well go to
sleep, for we can hardly reach our destination in less than thirty hours.

When I think of the trunk of this tree, and of how my dull mind has
never heeded it, I know that the soul of a savage is more sensitive than mine.
It understands better than my cast-iron brain what a tree is. The savage
discerns a spirit in it, he worships. I have never thought of anything in it
but a wood-pile. The savage perceives a kind of truth that is hidden from
all us bridge-playing joy-riders. Even a "vitalist" mystic has had more per-
ception than I. Henceforth I shall try to lift up my eyes to the structures
not made with hands. I shall never be able to see the spirit, nor can I ever
credit the "vital principle"; for to my prejudiced intellect these seem
fancies. But I can at least contemplate the unknown god of cytology and
learn to have a humble mind when I see a spire of marvels spreading its
magical green shops to the sun.

This trunk bears its leaves to a height of four thousand miles above the
earth and spreads them two thousand miles on every side. In its construc-
tion there were no cables or cement or steel girders; there were no materials
but soft, living cells that formed six-inch walls and pieced the walls to-
gether. Out of these tubular sections, whose average length is not more than
fifty feet, they devise continuous pipe lines from the most remote root-tip
to the highest and farthest needle — ten thousand miles.

On down the trunk we glide. We reach the level of the ground. We
continue down for more than a hundred miles, and then can feel that our
course is nearly horizontal. Our surroundings are cooler, for we are in a
root, traveling out toward a big branch of it.

The current has almost ceased to flow. It is constricted in a narrower
passage, and its load of foods is being doled out to hungry cells whose
energy must be restored. Have no fear of them. They know what food they
need and will not nibble at us. Be alert and don't let yourself get stranded
in the smaller and more closely packed cells that now surround us. Keep
edging your way along with all your might.

This rootlet is one hundred fifty yards thick at the point where we are,
five hundred yards from the very tip. We must force our passage amidst
these small, vigorous young cells that crowd before us so stoutly. It is hard

74 READINGS IN BIOLOGICAL SCIENCE

going. You grow breathless. Well, this is the best that giants can do in
such cramped space. We must give up while still three hundred yards
from where cells actually come to grips with the soil. We are at the edge
of a zone of a rootlet called its "gro\\'ing point," where cells are being
multiplied so fast that the tissue is warmed by their energy; the place is
a fountain of new cells which appear to press forward like a determined
rabble. But all is orderly. Each of the tens of thousands of individuals knows
how to place itself and what to do. If you stayed here a week you would
find that the rabble had shaped itself into rows of ducts, and fibers of
wood and bark, extending the Hues that we have followed through branches
and trunk and roots. This growing point is always extending the structure
of the root and pressing forward upon the tip, forcing it onward through
the soil.

Will you stop here and listen to some prosy words about the operations
in the tip, or will you now consent to be made small, so that you may see
something for yourself? Science can not reduce your size a great deal
more. Just let yourself be minimized to a tenth of your present stature,
till you are one thirty-thousandth of an inch tall, like one of the smallest
bacteria — that is all that is required.

While you were recovering from the vertigo of the operation I have
been carrying you back through the rootlet and out into one of the fine
hairs that grow from it. The cells here are actually smaller than those which
we saw in the needle, but to you, in your present state, they show a diam-
eter of one hundred twenty-five feet. Finding a passage between them
is possible, but difficult. We must take our time, looking for favorable
places where we can pry cells apart far enough to make way for our
bodies. Gradually, but sliding here and shouldering there, we pass a cell,
then a second, finally a seventh. We are at the outpost of a tree.

The outer surface of this outermost cell is wrestling with a bit of loam
that is compressed between a huge slab of mica and a boulder of quartz.
The loam is in possession of some molecules of water. It grasps them greed-
ily and tries to defend them. The wall of the cell presses close, squeezing
between the loam and its protecting slab and boulder, slowly gathering
the loam in its embrace, drawing the filmy bits of water by some attraction
that physics can not investigate. Slowly, relentlessly, powerfully the cell
continues its depredation. The loam is sucked dry. The cell gathers to-
gether its booty of moisture, conveys it to the inner side of itself, and pushes
it against the outer wall of the next cell. This receives the water and trans-
fers it to a third cell. The water is passed thus from "hand to hand," through
the hair, into a fibrous root, and on to a narrow tunnel like the one which
conveyed us down from the needle. The water is mingled with other drop-
lets in a stream which flows on, parallel to the sap-duct, on for a hundred
miles, on for a thousand miles, on and on till it is delivered to a needle and
used in a sugar-making disk.

THE STRUCTURE AND FUNCTION OF HIGHER PLANTS J $

The most painstaking study by the cleverest physicists has not revealed
certainly how a tree lifts its water from root to leaf. No process of capillary
action will account for the Hfting of a fluid through such a height.* Sir
Jagadis Chunder Bose, after years of careful examination, with the aid of
most ingenious and sensitive mechanism, has concluded that water is con-
ducted all the way by the action of individual cells, which pulse rhyth-
mically and exert energy as only living creatures could. The learned world
has listened to his theory respectfully. It may be correct, though the "men-
tal picture" which he promises is not one that I can make out. I can not even
tell whether the sap in his picture is moving through the interiors of cells
or in a passage between cells. If the picture is more lifelike than my un-
trained eye perceives, we shall learn once more that a tree is not a system of
mechanics, but an army of cooperating lives. That is to say, we have made
an erudite circle and have arrived at a term which means that we know-
nothing whatever about the lives or their cooperation. We have arrived
at the point where the savage starts his explanation of the spirit in a tree.

As we stand here at the edge of this marauding cell which plunders
for the maintenance of a chlorophyll grain sixty-five hundred miles away
in a needle, we wonder whence came its piratical instincts. It is a mass
of inherited desires and abilities. It was born of an ancestry of cells that
reaches back to a time, perhaps a hundred and fifty million years ago,
when this genus of tree was first evolved upon the earth. They have left
their record in the rocks for geologists to read.

The paleobotanist deciphers this record, and every syllable of his trans-
lation is scrutinized by rivals all over Christendom. The result of their
combined translations is a proof that this tree, Phius torreyana, was once a
flourishing species, spread far over the earth's surface. For some reason,
quite unknown to our best scholarship, the species declined in strength.
In area after area it dwindled, shrank, disappeared. Now the only known
remnants of the race are small clumps near San Diego and on Santa Rosa
Island, and possibly some stray individuals at a few other points. This kind
of tree has all but vanished. It will flicker out completely in a few cen-
turies, except as man fosters it. Why did it die?

Here is a flourishing specimen, seeming to have unlimited vitality,
growing lustily to a great height. Its vigor seems unabated. Why does its
race not succeed in the competition of nature? That is one more secret of
our pine tree.

• Capillarity and cohesion of water molecules is now considered a satisfactory
theory. — Ed.

y6 READINGS IN BIOLOGICAL SCIENCE

THE FINEST SHOW ON EARTH *
EDWIN B. MATZKE

If you were given the opportunity of viewing again one single scene
from all those that you have enjoyed, that constitute memory's picture
book of the past, which would you choose? Would it be one which por-
trayed the awe-inspiring grandeur of a total eclipse of the sun or possibly
one which recorded the glowing, changing colors of an alpine sunset? Or
would you turn to a page showing the brilliant patterns of a New England
landscape when the days are growing short and your breath rises lazily
before you? While a total eclipse and a sunset are passing fancies on the
part of nature, lasting for moments or minutes at the most, autumn foliage
in eastern North America clothes the hills in brilliant vestments for weeks
at a time.

To what are these colors of autumn due? The ordinary cells of plants
owe their green to two pigments, called "chlorophyll «" and "chloro-
phyll Z?." These can be extracted from the leaf with warm alcohol, and
the solution becomes a deep rich green, a green that through long associa-
tion with us on this earth has become soothing and restful to our eyes; no
color seems quite so pleasing as that of chlorophyll, no color is so impor-
tant, since only plants that contain this can manufacture foods, for them-
selves and for us. In addition to the two chlorphylls, two other pigments
are also present in ordinary leaves; these vary from yellow to reddish or-
ange. One of these, carotene, is common in carrots — a scientific justifica-
tion, it has been suggested, that "carrots are good for the complexion."
The yellow and orange pigments are less complex, chemically, than the
green chlorophylls, and they are also more stable. When the weather gets
cold in the fall, the green colors, which break down more easily, tend to
disappear, and then the yellow and orange, which have been present all
along but masked by the others, become visible. These are largely though
not entirely responsible for the golden tints of autumn. These four pig-
ments together constitute only a minute fraction of the fresh weight of the
leaves — about twenty-six hundredths of one percent — a very small frac-
tion when we consider how important they are, especially the chloro-
phylls. There is another group of soluble yellow pigments which are
not very significant in fall coloration.

Most striking of the colors of autumn are the reds. These are due to
an entirely different group of substances, called the anthocyanins, com-
pounds associated with sugars, dissolved in the cells of the leaves. These
vary from the brightest scarlet through all the shades of red and magenta
to the deep blues and purples found in some leaves and many flowers.

• Reprinted by permission of the Scientific Monthly, American Association for the
Advancement of Science. Copyright 1942.

THE STRUCTURE AND FUNCTION OF HIGHER PLANTS 77

Simple experiments show that the color of these substances depends partly
upon the amount of acid present. If the center of a head of red cabbage,
which is rich in these anthocyanin pigments, is cooked, and to the liquid
obtained a little vinegar is added(vinegar is acetic acid), the juice of the
cabbage will become bright red; if a little ammonia is poured in, the solu-
tion becomes blue to yellowish green. The greater the acidity, the deeper
the red color will be.

Various factors are responsible for the development of these red and
blue pigments. First there is the genetic makeup of the plant. Maples in-
herit the ability to manufacture these substances, while hickories do not;
the petals of the buttercup are never red, while those of the scarlet sage
rival the faces of the most highly embarrassed.

For the most part, light is important in the formation of the anthocy-
anins. The sunny side of an apple is brighter than the shady side; the "stem
end" is more richly colored than the "flower end." Perhaps in days gone
by you pasted your initials in opaque paper on green apples, and when the
fruits ripened there were the letters in green on a background of red. The
more modern version of this, as described by Arthur, is to paste Cellophane
on a green apple, put India ink marks on the cellophane, and then expose
the apple to a suitable lamp; the skin of the apple shaded by the ink re-
mains green. Photographic negatives have been printed on the skins of
apples in shades of red and green, using sunlight as a light source.

It has long been known that red leaves of the Virginia creeper contain
more sugars than green leaves on the same plant collected at the same
time. In 1 899 Overton put the leaves or leafy stems of various plants, such
as some species of lily, of holly and of columbine, into sugar solutions,
and after some weeks they became red. Injured branches of trees often
become bright red, while the rest of the tree is still green, presumably
because the sugars manufactured by the leaves are not transported away,
and consequently stay where they are made. Abundance of sugars favors
the development of the red pigments.

It is common knowledge that brisk weather — without prolonged frost
— is conducive to rich coloration, and experimental work supports this
general observation. Both with leaves and flowers this is true. A blue bell-
flower and a red primrose were pale, almost white, when grown under
warm greenhouse conditions. Cool weather, though preferably not too
frosty, stimulates colors in autumn leaves as well as in healthy youngsters.

Though abundant water favors the growth of plants, it does not result
in brilliant coloration. Of course drought is fatal, but a degree of dryness
toward the end of the season results in beautiful colors. Experimentally
this can be shown by watering sparingly some plants that are "vulnerable,"
and by watering others lavishly; the former will have the red pigments
more strikingly developed.

Although leaves rich in sugars are often briUiantly colored, plants grow-

7 8 READINGS IN BIOLOGICAL SCIENCE

ing in soil abundantly supplied with nitrogen are often just green. In gen-
eral both leaves and flowers of northern plants are brightly colored, due
to the strong light and low temperatures. However, in 1902, Wulff, col-
lecting plants far above the arctic circle in Spitzbergen, found that in
some areas visited by northern birds and fertilized by their excreta, which
are rich in nitrogen, the plants were a healthy green, while the same species,
growing in poor soil, were brightly colored. Anthocyanins develop best
when the supply of nitrates is limited, even if the other conditions are fa-
vorable, suggesting, perhaps, that opulence and loveliness do not necessarily
go together.

All these factors are important in the formation of these red-blue pig-
ments, known as the anthocyanins. Normally they do not act separately,
but through complex interrelationships, and there are exceptions to all
of them. Although light is so important in the formation of these sub-
stances, the root of the beet, which develops in the dark, is rich in antho-
cyanins. But in dealing with living things there are always exceptions —
little touches that make life worth while.

The drab brown colors of the late autumn, those of the sere if not the
yellow leaf, result largely from still another group of substances, the
tannins, or from compounds related to them. These are the same materials
that are derived from the bark of certain trees, especially oak and hemlock,
which are used in the tanning or hardening of leather. Tannins are almost
universally present in the higher plants, though generally not in quantity
sufficient to make their extraction practicable.

When the green pigments break down in the fall, the yellows which
have been present all along become visible; simultaneously the reds and
blues develop in certain plants so that various combinations and color
effects are produced. After all these have disappeared, the brown remains
— the brown that is destined to form a part of this good earth.

Most important of all our trees in producing the vivid colors of autumn,
particularly in northeastern United States, is the sugar maple. Sometimes
this is just yellow, but more often red pigment is developed, especially
toward the tips of the branches, where the illumination is most effective.
This tree is the one which is tapped in the spring, and from the sap maple
syrup and maple sugar are obtained. It forms extensive groves, especially
in New England, and is really the king pin in the coloration of the north.
There is a brilliance to the red of the sugar maple that is unrivaled in any
of our other trees — a brilliance that gives it an animation and almost a
touch of light-heartedness that rather belies the temperament of the sturdy
people with whom it shares the soil. In swampy areas similar effects are
produced by the red maple, though it, too, may be just a bright yellow.

Associated with the sugar maple are the birches, especially the white
birch. These are normally yellow in the fall, and it is common to see the
gold of the birches and the red of the maples standing in sharp contrast

THE STRUCTURE AND FUNCTION OF HIGHER PLANTS 79

to the dark green of the white pines and the hemlocks; such contrasts
make the colors appear all the more striking. This is especially true in
New England, \\here the '-'murmuring pines and the hemlocks" are so
wide-spread. The aspen leaves also add their touch of flickering yellow,
while the waxy barks of the white birches presage the snows that lie in
store.

The rolling hills and ancient mountains of our northeastern states form
a perfect setting, so that the trees for miles around may be seen at a glance
— as if to make it easy for us to enjoy the sight. The hills and valleys and
lakes and streams also offer a variety of conditions — of soil, of moisture
and even of temperature, and so are important in producing diversity and
intensity of color in plants growing close together, even in plants of the
same species.

South of New England the center of the stage is held not by the sugar
maple, but by the oaks. The warm reds and reddish browns are furnished
mostly by these trees. Each species of oak adds its own touch to the general
pattern. By far the most brilliant is the scarlet oak, which amply justifies
its name in the fall. Not a striking tree otherwise, the scarlet oak passes
unnoticed until it takes on its cloak of autumn, and then it stands out like
one whose modest virtues have been unappreciated. There is a whole
galaxy of oaks in eastern North America, each of which typically ripens
into a color that is largely its own. The white oak, whose staunch timbers
have been used so extensively in shipbuilding, often has leaves red above
and white underneath. When they blow in the breeze, the tree presents a
curiously changing color pattern. Pin oak may assume an orange-brown
color; chestnut oak becomes a bright yellow; black-jack oak may be
brownish red, but more often is a glossy light brown, suggesting the leather
of new riding boots; red oak passes from green to yellow to brown, while
black oak soon becomes a dull brown. In spite of all these variations in the
oaks, and in spite of the brilliance of their coloration, compared with the
sugar maple there is a slight touch of the sombre in their effects.

While the maples and oaks form the theme of this symphony, the varia-
tions are provided by many of our other trees. Dogwood, white or pink
at blossom time in the spring, is just as pleasing in the fall, with its red
leaves and red fruits; and dogwoods are found from Maine to Florida
and west to Texas. Along the banks of streams, and in low ground gen-
erally, the sour gum and sweet gum are often seen. These may also be red,
or they may be clothed in royal purple. Sour gum is one of the first trees
to turn in the fall — a harbinger of the great display to come. White ash
may be yellow, or it is sometimes reddish or bluish purple. Sassafras, whose
roots are sometimes brewed into a tea, especially in the spring, and served
(under protest) to children, adds its tone of bright orange to the drier
hillsides. Like the dogwood, it is widely distributed in eastern North
America.

8o READINGS IN BIOLOGICAL SCIENCE

While these trees wield a giant brush of red and purple, others, such
as the chestnut oak, are responsible for the brilliant yellow. Hickories,
especially saplings, often show the touch of Midas. There are hillsides on
which the tulip tree grows that look for all the world like the pot of gold
at the end of the rainbow. The tulip tree is one of our oldest trees, geologi-
cally speaking. It has literally come down through the ages. In the Blue
Ridge country it gets as much as two hundred feet in height and ten feet
in diameter. Also adding its light yellow to the autumn landscape, espe-
cially in the haunts of man, is the Ginkgo, maidenhair tree of the Orient.
With its fan-shaped leaves and exotic type of branching, it seems indeed
like a tree of the Far East, especially to an occidental. It is known defi-
nitely only in cultivation, having come to us as a temple tree from China
and Japan. Once found growing wild clear across the northern hemi-
sphere, it has aptly been called a "living fossil," for it alone survives of an
ancient group that has otherwise passed. Seward has suggested that each
year, for a short time, its leaves reflect the glory of that golden age when
it flourished so abundantly.

Last of the trees to turn is the black cherry. Rather appropriately, it
takes on all shades, from yellow to deep red to dark purple — a fitting re-
sume of events that have transpired, and all the more striking when, in
November, the skies are often dark and even the noon-day shadows
are long. At this time, too, the steel-gray bark of the trunks of the beech
stands in marked contrast to its light brown leaves.

Although trees play the major role in this whole display, shrubs also,
contribute, especially the sumachs and the blueberries. Most of the su-
machs, like the dwarf and the smooth, become bright red or scarlet. At
times though, the staghorn sumach, whose twigs are downy like antlers
in spring, takes on all the colors of the rainbow, from violet to red, some-
times in one leaf, and almost in one leaflet. "Infinite shades of color" says
the artist; "gradual changes in acidity," says the scientist.

Related to the sumachs is the poison ivy, usually a vine, but shrubby
at times. Its leav^es are often bright red, in contrast to the ivory white
fruits. The latter look like simple symbols of purity, though they are
poisonous. Boston ivy shows similar color effects in the leaves, but with-
out a trace of malice.

No other shrubs are so common in eastern North America as the blue-
berries; some of them are to be found growing in dry soil, while others
inhabit swamps and bogs. Almost universally they turn a bright red in
the fall; they may augment the colors of the maple, the oak and the sour
gums, or they may stand in sharp contrast to the green of the pitch pine,
the southern white cedar and the mountain laurel. Due to the oaks, sumachs
and blueberries, much of New Jersey looks toward the end of October
as though some giant had passed through the countryside with a single
large pot of red paint and had applied it lavishly. Barberry, including the

THE STRUCTURE AND FUNCTION OF HIGHER PLANTS 8 1

cultivated form, becomes a bright, slightly rusty red. On Cape Cod and
in New Jersey the cranberry plants in the bogs turn a dull, reddish purple
after the fruits have been picked; at the same time glasswort splashes its
vivid red against the brown of the grasses in the salt marshes along our
coast.

In dry, rather sandy soil the grasses, especially the beard grasses, may be
seen bowing in unison to let the breeze go by. These also become colored
in the fall, forming reddish brown carpets on the hillside. Very slowly
do they fade, so that the tints of autumn may still linger at Christmas time;
and these grasses often stick up hopefully through the first thin snows.
Only long after the winter silence has descended do they fade into a pale
yellowish brown.

Not a httle is added by the fruits that ripen in the fall. Bittersweet
sprawls and twines and shows its orange capsules and scarlet seeds; hollies,
growing in swamps as well as in sands, mature their red berry-like fruits;
barberry bushes are often laden with red; while hawthorn, after the leaves
are gone, shows brilliant red against the blue of the autumn sky.

These are some of the more important contributors to that symphony
of color that is played each year on the hillsides of North America. If
there is a "hard-frost" or a pronounced "dry-spell," the performance is
syncopated, leaving the dark green of the pines and hemlocks and spruces
enlivened only by the barks of such trees as the birch, the beech and
the red maple.

The brilHant display of autumn is really the result of two sets of fac-
tors; one is the wonderful assortment of broadleaved trees in the East,
capable of developing these colors; the other is the weather — the clear,
bright days and cool, crisp nights that are so characteristic of the fall in
our eastern states. "Football weather" is conducive to brilliant foliage, as
well as to husky voices on Sunday morning.

On what parts of the earth does this coloration occur? There are only
three large areas of temperate broad-leaved forests on this earth — one in
eastern North America, one in eastern Asia and one in Europe, including
central Europe and the British Isles. In the southern hemisphere such
forests are almost lacking, except for a small region in southern South
America, mostly in Chile, and very limited areas in Tasmania and New
Zealand.

Eastern North America and eastern Asia are strikingly alike in their
plant populations. It may seem rather anomalous that floristically there is
a greater similarity between eastern North America and eastern Asia than
between our own East and our own West. No places on this earth have a
richer assortment of valuable broad-leaved trees than eastern North Amer-
ica and eastern Asia. Our West has matchless forests of conifers, like the
pines, Douglas fir, redwood, and hosts of others. In fact, many of the
lands that are washed by the waters of the Pacific are rich in conifers.

82 READINGS IN BIOLOGICAL SCIENCE

But the West is relatively poor in broad-leaved trees. Climatically, eastern
Asia, including much of Japan, is also similar to eastern North America.
Consequently, it is logical to find that these two regions both show brilliant
colors.

On the other hand, much of northern Europe has cool, damp, cloudy
weather in the fall. This is not so true farther south, so that in the Danube
valley beautiful foliage does occur. In parts of the Alps, due mostly to
shrubs, the colors are also pronounced.

Continental Europe, furthermore, does not have the wealth of broad-
leaved trees that occurs in eastern North America, though many of the
missing species will grow there if planted. In fact, many of them are found
in Europe in fossil form. When the glaciers came down from the north
in the last ice age, the plants in North America advanced south before
them. Our mountain ranges run north and south, so that this was possible.
In Europe, when the ice sheets came down, the flight of the plants was
impeded, since the mountain ranges run mostly east and west. Local moun-
tain glaciers advancing probably made the escape still more difficult, and
consequently many of the trees perished. The sweet gum, the tulip tree,
the hickory and the sassafras, for instance, grew in Europe until the last
glaciation. This is known from fossils. Partly because of climate and
partly because of the relative paucity of broad-leaved trees, Europe does
not have the display that we have here. Eastern Asia largely escaped the
last glaciation, while Greenland and Antarctica have not emerged from
it to this day.

One topic more might be discussed — namely, the significance of colora-
tion in plants. It is well known and generally accepted that insects are
attracted to flowers partly on the basis of their color, though bees, like
many men, are red-green color blind. Young leaves unfolding in the spring
often show the same tints that are developed in the fall; and it has been
suggested that these pigments serve to absorb light and thus raise the leaf
temperature. Others claim that the pigments act as a protective screen
against certain rays of light that may be deleterious in various ways.

While these last two explanations may possibly be of some significance
in autumn coloration, it seems hardly probable that the development of
these striking colors in the late fall is very important to the plant. The same
trees may get along perfectly well without them, and often do. It appears
more likely that the conditions are favorable, the stage is set, and the show
goes on, without any deeper significance. Perhaps this is the botanical
expression of "art for art's sake." In any event, it is a gracious way of say-
ing good-bye.

THE STRUCTURE AND FUNCTION OF HIGHER PLANTS 83

"supernatural" plants *

KARL C. HAMNER

First of all, let us supply the foundation by determining just exactly
what a plant hormone is — the importance of which cannot be over-
emphasized. The name hormone was first applied to substances produced
in certain organs of the animal's body and carried by the blood current to
other organs where their effects were manifested. Plants, of course, do not
have a blood stream, but it has been shown that there are substances pro-
duced in certain localities in the plant and transported to other localities
where the effects become evident. These have been called plant hormones.

We are all familiar with the fact that plants turn toward the light.
One of our favorite songs contains the following lines, "As the sun-
flower turns toward her god when he sets, the same look which she turned
as he rose." This is a recognition of the responses of one plant to light. If
you have ever grown seedling plants in your room, you may have noticed
their tendency to grow toward the window. These responses to hght are
brought by a plant hormone.

Many years ago, early plant scientists were interested in finding out
why plants grew toward the light. Working with tiny oat seedlings, grow-
ing in dark basements, they found that the plants did not bend toward
the light if the tip of the plant was removed. If they removed the tip of
the plant and illuminated one side of the tip leaving the rest of the plant
in complete darkness, they could cause the plant to bend by putting the
tip back on. The plant always bent toward the direction from which
the tip had been illuminated. They were able to extract from the tips a
substance which would cause the plants to bend even though the tip was
not present. They identified this substance as a particular chemical com-
pound which they called auxin. Its action on the plant is caused by the
fact that it promotes growth in the cells on the side of the plant to which
it is applied. When a plant is illuminated on one side this hormone travels
down the shaded side of the plant causing greater growth there and thus
causing the plant to bend toward the light.

Undoubtedly, the discovery of auxin has considerable practical value
and may make quite a difference in our every day living. The chemist
not only has identified naturally occurring auxins, but he has also syn-
thesized new compounds which work just as well, or even better, than
the ones produced by the plants themselves. These chemical compounds
have proven very useful. A solution containing some of these chemicals,
or a lanolin paste of them, may be applied to cuttings in order to stimulate
a more rapid root formation. Sometimes the rapidity with which roots

* Reprinted from one of a series of radio broadcasts entitled Excursions in Science,
General Electric Company, 1946.

84 READINGS IN BIOLOGICAL SCIENCE

appear, after the chemical has been appHed, is truly remarkable. Solu-
tions of auxins have been sprayed on plants when they were flowering
and frequently resulted in the development of seedless fruits.

An even more important practical application has been the use of auxin
solutions to "stop drop" of apples. Apple trees are sprayed with these
solutions shortly before harvest and the auxin causes the fruits to hang
on for a much longer period than they would otherwise, giving the
farmer more opportunity to complete his harvest before many of the ripe
fruits have fallen.

Recently, there has been a new development and perhaps the most im-
portant application of auxin yet discovered. It has been found that cer-
tain weeds, when sprayed with a high concentration of auxin, are com-
pletely killed. In some cases the solution will selectively kill weeds and
leave the desired plants unharmed. The use of one of these auxins, known
chemically as 2, 4 dichlorphenoxy acetic acid (or 2, 4 D) may save farmers
millions of dollars through the elimination of bind weed on many of our
midwestern farms.

So you see, there has been a great practical application of the discovery
of this plant hormone — a discovery which was brought about because
certain plant scientists many years ago were interested in an understand-
ing of why the tiny seedlings grew toward the light.

Apparently there are several other kinds of plant hormones, although
none of these have been identified chemically. Evidence that these hor-
mones exist is based upon experiments in which the plant receives a
stimulus in one organ and the effect is produced in some other organ.
Evidence of this kind indicates that flowering of some plants may be
caused by a hormone.

Let us consider, for example, some of the responses of the ordinary
cocklebur plant. The time at which this plant flowers is determined by the
length of the day. It does not flower in the middle of the summer when
the days are long, and it is stimulated to flower when the days become
short in the late summer and early fall. You can keep the plant from
flowering at any time of the year by exposing it to artificial light at night.
On the other hand, you can cause it to flower in the middle of the sum-
mer when the days are long by placing a box over it at five o'clock at
night and removing the box at eight the next morning, thus giving the
plant a short day treatment. It is not necessary to cover the entire plant.
You may place one or two leaves of the plant in complete darkness at
five p. M. each day by tying a black bag around these leaves and re-
moving the bag at eight a. m. each morning. Thus, the plant will flower
if a few of its leaves are exposed to short day. The leaves receive a
stimulus and transmit it through the stem to the buds which exhibit the
responses.

But this is not the only evidence that a flowering hormone exists. If a

THE STRUCTURE AND FUNCTION OF HIGHER PLANTS 85

cocklebur plant is caused to flower in the middle of the summer bv ex-
posmg It to short day conditions, other plants may be caused to flower
by grafting them to the plant which was originally treated with short day.
If one branch of a cocklebur plant is induced to flower by exposing it to
short day, all of the branches on the plant will flower whether or not they
are exposed to long day or complete darkness. iMany types of plants re-
spond in a manner similar to cockleburs. Grafting experiments have shown
that the stimulus for flowering may be transmitted from one species of
plants to another.

All of this evidence indicates the presence of a hormone for flowering.
Of course, one must realize evidence for a flowering hormone is circum-
stantial. We will not be able to say with certainty that such a hormone
exists until the chemist has identified it, synthesized, and produced its
effects by injecting it.

Assuming that scientists can find out what this hormone is, the point
may be raised of whether or not this discovery will prove important. There
is little difficulty in stating its value. It would be hard to speculate as to
what we might expect this new hormone to do, but an attempt to draw a
parallel with the discovery of auxin could be made. One may wonder
what importance would have been attached to the efforts of the early
plant scientists who were trying to discover the plant hormone which
caused little oat seedlings to bend toward the light. It is quite possible
that no one foresaw the applications which would be made of this hor-
mone after its discovery. The plant scientists working on this problem
spent much of their time in dark basements where they grew their
seedlings, and they were considered useless but probably harmless, by
their neighbors, even by their fellow scientists. Yet we know of the great
developments which have come from their discoveries. Thus we can
reasonably assume important practical applications of the flowering hor-
mone after its isolation and synthesis.

^y ^^ ^'^

>>>>>>>>>>>>>>>>>>>>> » > > >><-<■<-< <<<<<<<<<<<<<<<<<<<< <■«•

IV

Nutrition

THE kinds and amounts of foods that we consume determine to a
large extent our individual health and our fitness as a nation. This is
brought out forcefully, of course, when a person exhibits signs of some
specific deficiency in his diet or when a nation suffers from famine.

There is probably no subject of biological interest which is con-
taminated with more misinformation than that of foods. Many people
seem to be obsessed with the idea that the normal diet contains an in-
adequate amount of vitamins and that they must perforce supplement
their diet with regular and expensive dosages of vitamins. It cannot be too
strongly urged that these products be taken only when the family physi-
cian recommends them for some specific condition. Another peculiarity
of our food problem is that processors remove some of the minerals
and vitamins and then add them with a great deal of unnecessary fanfare.

Probably the largest percentage of misleading publicity revolves around
the packaged "health foods" for constipation, for ulcers, and for diabetes.
Then we have the various soaps and lotions which will, apparently with-
out any aid, bring the bloom of health to "tired" skins and, in the majority
of cases, assure one of a "successful love life."

At the present time proper nutrition is one of the world's most pressing
problems since hundreds of thousands of people are feeling the effects of
the serious dislocation of the food raising and distribution activities of
their countries. A nation is never contented on an empty stomach.

FOOD AND FITNESS *

A. J. CARLSON

Our country produces probably the greatest variety and quantity of
good foods. Are we making the most of this resource for optimum health?
For the last ten years we have been told that one third of the American
people are ill fed, that these forty -million American citizens suffer from
malnutrition. Is this true? And if it is true, what are the reasons for it, and
what can we do about it? In fact, very recently we were told much more.

* Reprinted by permission of the Scientific Monthly, American Association for the
Advancement of Science. Copyright 1942.

86

NUTRITION 87

At the National Conference on Nutrition for Defense, held in Washing-
ton, D.C., a year ago, Dr. Thomas Parran, chief of the U.S. Public
Health Service, said: "Studies of family diets by the Department of Agri-
culture in all income groups of the Nation show that one third of our
people are getting food inadequate to maintain good health" and "less
than one fourth of us are getting a good diet." If this is true, that makes it,
not forty million, but about one hundred miUion Americans with an
inadequate diet, from any and all causes. The question is: Is this true?
These alarming claims for national malnutrition appear to be based pri-
marily upon a series of surveys conducted by the Bureau of Home Eco-
nomics of our Federal Department of Agriculture, assisted in some of the
field work and statistical analysis by the Department of Labor. These
surveys embraced some 4,000 urban and village families of various levels
of income and some 2,000 rural families of varying levels of income, se-
lected from representative regions of our country. The surveys consist
in reports from these families as to how much money they spent for food,
and what kinds of food were bought, and in the case of rural families, how
much and what kind of food they consumed from the crops on their own
farms. These field investigators (some of them on WPA) had to take or did
take the people's word for all these alleged facts. It is impossible to deter-
mine the degree of accuracy or honesty (accuracy as to memory) of what-
ever member of these families gave the facts or alleged facts to the enumer-
ators.

Nor do the surveys indicate the amount of foods actually eaten or the
amount of food wasted. The latter factor is probably not inconsiderable,
particularly in the families of the higher income groups. I know of no
statistics on this point, but on the whole, my experience indicates that
the food waste at the table increases with the economic prosperity of the
family.

On the basis of the kind and quantity of the food bought or grown on
the farms, the Bureau of Home Economics estimated the diets of these
families as excellent, good, fair or poor. We wish to point out that no
physical or medical examination was made of the members of these fami-
lies. Not even such a simple physical fact as the determination of the body
weights of the people involved seems to have been undertaken. I can
only express my great regret that the value of these statistics must so largely
be left up in the air as regards evidence for good or* bad nutrition in our
country by neglecting such an obvious factor as medical evidence of the
health status of these people concerned. Good medical examinations of
members of around 6,000 families in our country does not seem a super-
human task. I feel certain that if competent medical men in the U.S. Public
Health Service, in the Bureau of Home Economics of the Department of
Agriculture or in the Federal Department of Labor were not available, a
suitable approach to national and state medical societies would have re-

88 READINGS IN BIOLOGICAL SCIENCE

suited in cooperation sufficient to carry out such a medical sur\^ey at little
or no cost to the government. The surveys as conducted were made at
considerable cost to our tax-paying citizens.

Is that the only evidence of national malnutrition? Do our hospital
records, our mortality statistics, our medical examination of our young
men for the Army and the Navy point to a nationwide malnutrition in
America? Mortality statistics, even were they reliable, would only reveal
extreme malnutrition. They would not tell us much about early stages
of malnutrition. Between three and four thousand people are recorded as
dying from pellagra (a disease due to an inadequate diet) each year. There
is no recent rise in this category. Of course, there are many more people
sick from pellagra than people who die from this disease, possibly
as many pellagra patients as 100,000 in our country each year. Advanced
scurvy is now almost unknown in the United States. Beriberi is some-
what less rare, especially if we include those cases due primarily to
chronic alcoholism and consequent failure to eat enough good food.
Rickets is not a killing deficiency disease. We may have anemia from
too Httle iron in the diet; but lack of iron is just one of the many
causes of anemia. So national mortahty statistics fail to answer our
question, but so far as they go, they do not point to a state of well-nigh
universal malnutrition in the United States. And the same is true of records
of our hospital admission. Of course, you may reply that doctors do not
recognize early stages of malnutrition. Well, if physicians don't, are WPA
workers and Washington politicians any more competent in this field?
According to Colonel Rowntree, M.C., U.S. Army, the first 800,000
Army draftees of 1941 examined were on the average 67^/4 inches tall, or
of the same stature as our 191 7-1 8 Army draftees, but our 1941 draftees
averaged 8 pounds heavier than those of World War I. According to Gen-
eral Hershey rejections of draftees on account of underweight are so far
about the same as the rejection for obesity, or each around 4 per cent. So
you see even the story of our draftees does not point to a universal and
demonstrable malnutrition. According to the Statistical Bulletin of the
Metropolitan Life Insurance Company, the average length of life as com-
puted on the basis of mortahty of the company's industrial policy holders
in 1 94 1 was 63.42 years. This is an all-time high for the sixty years that
the company has recorded this information. This docs not support the
claim that one hundred miUion Americans suffer from malnutrition.
But I am not willing to go all the way in supreme optimism, as does Mr.
J. R. Hildebrand {National Geographic Magazine, March, 1942), who
asserts that our "machine food age — born of roads, research and refriger-
ation— has made the United States the best-fed nation in history." We
have the food to do it, had we the intelHgence.

Well, what happens to us when we do not eat enough good foods? Can
we know, without asking a doctor, when we suffer from malnutrition?

NUTRITION 89

And if we ask the doctor can he tell us when and what? The simplest
situation is this: Assuming absence of chronic diseases, if an adult does
not eat enough for energy needs he loses weight, if a child does not eat
enough for energy needs he soon ceases to grow. Any layman can strip
and step on the scales. The physical and mental impairments following pro-
longed inadequate intake of essential protein, essential fatty acids, essential
inorganic salts and vitamins are more insidious. They can not at present be
diagnosed even by the physician, unless they are well advanced, and by
exclusion of many other factors that may produce similar symptoms —
such general symptoms as decreased physical and mental endurance, de-
creased appetite, etc. The anemias we encounter in the population are
usually not due to too little iron in the diet. Nervous disorders and poor
intelligence are very rarely due to vitamin deficiencies. The signs and
symptoms of such dietary deficiency diseases as scurvy, rickets, pellagra,
beriberi, "war" edema (protein deficiency) any up-to-date doctor can
detect and eliminate. But no one (doctor or layman) can be sure in regard
to the early stages of these dietary deficiencies. We have recently been
told by a national committee of physicians, who should know, that one
of the first signs of malnutrition is decreased appetite, and that laymen
can diagnose their own state of nutrition by the state of their appetite for
food. This is too good to be true. If it is true, and it is also true that one
hundred million fellow citizens suffer from malnutrition, it is clear that
the American appetite for good food is sunk, and that it probably will
take something more potent than synthetic vitamin pills to restore it to a
level of national safety.

This sounds discouraging, if not alarming, at least to laymen. Must
our national safety and well-being in the matter of nutrition be thus left
in the fog, pending further medical and nutritional research? Not at all.
America is a paradise in the matter of abundance and variety of all the
foods requisite for an optimum human diet. And if we are average normal
men and women, we still have our primitive urges of hunger and appetite,
notwithstanding recent published assertions to the contrary. How do you
suppose our ancestors carried on, in the total absence of modern knowl-
edge of food chemistry, vitamin requirements and the alleged necessity
of "a pint of milk a day"? I do not think Sioux Indians got much milk from
the wild buffalo. The American Indian had neither cows nor goats. And
yet he carried on. It is evident that for the greater part of human history
man did very well nutritionally by eating enough of all available varieties
of natural foods, guided by his hunger and appetite. Nutritional safety
lies in omnivorousness, in consuming, so far as possible, foods in their
natural states, and, in the case of fruits and vegetables, eating some of them
raw. Some of our malnutritions started with the processing, the refining
and the "purification" of such foods as the cereal grains, modern milling
processes shunting the most valuable part of these natural foods into the

90 READINGS IN BIOLOGICAL SCIENCE

mouths of chickens, cattle and hogs. The cereal grains hold valuable pro-
teins, vitamins and minerals. Human dietary safety on this front would
seem to be: Go back to first principles — putting the whole grain into the
flour and the bread. This can be done. We can learn to like it. There
is no more "purity" or nutritional virtue in white bread than in white
winter butter. I think we could learn to prevent the oxidative rancidity
of whole grain flour. And until we have that problem licked, what is the
matter with storing the wheat and milling the flour as we need it? I do
not see any essential economic principle in storing the flour in place of
storing the wheat. In my judgment, the recent addition of a little of the
vitamins and minerals now milled out of the grain and singing peans of
dietary salvation over this "enriched" flour and bread is not a sound policy
either for to-day or to-morrow. Let us get back to first dietary principles
on this front also. The whole wheat, rye or rice grain is one of our least
expensive protective foods. On the whole we can trust nature as to the
genuine nutritive elements in the whole grain — yes, trust nature further
than the chemist and his synthetic' vitamins. Recently, Professor Drum-
mond (Jo7ir?ial, American Medical Association, March 7, 1942), the
scientific adviser to the British Ministry of Food, voiced this reluctance
to put the dietary safety of a nation on synthetic vitamins as a long-range
policy. He thinks we must and should provide the natural vitamins in the
natural foods. I stand on that platform, until we know a great deal more
than we know to-day about foods and human nutrition.

How vital are vitamins? What happens when our breakfast, lunch and
supper do not adequately balance with all the known vitamins every day
in the year? The vitamins are vital. Even the kangaroo and the crow do
not get on without them. They get all the vitamins required in their
natural food. So did our ancestors. So could we. On an adequate abundance
of natural foods we store vitamins in the body against weeks and months
of vitamin scarcity. If we live mainly on such vitamin deficient foods as
white bread, polished rice, fat salt port, refined sugars, refined and hy-
drogenated vegetable oils, refined lard, etc., serious things happen to our
health when our body stores of vitamins are depleted or nearly depleted.
It should be obvious to all laymen that every meal every day does not need
to be vitamin balanced. Our body stores take care of our urgent needs for
weeks or months, unless we have already subsisted on the minimum for
some time. It is a fact that an adult man in average good health can go
without any food whatever for at least forty days, without showing any
recognizable vitamin deficiency. At the end of a forty-days' fast the man
is considerably emaciated and more readily fatigued, but his appetite for
good food is keener than ever. There is to-day entirely too much blarney
and ballyhoo about synthetic vitamin pills. Under any and all circumstances
these pills are said to give us the abundant life, including intelligence, men-

NUTRITION 9 1

tal stamina and moral conduct! The tragedy here is this: Few if any of the
people who can afford to buy these pills need them, few if any of those
who need them can afford to buy them. The consumer should insist that
advertising of food conform to honest and factual education of adults
in nutrition, for it is obvious that the consumer pays the freight of all
food advertising in the increased cost of the advertised foods.

We are urged to drink milk, and to eat meats, eggs and vegetables for
our needs of inorganic salts. Is that a good insurance? Is it enough? Can we
get adequate mineral insurance at less cost through other foods? While
it appears true that herbivorous mammals have sought "salt licks" for
countless ages, and our forebears fought wars for possession of sea salt as
their more sophisticated descendants now do battle for crude rubber and
mineral oil, it seems obvious that except for the element iodine in restricted
areas of the earth the dietary needs of minerals were efficiently met bv the
common non-purified, non-processed natural foods. So far as I know this
would still hold true, except for the cooking of such foods as meats, fruits
and vegetables and the habit of discarding the cooking water. To be sure
the otherwise excellent natural food, milk, is so deficient in iron that an
exclusive or almost exclusive diet of milk for weeks or months brings on
an anemia due to the iron deficiency in the diet. How does the American
dietary stand as to some of the essential mineral needs such as calcium,
phosphorus, iron and iodine? The iodine deficiency in the States whose
soil and water Mere depleted of iodine by the waters from ancient glaciers
is now taken care of by putting the iodine back into our table salt. The
iodine was there before our ingenious chemists learned to take it out. In
so far as purification deteriorates our food, the science of chemistry does
not serve man's welfare. Professor C. H. Sherman, of Columbia Univer-
sity, an outstanding expert on nutrition, has long held the view that the
American diet is probably too low in calcium and possibly in phosphorus
for optimum nutrition. This problem is complicated by the fact that a
modicum of vitamin D is involved in the adequate absorption and utiliza-
tion of calcium and phosphorus, particularly in the growth and main-
tenance of our bones. Can not the possibility of a dietary danger in this
field be met, universally and ivithont cost, by adding a little calcium,
phosphorus a?id iron to our table salt? This should offer no insurmount-
able difficulties, and there is no evidence that a slight excess above actual
needs of these minerals works any injury to our health. We are urged to
eat milk for its calcium. Yes, milk is a good source for lime. But milk is a
relatively expensive food, and even in our country, with a plethora of
foods there is not enough milk to go around, at least as long as we insist
on butter and cream for our table and turn so much of the valuable skim
milk into channels other than human food. I think we should put a Httle
lime, phosphorus and possibly iron into our table salt as a national insurance

92 READINGS IN BIOLOGICAL SCIENCE

towards good nutrition. But I wonder how many vitamin B pills we must
consume before we nurture sufficient intelligence to take this apparently
rational step.

It seems clear that we do not know the extent of malnutrition in our
country. But some malnutrition, especially pellagra, obesity, underweight,
anemia, does prevail here. Why? The causes for the malnutrition that
does prevail are both numerous and complex. Among these are: chronic
infections, worry and mental strain, faulty dietary habits, ignorance as to
what makes up an adequate diet, personal laziness, poverty, misleading
food advertisements, denaturing of such staple and standard foods as flour
(wheat, corn) and bread, possibly too great consumption of purified sugars
and candy, waste of good foods, especially fruits and fats, etc.

Since man and his health constitute our most important natural resource,
we must proceed without delay and with all the brains at our command
to find better and more reliable methods to diagnose the signs and symp-
toms of incipiejit dietary deficie?icies. Such knowledge will give us a
clearer understanding of what constitutes an optimum diet for optimum
health, so far as health is determined by diet alone. This, it seems to me,
is a primary charge on the science of medicine, of biology, the science of
chemistry. But we who labor in these fields will proceed faster along these
lines, if we are encouraged by an understanding of the urgency and the
difficulties in the problem and the cash cost of its solution on the part of all
citizens.

Pending this greater scientific understanding as to human food needs for
optimum health, these important things can and should be done now: (a)
cleanse our present food and nutrition education of all fads, of all selfish
commercial and myopic political propaganda; and (b) move our nutrition
education from the ivory tower down to comprehension and appreciation
of the common man. We have the brains and the cash to do it. Have we the
will to carry on this hard task, when a possible superior health for all is
the only goal, the only reward? I wonder.

>>> <<<

WHY WE EAT WHAT WE EAT *

WARREN T. VAUGHAN

Why do we eat what we eat? Possibly this should be preceded by an-
other question, "Why do we eat at all?" The answer is elementary: we eat
because we have to, because we are hungry. Also we eat because we like
the taste of things. Many a fat old dowager eats chocolate peppermints,
not because she is hungry but because she likes chocolate peppermints.

• Reprinted by permission of the Scientific Monthly, American Association for the
Advancement of Science. Copyright 1940.

NUTRITION 93

As a corollary, we also eat because we are in the habit of eating. In this
country we are in the habit of eating three meals a day. The Britisher is
not actually a different species of animal that requires four meals daily,
but he has found tea and crumpets in the afternoon a pleasant custom and
has made it habitual.

The same three premises will be found to apply also to the original
question. What we eat depends in part upon necessity, in part on habit and
in orreat measure on taste. Convenience is also a factor. The newborn babe
does not suckle at his mother's breast primarily because he or his mother
knows that mother's milk contains most nearly the ideal proportions of
protein, fat, carbohydrate and minerals. He does so in part because it is
the most convenient thing to do. Mother's milk is not an absolutely neces-
sary food. Many children are raised, from birth, on cow's milk, and some
who are allergic thereto thrive on substitute food mixtures which contain
no milk of any sort. ^

Down through the ages, from the earliest savages, dietary habits have
been conditioned in great measure by the availability and convenience of
the various foods, their palatability and by past experience with them on
the trail-and-error basis. Experience has taught us concerning their taste,
nutritional value and harmlessness.

As we sit in one of the more sumptuous restaurants in a large city and
glance over the many pages of the a la carte menu we might wonder to
what kind fate we owe our opportunity to order any number of the most
delectable concoctions garnered from the farthest corners of the earth.
Aladdin could not have done as well, since many of the finest of these
foods were unknown to him in his remote time. We no longer stroke
the lamp, but with a few strokes of the pencil we are far better off than
he was. Today nearly all of the really good foods on earth are available
nearly every\\here, convenient as the corner grocery, palatable as man and
nature can render them and guaranteed reasonably harmless by food laws
and inspection. A good family dinner of today would render a Roman
emperor of the banquet era green with envy.

How has this been accomplished? Several years ago an interesting novel
started with the collapse of a bridge, the Bridge of San Luis Rey. On the
bridge at the moment of the catastrophe there were a number of persons,
some of them total strangers. The remainder of the book traced the former
life of each of the victims up to the moment of the collapse, thus bringing
to light those forces which gradually brought these victims together for
their final destruction. As we sit, ready to destroy the delicacies before us, it
would be interesting to trace them, likewise, back to their original sources.
Space will not permit discussion of too large a number of our victims, but
those selected will serve as examples for the experiences of others.

Our story must start with earliest times, when more or less isolated
groups of the human race were scattered here and there over the earth,

94 READINGS IN BIOLOGICAL SCIENCE

and before the words trade and commerce had been invented. Shall we
start with the Garden of Eden near the eastern end of the Mediterranean or
shall we be more modern and commence on the plateaus of Tibet? Shall
we be ultra-modern and assume that those precursors which ultimately
became man might, like plants, have started at several places on the earth,
provided conditions were right? It makes little difference in the present
discussion, although in passing we might point out a fallacy in the story
of Eden. Tradition today has it that the apple was the cause of the down-
fall. Botanists tell us, however, that this fruit had its origin in cooler
climates, northern Europe and especially northern Asia. The apricot ap-
pears to have been the more likely contender for the honor, since it ap-
pears to be indigenous to Asia Minor. One might argue that if the apple
story is true, the Garden of Eden was not in Asia Minor but more nearly
at the site now more widely accepted as the cradle of the human race.
Parenthetically, however, the Bible makes no mention of an apple. It merely
alludes to the fruit of the tree of knowledge.

We might use the apple as an example of the method of propagation and
distribution of foods. It seems improbable that all varieties of apple came
from a single ancestral tree. Today there are thousands of varieties within
this genus. Mains. Some are edible, while others are not. It seems probable
that, under proper conditions, plants closely resembling each other and
now all grouped within the apple genus took their origins independently,
in the same way that the wheat of today was derived from the wild grasses
of Asia Minor, while Indian corn was developing entirely independently
from the teosinte grass of Mexico or from another local ancestral grass.

The crab apple of North America is indigenous to the New World
and presumably was developing independently while the finer edible
apples were evolving in Eurasia. But the point to be made is that those
varieties which came to be used as foods usually took their origins from
some unusually fortuitous specimen and have been distributed across the
continents from this original source. Today North America is the great-
est apple region in the world. We have our indigenous members of the
genus, most of which are still wild and scarcely edible, but the cultivated
apple of North America was originally imported into this country from
Europe and more remotely from its original habitat in the cooler climates
of the Old World. To be sure, man has improved the fruit by fertilization,
selection and cross-breeding, until there are now hundreds of more deli-
cious varieties descended from the original parent.

But the happy fact is that most of those foods cultivated for use by man
may be traced back through historical records to an approximate original
source, even though there are inferior domestic varieties which are prob-
ably indigenous to particular areas.

It makes a rather thrilling picture to visualize nomadic tribes wandering
here and there within rather restricted areas; coming by accident upon an

NUTRITION 95

unusually delectable specimen of a plant which they have been accustomed
to use as food; returning to the same plant whenever feasible, to again
enjoy its delicious morsels; and then, as they become less nomadic, taking
seeds or cuttings from this particular specimen, to plant in a more conven-
ient place nearer home; nurturing it most carefully, protecting it from the
weather and feeding it as it grows, thus establishing the earliest rudiments
of husbandry. Into the sequence of the picture, next comes contact, either
peaceful or warlike, with other more or less remote tribes; realization that
others have likewise developed better specimens of different foods; and the
resulting exchanges by barter or by importation following conquest, this
being the first step in the spread of cultivated foods across the earth.

Much of this occurred in prehistoric time. Carbonized apples have been
found in the habitations of the prehistoric Swiss lake dwellers. It is true
that these may have been the original wild apples rather than cultivated
varieties. Apples were known to the ancient Romans and Phoenicians, who
raised them in their gardens.

Before the dawn of written history man made a great discovery which
enabled him to depart from that nomadism which forced him to change
his abode with the seasons, so that he might always be where food was
available. The discovery enabled him to remain permanently in one place.
This was the cultivation of wheat and the making of flour which could be
baked into bread for use when fresh vegetables and game were not avail-
able.

The origin of wheat is not definitely known, but it appears to have
been developed originally from the wild grasses of Asia Minor or Egypt
or around the shores of the Caspian Sea. It was introduced into China about
3000 B. c. and was described as being present in Egypt about 2440 b. c.
It was used by the Swiss lake dwellers. Fortunately, other groups had also
learned to cultivate grasses indigenous to their own territories for use as
food. Rye is supposed to have originated in the Orient. It has been culti-
vated by man probably as long as has wheat. Both were used in the Bronze
Age. However, rye was not cultivated in ancient India, Egypt or Greece.
It is today the principal cereal of northern Russia, Scandinavia and north-
ern Germany.

Barley was probably the first crop grain of the human race. It was de-
scribed in Egypt as early as wheat, and the Egyptians claimed it to be the
first of the cereals used by man, introduced by their goddess, Isis. It was
a sacred grain to the early Greeks, used in sacrifices and in the cereal
festivals. Pliny called it the most ancient cereal. The Cimbri, early pro-
genitors of the Britons, made their bread from barley, which remained
the chief food grain of England until as recently as the eighteenth century.

Rice is the most extensively cultivated of the grains and is the principal
cereal food for over one third of the entire population of the earth. It
appears to have originated in tropical Asia and was introduced into China

96 READINGS IN BIOLOGICAL SCIENCE

about 3000 B. c. The ancient Romans knew the grain, but it was not
introduced into cultivation in Europe until the sixteenth century.

Corn appears to be indigenous to the region of Mexico. It has been in
cultivation since prehistoric times and is unknown in the wild state. Colum-
bus first saw corn in Cuba in 1492. He carried it to Spain, from where it
was rapidly distributed to most of the regions of the earth. When the
new world was discovered corn was in cultivation from Canada to Brazil
and from California to Chili. Some of the Icelandic sagas described as early
as 1002 A. D., what may well have been corn on the New England coast.
The early explorers following Columbus described the cultivation of corn
and lima beans, along with pumpkins, by the Indians in the New England
region.

As tribes grew larger and, for economic reasons and purposes of pro-
tection, banded together into nations, the distribution of cultivated foods
within the nations was facilitated and commerce between them developed.
Now, perhaps, we are in the era of the caravan routes across Asia, when
trade dealt not only with hides and cloths, precious metals and jewels
but also with the less highly perishable of the foods from foreign lands.
Chang Chien, Chinese explorer, had established overland trade routes
between China and the Roman Empire by 115 B.C. As the routes of
travel, by land and by sea, reached farther and farther, the spices even-
tually made their appearance in the Alediterranean countries. They were
not quickly perishable, and they stimulated the palates of the Europeans
as nothing had done before. Almost from the day of their appearance,
exploration and commerce were guided in great measure by the desire of
the white man for spices and more spices. This desire was a potent factor
in Columbus' discovery of America, Magellan's circumnavigation of the
globe, and the early settlements in America under the British East India
Company. Love of spices was the cause for many a war. Attila, the Hun,
required three thousand pounds of pepper as a part of the ransom of
Rome. Many were the massacres countenanced in the Dutch East Indies
in an effort to retain a monopoly on spices.

As the various peoples learned of the uses of their own foods, and their
value in commerce, they often made every effort to establish monopolies.
On many occasions attempts were made, sometimes successfully, to steal
the secrets. An outstanding example occurred, not in horticulture but in
sericulture. The Chinese had preserved the secret of silk manufacture for
many centuries. In 552 a. d. two monks who had lived for some time in
China first smuggled silk worms, in a hollow bamboo, to Constantinople,
where, under the protection of the Emperor Justinian, they inaugurated
the silk industry in Europe.

Coffee was indigenous to Abyssinia, where the natives ate the raw grain
as a stimulant. In the fifteenth century the Arabs discovered the value
of the bean and started its cultivation in southern Arabia. From the port

NUTRITION 97

of Mocha, knowledge of it spread to Egypt and Constantinople in the
sixteenth century, to Venice and then to England in the seventeenth cen-
tury. It was then that coffee houses and cafes sprang up in the European
centers. Religious zealots denounced coffee as an intoxicating drink. The
Arabs kept their secret until the eighteenth century, when coffee was
grown successfully in Java. Today Brazil is the world's greatest coffee-
producing country.

Chocolate first became known to the white man when Montezuma,
the Aztec Emperor, gave Cortez a drink of the delicious beverage from a
golden cup. The Spaniards carried cocoa back to Spain, keeping its source
secret for many years, selHng it at a high price, as chocolate, to the wealthy
classes in Europe.

Cinnamon, native of Ceylon, was known to the ancient Hebrews, Greeks
and Romans, but was not cultivated by them. It was carried across Asia
Minor by the Arabs, who kept its source secret for nearly one thousand
years.

Apricot is native of Armenia, Arabia and the upper portions of Central
Asia. The fruit was held in such high esteem that, according to Disraeli,
Tradescant joined a crusade against Morocco in 1620 for the sole purpose
of steaHng apricots for import to Britain. The cultivation of apricots in
England dates from that time.

In one way or another, we see, then, that foods relished by one group
of persons were gradually disseminated to other parts of the world. At
times the route was quite circuitous, as in the case of the Irish potato. This
food, native of the mountainous regions of Chili and Peru, was unknown in
the hotter climate of Mexico, at the time of the discovery of America.
From South America it was carried to southern Europe, whence it made
its way to Ireland. It was later introduced into New England by a group
of Irish colonists. Here was a New World plant, introduced into a differ-
ent part of the New World via the Old World. In this way it succeeded
in passing the barrier of the tropics, where it does not grow. Its cousin,
the tomato, made easier progress northward from South America, since
the barrier did not prevent its propagation. Early explorers found the
edible varieties in wide use in iMexico, as well as South America, and ac-
cording to Jefferson it was being groM'n in Virgina in 1781. It was not,
however, until after 18 12 that the tomato came into use as a food in this
country. The prejudice against it was probably due to two factors. To-
matoes were supposed to be poisonous, possibly because of their relation-
ship to the deadly nightshade. Also, the earlier tomatoes which had not
been intensively cultivated were by no means as good as they are today.

The foods which we eat today may be fairly accurately traced back to
nearly all parts of the world. To Asia we are indebted for tea, rye, onion,
rhubarb, buckwheat, radish, pistachio, licorice, peach, cucumber, almond,
grape and the soy bean. Tropical Asia has contributed the citrous fruits.

98 READINGS IN BIOLOGICAL SCIENCE

rice, cottonseed, egg plant, black pepper, taro (dasheen, cocoyam), mango,
mangosteen and endive. The islands of the Pacific and Indian Oceans
were the source of coconut, bread-fruit, nutmeg and grapefruit. If there
were no Ceylon we should have no cinnamon. Northern Europe and Asia
comprised the birthplace of the edible varieties of apple, fennel, currant
and gooseberry, while the mustard or cabbage family — turnip, rutabaga,
cabbage, cauliflower, mustard, kohl-rabi, broccoli, Brussels sprouts — are
indigenous to northern Europe.

From the region of the Caucasus Mountains we have obtained asparagus,
quince, pear and plum. Asia Minor and the eastern end of the Mediterra-
nean, where men made such early progress, is fairly well determined as the
original home of wheat, barley, shallot, fig, date, English walnut, apricot,
olive and artichoke. Garlic, although favored in Italy today, took its
source from Tartary.

Southern Europe has contributed parsnip, celery, leek, chestnut, filbert,
carrot and lettuce. The last may also have been indigenous to the Orient.

Africa has contributed no great quantity of food, but their quality
is good. Spinach is said to have originated in northern Africa, watermelon,
cantaloupe, and akee from tropical Africa and coffee from Abyssinia.
The original home of the oat has been placed both in Abyssinia and the
Danube River basin.

The New World has been no mean contributor. From North America
come huckleberries, cranberries, pecans, hickory, pumpkin and possibly
the kidney bean. Cocoa, corn, avocado, peanut, allspice, guava, vanilla,
sapodilla, papaya, star-apple, cassava, chocho and sweet potato stem from
tropical America, while pineapple, lima bean, Irish potato, tomato, mate
and the herbaceous peppers found their origin in South America. A few
foods were already so widely distributed in a cultivated or semi-cultivated
form at the commencement of exploration that their original sources must
remain unknown. This applies particularly to banana, plantain, ginger
and yam.

Nor is the list complete. Within the last half century we have observed
many new importations, particularly in our own country, where chmatic
conditions are so varied that both tropical foods and those that thrive in
the cold northern climates may find suitable conditions for growth. The
labors of the Bureau of Plant Importation, so delightfully described by
David Fairchild in his memoirs, "The World Was My Garden," have made
available within our own boundaries many of the most delectable of foods,
especially those fruits indigenous to the tropics, such as mango, mango-
steen, sapodilla, guava and akee. As time goes on these will undoubtedly
come into more wide-spread use, as have their less perishable tropical
cousins, orange, grapefruit, banana and pineapple.

The foods that we eat today stem from three general sources: (i) those
indigenous to America; (2) those imported by the early colonizers from

NUTRITION 99

the older civilizations, which in turn had collected them from remote
places; and (3) the newer tropical foods which are just making their start.

The history of the cultivation of foods parallels the history of the human
race. However, it has not been until well within historical time that com-
merce and exploration have made such wide varieties so generally avail-
able. We read of the banquets of King Solomon and the extravagant feasts
of Belshazzar, and of the Roman banquets, some of which are reported
to have cost the equivalent of a thousand dollars per guest. Let us sit in
at some of these meals.

The ancient Hebrews, who learned their cookery from the Egyptians,
made quite a ceremony of their feasts. Three successive invitations were
sent to each guest. When all were gathered together they sat cross-legged
around a low table. The food was mainly a stew, since knives and forks
were not available. The cut-up morsels were folded by the guest between
slices of bread and eaten. The grease was rubbed from the fingers onto
other pieces of bread, which were thrown to the dogs, waiting as anxiously
as they do today. Servants were ready with pitchers of water for washing
the hands. There were two persons to a dish. The food included flesh, fish,
fowl, melted butter, bread, honey and fruit, four or five dishes in all.

The Greeks inaugurated the system of eating in a reclining position,
while being sprinkled with perfumes to combat the odor of perspiration.
They had two courses. The first was fish and meat, vegetables and entrees.
The second, pastry and fruit, was followed by salty cakes, cheeses and the
like to promote heavy drinking. This was accompanied by music, songs and
slave dances, and garlands were entwined about the heads of the partici-
pants "to counteract the action of the wine."

The Romans learned cookery late. In 174 b. c. there were no cooks nor
public bakers in Rome. The common people lived on a porridge made of
pulse. There were several vegetables. Fish, domesticated animals and wild
game helped out. The wealthy learned of the luxuries of the table from
the Asiatic wars. They went mad on the subject of gastronomy. The best
cooks were the most expensive slaves. The Emperor Vitellius, an enor-
mous eater, sent his legions to every part of the empire to procure new and
exotic foods. In a typical Roman feast the first course, merely an ap-
petizer, consisted of conger eels, oysters, mussels, thrushes served on
asparagus, fat fowls, shellfish and matrons. The second course had more
fish, venison, wild boar and wild fowl. The third, or main, course included
the udder of swine, boar's head, fricassees of fish, duck and other fowl,
pastries and bread. Cheeses, lampreys, tongues of nightingales, brains of
peacocks and flamingoes, mushrooms and the rarest vintage wines were
served.

While Petronius' description of Trimalchio's feast is satirical, we may
presume that the foods listed were the delicacies of the time. Also, he
could not have mentioned any foods that were then unknown. We may

lOO READINGS IN BIOLOGICAL SCIENCE

therefore list some of the favorite foods of the days of Nero, as follows:

Meats. vSausage, beef, kidney, pork, bacon, lamb, lambstones, sweetbread,
liver, chitterlings (present-day chitlings).

Seafood. Lobster, pilchard (sardine), mullet, sole, lamprey (an eel-
like fish), snail.

Fowl. Wheatear, goose, capon, blackbird, pheasant, guinea, stork, thrush,
peacock, gizzard.

Game. Hare, boar, bear.

Fruits. Damson, pomegranate, fig, date, apple, peach, grape, raisin,
quince, olive.

Vegetables. Chickpease, pulse (a legume), scallion (shallot or onion),
mustard, beet, lupine (a legume), turnip.

Seasoning. Pepper, vinegar, cumin (a spice of the caraway family).

Nuts. Almond, chestnut.

Sweets. Honey.

Dairy Products. Hen's eggs, goose eggs, cheese.

Confections. Tarts, custards, marchpane, junket, household-bread.

This was the day of the vomitoria, when the gluttonous banqueters
stepped aside into special rooms provided for the purpose, emptied their
stomachs and returned to start again. Perfumes, music, dancing, dice,
gambling and votive offerings to the gods provided the divertissement.

There must have been considerable monotony to the diet. So many of
our more delectable fruits and vegetables were lacking. There were no
potatoes, tomatoes, chocolate, vanilla, corn, peanuts, pecans, rice or coffee.
The list is not complete. They lacked many of the spices which are so
popular today. According to story, garum was their favorite sauce. This
was made from the entrails of fish allowed to ferment until liquefied, sort
of a prehistoric Worcestershire sauce or anchovy paste. This story was
told by Horace, who was the cartoonist of the day and incHned to exag-
gerate. It may not be quite true.

The Britons learned cookery from their Roman conquerors and from
Germanic immigrants.

In the Dark Ages, all Europe forgot how to cook. Charlemagne's ban-
quets were barbaric affairs, with never more than four dishes, chiefly spit-
ted meat. With the Crusades the art was reintroduced again from the East.
The Medici of Florence were chiefly responsible for the renaissance of
cookinff. Catherine de Medici introduced it into France, where, from the
point of view of the epicure, it has remained paramount ever since.

Such, then, is the story of why we eat what we are eating today. It is the
thrilling history of man, responding first to necessity, later urged on by
the need for availability and convenience, and subsequently developing the
urge for new tastes and for greater palatability of his sustenance. It is the
story of patient husbandry through the ages, of disease and death follow-
ing trial-and-error, of avarice, thievery and war. It is the story of ex-

NUTRITION lOI

ploration and discovery. When, today, we complain that our soup is not
properly seasoned, that our melons are not sweet enough, when we com-
plain of the dryness of our grapefruit or of the sogginess of the sweet
potato, let us, instead, give thanks to those unsung heros of the past whose
exploits have made it possible for us to sit each day at dinners such as were
never dreamed of by the epicures and gluttons, kings and emperors of
bygone days.

>>><■<<■

FADS, FANCIES AND FALLACIES IN
ADULT DIETS *

RUSSELL M. WILDER

Many years ago, as a student in Heidelberg, I read an essay by a famous
physiologist. It dealt with the borders of the realm of science. The domain
of scientific knowledge was symbolized by an ancient kingdom. There
was a central capital; a limited region roundabout was well ordered and
habitable, and surrounding this latter was a dense forest. This forest was
haunted by goblins. Some of these were only fantasies, figments of the
imagination of the inhabitants of the cultivated part of the land; some
in truth were mischievous demons. A number of highways radiated from
the capital, but although they were conceived with the military purpose
of ultimate extension to the borders, they mostly ended where the forest
began, and beyond their endings few men dared to venture.

Consider the effect on this kingdom of science that came from the
pioneer efforts of Louis Pasteur. The path he blazed through the forest
of ignorance has been widened and straightened by the scientists who
followed him, and now has been converted into a highway which is paved
and illuminated as far as the frontier. Mankind thus has been protected
from most of those diseases caused by parasites. In consequence, the
pestilences of the past no longer haunt us, childbed fever has lost its ter-
rors, and the mortality of infants has fallen dramatically. In consequence
also, surgeons operate safely, and public health campaigns are ordered
with such assurance that most of the so-called infectious diseases in time
undoubtedly will be eradicated from the earth. I have in mind such diseases
as yellow fever, typhus fever, hookworm disease, tuberculosis and syphilis.

Sometime after Pasteur another path was blazed through the jungle,
and this now is being widened, straightened and lighted into a highway.
You have heard the story of Eijkmann, in the Dutch East Indies, who
observed the weakened legs of chickens fed with polished rice and showed

* Presented before the Minnesota Chapter of the Society of the Sigma Xi, Scientific
Research Society of America, February i8, 1938. Reprinted from the Sigina Xi Quar-
terly with the permission of the Society of Sigma Xi. Copyright 1938.

I02 READINGS IN BIOLOGICAL SCIENCE

that giving the hulls of rice would cure the malady. That was pioneering.
Alono- the trail came Takaki, who eliminated the disease known as "beri-
beri" from the Japanese navy. In Funk's paper, published in 191 1, entitled
"The Etiology of Deficiency Diseases," there appears for the first time the
word "vitamin," applied to a substance Funk had extracted from rice hulls,
with which polyneuritis in fowls and beriberi in man could be cured. The
blazing of the trail was completed, and road-building began. Knowledge
which previously had been developed was incorporated in the new nutri-
tional highway, knowledge of calories, of mineral materials, of the rela-
tive value in nutrition of different proteins, and already in a space of time
shorter than the lives of most of us firm foundations have been constructed
and the more dangerous turns of the road have been permanently erad-
icated.

With this highway safe for travel, the next thing to be done was to
tell the people about it, to convince them of its stability, to provide rules
of the road which would insure safe driving and prevent "jay-walking."
The telling has been undertaken with unlimited enthusiasm, but not always
by those best qualified, and too frequently by men whose interest was
motivated by the commercial advantages obtainable. Promoting the vita-
mins, indeed, was done with such a blaring of trumpets that cautious men,
including many physicians, who had the real interest of the public health
at heart, became fearful that more harm would result than good. Their
cautiousness has aroused the resentment of some of the experimentalists in
nutrition which is not deserved. Physicians have learned from bitter expe-
rience to be critical of new knowledge pertaining to health. Their fingers
have been burned too often.

Not more than thirty years ago, when knowledge about parasitic disease
had reached a stage of development comparable to what now is known
about nutrition, there still were surgeons and other educated people who
pooh-poohed the "germ theory." I well recall the extreme disgust with
which an orthopedic surgeon, having completed the manipulative care
of a fracture in a case also requiring blood letting, would call on his junior
associate to perform this part of the treatment and say to us students on
the benches: "This job is one for a 'sterile' surgeon." I remember too how
shocked we were that an older general surgeon refused to have anything
to do with rubber gloves and the then still new ideas about asepsis. Even
today the public has much to learn of the dangers which lurk in un-
pasteurized milk, and of the wherefores of public health measures.

The attitude of the average doctor toward the newer knowledge of
nutrition is probably a reflection of the pubHc mind. Like newspapers,
they say, doctors give the pubHc what it wants, and health measures are
resisted by most people as infringements on personal rights. Doctors gen-
erally are called when somebody is sick. "Neither they nor the public
think primarily in terms of prevention. They don't seem to realize that

NUTRITION 103

a large part of the prevention, even of infectious diseases, is dependent
upon physical stamina, which in turn is partially dependent upon nutri-
tion. The medical profession, because of this public attitude, is made up
of trouble-shooters." I suggest that this is a reasonable criticism, both of
the public and of very many, and perhaps a majority, of the members of
my profession. Well people have not taken to the idea, said to have been
prevalent in China, of paying doctors to keep them well and I think it is
true that the average doctor in the private practice of medicine is not
conspicuous for social-mindedness. However, there are thousands of ex-
ceptions. It must not be forgotten that promotion of most of our health
legislation has been effected largely through the efforts of organized
medicine.

The task which today confronts those of us who are interested in the
public health differs in many respects from that which was accomplished
so successfully by our fathers and grandfathers. It was possible to provide
by legislation for protection against infectious disease and the number of
people that needed to be educated about sanitation were relatively few. In
matters pertaining to diet, legislation can help much less and progress
must depend on universal education. Unfortunately, most people will
never read "Man, Bread and Destiny" or Sherman's monograph on "The
Chemistry of Food and Nutrition," or any of the many other authorita-
tive treatises available on the subject of nutrition. Most people, I am sad
to say, cannot even distinguish between authority and quackery. Most of
them, so long as we retain the present system of economics, will get most
of what information they ever receive from commercial advertising, which
by its very nature cannot be disinterested.

To meet the problem of mass education in matters of nutrition, the
Council on Foods was organized. At first it was called the "Committee
on Foods of the Council on Pharmacy and Chemistry of the American
Medical Association." The pages of popular magazines and newspapers
were filled with advertisements of food products. The growers, producers
and distributors of such products had learned the value of the health appeal.
Great campaigns were promoted by co-operative organizations in favor
of meat, of flour, of vegetables and other natural foods, as well as of
packaged and prepared foods, with or without additions of minerals and
vitamins. Copywriters were especially alert to dramatize the interest in
vitamins, but proteins also received attention, as well as calories "for
energy" iodin to "prevent goiter," iron to "combat anemia" and other
minerals for other purposes. It seemed that some authoritative body was
needed which could pass judgment on food products and food advertising
in the same way that the Association's Council on Pharmacy and Chem-
istry had functioned so effectively in the field of drugs, and that thereby
the mass education effected by advertising could be guided so that truth-
ful information would be disseminated. The power of advertising is ter-

104 READINGS IN BIOLOGICAL SCIENCE

rific. "It speaks and the whole world listens." The money spent annually
exceeds a billion dollars, and I am told that the advertising of foods repre-
sents a substantial part of it. If this tremendous power could be turned
to the socially useful purpose of disseminating truthful information about
foods, it might not be impossible to make our people the healthiest and
most vigorous men and women the world has ever known. On the other
hand, like a sales tax, the cost of food advertising is borne chiefly by
those who can least afford it, and to assess them for the disadvantage of
receiving misinformation is to add insult to injury.

Manufacturers of food products, distributors, and others interested in
the promotion of natural or processed foods for which claims are made
in relation to the promotion or maintenance of good health, are asked to
present to the Council not only the product but also the advertising ma-
terial used for advancing sales, and if these conform to certain standards
the product is accepted as complying with the rules of the Council. Ac-
ceptance is necessary before any food product may be advertised in any
of the publications of the American Medical Association. One of these,
the Journal of the American Medical Association, goes to every physician
in the land. The product also will be listed in a book to be published on
"Accepted Foods," and the manufacturers are allowed to display, on
the package label and in accompanying advertising matter, a seal to in-
dicate that the product and advertising has been accepted — The Seal of
Acceptance.

A number of great advertising agencies and many manufacturers early
indicated their willingness to cooperate, and now the number of food
products which have earned the right to display this seal is impressive.
An enormous amount of advertising literature has been reviewed and
approved. Much of the labor of the Council may go unrecognized be-
cause it consists of the elimination of misleading health claims before they
appear in the printed advertising. A great deal of advertising literature,
particularly that prepared in the form of educational charts, goes to
schools, and the importance of the reviewing and revising that this ma-
terial receives cannot be overestimated. Many school teachers have learned
not to use matter for display which does not carry the Seal. By these
means those companies and advertising agencies which are willing to
tell the truth about their products, and thereby assist the cause of good
nutrition, are given a distinct commercial advantage.

The principal rule for consideration of a food by the Council is that no
product will be accepted or retained when the manufacturer or his agent
makes false, exaggerated, or misleading statements as to its source, method
of collection, preparation, or as to its value for nutritional purposes. Also,
if it is the opinion of the Council that the general policies of a given firm
are clearly detrimental to the welfare of the public, its products, other-
wise unobjectionable, may be rejected. In addition, certain practices of

NUTRITION 105

unfair advertising are discouraged, especially that of making disparaging
statements about the wares of competing firms. . . .

The work of the Council on Foods and that of the councils supported
by the American Medical Association for the consideration of drugs and
of apparatus for physical therapy necessitates the employment of a staff
of thirty-seven secretaries. The salaries of these secretaries, together with
the necessary expense for office space and facilities, are assumed by the
American Aledical Association, whose burden is further increased by the
fact that much advertising is lost to its publications because of products
which fail to meet the standards set by these Councils, and which con-
sequently are not permitted to advertise in any of its journals. No re-
muneration of any kind is received by the members of the Councils, and
the charge that the Councils ever are influenced in deciding on a product
by whether or not it is advertised in these journals is false. No single mem-
ber of these councils would continue to serve if there were the faintest
truth in such an allegation. The idea is preposterous.

In addinon to passing on submitted products, the Council reserves the
privilege of publishing informative statements about foods of any kind,
whether or not these are eligible for consideration or have been sub-
mitted. The privilege, as a general rule, is exercised only in the case of
firms whose advertising is flagrantly deceptive.* An example cited by the
Council was "Ovaltine," manufactured by the Wander Company of
Chicago. In the issue of December 1 2, 193 1, of the Journal of the American
Medical Associatioji appeared a report by the Council from which I
have taken the following excerpts:

The advertising claims made for "Ovaltine" were that it was a "Swiss food dis-
covery" and "a scientific food concentrate containing in highly concentrated
form practically every single food element necessary for life" . . . "recom-
mended by 20,000 physicians the world over ... as a building and restorative
food for convalescents and invalids, for stomach disorders and feeble digestion,
for nervous and run-down conditions, as a means of inducing calm, restful sleep."

It was claimed furthermore, and I can cite only a tenth of these claims,
that " 'Ovaltine' actually makes children want to eat more — and increases
the nourishment and digestibihty of every bite they take."

The product, as advertised, was a concentrated form of malt, milk and
eggs flavored with cocoa. The Council (then the Committee) found
"Ovaltine" to be "an example of the way in which our recognized foods
are exploited like 'patent medicines' to credulous and ignorant people."
Here is the emphasis on impaired digestion, sleeplessness and nervousness;
here again are the pseudo-scientific claims, here again are the exploitation
of a foreign chemist and the mystery associated with the type of ad-
vertising that was used to build "Santogen," the glorified cottage cheese,
into America's most popular nerve tonic, more than a decade ago.

• The opinions expressed are not necessarily those of the editor or publisher. — Ed.

I06 READINGS IN BIOLOGICAL SCIENCE

This is only one example of dozens of similarly plain-spoken judgments
by the Committee, or the later Council. Among the products to be found
non-acceptable was Fleischman's yeast, distributed by Standard Brands,
Inc., New York.* Numerous reasons were given. I can quote only one
paragraph of the decision. It appeared in the issue of the Journal of the
Americmi Medical Associatio?i for January 24, 1937: "Illustrations of
athletes are presented, with the comment that 'their sturdy build shows
they are abundantly supplied with the four important health-building
vitamins' would seem to imply that nothing else need be considered in the
diet. No mention is made of vitamin C, nor is any mention made of
calories or protein, or other dietary essentials, or the countless other fac-
tors involved in the maintenance of good health in addition to the four
vitamins. A, B, D, and G." The objection in this case was to a sin of
omission, the omission involving deception. Much else was found in the
Fleischman advertising which was non-acceptable. The report continued:
"There are now available on the open market a number of fresh and
dehydrated yeast preparations which are advertised conservatively with
claims based on the actual composition of the product. Fleischman's yeast,
in contrast, is sold with grossly exaggerated or unwarranted claims." The
adverse decisions of the Council on Ovaltine and Fleischman's yeast, and
many other similar rejections, do not imply that the products in question
are not wholesome foods. The fault, in most cases of rejection, is in the
advertising. Another example cited by the Council was Welch's certified,
pure pasteurized grape juice. There are many nutritional advantages in
grape juice. It is a pleasant wholesome beverage, a good source of vitamin
C and of certain minerals, a very acceptable product. The Welch Grape
Juice Company, however, "leads the reader to believe that its product has
specific properties for reducing weight, which is untrue; it cannot 'bum
up fat' and its sugar chemically plays the same part in metabolism as does
any other available carbohydrate. Welch's is anything but 'the big ele-
ment in the build-up diet of the child, comparable to mother's milk,' as
claimed. Its advertising is manifestly an artfully designed piece of de-
ception to enmesh the credulous and those uninformed in nutrition and
physiology, a hodgepodge of nutritional and physiologic chicanery, falsi-
ties, vagaries, misrepresentations and claptrap, a revival of the nostrum
blurbs of the past." These pleasant phrases are quoted from the decision.
Perverse advertising of this character brings good advertising into dis-
repute and does harm to the majority of the food trade. The company,
when informed of the opinion, failed to express willingness to accept the
changes suggested, and therefore its product was rejected.

This brings up the subject of foods with therapeutic claims. The
Council considers them separately, and beheving that treatment of exist-
ing disease is a subject in which only physicians are competent to act, it

* Fleischman's yeast is now advertised in a much more acceptable manner. — Ed.

NUTRITION 107

permits such claims only when the advertising is limited to medical
journals. The layman is cautioned to beware of so-called "health foods"
for which the makers claim curative or health-giving properties. The
Council has been explicit in defining the proper use of such terms as health,
healthful and ^wholesome. It permits statements of well-established nutri-
tional or physiologic values of foods, but consider the term health food,
and claims or statements to the effect that a food gives or assures health,
to be misinformative: "An adequate or complete diet and the recognized
nutritional essentials established by the science of nutrition are necessary
for health, but health depends on many other factors. . . . No one food
is essential . . . and there are no health foods. The term healthful . . .
as used, commonly means that the food described corrects a possible nutri-
tive deficiency or some abnormal condition in such a manner as actively
to promote health. It incorrectly implies that the food possesses unique
(or unusual) health-giving properties . . . which makes its use in ad-
vertising . . . misleading."

Advertising through the mails, although regulated by the rules of the
Post Office, is very difficult to control. "Sucker lists" are compiled by
professional snoopers who sell them to the purveyors of nostrums for the
exploitation of the sick. For instance, persons who have diabetes, as I
know from a large experience, soon are found out by these vampires, and
from then on are deluged with intimate, solicitous letters advising a trial
of this or that "cure," or the use of some so-called "diabetic food." A gen-
eral decision of the Council on so-called "diabetic foods" reads as follows:

There is authoritative evidence that commercially prepared special diabetic
foods are of limited usefulness to the diabetic patient and that the availability of
insulin makes them no longer necessary. Artificial substitutes for ordinary foods
are not to be favored; it is much better for the diabetic patient to learn how to
plan his diet with foods in common use and readily available. The diet should be
exactly prescribed in carbohydrate, protein and fat and total calories.

The designation of a food as a diabetic food merely because it is low in carbo-
hydrate is now unwarranted and misleading and gives the erroneous impression
either that the food, taken in unrestricted quantities in diabetes, is harmless or
that it has remedial action. Except for the necessity of restricting foods to avoid
overstepping the food tolerance, there are no special diabetic nutritional require-
ments. The exploitation of starch-free or low carbohydrate foods containing an
excess of protein for use by diabetic patients is unwarranted. Protein may be
tolerated almost as poorly, if not quite as poorly, as starch in diabetes.

The Council does not limit its activities to criticism. Where popular
prejudice is found to be injurious to the food industry an attempt is made
to combat it. Such prejudice also is socially disadvantageous. In some
cases it represents the survival of antiquated scientific opinion, but usually
it has been built up by the preachments of faddists or by the advertising
of competing foods. Specific instances of wholesome foods that have been
hurt by such prejudice are oleomargarine and white bread. The Council

Io8 READINGS IN BIOLOGICAL SCIENCE

has attempted, by publishing the true facts, to correct the false impres-
sions. Thus several brands of oleomargarine bear its Seal of Acceptance,
and much has been done to wear down the opposition to bread. Let me
quote from Dr. Fishbein's comment on bread:

Before making a definite statement as to the actual value of white flour bread
as contrasted with whole wheat, it should be emphasized again that neither white
flour bread nor whole wheat bread constitutes a single article in diet for any in-
telligent person. x\s pointed out by McCollum, there are many reasons why the
American can eat white flour bread satisfactorily. "White flour," he says, "keeps
much better than whole wheat flour, and so can be handled with less commercial
hazard. The American public likes white flour bread, and I do not see any reason,"
he continues, "why this taste should be disturbed. The important thing is to insist
upon the consumption of a sufficient amount of what I have termed the protec-
tive foods — milk and vegetables of the leafy type — to insure that calcium de-
ficiency, and the vitamin deficiency of white bread, will be made good."

The supporters of whole wheat as against white flour for dietary purposes
argue that the human bowel requires a certain amount of roughage in order to ex-
ercise its functions satisfactorily. This point must not be considered without
reference to the varying conditions that may exist in different individuals. Dr.
W. C. Alvarez of the Hooper Foundation for Medical Research has vigorously
attacked the unguarded and unqualified recommendation of coarse food sub-
stances: "Some men and women can be greatly helped by bran," he says, "and
their constipation can be cured if they happen to have the digestion of an ostrich;
but if they happen to have congenitally defective or handicapped digestive tracts;
if they have ulcers or narrow places, they cannot handle the mass of indigestible
material, and they promptly get into trouble." Many other dietary substances
such as celery, lettuce, spinach, and raisins provide roughage. Why ask bread to
be like Messalina — all things to all men?

The various activities of the Council not only have borne fruit as re-
gards the standards of advertisers of accepted products; the influence also
is apparent in the advertisements of products not submitted or even of those
that have been rejected. This is true for Ovaltine and Fleischman's Yeast, to
which reference was made above; not tliat the advertising of either of these
products would be acceptable now, without considerable revision, but
that in both cases improvement has occurred. The same can be said of
the advertising of the Kellogg products from Battle Creek and of Cream
of Wheat, and numerous other well-known brands of processed foods.
Advertisers are appreciating that elevating their standards is as helpful
to them as it is to the public.

An authoritative pamphlet entitled "Facts, Fads and Frauds in Nutri-
tion," prepared by Mitchell and Cook and published by the Massachusetts
State College, contains the following quotation from Dr. L. Jean Bogert:

The fact is that food fads flourish because people want them. It makes little
diff"erence to the food faddist whether the particular dietary cult he follows in-
corporates a few grains of truth along with the dross or not; he is attracted to
this cult because it satisfies some craving to try a novel dietary, to be in fashion,
to attract attention by being unusual in diet, or from the desire to do something

NUTRITION 1 09

about his health. He may benefit by the simpler diet, more regular living, and
especially through the belief that he will be helped, but this proves nothing as to
the theories on which the cult is based, and the same results might have been more
painlessly attained by other means. The food faddist represents a psychological
type and often drifts from one dietary cult to another; as long as we have this
type of people in such large numbers, diet fads and cults will persist and will be
profitable to their originators.

At the risk of repeating what already may have been told, I must reiterate
the general principles of good nutrition; because these are the "rules of
the road" of the highway of nutrition. They are:

1. Eat more liberally of what McCollum names "the protective foods," milk,
cream, eggs and cheese, green vegetables and the principal fruits. The American
diet probably is sufficiently supplied with meat, potatoes and other tubers, dried
beans, peas, and nuts. You probably could do with somewhat less flour and much
less sugar.

2. Go in for variety in purchasing food. Not everything is known about what
is essential. The principal food factors have been isolated, but there are others not
yet identified. Safety lies in diversification of the diet, and danger attends restric-
tion. No one food is a perfect food.

3. Watch your weight. Obesity shortens life expectancy and favors the devel-
opment of diabetes and other so-called degenerative diseases. If the body weight
lies above the standards set by the actuarial tables of the life insurance companies,
limit the intake of fats, starches and sugar, but not that of mUk or other protect-
tive foods.

4. Don't expect too much, even of a perfect diet. Other things than food can
cause ill-health. The rules of the road are designed for community health, and
may need modification to meet the requirements of certain individuals.

Truthful food advertising provides people with the information they
need to understand nutrition, and better nutrition unquestionably will
benefit our people immensely. On the other hand, incorrect or fraudulent
advertising works immeasurable harm. Therefore, I would like to add one
more rule to the "rules of the road." It is to follow the highway markers
placed on the package labels and advertising matter of those products
which have been accepted by the Council on Foods — The Seal of Ac-
ceptance. When purchasing foods give preference to brands that bear
this label. Thereby you will protect your family; also you will help to
convert food advertising into a socially beneficent institution carrying
truly educational information about foods and nutrition to the conscious-
ness of those less able than you are to protect themselves from prejudice,
fads, fancies and fallacies.

>>>>>>>>>>>>>>>>>>>>>>>>>>>«■<<<«■<■<<<«<<<<<<<<<<<<<<

V

Circulation

IT seems but yesterday when men spoke with bated breath of the "great
killers" such as the black death, typhoid fever, diphtheria, and tuberculo-
sis. At the present time we are hearing more and more about heart disease
and its leadership in the decimation of mankind. Many believe that a large
part of the increase in disorders of the circulatory system is due to the in-
creased nervous strain of modern living and the inability of the system to
repair itself fast enough. Whatever the reason, medical men are alarmed at
the trend.

As the late Dr. Alexis Carrel pointed out — man is delicate. Every year,
in the United States, there are about 100,000,000 illnesses, serious or slight.
In the hospitals, 700,000 beds are occupied every day of the year. The
care of these patients requires the efforts of 145,000 doctors, 280,000
nurses, 60,000 dentists, and 150,000 pharmacists. It also necessitates 7,000
hospitals, 8,000 clinics, and 60,000 pharmacies. The public spends annually
$715,000,000 on medicines. Medical care, under all its forms, costs about
$3,500,000,000 yearly.

As the viruses, bacteria and other infectious agents are gradually but
inexorably brought under control, the degenerative diseases are allowed
to show their full potentiality and this is one of the reasons why the afflic-
tions of the heart have inched their way upward into a position of leader-
ship. Medical science now has another very real and difficult problem to
solve.

THE HEART AND CIRCULATION *

A. J. CARLSON AND V. JOHNSON

Grossly, blood appears to be a homogeneous, red, viscous fluid. But
microscopically, one can see that it is composed of discrete particles sus-
pended in a watery fluid. The particles, called the formed elements, con-
sist of the red blood cells, the white blood cells, and the platelets. These
may be separated from the fluid portion, or plasma, simply by allowing
blood, treated to prevent clotting, to stand in a tube. The formed ele-

• Reprinted from Machinery of the Body, revised edition, by A. J. Carlson and
V. Johnson by permission of the University of Chicago Press. Copyright 1941.

no

CIRCULATION I 1 1

merits are slightly heavier (sp. gr., 1.090) than plasma (sp. gr., 1.030), and
they slowly sink by gravity. This difference in specific gravity is insuf-
ficient to cause settling of the- formed elements from plasma in the circula-
tion where blood is kept in continual agitation.

The formed elements make up about 40-50 per cent, of the volume of
whole blood; and plasma, 50-60 per cent. These figures vary somewhat,
even in health, with temporary physiological changes in the water con-
tent of the blood. If one sweats profusely, the cells are temporarily more
concentrated, and the volume percentage of the plasma is reduced. If con-
siderable water is drunk, for a short time there will be a larger proportion
of plasma. In any case, the fluctuations are slight and temporary, and the
relative proportions of cells and fluid remain fairly constant.

Approximately 90 per cent, of the plasma consists of water, in which
many substances are dissolved or suspended. Obviously, at one time the
plasma contains every product which tissue cells use and obtain from the
outside and also all substances produced by cells which are transported
to other organs to be used, in turn, by them, or excreted from the body.
In addition, other materials are found, all of which contribute in some
way or other to the maintenance of the relative constancy of the internal
environment of cells.

In view of the importance of the circulating fluid, it is not surprising
to find that elaborate mechanisms have been evolved which guard against
its loss should a blood vessel chance to be ruptured. One of nature's de-
vices in invertebrates has been to produce spasms or strong contractions of
ruptured vessels, which serve to pinch off the opening. In vertebrates the
same end is served by the coagulation or clotting of blood, which everyone
has observed in his own blood escaping from a ruptured vessel. When
blood is drawn from a vein into a beaker, it retains its fluidity only a short
time. It is converted into a semisolid gelatinous mass, or clot, in some four
to eight minutes. If clotted blood is examined under the microscope,
threadlike or needle-like processes are seen to appear. As they increase in
length and number, they form an entangled interlacing netw'ork called
fibrin. Between the meshes the formed elements (red and white blood
cells) and some of the fluid become entrapped in the solidifying mass.
As it solidifies, the clot also shrinks, squeezing out from its interstices a
straw-colored fluid known as serum, which collects above the clot and
retains its fluid consistency indefinitely.

Two distinct factors seem capable of initiating the clotting process:
contact of the blood with injured tissues or damaged cells or contact of
blood with "foreign" surfaces possessing certain physical properties dif-
ferent from those of the smooth lining of the blood vessels, with which the
blood is normally in contact.

Contact with injured cells — If blood is drawn into a vessel whose inner
surfaces are properly prepared, taking care that fluid from tissues neces-

112 READINGS IN BIOLOGICAL SCIENCE

sarily injured in the experiment at no time comes into contact with the
blood, clotting fails to occur, or is greatly delayed. This fluid blood, even
after hours, can then be made to clot within a few minutes by adding juices
compressed from almost any tissue. Something present in cells generally,
hberated when they are injured, is able to initiate the clotting process.

Contact with foreign surfaces: platelet disintegration — If blood is drawn
carefully, so as to avoid contact with injured tissues, it will clot in the
normal time if the container is glass. But, if the glass beaker is lined with
parafHne, clotting will be delayed. The essential difference here seems to
be the physical nature of the glass or paraffine surface to which the blood
is exposed. Just what this difference is, is not clear, except that watery
solutions "wet" a clean glass surface but drain from a paraffine or waxy
surface, leaving it quite dry. In general, surfaces which are "wet" by
water, on which a thin film of water tends to remain after most of the
water is drained off, behave like glass as regards clotting. Surfaces which
are not "wet" by water, in general, retard clotting.

Clotting can even be induced in the blood vessels when the blood is
exposed to the proper surfaces. If a pin is stuck through a vein, a thin
clot forms on the pin as the blood flows by. Or, if particulate matter of a
suitable kind is injected, each particle soon comes to be covered with a
thin clot.

Just why this happens is not clear. But, if the process is carefully ob-
served under the microscope, it will be seen that certain of the formed
elements of the blood — the blood platelets — collect upon surfaces like
glass and quickly disintegrate. At a paraffined surface this occurs only
slowly. The platelets seem to be involved in these surface relationships,
and their disintegration apparently initiates clotting. This can be verified
in other ways. If blood is drawn into an ice-cold vessel, and is immediately
cooled sufficiently, clotting does not take place, and examination reveals
that the platelets have remained intact. As soon as the blood is again
warmed, the platelets quickly disintegrate, and clotting occurs. Why
platelets respond in this way to temperature changes is not known, but
the important consideration here is that the clotting seems to be dependent
upon platelet disintegration. Various chemicals are also known which de-
lay the breakdown of platelets. They all retard clotting.

THE RED BLOOD CORPUSCLES

The red blood cells, or erythrocytes, are the most numerous of the
formed elements, each cubic millimeter of human blood containing four
and a half to five millions. Human erythrocytes are biconcave disks, a little
less than 0.008 mm. or about H,2oo inch in diameter. They are normally
of such uniformity in size that histologists frequently use them as handy
units of measurement, including a red cell in a drawing to indicate the
size of the cells in any tissue, relative to this nearly uniform red-cell size.

CIRCULATION 1 1 3

They appear to be perfectly homogeneous, although there are indications
that some internal structural differentiation of parts exists.

The striking visual characteristic of mammalian red cells is the absence
of a nucleus. This at once raises the question, "Are these cells really alive?"
Evidence has been presented that the life of any cell is in some way bound
up with the nucleus. Certainly, these red cells are alive during the early
stages of formation before they pass into the circulating blood. For at this
stage they possess perfectly normal nuclei. At this developmental stage
they must be considered alive. And, indeed, even the mature red cells of
vertebrates other than mammals are nucleated. But in man and other mam-
mals the nucleus is lost before the cell becomes a functioning unit. It may,
therefore be more accurate to refer to these structures not as cells but as
corpuscles — "httle bodies." Perhaps the relatively short period of time
during which red cells course through the blood stream — about ten to
thirty days, on the average — is in some way related to this absence of a
nucleus.

HEMOGLOBIN

The most interesting chemical entity in the cell is hemoglobin, which is
a protein (globin) in combination with an iron-containing pigment
(hematin). It constitutes 95% of the solids of these cells. Each 100 cc. of
blood contains a total of about 15 gm. of hemoglobin. The main func-
tions of the red corpuscles are carried out by means of this substance,
which incidentally, also confers upon blood its red color. This pigment
has the capacity for combining spontaneously with oxygen when free
oxygen is present in relative abundance in the environment. The union
is a loose one, so that, when the surroundings contain little or no free
oxygen, the oxygen breaks apart from the molecule and, by physical dif-
fusion, passes into the oxygen-poor regions.

ANEMIA

Anemia is an abnormality in which the red cells of the blood are re-
duced in number, or are deficient in hemoglobin, or both. Instead of a
normal count of about five million cells, the anemic individual may have
but four or three or even less than one million cells per cubic millimeter
of blood, depending upon the severity of the anemia. Anemia is an ab-
normal state in which there is a breakdown of the formation-destruction
balance which normally maintains the physiological constant of about
five million.

The harm done to the organism in any anemia depends upon the chief
function of the red cells, namely, that of transportation of oxygen. If
there is a deficiency either of red cells or of hemoglobin, the quantity of
oxygen supplied to the tissues generally is reduced, cell oxidations are
hampered, energy liberation inadequate, and normal cellular function

I 14 READINGS IN BIOLOGICAL SCIENCE

impaired. Muscles fatigue quickly, and, if the anemia is severe, they func-
tion scarcely at all, and the patient is bedridden, able to carry on only the
minimal energy-liberating reactions requisite for bare maintenance of life.
When even this is no longer possible, cellular death and death of the or-
ganism occur.

Of special interest is the condition known as "pernicious anemia." It
derives its name from the fact that prior to 1927 this condition was as
uniformly fatal as inoperable cancer. The blood count decreases for a
time, there might be then a remission with a return of the count toward
normal, and then a relapse more severe than the first attack. In each new
attack the count goes lower, culminating in death after two to five years.
Formerly, nothing could be done to stop this inevitably fatal course.

Some years ago a group of investigators at the University of Rochester
under the direction of Dr. Whipple became interested in experimental
anemias produced in animals by repeated extensive hemorrhage. They
observed the effects of various foods upon recovery from the anemia.
They tried many foods quite empirically and at random, guided by no
preconceived notions or hypotheses. Of all the articles they fed, they
found that Hver had the most striking effect. Of all the dogs made anemic
in the manner described, those fed liver recovered more rapidly than
the others.

Now, of course, this experimental anemia was not pernicious anemia.
The latter condition in man displays features which are quite distinct from
most other anemias. The appearance of the red blood cells is abnormal,
and serious changes in the alimentary tract and central nervous system
occur. The dogs showed none of this.

Yet here was a case in which red-cell production was in some way en-
hanced by the ingestion of a specific food, namely, liver. Why not try
it, at least, upon patients with pernicious anemia? And so in 1927 two
Harvard University physicians, Minot and Murphy, fed large quantities
of liver to their patients daily. A striking recovery was effected. In the
intervening years many investigators have confirmed these findings. A few
days after beginning of liver feeding, the blood count commences to
rise and in a few weeks approximates or even reaches the normal, and
the subject is comparatively well. Note that Hver does not cure the condi-
tion. When the liver intake is stopped, the anemia promptly returns and
unless liver feeding is reinstituted, death is sure to follow.

THE WHITE BLOOD CELLS

The white blood cells are less numerous than the red cells, a cubic mil-
limeter containing about 7,000 of them. They are semi-transparent and are
difficult to see unless they are stained. This applies to most of the cells
of the body except the red cells, which are naturally colored. The white
cells are devoid of hemoglobin and differ from the red cells in other

CIRCULATION 1 1 5

Structural features as well. They are always nucleated, even in the ma-
ture form circulating in the blood.

Though fewer in number, the white cells are no less important than
the red cells. When they are markedly reduced in numbers, as occurs in
certain diseases, the individual becomes quite susceptible to infections,
especially around the mouth and throat. Very great reduction in numbers
(e. g. to 500 or 1,000) is fatal.

The best known function of the white cells or leucocytes is in the pro-
tection of the body against infectious disease. These cells, though usually
spherical in the blood stream, possess the capacity for changing their
shape and moving about in the tissues, ameba-like. Furthermore, they dis-
play the primitive capacity for engulfing particles by phagocytosis and
for destruction and digestion of such particles as are of an organic nature.
However, it is only in emergency situations that these activities come into
play — that of invasion of the body by infectious organisms, or in other
cases of tissue destruction.

In the immediate vicinity of infections by certain kinds of bacteria
a remarkable series of reactions occur. When bacteria lodge in the
deeper layers of the skin, they commence to destroy the tissues of the skin
partly by means of toxic products which they liberate in their metabolism.
Changes soon take place in the adjacent blood vessels. They dilate widely,
leading a great quantity of blood into the infected region, producing the
familiar reddening, and, because blood is warmer than skin, a character-
istic, localized warmth. Quantities of fluid enter the tissue from the blood
vessels, causing a swelling.

In all this the blood leucocytes display a typical behavior. They seem to
adhere to the blood-vessel wall in the injured area, and, by ameboid move-
ment, they migrate through the vessel wall in great numbers. Free from
the circulating blood, they migrate toward the bacteria and phagocytize
them. Fragments of local cells killed by the bacteria are also engulfed
by the leucocytes. The ingested bacteria are usually killed and digested,
but in the course of this process numbers of the leucocytes themselves
may be destroyed by bacterial poisons. As they disintegrate, the leucocytes
liberate their digestive enzymes, which, in turn, act upon other nearby
dead cells and cell fragments. The net result is the local accumulation of
blood and tissue fluids, digestive enzymes, dead tissue cells, living and
dead leucocytes and bacteria, and cell fragments in all stages of disintegra-
tion. The whole conglomerate, thick, semifluid mass is called "pus," A
rather large collection of pus is called an "abscess."

Fluctuations in the White Count — In the level of the white-cell con-
tent of the blood we encounter another example of a physiological con-
stant. Physiological constancy is relative. There are fluctuations, and the
normal is more often correctly expressed as a range, with certain upper and
lower limits, than as a fixed, dead level. The normal range is larger for the

I 1 6 READINGS IN BIOLOGICAL SCIENCE

white cells than for the reds. Counts anywhere from about 5,000-9,000
per cu. mm. are found in normal adult individuals and are said, therefore,
to lie within the range of the normal. Even in this same person fluctua-
tions of this magnitude may occur from time to time. Attempts to cor-
relate these changes with other normal physiological activities have not
always been very successful. It has been said by some, for example, that
during digestion or muscular exercise or exposure to cold there is a tem-
porary increase in numbers. Other investigators have been unable to con-
firm these findings. To estabHsh relationships of this sort would be most
important, for it might yield suggestions as to the possible functions of
the white cells in the normal individual.

There is no question about the increases in the white count which
attend certain infections. In pneumonia, appendicitis, tonsillitis, and many
other infectious diseases, the white count is elevated to 12,000, 15,000,
25,000, or perhaps even to 50,000. This we call a "leucocytosis." With the
aid of the white count, therefore, it is possible for physicians to detect the
presence of infections in internal structures like the appendix, which are
hidden from view. Within limits, the degree of the leucocytosis parallels
the severity of the infection, so that counts taken at frequent intervals
often give evidence as to whether the infectious process is increasing in
severity or is subsiding.

THE BLOOD PLATELETS

The third and last kind of formed elements are the blood platelets. They
are roughly disk-shaped, far smaller than red cells, and show none of the
special internal structural difi"erentiation characteristic of cells. Their
origin is obscure, although it is suggested that they too arise partly in the
red bone marrow because bone-marrow injury often markedly reduces
their numbers. Recent observations indicate that they are also formed by
phagocytic cells in the lungs. A platelet count is difficult to make because
of the rapidity with which these bodies disintegrate in abnormal sur-
roundings. Such counts as have been made indicate that the normal varia-
tions cover a \vide range. Though averaging about 250,000 per cu. mm.,
counts anywhere from 200,000 to 600,000 have been considered normal.

CIRCULATION OF THE BLOOD

The heart is a muscular organ lying within the thorax, inclosed in a
sac of fibrous connective tissue (the pericardium). In mammals it is com-
pletely divided by a partition into two parts, the so-called "left heart"
and "right heart." Leading from the left heart is a large vessel, the aorta,
which arches upward, backward, and then downward, extending to the
lower abdominal cavity. All along its course it gives off" arteries, which
branch more and more profusely into smaller and smaller vessels, the
capillaries, whose walls are but one cell in thickness, whose internal call-

CIRCULATION I 1 7

ber is about that of a red-cell diameter, and which are diffusely distributed
to organs and tissues everywhere.

The capillaries then unite -to form tiny veins which, in turn, join to
form larger and larger veins. The veins of the lower portions of the body
empty into the inferior vena cava, and the veins of the head and neck are
tributaries of the superior vena cava. These two large venous channels
empt)^ into the right heart, completing what is known as the systemic
circulation.

From the right heart springs the pulmonary artery, which soon divides
into two, one for each lung. Each pulmonary artery divides into smaller
and smaller arteries and finally into the lung or pulmonary capillaries,
which penetrate all parts of the organ. These, again, collect into larger
and larger veins, finally forming the pulmonary veins, which empty into
the left heart. This makes up the pulmonary circulation. (The left and
the right heart are each divided into two chambers.)

The atria or auricles (the receiving chambers, one on each side of the
heart) have distinctly thinner walls than the ventricles (the pumping
chambers, one on each side of the heart). The thicker walls of the
ventricles are responsible for almost all the pumping action of the heart.
The walls of the left ventricle are much thicker than those of the right.
This we relate to the greater work done by the left ventricle. It pumps
blood through the entire systemic circuit, while the right ventricle has
the easier task of pumping blood only through the lungs, a much shorter
distance.

On each side of the heart is a valve system, betu'een auricle and ventricle,
which permits blood to flow only from the auricle to the ventricle, and
which is closed automatically by blood starting to move in the reverse
direction. These are the right and left auriculoventricular valves. Guard-
ing each exit from the ventricles are also valves of a somewhat different
construction, called the semilunar valves, from the fact that each is made
of three half-moon shaped leaflets. The long margin of each leaflet is at-
tacked to the vessel wall, the short margin being free. The aortic semilunar
valves are located at the beginning of the aorta. They permit blood to
flow from the left ventricle into the aorta, but they are closed by any
reflux of blood in the reverse direction. The pulmonary semilunar valves
lie at the beginning of the pulmonary artery and prevent backflow of
blood from the pulmonary artery into the right ventricle. There are no
true anatomical valves at the orifices of the left and right auricles, where
the veins empty into the heart.

The automatic rhythmicity of the heart has received much attention.
The heart is not entirely peculiar in this respect, for rhythmic responses
are the rule in many organs and systems. The intermittent nature of the
breathing movements is a good example, involving rhythmic contractions
and relaxations of the muscles of breathing. But this is different from the

I 1 8 READINGS IN BIOLOGICAL SCIENCE

cyclic action of heart muscle in the following respect. If the nerves of
the muscles of breathing are severed, the movements cease at once. Their
contractions are entirely dependent upon rhythmic activation through
their external or extrinsic nerves. The beating of the heart, on the other
hand, continues even after all its nerves are cut. The rhythmicity and
automaticity are inherent in the heart itself. In fact, if the organ is com-
pletely removed from the body, it will continue to beat for some time.
Nor is the integrity of the organ itself required for this automaticity. A
bit of the heart muscle, cut off from the organ, may continue to contract
rhythmically. Even in tissue culture, microscopic pieces of cardiac tissue
sometimes continue to pulsate.

During each cardiac cycle, characteristic sounds are produced by the
heart. They can be heard by placing the ear against the chest over the
heart, or by leading the sounds to the ears through the tubes of an instru-
ment called a stethoscope, the receiving end of which is placed over the
heart. In each cycle two distinct sounds are heard, termed the "first" and
"second" heart sounds. The first is low pitched, the second is sharper,
louder, higher pitched, and of short duration. The only way to appreciate
what these sounds are Uke is to listen to them. They roughly resemble the
sounds of the syllables "lubb-dup."

The second sound is known to be due to vibrations set up by the sudden
closure of the semilunar valves very soon after the beginning of ventricular
diastole. Experimental injury to these valves modifies the sound, cor-
responding to faulty function. If they are slit open, for example, so that
they do not close tightly in diastole, and blood therefore leaks back into
the ventricles, the second sound is of a rather soft hissing character, called
a "murmur." Instead of the normal "lubb-dup," there is heard "lubb-
shhh."

This finding is of significance not only in indicating the cause of the
second sound but also in detecting the existence of defective valves. If
the valves are damaged by syphilis, for instance, the presence of the injury
may be detected by the abnormality of the second sound.

The first heart sound is of more complex origin. It is partly due to
vibrations set up by closure of the auriculo-ventricular valves at the be-
ginning of ventricular systole; for, if these valves are damaged experi-
mentally, or by disease, the sound is somewhat modified. However, the
sound persists even though, for the moment, the flow of blood through
the heart is stopped experimentally. During such time, of course, all valve
action ceases. The second sound is eliminated, but the first persists in
modified form. It is thought that for the most part this sound is caused by
vibrations set up by the contractions of the muscle fibers. Even skeletal
muscle fibers produce such vibrations, giving rise to sounds which can be
heard by placing a stethoscope on any contracting muscle.

Throughout the vascular system all the vessels are hollow tubes of dif-

CIRCULATION II9

ferent diameters, ranging from the large aorta, an inch in diameter in man,
to the microscopic capillaries barely large enough to admit a red blood
cell. Variations in the thickness of the walls roughly parallel the variations
in internal caliber, the wall of the aorta in man being about one-eighth
inch in thickness, the capillary walls being of microscopic size. The actual
internal structure as well as the thickness of the vessel walls are signif-
icantly different in different parts of the vascular tree. These structural
differences are of considerable importance to the physiologist, who finds
an intimate interrelationship here between structure and function.

Much of the wall of the aorta and larger arteries consists of smooth
muscle. The spindle-shaped cells are arranged circularly around the vessel.
Contractions or relaxations of these fibers are capable of changing the
caliber of the vessels.

The outermost coat of the arteries is made up largely of connective
tissue, which also invades the muscular layer to a certain extent. In the
connective-tissue layer proper there are a great many elastic fibers, which
give the vessel its elasticity and distensibility, so important in the circula-
tion. The connective-tissue layer renders the wall tough and resistant,
so that, though it "gives" somewhat under high internal pressures, it re-
sists rupture even by very high pressures.

The arteries and veins are lined with thin, flat, epithelial cells which
always present a smooth surface to the moving blood.

The extremely fine final terminal branches of the arteries just before
the capillary bed is reached are termed arterioles, or "little arteries." They
possess all the layers found in the larger arteries, although each coat is
much thinner.

The veins are structurally like the arteries except that their walls are
thinner. Because there is less muscle than in arteries or arterioles, there is
considerably less possibility of active change in the cahber of the veins.
They are rather easily collapsed, as can be demonstrated on the super-
ficial veins of the skin.

Connecting the arterioles with the veins is the capillary bed. As we
pass from arterioles to capillaries, two significant anatomical changes are
apparent. The walls now become exceedingly thin. The capillary vessels
have lost all the coats of the arteries except one — the thin, flat, innermost
cell layer. There are almost no connective tissue and no true muscle (ex-
cluding Rouget cells). For the most part the wall consists simply of a
tubular extension of the continuous smooth lining of the arteries.

Also, the branching of the vascular tree is here more profuse than at
any other part of the system. One arteriole breaks up into a number of
capillaries whose individual diameters are only a little smaller than those
of the tiniest arterioles.

Mention has been made of the fact that the veins are more easily col-
lapsible by externally apphed pressure than are the arteries. This is not due

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SO much to the thinner walls of the veins as to the low pressure of the blood
within. If we measure the average pressure of the blood in successive re-
gions of the vascular tree, we find that there is a continuous decrease from
the heart through the arterial and capillary and venous regions. In the
aorta close to the heart the average pressure is always highest. It is lower
in the arterioles and capillaries and still lower in the veins. The lowest
pressure is in the veins closest to the right auricle. At this point the pres-
sure is about at atmospheric pressure or (in mammals) even lower. The
rate at which blood escapes from a hole in a vessel demonstrates these
differences very well; it spurts rapidly from an artery and flows much
more slowly from capillaries or veins. Even large vessels in the neck near
the heart may bleed very little through a small hole.

The heart is capable of adjusting its output to the rate of activity of
the body. When more blood is required, mechanisms are automatically
set into operation which increase the rate and strength of the heart beat
and hasten the rate of the circulation. But note that this mechanism alone
would increase the rate of blood flow to all the organs simultaneously.
It allows for no differentially greater flow to one organ or system than to
another. If the heart pumps more blood, all organs share in the general
increased blood flow. Not only can the output of the heart change, but
also there are mechanisms which change the distribution of the blood
to the various organs differentially, in accordance with their varying rates
of metabolic activity.

Disorders of the blood vessels are fairly common and their effects are
to be understood on the basis of the disarrangements of blood-vessel physi-
ology which they entail. Some blood-vessel defects have already been re-
ferred to in connection with intra-vascular clotting of blood. Plugging
of an infected blood vessel with a thrombus often serves the useful end
of decreasing the bursting of the damaged vessel, but it also may produce
serious damage or death. Plugging of vessels to parts of the brain or to
the heart may be suddenly fatal.

The effects of occlusion depend, first, on the importance of the organ
whose vessel is occluded and, second, on whether or not other vessels also
carry blood to that organ, as is generally the case.

Allied in their effects to those of complete obliteration of vessels are
conditions which abnormally narrow the caliber of vessels. This may be
in the nature of a more or less localized blood-vessel spasm, or a thicken-
ing and hardening of the walls of the arterioles and arteries. Again, the
effects depend upon what blood vessels are involved. Hardening (and nar-
rowing^) of the arteries of the brain may so interfere with proper nutri-
tion of that organ as to cause serious mental derangements. Involvement
of the kidney vessels may so damage those organs as to make impossible
the proper elimination of wastes.

Hardening of the arteries is essentially a disease of the old. It seems in

CIRCULATION 1 2 I

part to be a specific manifestation of the unexplained but rather general
loss of elasticity of many tissues in old age. This effect upon the skin of the
aged is known to all. But many aspects of hardening of the arteries are
puzzling. The narrowed caliber of the vessels and the change in structure
of the walls have not as yet been satisfactorily accounted for.

Usually associated with hardening of the arteries is a chronic eleva-
tion of the arterial blood pressure. The systolic pressure may rise to 250
or 300 mm. Hg. By some, this is looked upon as a compensatory adjust-
ment, by which blood is forced through the narrowed vessels, and a more
or less adequate circulation is maintained. The seriousness of high blood
pressure (hypertension) lies partly in the danger that some blood vessel
may rupture. Rarely does this occur in large vessels, with dangerous ex-
tensive hemorrhage. More often it involves vessels of such size that the
loss of blood per se is not important. But if this bleeding occurs in a vital,
and particularly a friable, structure like the brain, serious damage may
result. Many brain cells may be torn and damaged by the blood escaping
under high pressure. Everyone knows of individuals who have suffered
such a "cerebral accident," which often causes paralysis, and is commonly
known as a "stroke." The rationale of having people with high blood pres-
sure lead as quiet a life as possible is obvious when we recall that muscular
exercise and excitement elevate the arterial blood pressure. This, of course,
would increase the danger of rupturing a vessel.

LYMPH AND LYMPH VESSELS

The lymphatic system is a circulatory system having rather intimate
anatomical and physiological interrelationships with the blood-circulatory
system, similar to it in certain respects and quite different in others. Lymph
vessels, like blood vessels, are distributed to all parts of the body. We may
liken the system anatomically to the capillaries-plus-veins portion of the
blood-circulatory system. The lymphatic system possesses no counterpart
of the arteries and, consequently, does not have a true continuous closed
circulation. The fluid of the vessels, called "lymph," enters the system in
the lymph capillaries, which resemble other capillaries except that they
appear to be closed at their terminal ends. The lymph flows from the capil-
laries of all parts of the body into larger and larger vessels resembling
veins in that they possess valves and are thin walled. In fact, the lymph
vessels have even thinner walls than the veins. Larger and larger vessels
finally converge to the left-shoulder region in the thorax, where the lymph
empties into a large vein of the blood-circulatory system.

But where does the lymph come from? From where does it pass into
the closed lymph system? Lymph, in general, originates as tissue fluid —
the fluid which surrounds all cells. This, in turn, has reached the cells
from the capillaries of the blood-circulatory system. Thus fluid may
reach the cells by only one route — the arteries, arterioles, and finally capil-

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laries, through whose walls it passes by diffusion and filtration. But there
are two possible return routes. The fluid (lymph) either may re-enter the
capillaries and be carried onward in the venous stream or may enter the
lymph capillaries. The exact mechanism is not known. At any rate, once
in a lymph capillary, the fluid slowly moves on in a devious course through
larger and larger vessels, empties into the large vein mentioned, and so
eventually returns to the heart.

From this it is apparent that in composition the lymph must resemble
blood. It consists of those constituents of blood which are able to penetrate
the capillary wall, plus elements that may be added to it by the tissues. It
contains no red corpuscles and has much less protein than blood plasma.
Otherwise it closely resembles blood plasma in composition.

At rather frequent intervals along the course of a lymph vessel are struc-
tures called lymph nodes. These are made up essentially of a network of
connective tissue, in the meshwork of which are located two special kinds
of cells. These are (a) cells which mature into one kind of white blood
cell — the lymphocytes — and (b) phagocytic cells which possess the same
capacity as ameba for engulfing particles. As the lymph flows through the
vessels, its course is interrupted by the nodes, through which it must pass,
trickling through the packed lymphoid cells and phagocytes. The lymph
nodes, as we may judge, play a large part in determining the peculiar func-
tions of the lymphatic system.

What are these functions? In the first place, the lymph system helps
return tissue fluids to the blood circulation. In these fluids are some of the
waste products of metabolism on the way to excretion. But why cannot
this return be carried out adequately by the capillaries and veins of the
blood-circulatory system? Why have the two routes of return? With our
present information we cannot answer these questions entirely satisfac-
torily. It seems to be true, however, that solid particles seem to be able to
get into the lymphatic capillaries much easier than into the blood capil-
laries. Then, as the fluid trickles through the lymph nodes, some of these
solid particles are filtered out and thereby prevented from entering the
blood stream. In the lymph nodes near the lungs of city dwellers, for
example, so many particles of dust and soot are filtered out that in the
course of a normal lifetime the nodes become very dark or even black in
appearance.

Bacteria in the lymphatics may be filtered out and phagocytized in the
lymph nodes.

Sugars and amino acids are absorbed chiefly into the blood capillaries
directly. But the fats that we ingest, digest, and absorb pass mainly into
the lymphatics. Of course, even the fat soon gets into the blood stream
via the lymphatics.

Another function of the lymphatics is the manufacture of lymphocytes.
They course along with the lymph and, with it, enter the blood stream.

CIRCULATION I 2 3

YOUR HEART *

It is true — that there is an actual increase in heart disease, but this in-
crease does not apply to all the people, Americans as a whole are living
much longer than they used to live, because comparatively few lives are
now cut short by the infectious diseases of childhood and youth. As a result
there are many more older people in the population than there used to
be, and it is in the older ages that the heart is most hkely to get in trouble.
The increase in heart disease that we hear so much about is primarily a
problem of late middle and old age. In youth and early middle age there
is much less heart trouble than there used to be.

It is not true — that nothing can be done about heart disease. The
heart may bear much and not break. It has tremendous reserves of power.
The verdict of heart trouble in most cases does not mean death overnight.
Thousands of persons with damaged hearts are living comfortable, happy,
useful lives right now because they are cooperating with their doctors in
giving their hearts a chance. Many of them may live as long as they could
reasonably expect to Hve without heart trouble. Some of them even have
a chance of complete recovery.

HEART FACTS

Your heart is only as big as your fist, but most of its bulk is muscle. It
has just one job — to pump out into the arteries the blood returned to it
by the veins. All the millions of cells in the body depend upon the rapidly
circulating blood stream for the necessities of life and the removal of
wastes. The brain in particular must have a continuous supply of fresh
oxygen. Since the brain runs the body, death comes within seconds — at
most a very few minutes — after the heart stops beating.

The amount of blood in your body is comparatively small — it makes
up only about 8 per cent, of vour body weight. But to keep that blood in
circulation through miles of blood vessels during an ordinary day of
work, play, and rest, the healthy heart pumps from 9 to 10 tons of blood at
an average daily rate of 70 strokes per minute. The normal pumping action
of the healthy heart is a continuous series of regular contractions and
relaxations — beat — rest, beat — rest, beat — rest, and so on for about 2^4
billion times if the pumping continues for 70 years.

When you are "taking it easy," your heart takes it easy. It then rests
nearly twice as much as it works. But during periods of exceptional
physical exertion or emotional stress it may beat twice as fast as usual
and pump out twice as much blood. The faster the heart beats, the harder
it works and the less time it has to rest. On this important fact is based

• Reprinted from Yo7ir Heart by permission of the Metropolitan Life Insurance
Company and the American Heart Association, 1946.

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much of the medical advice we are given regarding the protection of the
middle-aged healthy heart and the care of the sick heart.

COMMON TYPES OF HEART DISEASE

Heart disease is a convenient term used to cover a multitude of different
diseases, most of which are quite unrelated except as they all involve the
heart or blood vessels.

1 he most common types of heart disease are those associated with in-
fections, especially rheumatic fever and syphilis; or with high blood pres-
sure; or with disease of the coronary arteries. Other less common but im-
portant types are caused by defects present in the heart or blood vessels
at birth (congenital defects), or by overactivity or underactivity of the
thyroid gland.

The Young Heart

HEART DISEASE ASSOCIATED WITH INFECTIONS

Generally speaking, it is possible for the heart to become involved in
practically any infectious disease if the germs causing it or their poisons are
carried to the heart in the blood stream, or if the heart becomes exhausted
in the fight put up by the body against the disease. In these days, however,
very few cases of heart disease are caused by infections other than rheu-
matic fever and syphilis. One important reason for this is that many com-
municable diseases are now being prevented by immunization, or are being
treated successfully with serums or drugs before they have a chance to
infect or weaken the heart.

Heart disease caused by an infection goes by the name of the part of
the heart affected, plus the ending itis, which means "inflammation of."
Hence we have myocarditis, inflammation of the myocardium, or heart
muscle; pericarditis, inflammation of the pericardium, the bag of membrane
enclosing the heart; aortitis, inflammation of the aorta, the great blood
vessel leading out of the lower left chamber of the heart; and endocarditis,
inflammation of the endocardium, the membrane which lines the hollow
heart muscle. Since the endocardium covers the valves of the heart as well
as its inner walls, endocarditis frequently leaves scars which may cause
narrowing (stenosis) of one or more valves or may interfere with their
proper closing.

Rheumatic Heart Disease. Rheumatic heart disease begins nearly always
in childhood between the ages of 6 and 12 as the result of one or more
attacks of rheumatic fever. Many cases of rheumatic heart disease in adults
may be traced to a partly forgotten or mild attack of rheumatic fever or
chorea (St. Vitus's dance) in childhood.

The cause of rheumatic fever, which plays such havoc with young
hearts, is not clear. The solution to the whole puzzle is now one of the chief
objectives of medical research. Just as a lighted match starts a fire in

CIRCULATION I 2 5

kindling already laid in a stove or fireplace, so an attack of a disease caused
by germs of the streptococcus family — for example, tonsillitis, scarlet
fever, or streptococcal cold— often lights up rheumatic fever in a child
or young adult who is susceptible to it. What makes an individual suscep-
tible seems in most cases to be an inherited tendency to rheumatic fever,
which may be increased by poor diet, inadequate protection from cold
and damp, and crowded living conditions that give germs a chance to
spread easily from throat to throat. Unfortunately, one attack of rheumatic
fever makes a child more susceptible, rather than immune, to further at-
tacks, and repeated attacks are more likely to damage the heart.

The earliest symptoms of rheumatic fever may be slight fever, nose-
bleeds, loss of appetite, failure to gain weight, and pain (often vague and
fleeting) in joints and muscles. The uncontrollable twitching or jerking
of the face, arms, or legs, commonly known as St. Vitus's dance, is some-
times a sign of rheumatic fever. This disease may attack all parts of the
heart and, in some cases, clear up with little or no trace. But commonly it
leaves scars in the endocardium which interfere more or less with the work-
ing of one or more of the valves of the heart. By following the advice of
the physician with regard to work and play, individuals with rheumatic
heart disease, whose hearts have not been too severely scarred, may lead
productive and normal or near-normal lives.

Prompt and continuing medical care during attacks of rheumatic fever
is essential, and good nursing care is of prime importance. The child must
be kept in bed during the active stage in order to give the heart the rest
it requires to make as good a recovery as possible. The doctor is the one
to say when the child may get up and how active he may be as he returns
to normal living.

The best, but not absolutely certain, protection against recurrences is
periodic medical supervision, with emphasis on the proper balance be-
tween rest and activity, good nutrition, and protection from respiratory
infections. The use of sulfa drugs under medical supervision to ward off
the streptococcus infections which so often light up rheumatic fever is
giving promising results in preventing recurrences in susceptible chil-
dren.

Syphilis of the Circulatory System. Syphilis continues to be a common
cause of infectious disease of the heart and blood vessels. This disease does
more damage to the aorta than to other arteries or to the heart itself. Prob-
ably the germs (spirochetes) of syphilis invade the heart and aorta soon
after they first enter the body, but as a rule actual disease of these organs
does not appear for many years. Fortunately syphilis of the heart and
arteries is now a preventable disease, since the spirochetes can be destroyed
before they damage the aorta or heart if treatment is begun in the first, or
chancre, stage.

Bacterial E7ido carditis. This serious infection of the endocardium, or
heart lining, is caused in most cases by an invasion of bacteria of the coccus

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family. These bacteria are much more likely to gain a foothold if rheu-
matic heart disease or a congenital defect or some other abnormal condi-
tion already exists. The rare acute form is caused by any one of several
different kinds of bacteria which may enter the blood stream and attack
the heart in the course of an illness elsewhere in the body — for example,
pneumonia or meningitis. In the more com.mon subacute form, Strep-
tococcus viridans (the green streptococcus) is usually responsible. This
germ hides and multiplies in blood-clot nests in the endocardium. With
the sulfa drugs and penicillin at the physician's disposal, the outlook for
the control of bacterial endocarditis is much more hopeful than it was a
very few years ago.

The Middle-Aged Heart

HEART DISEASE ASSOCIATED WITH HIGH BLOOD PRESSURE

High blood pressure, or hypertension, is the most common cause of
heart disease in middle age. What hypertension is and why it causes heart
disease are known. But what causes hypertension itself is still a puzzling
question. Many cases of hypertension are associated with disease of the
kidneys (renal hypertension) or with a disease or functional disturbance
of the nervous system or endocrine glands. The majority of cases of hy-
pertension, however, are labeled "Cause Unknown."

High blood pressure which develops without any discoverable cause
is called essential hypertension. It seems to run in some families, many
members of which through several generations have had essential hyper-
tension or troubles associated with it. Also it appears to be most common
among people who are overweight.

What ''Blood Pressure'^ Is. Everyone has blood pressure. It is simply
the pressure of the blood against the walls of the arteries which are always
completely filled with blood. Everyone's blood pressure goes up and down.
It is highest during systole, the period when the heart pumps a fresh load
of blood into the elastic-walled arteries which stretch to accommodate it,
and lowest during diastole, the period when the heart pauses between
beats to fill with blood. High blood pressure is commonly taken to mean
high systolic pressure. However, the diastolic pressure is fundamentally
the more important of the two, because it represents the basic pressure
exerted on the arterial walls independently of the additional pressure due
to the contraction of the heart. The physician also attaches great impor-
tance to the relationship between the systolic and diastolic pressures. The
difference between the two is called the pulse pressure.

The second factor which makes everyone's blood pressure normally an
up-and-down affair is the way the arterioles behave during emotional
stress. These tiny blood vessels are the smallest branches of the arteries.
They are controlled by nerves which automatically make them constrict

CIRCULATION I27

(tighten up) or dilate (open wider). They tighten up when you are all
keyed up with joy, fear, anger, worry, or working under tension. When
they constrict, less blood can get into them from the arteries, and so the
pressure of blood in the arteries goes up. When the excitement is over
they dilate (open wider), and the pressure goes down.

Hyperte?]sion, or high blood pressure, weans simply that through some
nervous or toxic influence the arterioles throughout the body — and there
are miles of them — are kept more or less constantly in a constricted, or
tightened-up, state.

Hypotension, or loiv blood pressure, means that the blood pressure re-
mains more or less constantly within or below the lower limits of normal
pressure. Unlike high blood pressure, it does not cause heart disease. In-
deed, low blood pressure seldom causes real illness of any kind, and definite
diseases in which it occurs are very rare. Individuals who are physically
below par, especially if they are underweight, may have hypotension.
However, the blood pressure of many healthy individuals tends to be
lower than the average for their age. If your doctor concludes that you
are one of these "low-normal" individuals, you may consider yourself
fortunate because you may expect to live longer than other people.

H01V High Blood Pressure Affects the Heart and Arteries. The effect
of hypertension on the heart is what you might expect if you screwed
down the nozzle of a hose connected with a water pump. Just as the pump
would have to work harder against increased resistance in the hose to keep
water spraying out of the nozzle in the same volume as before, so the heart
must work harder against increased resistance in the arteries to keep blood
flowing through the constricted arterioles at nearly the normal rate. To
take care of this extra work the heart muscle is forced to enlarge. And
often, but not always, the walls of the arteries become scarred and thick-
ened— a process called sclerosis, or hardening, of the arteries (arterioscle-
rosis).

A strong heart and wear-resistant arteries may be able to cope with high
blood pressure for years without much trouble. In some cases there may be
no symptoms at all; in others, there may be headaches, dizziness, general
aches and pains, and possible shortness of breath. These symptoms also
appear in other common conditions. Instead of wondering whether you
have high blood pressure the sensible thing to do is to see your doctor.

Sometimes high blood pressure clears up of itself before it has a chance
to damage the heart and blood vessels, or it may be lowered to a safe level
by drugs or diet or surgery if it is discovered in time. Even malignant hy-
pertension, a severe form of high blood pressure which often progresses
very rapidly, has recently been treated with good results in some cases.

Persistent high blood pressure, however, nearly always results in en-
largement of the heart muscle — the first step in the development of hyper-
tensive heart disease. The progress of hypertensive heart disease to the

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point of heart failure can often be delayed for many years, even into old
age, by following the doctor's advice and leading a life of moderation in
all things — in work and play, in eating, in smoking, in emotional reactions.

The Aging Heart

CORONARY HEART DISEASE

Heart disease caused by disease of the coronary arteries, which have the
job of supplying the heart muscle itself with blood, is most common after
age 50. Thickening of the coronary arteries (coronary arteriosclerosis),
usually associated with hypertension, is the chief cause of coronary disease.
Its harmful effect on the heart is explained by the reduction of the blood
supply of the heart muscle (the myocardium) which occurs when the
coronary arteries are narrowed or blocked. However, the reserve strength
of the heart muscle and its blood supply are both so great that they are
not easily exhausted. Many people are able to live quite comfortably with
coronary heart disease if they are careful not to place too great a strain
on their hearts. With the object not only of prolonging their lives but
also of enabling them to be useful and happy, the physician helps them to
strike a balance between too many and too few restrictions. The main
thing to strive for is equanimity. Some people with a comparatively small
amount of heart damage and disability make themselves worse through
sheer nervousness.

A?ighM Pectoris. The inability of the coronary arteries to perform their
duty properly is made plain by a symptom so important that it is often
regarded as a disease in itself. This symptom is called angina pectoris.
Angina pectoris is a painful, strangling, oppressive sensation under the
breastbone, frequently radiating down the arms, which is brought on by
exertion and lasts for only a few minutes. It is not like any ordinary pain
in the chest, and a person who has had it once seldom needs to be persuaded
to see a doctor.

Coronary Thrombosis. The most serious "accident"which may occur
in coronary disease is the sudden closing (occlusion) of a coronary artery
by a blood clot (thrombus). It causes severe crushing pain in the chest,
accompanied by weakness, pallor, and sweating, which persists in spite
of rest. Sometimes the pain is mistaken for acute indigestion. A doctor
should be summoned at once, because this is a real heart emergency. How-
ever, the great majority of persons survive the first attack of coronary
thrombosis, and most of the survivors live for many years. After the dam-
age done to the heart muscle has had opportunity to heal through a long
rest in bed, the heart has an excellent chance to recover sufficiently to
allow normal or near-normal activities.

CIRCULATION . 1 29

SIGNS AND SYMPTOMS

It is important to realize that the heart may be innocent of causing many
of the feelings of discomfort which are frequently blamed on it. The
cavity of the chest and the upper part of the abdomen, which is separated
from the chest by only a thin sheet of muscle, are packed tightly with
organs. Any extra pressure, such as gas in the stomach or small intestine,
for example, may give rise to pain in the chest with which the heart has
nothing whatever to do. On the other hand, any discomfort in the chest
which is directly related to exertion or excite?7tejjt should be a signal to
consult a physician.

The heart itself may at times act queerly without having anything or-
ganically wrong with it. Common but annoying experiences of this kind
are skipped beats, palpitation (consciousness of the heart beat), and very
rapid beating of the heart. Noticeable misbehavior of the heart beat, or
any other annoying symptoms which may make you think you have heart
trouble, should always be investigated by a physician. If the physician,
after a careful examination, says that nothing is wrong with your heart,
believe him. Many people make themselves miserable by continuing to
think that they have heart disease, even after one or more physicians have
told them that their hearts are sound.

There are a few symptoms which should always be investigated, be-
cause they indicate the need of medical attention whether they are due to
heart trouble or not. One of these is shortness of breath when at rest or
on exertion which has not previously caused breathlessness. Shortness
of breath associated with moderate exertion is an early symptom of a
weakened heart muscle. It is caused most commonly by the congestion
of blood in the lungs which occurs when the left side of the heart fails to
pump on all the blood it receives from the right side via the lungs. Sudden
acute attacks of breathlessness may come on while in bed at night. When
asthmatic breathing complicates this form of breathlessness, the condition
is called cardiac asthma.

Swelling of the feet and ankles is another early sign of possible heart
weakness. When the circulation is slowed up because the heart fails to
pump with its customary vigor, fluid may gather in the tissues and cause
swelling, which is usually first noticed in the feet and ankles.

THE HEART-BLOOD VESSEL EXAMINATION

The ideal way to forestall the onset of heart trouble is to see your doctor
for a check-up every year and to consult him between times at the appear-
ance of one or more of the symptoms which may or may tiot indicate heart
trouble or hypertension.

If you tell the doctor you are worried about your heart or your blood

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pressure, the first thing he will do is to ask you to describe your symptoms.
Symptoms are indications of trouble, like pain, which only you can feel.
As they give the doctor important information about you, it is essential
that you describe them honestly and carefully. The doctor will then pro-
ceed to look for signs of trouble — things which he himself can detect
with the help of various instruments and tests.

CHECKING UP ON YOUR BLOOD PRESSURE

In taking your blood pressure your physician will measure the amount
of pressure exerted by the blood against the main artery of your arm at the
peak of the heart beat (systole) and at the pause between beats (diastole).
The apparatus the doctor uses is famihar to almost everyone because blood
pressure is now measured in the course of practically every m.edical exam-
ination, although this procedure came into general use only a generation
ago.

If necessary, the doctor will also examine the interior of your eyes with
an instrument called an ophthalmoscope, which enables him to see the mi-
nute blood vessels at the back of the eye. Since these blood vessels are
similar to those in other less accessible regions of the body, the ability to
observe them directly gives the doctor an idea of how good your blood
vessels are. From an analysis of your urine (urinalysis), and perhaps by
other tests of kidney function, your doctor will gain valuable information
about the condition of your kidneys. This knowledge is important be-
cause high blood pressure or hypertensive heart disease is sometimes as-
sociated with kidney disease.

CHECKING UP ON YOUR HEART

Usually the physician first feels (palpates) and taps (percusses) the
cardiac region of the chest to determine the position, size, and shape of
your heart. In addition, he may ask you to stand behind the screen of a
fluoroscope while he studies the shadow of your heart cast by X-rays on
the screen. To have a permanent record for further study and future com-
parison, he may also have an X-ray picture taken.

By listening to the sounds made by your heart in action through a
stethoscope, which magnifies them, the doctor is able to detect "murmurs"
or other deviations from normal. Heart murmurs are gentle, blowing
sounds which may or may not indicate that something is wrong with the
heart. A great many murmurs have little or no importance. Others may
indicate that damage has been done to the valves or heart muscle as a
result of rheumatic heart disease or some other condition.

The physician may also wish to have an electrocardiogram made. This
is a written record of the electrical activity which sweeps down and over
your heart at each heart beat. The sensitive apparatus that does the writing
at the dictation of the heart is called an electrocardiograph. The physician

CIRCULATION I 3 I

can tell whether the wave patterns recorded in an electrocardiogram are
normal or abnormal, and so gain additional evidence about the condition
and action of your heart muscle.

In addition to these methods of examining the heart, there are many
others which your doctor will use if he thinks it necesary. For example,
the extent and speed with which the red cells of the blood settle down when
a sample of blood is allowed to stand in a column (sedimentation test) is
a valuable means of uncovering rheumatic and other infections. Deter-
mining the way the heart behaves in various forms of physical exercise
may be used in testing the heart's function. In short, there are now so many
ways of taking the guesswork out of the heart examination that it is no
wonder that our doctors today are able to make more accurate diagnoses
than could doctors in the old days.

LIVING WITH HEART DISEASE

If the doctor finds that you have any form of heart trouble after making
his examination, he will tell you because he must depend upon your co-
operation. He has at his command many potent drugs and new surgical
techniques, but he cannot live your life for you. And in the long run it is
the way you live, more than the medicines you take, that determines how
long and how happily you will live with an impaired heart.

The object of the way of living which doctors usually recommend for
persons with heart trouble is the lifting of all removable burdens — for ex-
ample, those imposed by fatigue, obesity, infections, and emotional upsets,

EXERCISE AND REST

The speeding up of the heart's action which accompanies sudden or vio-
lent or prolonged physical exertion can easily be accommodated by
healthy young hearts, but it puts an extra and unnecessary strain on dam-
aged or middle-aged hearts. The amount of exercise which a person with
heart disease or high blood pressure may take will be carefully prescribed
by the physician, and the patient must use judgment and discretion in
carrying out the doctor's advice according to his ability to perform with-
out getting tired or out of breath.
Things to remember are:

1, Don't run or walk fast to catch anything — train, bus, streetcar, plane, or
any other vehicle. As the saying goes, "It is better to miss it and live than catch
it and die,"

2, Don't walk against a high wind, as this throws an extra strain on the heart,

3. Don't do any more climbing than is necessary — if you must go upstairs or
up hill, do it slowly with frequent rests,

4. Slow up — use moderation — in everything you do. Get out of bed slowly
— never jump out. Cut down the speed at which you work, or work for shorter
hours if possible. The doctor may advise a change of occupation if your present
work is too fatiguing.

i32 READINGS IN BIOLOGICAL SCIENCE

5. Go to bed early. Take a nap or at least lie down during the afternoon. When
you are asleep or resting, your heart gets extra rest.

EATING

Eating big meals taxes the heart, since its work is increased during di-
gestion. Also, overeating is the most commoji cause of obesity, and carry-
ing around aji extra load of fats puts extra strain on the heart.

When a person is sick in bed with heart trouble, the physician usually
restricts the amount of food and fluid allowed. In all cases, moderation
in eating is usually advised both to keep weight down and to lighten the
work of the heart. Five or six light meals a day are sometimes better for the
heart than three large, heavy meals. In some cases the doctor may prescribe
a special diet. There is no one special diet which will apply in all cases.
Specific dietary instructions must be provided by the physician to fit the
need of each individual.

SMOKING

So far as we know now, smoking tobacco does not cause actual heart
disease, but excessive smoking may cause disagreeable disturbances of the
heart beat, even in healthy people, and aggravate the symptoms in certain
types of heart disease. Recent experiments have shown that smoking to-
bacco makes the arterioles tighten up, just as they do under emotional
stress, and constriction of the arterioles raises the blood pressure. Hence
smoking may have a harmful effect in arteriosclerosis and heart disease asso-
ciated with arteriosclerosis and high blood pressure. A person with heart
trouble or hypertension may feel better if he avoids the use of tobacco, and
in some cases the physician may forbid smoking.

AVOIDING INFECTIONS

A person whose heart is already handicapped must take care to avoid
the added burden and possible risk of further damage imposed by infec-
tions, such as colds, sore throats, pneumonia, and infections of the sinuses
and teeth. Anyone with heart trouble who develops an acute infection
should go to bed and call his doctor. On recovery he will require a longer
convalescence and a more gradual return to work than would a person with
a normal heart.

KEEPING IN TOUCH WITH THE DOCTOR

A person with heart trouble must keep in close touch with his doctor.
His diet, weight, activity, rest — in short, his way of life — are more im-
portant than drugs and require constant medical supervision. Although
some forms of heart disease are benefited by medicines, the drugs em-
ployed are extremely powerful, and their effect on a particular patient
must be checked frequently.

I

CIRCULATION i 3 3

PHILOSOPHY OF LIFE

Cultivating a serene, optimistic outlook on life helps a great deal in re-
lieving an impaired heart of unnecessary strain. This may be difficult for
people who have always been high-strung — quick on the emotional trigger
— prone to work too hard or worry too much. Yet the people who are
willing to slow up their previous living pace — to go ahead with less speed,
less haste, less worry, less fear; who accept the situation and adjust to it
cheerfully, coaxing their hearts along without letting their impairment
become an obsession — these are the people who have the best chance of
a full, happy, and prolonged existence despite heart trouble.

■>>><■<-<■

■»■>»>>>>>>>>>>>>>>>»■»■»■><<<<<<<<<<<■<<■<<<<<<<<<<<<<<

VI

Nervous and Endocrine Control of the Body

THE great development of the cerebrum in man is responsible, in a
large way, for man's preeminence over the lower forms of life. For
example, the periodic triumphs of the insects over man are not planned by
the insects. On the other hand, man's reasoning is enabling him to control
the bisects.

It is, indeed, a long jump from the withdrawing from contact of its
pseudopodium by the simple, one-celled A?neba, a type of nervous re-
sponse, to the creative genius of an artist or the working out of a formula
by a physicist. Evolution means change and the nervous system has
evolved according to the same laws as other parts of man. Sometimes
evolution has taken peculiar turns. Witness the now-extinct dinosaur
who had two brains, one in his head and the other in his sacral region so
that he could make both head and tail of it.

Concerning the brain, there are many types of untruths extant. One
is the false study known as phrenology by means of which one is sup-
posed to tell certain qualities of the brain by fingering the bumps on the
cranium. Some people believe too that the size of the brain is an indication
of the quality while others hold that the more convolutions one's cere-
brum has, the greater is one's thinking ability. Of course, these ideas are
no longer valid.

The study of the ductless glands and their products is now one of the
most active fields in animal physiology. Malfunction of these important
structures is now known to cause certain types of diabetes, goitre, steriUty
and so on. Some of these products or hormones have been isolated and
purified sufficiently so that cures for certain conditions are possible. Hopes
run high at the present time for the use of hormones in a more sustained
attack upon human diseases and even upon abnormal behaviour.

134

NERVOUS AND ENDOCRINE CONTROL I 35

THE BACKGROUND OF HUMAN MENTALITY *
RALPH LINTON

Human behavior is vastly different from the behavior of the other
mammals, even that of our cousins the apes. Nevertheless, just as the
physical differences between men and apes diminish in importance and
cease to be a bar to relationship when they are studied against the back-
ground of mammalian variation, the differences in behavior diminish in
importance when they are seen in their proper perspective. There is a
gap to be sure, and this gap will never be bridged by fossil evidence of
the sort which is gradually bringing the structure of men and apes into a
continuous evolutionary series. Behavior does not fossilize, and the actual
links disappeared when the half-men of the late Pliocene and early Pleis-
tocene became extinct. However, human and animal behavior can be
shown to have so much in common that the gap ceases to be of great
importance.

The outstanding quality of living as opposed to dead matter is that
living matter responds to stimuli in ways which increase its chances of
survival. The living being apprehends its environment and acts to adapt
itself to it. This irritability of protoplasm, its capacity to receive and
transmit stimuli and to react to them purposefully, is the foundation of
behavior. It is equally characteristic of the amoeba, that speck of jelly
which lies at the root of the animal family tree, and of man, who has
perched himself on its highest branch.

In unicellular organisms such as the amoeba all parts of the individual
are sensitive to all sorts of stimuli and the whole individual responds to
them. In slightly more complex organisms, where a number of cells have
banded together for their mutual advantage, there is a specialization in
function. The surface cells receive and transmit stimuli while the interior
cells respond to bring about the changes necessary for the survival of the
organism. In still more complex organisms, including our own, there is
a further specialization in function. All such organisms begin as mere
aggregations of cells which become differentiated into a surface layer,
highly sensitive to stimuli, and a less sensitive interior. As the individual
develops, part of this surface layer remains on the outside and develops
into the skin and the various sense organs. Another part is folded in and
buried among the less sensitive cells. This becomes the nervous system.
The buried part of the original sensitive surface layer specializes in the
transmission of stimuli just as the exposed part specializes in their reception.

In animals organized on the radial principle, such as jellyfish and allied
forms, the nerves form a continuous net. In those organized along axial

• From The Study of Man by Ralph Linton, D. Appleton-Century Company, Inc.
Copyright 1936.

136 READINGS IN BIOLOGICAL SCIENCE

lines, which includes all long, bilaterally symmetrical beings from worms
to men, there is an axial nervous system. This means that there is a main
trunk of nerves running down the center line of the animal with branches
leading off from it to the various organs. From our point of view, these
organs may be divided into two classes, the receptors, such as eyes, nose,
and ears, which are in touch with the outside world and receive stimuli
from it, and the effectors, such as the muscles, which act to bring about
changes adapting the individual to his immediate surroundings. The func-
tion of the nerves is to carry stimuH from the receptors to the effectors
much as a telephone line carries messages from one person to another.

The link-up of receptor, conductor, and effector is known as the reflex
arc and is the mechanical basis of behavior in all organisms advanced
enough to have nervous systems. In those which have axial nervous sys-
tems, the structure of the conductor part of this circuit is highly compli-
cated. The nerves which link receptor and effector are composed of a
series of specialized cells, 7ieurons, whose ends approach but do not ac-
tually join each other. The gaps between the neurons are called sy?iapses
and play a vital part in all the more complicated forms of behavior.
Neurons are so organized that they will carry impulses in only one direc-
tion. The impulse started by a stimulus impinging on one of the receptors
passes along the connecting neuron at the rate of about 400 feet a second
until it comes to a synapse, which it jumps, passing on into another neuron,
and so on until it reaches the effector. At the synapses there is a resistance
of some sort which affects the impulse. It may be slowed down or even
blocked at the point. It may also be deflected to any one of several neurons,
if their ends lie close enough, or split so that it continues to travel down,
several of them simultaneously to different effectors. However, the re-
sistance to impulses offered by the synapses diminishes with use. The oftener
a synapse has been jumped, the easier it is for the next impulse to jump it.
This wearing of paths through the synapses is the neurological basis of
learning and habit formation.

In the more complex organisms, such as our own, there is a constant
reception of varied and often conflicting stimuli. The impulses arising
from these stimuli have to be sorted out and directed to ensure the sort
of reaction which will be most profitable to the whole body. The con-
ductors of the various reflex arcs are therefore routed through various
reflex centers, which serve somewhat the functions of a telephone central.
In these centers the ends of many neurons are brought close together so
that the incoming impulses can be sorted out, switched from one line to
another or distributed. Just how the reflex centers distinguish between im-
pulses, inhibit some, and direct others is still a profound secret, but they
do this in frogs and philosophers alike. The mechanics of the reflex arcs
and reflex centers are the same in all animals having axial nervous systems.

The main trunk of an axial nervous system (in vertebrates, the spinal

NERVOUS AND ENDOCRINE CONTROL I37

cord) is itself a reflex center. All impulses are routed through it on their
way from receptor to effector. However, within this trunk there are
specialized areas which have superior powers of discrimination. These
might be compared to district, as opposed to local, telephone centrals. In
axially organized animals one of these superior reflex centers is always
located at the forward end of the main nerve trunk, in the head, where it
is in close touch with the speciahzed sense organs also located there. In
vertebrates this forward reflex center, the brain, dominates the other
reflex centers. To continue the telephone simile, the brain is a sort of super-
central which leaves routine business to the district centrals in the spinal
cord and elsewhere but which has forwarded to it all calls which are of
uncertain significance or which seem to require special action.

The dominance of the brain over the other reflex centers was much
less marked in the early vertebrates than in the later ones. In some of the
dinosaurs, for example, the brain was actually smaller than the reflex center
at the rear end of the body. One of the most important features of verte-
brate evolution has been the increase in brain size relative both to the size
of the body and to the size of the other reflex centers. Coupled with this
there has been a steady increase in complexity of brain structure and in
specialization of function within the brain.

In the lower vertebrates the brain functions mainly in the direct re-
ception of stimuli from the sense organs and in making automatic ad-
justments to these stimuli. At the amphibian level a new division of the
brain appears, the cerebrum. This specializes in more complex and selec-
tive reactions. As we come up the evolutionary scale, the cerebrum in-
creases in size in relation to the other parts of the brain and more and more
takes over the function of directing the individual. In primates and espe-
cially in man it quite overshadows the rest of the brain and takes care of
the organism's activities, with the exception of a few simple necessary
ones such as breathing, swallowing, and changing the size of the pupil of
the eye.

The cerebrum is made up of an enormous number of neurons set in a
bed of connective tissue. There are at least 10,000,000,000 of these in the
brain of a normal human being. Each neuron is separated from its neigh-
bors by synapses. The paths of impulses through this maze of neurons and
synapses are not organized at birth but are established by the process of
path-wearing already described. Every time an impulse passes through
the cerebrum on its way from receptor to effector a large number of
neurons and synapses are involved and there is a change of some sort in
the cerebral structure. These changes are the structural basis of memory
and habit in the individual. The cerebrum is a specialized organ for learn-
ing and also for those higher forms of selection and integration of stimuh
which we call thought.

The nervous system is the foundation of behavior, and, as far as we can

138 READINGS IN BIOLOGICAL SCIENCE

determine by any means now at our disposal, there is nothing distinctive in
the human nervous system. In this just as in every other part of their
physical structure men fit squarely into the general mammalian patterns.
Even the human brain is almost identical with the anthropoid brain. We
must grant that the structural and mechanical elements underlying be-
havior are the same in men and in animals. Let us see whether the uses to
which this equipment is put differ in the two cases.

All behavior consists of reflexes, combinations of stimulus and reactions
made possible by the structural and mechanical features just described.
Reflexes are of two types, unconditioned and conditioned. In imcojidi-
tioned rejiexes the path of the impulse from receptor to effector is al-
ready established when the individual is hatched or born. The link-up of
the elements within the reflex arc is hereditary, like any other part of the
individual's physical structure. In conditioned reflexes the path of the
impulse from receptor to effector is not determined at birth. The link-up
of the elements within the reflex arc comes as a result of selection and
routing of impulses within the reflex centers coupled with the gradual
wearing of paths through the synapses. The unconditioned reflex is the
foundation of automatic or instinctive behavior, the conditioned reflex is
the foundation of learned behavior. All animals with nervous systems
have reflexes of both types, but the relation which the reflexes of each
type bear to the total behavior of the individual varies tremendously with
the kind of animal. For example, insects owe most of their behavior to un-
conditioned reflexes, while men owe most of theirs to conditioned reflexes.

It used to be believed that animal behavior was controlled by instinct,
human behavior by a mysterious and purely human quality called thought.
No psychologist holds this view to-day. What we call thought is really
an integral part of behavior, for there can be no mental activity without
muscular activity of some sort. The muscular activity may be reduced to
the point where it can be detected only by the most delicate instruments,
but it is there just the same. Thinking is as much a matter of reflex arcs
as is the winking of the eye. It is based on a combination of unconditioned
and conditioned reflexes and on the selection and routing of stimuli.

In a comparative study of the mental activities of men and animals, the
investigator is handicapped at the outset by the fact that with animals
there can be no recourse to the introspective method. If any student could
be a white rat or a chimpanzee for a half an hour he could give us a clearer
picture of what goes on inside animals' minds than we are likely to get in
twenty years of experimental work. As it is, we can only deduce the mental
processes of animals from their behavior. If we approach the human mental
processes from the same angle, the results are almost identical.

Let us take first of all the matter of learning, i. e., of establishing condi-
tioned reflexes. In experiments at the University of Wisconsin the ability
for learning mazes in white rats and in sophomores was tested and com-

NERVOUS AND ENDOCRINE CONTROL I 39

pared. The results revealed no important differences in the learning proc-
esses of the two groups, while in speed of learning the rats had somewhat
the best of it. Of course maze-Jearning presents a problem of a very simple
sort, with a solution dependent on trial and error and the establishment
of habits through repetition. There is no need to establish complicated
reactions.

Perhaps the most interesting experiments in animal learning which have
been made to date are those being carried on at the time of this writing by
Dr. Wolfe at the Institute of Human Relations at Yale University. Dr.
Wolfe has been experimenting with young chimpanzees, using slot-
machines which have been dubbed "chimpomats." By the insertion of
poker chips, the chimpanzees get food. The chimpanzees have learned
not only to insert chips, but to distinguish between chips of different sizes
and colors, using each type of chip in the proper machine and inserting
two chips where two were required. They learned the process first by
imitating their human instructor and then by imitating one another.
They have established associations between the chips and food which
are so strong that they will work as hard to get the chips as to get the food
itself. When chips are scattered among them in their living quarters, where
there are no "chimpomats," they will select those which are of value and
keep them until they are taken to the room where the "chimpomats" are.
The stronger will also take chips from the weaker in very human fashion.

It is safe to say, that is, there are differences in the learning processes of
men and animals; these differences are quantitative rather than qualitative.
Men may learn more or learn more readily, but they learn in the same
way. It is in the solving of problems, where the individual has had no
opportunity for learning, that the mental superiority of human beings is
most evident, so let us see whether there are any fundamental differences
in the human and animal thinking processes.

It has been held that the superior performance of men in solving new
problems is due to their having imagination and reason, qualities which
animals lack. Recent experiments make this appear improbable. Imagina-
tion is the ability to picture in the mind situations which are not present.
Reason is the abihty to solve problems without going through a physical
process of trial and error. Reason would be impossible without imagina-
tion, for in reasoning the situation has to be comprehended and the results
of certain actions have to be foreseen. The trials are made and the errors
eliminated in the fn'md. If we study human and animal behavior from the
same objective standpoint, it seems certain that if we allow these qualities
to men we must allow them to animals as well.

When the young chimpanzees pick up the chips scattered in a room
where there are no "chimpomats," selecting those which are usable in
the machines and discarding those which are not, they show imagination.
They must have some sort of mental image of the machines and of the

140 READINGS IN BIOLOGICAL SCIENCE

use to which the chips can be put. Moreover, from their behavior in the
fact of situations new to them we must allow them at least the rudiments
of reasoning power. One of the best-known experiments used to determine
this consists in putting a banana in the middle of a pipe, where the ape
cannot reach it from either end. After trying direct methods and con-
vincing himself that they are useless, the ape will take a stick and push
the banana along the pipe, then go around to the other end and get it.
Between the first direct attempts and the use of the stick there will usually
be a period of physical quiescence during which the animal is mentally
sizing up the situation. During this period mental images of the banana
in various non-existent positions must be formed and various methods of
getting it into one of these positions pictured, tested against past experi-
ence, and discarded, for when the ape begins operations once more he
usually seems to have a clear idea of what he is going to do. Moreover,
once the problem has been solved, the solution is remembered and the
same thing will be done immediately when he is again confronted by the
same situation. Apes can even go a step further and fit two sticks together
to get a poking tool of the necessary length. In one instance a female
chimpanzee confronted by the pipe-and-banana problem and given a
pair of sticks which could be fitted together tried them singly and then
gave up and began to play with them. When they fitted together by
accident, she showed signs of considerable excitement, took them apart
and fitted them once more, then used them to get the banana. Even after
getting it, her interest in the sticks continued, and she kept joining and
separating them until she had mastered the principle. It is difficult to see
how the mental processes underlying such behavior differ from those of
a man who makes a discovery and realizes its possible application. Apes
will also cooperate in projects for getting food, showing by their actions
that they are able to comprehend both the basic situation and what the
other apes who are working with them are trying to do.

In all fields where exact tests can be applied, chimpanzees seem to have
the same mental powers as human children three to four years of age.
There is a strong presumption, therefore, that the differences in animal
and human mentality are purely quantitative. The ape stops at a certain
point in the development of the mind, while the human goes on. However,
as the ape cannot tell us what is going on inside his head, the best that
we can do at present is to render the Scottish verdict of "not proven." Even
if there are qualitative differences in human and ape thinking, so many
of the thought processes appear to be the same that no scientist would
doubt that human thinking is a direct outgrowth of animal thinking. Human
intelligence, like the brain which produces it, is the result of certain
recognizable tendencies in mammalian evolution.

No one can deny that there are profound quantitative differences in
human and ape thinking. The facts are too obvious to require exposition.

NERVOUS And endocrine control 141

At the same time, even the quantitative differences must not be over-
estimated. The complexity of normal human activities as compared with
those of animals does not give us a just basis for measurement. In both men
and animals most behavior is'a matter of habit. Having learned to do a
thing, we can thenceforth do it without having to think about it. Our
thinking ability is only brought into play when we are confronted by new
situations. The civilized man can do more things than the savage because
he has had an opportunity to learn to do more things. All the tests which
have been applied to the two to date seem to show that their innate mental
ability is approximately the same. In the same way, men have better oppor-
tunities for learning than apes and this puts them far ahead. The superior
mental equipment of men is responsible for the existence of this wealth of
things to be learned, but the vyealth has been produced by many brains
working over many generations. It could not have been created by any one
mind. The son of a civilized man, if he grew up in complete isolation,
would be nearer to an ape in his behavior than to his own father.

THE ENDOCRINE CONTROL OF THE BODY *
MICHAEL F. GUYER

Human behavior is not confined to a mentor in a bony capsule at the
upper end of the spinal column; the whole body participates. The extent
to which this is true can be fully appreciated only after acquaintance with
the remarkable part played by certain internal secretions — hormones as
they are called technically — in our physical and mental well-being. So
spectacular and obvious are some of the effects of these that public interest
has been aroused, with the result that there has been a rather wild exploita-
tion of this field in the press under such captions as, "The Chemistry of
the Soul," "The Glands of Destiny," "Rejuvenation through Monkey
Glands," and equally sensational titles. If one accepts at face value the
twittery eloquence of the professional word shngers who write under
such headings, then this is surely the date of the endocrine glands! We
used to dream of romance, with each yearning soul finding its unerring
way to its predestined mate; we now talk of propinquity and hormones.
We used to preach thrift; of late we have been practicing New Dealism
which feeds us by destroying our food and protects us from penury by
squandering our savings (in this connection there is a suspicion of hyper-
trophy of some endocrine gland which has to do with bone deposition in
the head region). We used to hear of sin; we next found psychoanalysis
with its slogan of unsatisfied self-expression; but now the devil turns out

* Reprinted from Speaking of Man, by Michael F. Guyer with the permission of
Harper and Brothers. Copyright 1942, by Michael F. Guyer.

142 READINGS IN BIOLOGICAL SCIENCE

to be only good hormones gone wrong. The mooning, lovelorn Romeo
of the Mid-Victorian age has become the saxophone addict of today who
brays his way into the favor of his ladylove. The languishing Lydias of
yesteryear with their scented elegance and euphemistic indirection have
given place to the leaping Lenas of today with their cigaretted breath and
cocktailed assurance. To what else can such a revolution be due if not to
some reversal of the endocrine glands? In these times, indeed, when chil-
dren run their parents, freshmen instruct their professors, and wives sup-
port their husbands, reversal seems the order of the day, and on what else
can we blame it in this scientific age if not on the latest biological dis-
covery?

The facts regarding hormonal effects are so striking in themselves as
not to require such epic heightening. In no field of biologic research are
more brilliant discoveries being made than in that of the so-called "internal
secretions," nor do any recent scientific disclosures hold out greater
promise of increasing human welfare and happiness than do these. Since
the secretions in question do not pass out from their place of origin
through ducts as do ordinary glandular products, but are absorbed directly
into the blood or lymph and circulated throughout the body, the glands
which produce them are called the ductless or eiidocrme glands.

Hormones are second in importance only to the nervous system in
keeping the parts of the body in harmonious operation. They can stimu-
late or inhibit the activity of some organ or tissue in a part of the body
far distant from the source of the secretion itself, and what we are,
physically, intellectually, and emotionally depends in no small measure
upon them. Many physical and even mental abnormalities are being
traced to hereditary or acquired imbalance of the endocrine glands.

In man and other vertebrates the known endocrine organs are special
areas in the pancreas called the "islets of Langerhans," the thyroid gland,
the parathyroids, the pituitary body, the adrenals, the sex glands, and
certain secretory structures in the walls of the upper intestine. Other
organs such as the thymus, pineal body, liver and stomach have been
suspected of endocrine functions although the evidence is as yet incon-
clusive. Hormones have within the past few years also been demonstrated
in several kinds of invertebrates, and hormone-Hke substances have even
been identified in plant tissues.

The pancreas is a gland concerned primarily with the elaboration of a
digestive fluid which is discharged through the pancreatic duct into the
upper intestine. Scattered throughout its substance, however, among the
lobules which secrete the ordinary pancreatic juice, are small independent
areas of a very different looking tissue known as the islets of Langerhans.
These cells secrete a substance known as insuli?! which passes directly
into the blood stream and serves, probably in co-operation with the secre-
tion of the adrenal glands, to control the metabolism of sugar in the body.

i

NERVOUS AND ENDOCRINE CONTROL 1 43

If these islets are incapacitated in some way an insufficiency of insulin
occurs and a condition known as diabetes (diabetes mellitus) results. A
characteristic symptom of this' form of diabetes is increase of sugar in the
urine. Sugar is the most available source of energy in the body and a simple
sugar known as glucose is always present normally in the blood to the
extent of o. i to 0.15 of i per cent. It is easily oxidized, hence most of our
body heat comes from the burning of this sugar. When the sugar metab-
olism of the body becomes so defective that sugar is constantly wasted,
through the urine, the condition is therefore a serious one. Insulin is now
widely used in the treatment of diabetes and is restoring the general health
and prolonging the Hves of many persons. Its discovery has meant for
diabetics a change from a life expectancy of two or three years to one
of twenty or more. Sir Henry Dale has depicted the helplessness of the
physician of only a few years ago when confronted by this then dreaded
disease, in the following words: "As a student in the medical wards, I re-
member hearing a great physician, faced with a case of diabetes, express
the view that it would have been better for the patient if his condition
had not been discovered."

It is interesting to note in this connection also that secretion of the
pancreatic digestive fluid itself does not proceed until the pancreas is
stimulated by a hormone known as secreti?i. Secretin in turn is produced
in the walls of the small intestine as a result of the entrance of the acid
contents of the stomach following gastric digestion.

The human thyroid gland consists of two lobes attached to the sides of
the lower larynx, connected by a narrow band across the mid-line. That
of an average-sized, normal man weighs from 20 to 25 grams. It is slightly
larger per unit of body weight in women, and still relatively larger in chil-
dren. Its secretion plays a very important part in maintaining a proper
balance of the nutritional and growth processes. The active principle,
known as thyroxhi, has been isolated in the form of an organic iodine com-
pound containing no less than 60 per cent, of iodine. It is now prepared
synthetically by chemists.

Thyroxin operates apparently by regulating oxidation rate. Overabun-
dance of its secretion {hyperthyroidis77i) speeds up the heartbeat, causes
higher temperature by raising the metabolic rate of body cells some 30
per cent or more, increases perspiration and, in general, overstimulates the
body activities. Hyperthyroid persons are usually highly nervous, over-
active and emotionally unstable. A condition known as exophthalmic or
toxic goiter, characterized by bulging eyes, excitability and thinness some-
times results. Surgical removal of part of the gland may effect a cure. On
the other hand, any condition of sustained emotional stress is likely to
induce thyroid overactivity. Thyroid insufficiency {hypothyroidism)
causes the chemical processes of the body to proceed sluggishly; glandular,
muscular and mental vigor are impaired; heat production is reduced, some-

144 READINGS IN BIOLOGICAL SCIENCE

times by as much as 40 per cent, and in adults there is often loss of hair.
The skin, especially of the face and hands, may thicken and become
puffy giving rise to a condition known as myxedema. Inadequate develop-
ment or atrophy of the thyroid in the young child produces a condition
known as cremiism characterized by retardation in mental, physical and
sexual development. The tongue and abdomen of the cretin tend to pro-
trude and the legs are usually bowed. Permanent dwarfism is established.
Such children, if treated in time with thyroxin or dried thyroid gland often
show remarkable improvement, both in body and mind.

Simple goiter usually reveals itself through pathological enlargement
of the thyroid gland. That iodine deficiency is an important and possibly
the sole cause is indicated by the fact that many remarkable cures have
been effected in early stages through the administration of iodine in some
form, and by the fact that this type of goiter can be largely prevented
through the use of food which contains traces of iodine, or by the oc-
casional addition of small quantities of iodine salts, commonly sodium
or potassium iodide, to ordinary food. That this is an important matter, is
evident from the fact that in the so-called "goiter belts" some 25 per cent,
of the men and some 50 to 60 per cent, of the women show at least traces
of thyroid enlargement. Goiter is very common in the Great Lakes re-
gion of our own country and is usually found in glaciated regions where the
iodine content of soil and water is low compared with that of coastal
plains. The Andean plateau in South America, the Alps, Pyrenees and
Carpathian mountain regions of Europe, and the Himalayan plateau in
Asia are all characterized by a high incidence of goiter.

The well-known experiments of Dr. Marine in Akron, Ohio, seem to
have been the beginning of our present-day widespread administration
of iodized salt to school children. He found that of 2,190 children treated
with iodine, only 5 had goiter at the end of the experimental period,
whereas of 2,305 similar children not given iodine 495 displayed goiter.
After eleven years of the systematic use of iodized salt on the part of
school children in Detroit under the supervision of the pediatric section
of the Michigan State Medical Society', the incidence of enlarged thyroid
had been cut from 35 per cent, to less than one per cent. Similar results
have been achieved in other states. Cleveland, Ohio, seemed to be an out-
standing exception at one time, inasmuch as, following the use of salt, the
drop in thyroid enlargement was only from 31 per cent, to 18.5 per cent.
When the city health department investigated the matter, however, it was
found that two of the local manufacturers of the iodized salt being used
were providing a salt that contained only one-third of the amount of
iodine stated on the label, and that, furthermore, a large chain store was
selling a brand that contained no iodine at all. In one canton of Switzer-
land where 50 per cent, of newborn babies had thyroid enlargement, after
the use of iodized salt was made compulsory for pregnant mothers, not a

NERVOUS AND ENDOCRINE CONTROL 1 45

single case of congenital goiter was found during three years of observa-
tion. It is an interesting fact that, 1,500 years before Christ, the Chinese
used iodized salt in the form of burnt seaweed or burnt sponge for the
treatment of goiter.

Frog or salamander tadpoles fed on thyroid are forced into precocious
maturity. Frog tadpoles quickly develop legs, absorb their tails, and trans-
form into miniature frogs, sometimes no larger than a fly. On the other
hand, a young tadpole deprived of its thyroid glands is unable to become
a frog though it continues to live, and may grow far beyond the normal
size of a tadpole. If at any time such a tadpole is fed thyroid, however, it
promptly undergoes metamorphosis.

It is perhaps a significant fact, according to Hoskins and Sleeper, that
more than 10 per cent, of the victims of the psychosis commonly called
dementia praecox — a malady that fills one-fifth of all occupied hospital
beds in the country — show some degree of thyroid deficiency, and gen-
erally improve after administration of thyroxin.

To discover if too much or too little thyroxin is present in an individual,
a test called the "basal metabolism test" is employed. A normal resting
person who has had no food for twelve hours produces a remarkably
constant amount of energy in a given time as shown by the even carbon
dioxide output which results from internal oxidation. In persons suffering
from goiter or from lack of thyroid activity, the severity of the condition
can be estimated by determining how far the rate of internal oxidation de-
viates from that of a normal individual.

The parathyroids in man usually exist as four minute glands weighing
in all not over two grains, although additional accessory parathyroid tissue
is not uncommon. Each is about the size of a small pea. They are closely
attached to the thyroid. Their secretion shares with Vitamin D, control
of the calcium and phosphorus content of the blood, and since calcium is
of prime importance in many physiological processes from clotting of
blood and muscular tone to formation of bones and teeth, and phosphorus
is likevv'ise indispensable, the proper functioning of these glands is all-
important to the organism. Parathyroid deficiency is characterized by
overexcitability of the whole nervous system, and often by epileptic-like
seizures; fractured bones are delayed in healing, and in the young, growth
of the skeleton is retarded. Complete removal brings about a condition
known as "tetany," characterized by painful spasmodic contractions of
the muscles of the extremities. The calcium content of the blood is greatly
diminished. The respiratory tract, the temperature of the body and the
heart are also affected. Injection of a soluble calcium salt will relieve the
attack of tetany and, for a time, restore the individual to normal. Death
results in a few days after the removal of the glands if the condition re-
mains untreated.

The pituitary gland is a small body of double origin, attached by a

146 READINGS IN BIOLOGICAL SCIENCE

Stalk to the base of the brain. In man it is about the size of a hazelnut and
weighs approximately 0.6 to 0.8 grams. It lies in a bony pit in the floor of
the skull. The forward part, called the miterior lobe, arises from the rear
of the embryonic mouth cavity; the posterior part, or posterior lobe,
originates as a down-growth chiefly from the brain.

Although of small size the pituitary body liberates a number of hor-
mones which not only afi^ect the body in general but also influence most,
if not all, of the other endocrine glands. The secretions of some of these,
in turn, influence the pituitary gland. Because of its manifold secretions
and widespread influence it has been called "the master gland" of the body
— also, "the conductor of the endocrine orchestra." Following its removal,
atrophy of the thyroid, adrenals and sex glands occurs. Underdevelop-
ment of the pituitary gland is usually associated with sexual infantilism;
the germ glands, or gonads as they are termed technically, never produce
gainetes (ova or spermatozoa), and their endocrine activities do not
appear. The result is that the accessory reproductive structures and the
secondary sex characters of the male or female never reach the adult state.
If, in experimental anim-als, the pituitary gland is removed during early
pregnancy, abortion results. This can be prevented, however, by daily injec-
tions of pituitary extracts, as can the other changes which follow removal
of the gland. Thus it is evident that all the phenomena controlled by the
sex hormones are dependent indirectly upon the normal functioning of
the pituitary body.

Two potent products have been obtained from posterior lobe substance.
One of these acts powerfully on uterine muscular contractions and is
sometimes used to hasten childbirth. The second substance aflFects the
smooth muscle of the arterioles; also, the volume of urine secreted. It has
been of use medicinally in control of diabetes insipidus. This form of
diabetes, which is unrelated to the commoner diabetes mellitiis, is char-
acterized by profuse secretion of dilute urine and excessive thirst.

The anterior lobe secretes at least six specific hormones; a growth hor-
mone; one which stimulates the thyroid; one which induces lactation; and
three, called "gonadotropic hormones," which incite various gonad ac-
tivities. The first recognized and perhaps the best known is the one that
promotes general body growth, particularly growth of the skeleton. Over-
activity of this lobe leads to gigantism, underactivity, to dwarfism and
persistence of the infantile condition. Giant rats have been produced by
daily injection of anterior-lobe substance into the body cavity of either
normal animals or those with excised pituitary. Autopsies on various hu-
man giants have revealed tumorous and enlarged pituitary glands. If the
excessive secretion begins in youth while the growth zones of the long
bones are still unossified, lengthening of the bones, particularly of the
arms and legs occurs, and a form of gigantism is the outcome; but if such

NERVOUS AND ENDOCRINE CONTROL 1 47

overactivity does not appear until maturity a different type of enlarge-
ment takes place in certain bones, notably those of the hands and feet, and
the cheekbones, jawbone and the bony ridges over the eyes, so that condi-
tion of deformity known as acromegaly results. On the other hand, the
well-proportioned, intelligent midget is commonly the subject of anterior
pituitary insufficiency. Such pituitary dwarfism in man can be success-
fully treated with anterior lobe extract provided it is administered before
the closure of the growth zones of the long bones which follows the ad-
vent of the adult sex hormones. This type of dwarfism is apparently un-
related to that caused by thyroid deficiency, since thyroxin will not cor-
rect it.

Repeated transplants of anterior lobe substance induce precocious sexual
maturity and ovarian growth. Young mice which ordinarily become
sexually mature at the age of about thirty-five days, following such treat-
ment may become fully mature by the end of twenty-one days. Biologists
at the University of Wisconsin have made practical use of this gonad-
stimulating property of anterior lobe material by using it to speed up
spawning in various fish. They were able thus to spawn rainbow trout
two months in advance of the normal time and so gain a longer growth
period of the young fry before transplantation from hatchery to stream.
What was more important, however, they showed that highly prized
game fish which have hitherto proved refractory to artificial spawning,
such as bass and muskellunge, can be made to spawn freely by such in-
jections. It thus becomes practicable to grow the young of such fish in
hatcheries for a time for later use in replenishment of fished-out waters.

The adrenal glands, as the name impHes, are associated with the kidneys.
Each gland is a double structure, consisting of a core or medullary por-
tion which is derived from the adjacent sympathetic nervous system, and
an enveloping cortical portion originating from the lining of the body
cavity. The secretions from the two parts differ in physiological action.

The secretion from the medullary portion called adrenalin, has not only
been isolated in a pure state but has also been synthesized in the laboratory
and is widely used as a drug.

Adrenahn is used medicinally to relieve bronchial spasms in asthma, and
in conjunction with local anesthetics, for constricting blood vessels and
thus preventing rapid diffusion of the injected substance. It is also occa-
sionally used in attacks of hives or of hay fever. Introduced directly into
the heart tissue in certain cases of collapse, it will sometimes initiate re-
newed contraction in a heart that has ceased to beat. It is also employed
to induce temporary elevation of blood pressure following collapse of
the circulatory system during surgical operations.

Professor Cannon and his associates concluded from their experiments
that under stress of such emotional states as pain, suffocation, fear or rage,

148 READINGS IN BIOLOGICAL SCIENCE

the adrenals are stimulated to an increased output of adrenalin. This, in
turn, supplies the body with muscular power to resist or carry out any
of the actions that may take place under these emotions for the welfare
or preservation of the individual. The sugar of the blood — the most favor-
able source of muscular energy — increases in quantity; if digestion is in
progress its activities are suspended and the blood is shifted to the organs
immediately necessary for muscular exertion — the lungs, heart and central
nervous system; the blood becomes more coagulable; heart action be-
comes more vigorous; muscular fatigue is counteracted by the extra hor-
mone; in brief, such fundamental readjustments are instituted as are favor-
able to great feats of strength or endurance, whether these be fighting
or running away.

The hormone activities of the gonads have long been known. Ovaries
and testes alike, besides forming germ cells, also produce internal secre-
tions which influence the individual profoundly, both physically and
mentally. The male gonads or testes have so-called "interstitial tissue" dis-
tributed throughout, between the sperm-producing tubules, and it is
from such interstitial glandular cells that the male sex hormone, testosterone,
is supposedly derived. Castration of male domestic animals is a common
practice and the modifications of the distinctively masculine features
that result are strikingly apparent. Also, larger, fatter and more docile
animals are thereby secured. Even human beings have frequently been so
treated, and it is only within relatively recent times that the castration of
boys to provide high-pitched voices for cathedral choirs has been aban-
doned. Once the secondary sex characters have appeared, however, they
are unaffected by later castration.

Much experimentation has been in progress with the lower animals in
recent years and many significant facts regarding the sex hormones have
been discovered. It has been found, for example, that the suppression of
the secondary sex characters and accessory reproductive structures can
be prevented in the young developing male castrate if repeated injections
of testicular extracts or the male sex hormone, testosterone, are given.
Testosterone has not only been isolated in pure form but can be artificially
synthesized by the biochemist. In such mammals as the rat or guinea pig,
if the ovaries of a female are transplanted into a male which has been
previously unsexed, the latter under stimulus of the ovarian secretions
assumes a behavior like that of the female. Its hair and skeleton come to
resemble more those of the female than of the male, and its rudimentary
milk glands become enlarged to functional size. If the ovary of a Mallard
duck is completely removed, at the succeeding moult she takes on the
very different plumage of the male. Likewise, if the ovaries are removed
from very young hens they develop to a greater or lesser degree the more
ornate plumage, the spurs, wattles, comb and larger size of the cock. The
development of these characteristics will be still further increased if extract

NERVOUS AND ENDOCRINE CONTROL 1 49

of the male gonad is injected, or if the gland itself is transplanted to such
castrates.

A condition which reveals- the importance of sex hormones in sex dif-
ferentiation was discovered by Professor Lillie in his study of the "free-
martin," a sterile female calf born as a twin to a male calf. In cattle, when
of twin embryos one is male, the other female, the blood vessels in the
fetal membranes of the two may fuse in such a way that their blood inter-
mingles. The male gonads develop ahead of those of the female with the
result that the male sex hormone is the first to pass into the joined cir-
culatory systems. It interferes with the growth of the ovary in the female
causing sterility and modifying more or less profoundly various of her
secondary sexual characters so that they tend to assume the male condi-
tion. Various other biologists have shown in several kinds of lower verte-
brates that when male and female embryonic or larval forms are grafted
together, the sex hormones of one may alter profoundly the sexual sys-
tem of the other.

In the female of the backboned animals, including man, the rhythmical
occurrence of ovulation is correlated with rhythmical changes in the
secretions of the ovary. In mammals the hormones so far identified with
the ovary have been derived from two sources; namely, the follicular
fluid which surrounds the Qgg before it is shed from the ovary, and a
yellowish mass of cells called the corpus luteimi which come to fill the
ruptured follicle after the t^^ has been discharged. The two hormones
differ decidedly in function although there appears to be a reciprocal or
supplementary relationship between them. The corpus luteum increases
in size for a time and then undergoes retrogressive changes and is finally
absorbed. The duration of this growth period depends upon whether or
not the discharged ovum has been fertilized and is developing in the
uterus. If such development is in progress the corpus luteum increases in
size and becomes what is known as the corpus luteum of preg7iancy. Its
persistence depends upon the length of the gestation period of the animal
concerned. If an embryo is not developing in the uterus, the corpus luteum
disappears shortly and a new follicle gradually accumulates liquid, projects
from the ovarian surface and at the proper interval discharges another
ovum. Thus the cycle of ovulation is repeated rhythmically unless inter-
rupted by pregnancy. Hormones from the anterior lobe of the pituitary
body also have a part in stimulating the ovary to ovulation.

The corpus luteum hormone seems to have as one of its functions the
preparation of the uterine wall for implantation of the fertilized ovum,
for if the corpora lutea are destroyed implantation does not occur. How-
ever, the uterine wall must first be sensitized by the follicular hormone
before the corpus luteum extract is effective. On the other hand, once
implantation has taken place, injection of follicular hormone will cause
abortion. A product has been isolated from the corpora lutea which relaxes

150 READINGS IN BIOLOGICAL SCIENCE

the pubis symphysis before parturition and thus facilitates bearing the
young. The same or similar relaxative hormone has also been recovered
from the placenta, or nutritive disk by which the fetus is attached, and
from the blood and urine of pregnant animals. The hormone from the
corpora lutea which inhibits ovulation during pregnancy also stimulates
the development of the mammary glands. Thus normal pregnancy is de-
pendent upon many balanced endocrine factors ranging all the way from
the periodic preparation for it to the insurance of a food supply in the
form of milk at its conclusion. A hormone which appears very early in
pregnancy makes it possible to diagnose human pregnancy with a high
degree of accuracy within the first month.

The great importance of endocrine glands in controlling the later de-
velopment of vertebrates, particularly the role they may play in determin-
ing the conformations of various parts of the body, opens up the broad
question of internal secretions as factors in human development. There
can be no doubt that many physical and even mental abnormalities in man
are traceable to deficiencies of the endocrine glands or to upsets of their
normal interrelations. Atrophy or hypertrophy of such a gland may pro-
duce profound effects in the furthermost reaches of the body. Height,
broad or slender form, length of arms and legs, shape of face, quality of
voice, distribution of hair or of fat on body, and even emotions are in
greater or less measure conditioned by the relative functionings of the
various endocrine glands during earlier development and later life. And
there is no reason to doubt that the amount and quality of the secretions
in various family strains are as much the expression of hereditary factors
as many other individual characteristics. The hereditary aspects of these
glands, however, are likely to be overlooked, because they are also subject
to environmental modifications, and because we are accustomed to think
of them in terms of their immediate activities instead of their genetical
constitutions.

Certain types of human defectives, such as cretins and so-called Mon-
goloids, even when of different races, often show marked resemblances.
The abnormalities in the case of cretins are ascribed to hormonal imbal-
ance— particularly to thyroid deficiency in the affected individual — and
those of the Mongoloids are suspected of being the result of endocrine
disturbances in the mother, or due to fetal nutritive insufficiency.

Either thyroid or pituitary deficiency is an important factor in dwarfing,
but it should not be overlooked that inheritance may have been the de-
termining cause for the changed condition of the gland in the first place.
That such developmental anomalies cannot always be attributed to im-
proper functioning of an endocrine gland of the affected individual itself,
however, is shown by the fact that some such defects appear far back in
the early fetus before its endocrine glands are functional. Nor can the
abnormahty be attributed in all cases to endocrine defects of the mother,

NERVOUS AND ENDOCRINE CONTROL I5I

since pedigree tabulations are known which clearly show that the condi-
tion can be transmitted from the paternal side.

As to just where to draw lines among hormones, vitamins and other
chemical substances of the body which likewise produce pronounced
physiological effects when present in almost unbelievably small amounts,
no one can yet say. The vitamins are of dietary origin. Absence of any
one of them from our food results in its own particular type of disorder.
The chemical structure of a number of both the vitamins and the hor-
mones is now known and that of others is in fair way of solution. It is
a significant fact that calciferol, the active principle of Vitamin D which
is sometimes called the sunshine vitamin, belongs in the same chemical
group (the sterols) with the male and the female sex hormones. An even
more surprising fact is that the cancer-producing constituent of coal tar
has a type of chemical structure that also suggests the nucleus of the
sterols. Nor is this relationship of the sex hormones and the cancer in-
citant merely a fanciful one, for when the latter is injected in properly
graduated dosage into rats, reactions characteristic of female sex hor-
mones are initiated.

Then, too, there are the recently discovered neurohumors — chemical
mediators between nerve endings and the organs to which their impulses
are transmitted. Some endocrinologists would recognize these as true
hormones. If so, the distinction which we commonly make between
endocrine and nervous regulation of the body becomes decidedly ob-
scured. The rate and force of the heartbeat, for example, is controlled by
two different nerves. Impulses from the vagus nerve render the beat
weaker and slower, those from the cardiac-sympathetic nerve, stronger
and faster. It has been discovered that the vagus produces its effect by
the release of a minute amount of acetylcholine; the sympathetic operates
by discharge of a substance very Hke adrenahn, called sy7npathin, of which
there are apparently two types, E. and I. The evidence is increasing, in-
deed, that transmission of all impulses from nerve fibers to receptive cells,
whether glandular, muscular or even other nerve cells, is of this same
chemical type.

And now what of romance, of drama? Has it all vanished into the
neutral drab of everyday scientific fact? Why, as someone pointed out,
even the dramatic tragedy which thrilled us in our childhood that Jack
Spratt could eat no fat, his wife could eat no lean, is doubtless reducible to
a mere difference in endocrine complex. Possibly Jack was a cadaverous
hyperthyroid and his buxom wife a slightly hypothyroid individual. And
probably old King Cole was a merry old soul merely because of well-
balanced endocrines. At least it is certain he would not have been merry,
had they been much out of balance! The broad fat tenor or the long thin
bass, is possibly but the puppet perpetrated by his hormones. Thus always
is the scientist taking the joy out of life by destroying our most cherished

152 READINGS IN BIOLOGICAL SCIENCE

illusions! Perhaps it is not inappropriate to point out in this connection,
however, that a beautiful painting is none the less beautiful to one who
happens to know the chemistry of pigments.

The emotional side of man is peculiarly sensitive to the ebb and flow of
the endocrines. Ugliness and beauty, melancholy and happiness, and even
to some extent goodness and badness, are reflections of hormonal har-
monies or disharmonies. The biologist can but pause and wonder at the
changes in behavior which sometimes follow even a slight shift in endo-
crine balance. Parathyroid deficiency, for example, with its ensuing deple-
tion of calcium and phosphorus in the blood, commonly means change
in an individual's whole attitude toward hfe so that he becomes irritable,
dissatisfied and disagreeable — a pest in home, school, or among companions.
Children afflicted with convulsive seizures, mental depression, spells of
irrational speech and terrifying dreams, or even those who manifest scream-
ing, fighting, maniacal attacks, have been brought back to normal, rational
behavior by means of parathyroid extract. The four parathyroid glands
of man — httle larger than four grains of wheat — constitute, indeed, a
slumbering volcano of misbehavior since, once their output is restricted
by injury, removal, or disease, a well-nigh demoniacal possession may fol-
low. In man, complete removal is followed by death.

Even old age seems to be the result of a slow alteration of the internal
chemical complex of the body following a gradual change of the endocrine
balance. Every individual, in fact, is really a different chemical medium at
diff"erent ages. Several features of old age, such as lowered metabolic rate,
feelings of chilliness, dryness of skin and scantiness of hair, picture dis-
tinctly thyroid deficiency. Concomitantly the thyroids of the aged show
evidences of atrophy including partial replacement by inert fibrous tissue.
Whether or not we shall eventually be able to counteract the seniHty-
inducing factors remains to be seen. This much is certain: death is not an
inherent attribute of living matter. There is no natural death among the
protozoa. The rolling, flowing amoeba which the indiff"erent freshman
eyes nonchalantly through his microscope, is venerable almost beyond be-
lief, for it is a bit of immortal living matter that began existence in the
heyday of life's creation. Moreover, although the natural lifetime of a fowl
is only six or seven years, tissue removed from the heart of a chick embryo
has been kept alive and growing in artificial cultures for over thirty years.

Then, possibly, if one but lets his fancy roam, there may be more ro-
mantic behavioristic applications of our rapidly accumulating store of bio-
chemical knowledge. May we not even come to the pass where our par-
sons, instead of trying to scare us out of hell, or hell out of us, will merely
line us up once a week for the proper dose of hormones or antihormones
as each case may require, and thus leave their sermon time free for the con-
templation of more pleasant things than the corrective terrors of the
damned? May not the timid lover be hormonized by his physician into

NERVOUS AND ENDOCRINE CONTROL 1 53

the courage of his convictions? On the other hand, where we now have
beauty parlors for hair curling and nail coloring, may we not in the future
have hormonal parlors where even the least colorful maiden may, for
ten dollars, receive a shot in the arm guaranteed to induce sufficient
"oomph" to overcome the matrimonial disinclinations of even the most
reluctant male? And there is the husband who is always falling in love
with every pretty face and who hath a roving eye. Perhaps the solution
for the future wife will be merely to take him to the proper endocrinal
studio for a hypoderm of anti-philanderine, and thus have him tuned down
a few octaves to the standard pitch of ordinary husbandly docility. Who
knows, perhaps even the mate-changing habits of our movie stars might
be attuned to the plodding pace of the great majority of our convinced,
if not convicted, monogamists, who drift along with one spouse, and with
neither prospects nor desires for the hazards of another!

>>><-<■<■

»>>>>>>>>>>>>>>>>>>>>>>>>><-<■<■<<<<<<<<<<<<<<<<<<<<«<■<■

VII

Reproduction

REPRODUCTION is Ordinarily thought of as an extremely complex phe-
^nomenon coupled as it is, sometimes, with spermatogenesis, oogenesis,
reduction division, copulation and fertilization. It becomes less complex in
appearance, at any rate, when we review the process in simple plants and
animals. Sexual reproduction in Farmnecium, for example becomes simply
the side by side conjugation of two specimens with the subsequent ex-
change of nuclear material.

When we examine some of the numerous instances of reproduction
in which no sex is involved, a type known as asexual reproduction, the
matter appears very elementary. In bacteria the cell simply divides into
two equal parts and each half then proceeds to grow into an adult bac-
terium. In yeast tiny protuberances called buds appear on the parent cell,
grow larger and eventually detach themselves or break off.

One aspect of this subject which needs amplification is that reproduc-
tion is the process by which immortality is attained. At first this may sound
fantastic but if one considers that tiny bits of living matter passed on to
the offspring from the parents in the form of eggs and sperms are lineal
descendents from similar structures passed on to them from their par-
ents and so on back to the dawn of man's emergence from pre-man, the
thought soon loses its aspect of improbability.

When we list the characteristics of life we frequently mention re-
production as one of the main features distinguishing it from the inorganic.
Stones do not beget stones nor does a piece of iron ore divide into two
pieces of ore, except by fracture. The dividing line is not as sharp as
formerly thought. Protein molecules as found in a piece of dried beef are
still protein molecules but they do not reproduce themselves. The es-
sential part of chromosomes, the genes, are now thought by many to be
large complex protein molecules and yet these do duplicate themselves
every time a chromosome divides lengthwise in cell division. The dif-
ference here seems to be that a living system is necessary in conjunction
with the molecules. That brings us back, of course, to the nature of life
and the student will observe that we have described a neat httle circle and
are now back to the same relative position where we were when we
started this discussion. Someday the answer will be forthcoming; some-
day all the proper types of bricks will be assembled, the bricks repre-

»54

REPRODUCTION I 5 5

senting research achievements, and someone can then build up the true
picture for us to see.

REPRODUCTION *

EMANUEL R ADL

I. MODES OF REPRODUCTION

One of the most important and characteristic features which differ-
entiates the Hving from the non-Hving, is the power of reproduction. No
organism is formed by the action of material forces, but each one is pro-
duced by a living predecessor. From the time of Aristotle, however, there
have always been some who have maintained this assumption to be in-
correct, and that there are certain circumstances under which spontaneous
generation may take place. Moreover, the method by which life arises
from life, a phenomenon without analogy in inorganic nature, presents a
problem which is just as obscure in the lowest types of life as in mankind.

Life renews itself in two ways: the first sexually, when two individuals
are essential for the production of the offspring; the second asexually,
when one individual alone can produce another.

In asexual reproduction a smaller or larger portion of the body
separates itself from the mother organism, and by growth and differentia-
tion develops into a new individual. This individual exists side by side with
the mother organism, which, in the meantime, has replaced the part cut
off. If the organism divides into two roughly equal halves we speak of
"fission"; "budding" takes place, on the other hand, when the newly de-
veloped organism separates from the body of the old one as a compara-
tively small branch. Finally, if it is produced from a single cell, which is
usually formed in a special organ of the mother body set apart for its pro-
duction, we speak of reproduction by "spores."

In sexual reproduction there are always two, if not independent in-
dividuals, then at least physiologically (sexually) different organs, whose
products unite: the male, which forms spermatozoa, and the female, in
which the ova are formed. In exceptional cases one of the sexes (the male)
can be suppressed. We then speak of parthenogenesis, when unfertilized
females lay eggs capable of development. Among the higher animals,
especially among mammals, parthenogenesis does not occur, although the
eggs of birds and mammals often begin to segment without being fertilized.
At a time when Darwin was still considering his theory, Hofmeister dis-
covered that even the so-called sexless Cryptogams reproduce themselves

* Reprinted from The History of Biological Theories by Emanuel RadI, translated
by E. J. Hatfield, with the permission of The Clarendon Press, Oxford, 1930.

156 READINGS IN BIOLOGICAL SCIENCE

sexually, but that here the sexual and asexual methods of reproduction
alternate in a peculiar way. The green mosses form eggs and sperms, but
the fertilized egg does not develop into another moss plant. It forms a
capsule on a brown stalk, in which asexual spores are formed. These fall
to the ground and eventually germinate to form a new sexual plant. Thus
the little moss plant has two life periods: in the first it lives as a green plant,
which forms sexual organs; in the second as a brown capsule, which forms
asexual spores.

The ferns, horsetails, and lycopods all go through these two phases,
though in them the sexual individuals are small and inconspicuous, while
the asexual, on the other hand, are large, being (in the case of ferns) the
actual fern plants, which bear asexual spores. Among flowering plants,
the first, or sexual phase, is very much reduced. While the algae repro-
duce themselves now sexually, now asexually, the higher plants, from the
mosses upwards, follow an ordered alternation of the two methods of
reproduction; the higher the plant, the more developed is its asexual phase,
and the more reduced the sexual phase becomes. The meaning of this al-
ternation is by no means clear.

More recently the analysis of the behavior of the chromosomes during
fertilization has shown that there are specific sex-determining chromo-
somes; further, that the inheritance of sex follows the same Mendelian
rules as does the inheritance of any other bodily character. This does
nothing, however, to help in the understanding of the whole phenomenon
of sex.

2. THEORIES ABOUT THE NATURE OF SEX

The philosophy of sex, to which man has always devoted much thought,
has passed to-day into the chromosome theory. Much of Aristotle's philo-
sophical system originated in the recognition of the difference between
the two sexes; this gave him his ideas about matter and form. In the fe-
male are embodied the passive principles, in the male the active, creative,
formative principles. Even Harvey allowed himself to be influenced bv
these ideas, and he compared the female uterus with the brain; as the latter
possesses the power to form images of external objects, so the uterus —
whose ideas are the eggs — forms them in the image of the fertilizing male.
In the speculations of the evolutionists of the eighteenth century the
broader aspects of sex were absolutely neglected. The result of the dis-
covery of eggs and spermatozoa was that the true nature of the problem
was obscured. They imagined that they could answer all questions on the
subject by examining those structures. The theory that the complete
man Hes already enclosed within the ovum or the spermatozoon suggested
that one sex, either the male or the female, represented a superfluous, pur-
poseless creation of mother nature.

The German romantic philosophers looked with wonder upon the

REPRODUCTION 1 57

phenomena of sex. Their most fundamental idea, that of polarity, was often
inseparable from the idea of the contrast between the sexes. Even Schopen-
hauer devoted a special chapter to observations on the metaphysics of sex-
ual love. Led by the poets, arid by Goethe — the man of the world, — these
philosophers were able to appreciate the fateful power of the differences
between the sexes. Since Darwin's time, however, biologists have not con-
sidered the subject of any paramount importance. It is true that Darwin
based his theory of sexual selection on the differences between the male
and female of the same species. This theory, however, lacks most of the
beauty which characterizes living nature. He only saw in these differ-
ences secondary adaptations to the external conditions of life. Since then
this subject has lost much of its significance. Blind to the processes of actual
life, and carried away by their observations of microscopic structure,
biologists have tended to look upon the problem of sex, under which,
according to some philosophers, all the problems of the world lie hidden,
as merely a problem of chemistry and of cell structure. From the fact
that the spermatozoon and the ovum are both cells, it was inferred that
there is no essential difference between them. By considering the sexual
cells from which they originate, instead of the adult individuals, in all
the fullness of their hfe and struggle, they concluded that there is no es-
sential difference between man and woman; the differences which actually
exist between them are, according to these theorists, merely special adapta-
tions for the purpose of facilitating the union of the spermatozoon with
the ovum.

All the contrivances connected with sex are variations upon one and the same
theme; firstly, they enable the sex cells to come together, and secondly, they in-
sure that the egg shall be nourished and kept in safety. We call the one set of con-
trivances "male," and the other "female." All these relationships are of a second-
ary nature, and have nothing to do with the real essence of fertilization; this is
the union of two cells, and is therefore purely a cell phenomenon. In these views
we agree with Weismann, Rich, Hertwig, Strasburger, and A4allpas, who have
expressed similar opinions (O. Hertwig, Allgemeine Biologic, 1902).

On this view one question alone remains: what is the meaning of the
process of fertilization itself? In the simplest forms of life, as, for instance,
the bacteria, there were originally no sexual differences. These developed
gradually, and began in the fusion of two otherwise similar cells. To facil-
itate conjugation one cell gradually assumed a passive role, and the task
of accumulating food; the other became more active, hence smaller, and
sought out the former. Thus began the differentiation between ovum
and spermatozoon. When, later, multicellular organisms developed, the
process of reproduction was taken over by a few cells, and for the purpose
of facilitating conjugation the two sexes became differentiated in various
directions.

This is the way in which Strasburger, Maupas, and Weismann ac-

158 READINGS IN BIOLOGICAL SCIENCE

counted for the development of sexual differences. The latter also thought
that these differences in sex play an important part in bringing about vari-
ation. The offspring inherits some characteristics from its father, others
from its mother, and hence embodies a new combination of characters.
Others have given such obvious explanations of all the facts connected
with sexual life that there seems to be nothing which is beyond the com-
prehension of these scientists! Do we ask what is the basis of sex-love.'
Jaeger puts forward the hypothesis that it consists in a similarity between
the exhalations of the male and the female, and in a chemical attraction
set up by these exhalations. Pfeffer has actually succeeded in obtaining a
proof of this hypothesis in the case of certain plants. Alantegazza also
gave a very similar explanation. Others, like Nageli, have considered that
the attraction is electrical in nature.

But why do two cells strive to unite? why the electricity and the chem-
ical attraction? The reason is not a very abstruse one! According to some
scientists cell conjugation developed from a kind of cannibalism. One
cell devoured its neighbour, became strong, passed on the capacity for
devouring its neighbour to its successors, and so conjugation began.
Jacques Loeb suggests (1906) that fertilization has the following signifi-
cance: the spermatozoon brings into the ovum certain chemical sub-
stances which hasten segmentation; this can, however, be brought about
without the help of the spermatozoon, merely by the influence of cer-
tain chemicals. A little potassium chloride or cooking salt is a substitute
for the male element, as has been shown at any rate in Echinidae worms,
starfish, and other animals. A mechanical stimulus (as has been demon-
strated on the frog) may act in the same way.

Boveri (1902), on his side, compared the egg to a watch which has not
been wound up; fertilization simply winds the spring, and this makes seg-
mentation possible. According to him the essential factor is the centro-
some, which enters the ovum with the spermatozoon. For Herbert Spencer
also the object of fertilization was no mystery; life is like a constantly
moving wave; the beginning of life resembles the heaving surface of the
water; it becomes calmer and calmer as development proceeds; in the
ovum such a peace prevails that a new impulse must come to it from out-
side; the fertilizing spermatozoon is like a stone thrown into a pond; life
is set in motion again, and the power for a new period of development is
given.^

When we contemplate the activities and struggles of the Universe, it
would seem as if the antithesis between male and female plays the most
important part in the whole drama. The most beautiful and the most vile
in practical life, in philosophy, and in literature, is developed under the

1 A systematic account of the problems of sex is given by P. Geddes and J. Thomp-
son in The Evolution of Sex, 1899; L. Dante, La Sexualite, 1899. H. His gives the his-
tory of the subject in "Die Theorien der geschlechtlichen Zeugung," Arcbiv. fiir An-
thropologie, iv, 1870 and 1872 (incomplete).

REPRODUCTION 159

spell of antithesis. It is the inevitable inspiration of the poet. In every
religion we find in its metaphysical foundations some solution of the ques-
tion of the relation between man and woman.

■>>><<<■

SEX *

MICHAEL F. GUYER

Most biologists would agree that the fundamental behavior patterns
of the animal world,whether of mice or men, are determined largely bv
the two elemental urges of hunger and sex. To these, fear might be added
as a close third. If one is to understand the human individual or human
society, therefore, he must make his interpretations with the consciousness
of these inclinations always in mind. To be sure, they may appear in many
secondary forms: that of sex particularly may take on a thousand dis-
guises. Nevertheless these universal drives are always in evidence to the
discerning eye.

One has but to pick up his daily newspaper to realize what share of
attention sexual affairs and their irradiations command in our enlightened
land. A4any newspapers probably give an erroneous impression about our
sexiness because they thrive on sensationalism. This fact in itself, however,
carries with it the conviction that they have a reading clientele avid for
their alleged revelations. By their constant harping on the theme of sex
and by playing up sexual delinquencies, real or fancied, on every occasion,
they have made us oversensitive to the subject and probably kept our
minds on it to an unwholesome degree. Through description and innuendo
certain newspapers have become veritable aphrodisiacs which keep many
of our more suggestible citizens at a fever pitch of amatory expectancy.
They give the impression that most of our people think of little else,
and this is far from true.

Most amusing of all, perhaps, is what seems to be the belief of the present
generation, particularly the rising section of it, that they have discovered
sex — that it came into being coincident with bobbed hair, bare knees and
their adolescent ballyhoo. The whole matter is highly comical when one
realizes that as a matter of fact old Father Stonehatchet or even an Eocene
monkey could give them the laugh on their naivete. However this may
be, in these piping days of swing and jollity, of saxophones and sexophiles,
it is the fashion for our young folks to appear sophisticated and daring.
Particularly smile-provoking are the supposedly spicy and "hard-boiled"
contributions which so often appear in our college or high school mag-
azines. Occasionally, it is true, one finds sexually minded individuals who

• Reprinted from Speaking of Alan, by Michael F. Guyer with the permission of
Harper and Brothers, Copyright 1942, by Michael F. Guyer.

l6o READINGS IN BIOLOGICAL SCIENCE

can't look at a monkey paperweight without wondering whether it's a
he or she^ and who, if they heard the name used, would suspect the sextant
of being an instrument invented by some Nevada judge to measure sex
appeal, but such persons are decidedly in the minorit}'.

Of course our young folks are sexy, as their parents, and their parents'
parents were before them, clear back to the primeval protoplasm of
creation's dawn, and also, of course, most of them have the same average
intelligence, capacity for necessary inhibition and common sense that
their parents had, and they will act, therefore, in much the same way,
including worrying over the rising generation. They may be a bit intox-
icated at present but surely will come the morning after when they will
sober down to the headache and the hard office chair.

Our young sophisticates profess to laugh at what they consider the
sentimentality of the past generation, but oh, who of us have not by some
misfortune been compelled to listen to their favorite songs which palpitate
over the radio! Those about some black or other hued "mamma," about
dancing with tear-stained eyes and love-anguished hearts, about their
"blues," their sighs and their various other emotional gripings, about the
little lovenests for two-oo-oo-oo, ad nauseam, until to the Mid- Victorian
"sentimentahst" it all becomes excruciatingly funny when not too bore-
some.

Not sentimental? Come to any one of the campuses of our larger coed-
ucational institutions and gaze at the throngs of ambulant adolescents, with
here and there and everywhere, soulful males and sighful females stroll-
ing hand-in-hand from class to class; any observer can see the humor of
the situation even though the performers do not. True, such displays are
staged mainly by traditionless youths from our larger cities, but individuals
of this type have swarmed into our colleges in such numbers in recent
years as almost wholly to eclipse the former college cHentele from homes
of refinement where good taste, delicacy of feehng and a sense of propriety
were not scorned as reprehensible repressions.

And then, take what our young sophisticates call music — jazz or swing
— a series of constipated, strangling sounds emitted in a skip-stop rhythm
which goes over and over and over the same inane Uttle theme, made
harsh by occasional clanging discords — apparently a sort of sauce pi-
qiiante to the ears of modern youth. Where a solo effect is introduced it is
usually given to that orchestral bastard of reed and brass, the saxophone,
whose every tone reveals its illegitimate origin.

What most people fail to realize is that sex is so universal in nature, and
therefore so commonplace as to be nothing unique, startling or all-absorb-
ing. One finds sex shadowed forth in the first dim gropings of the lowliest
living matter. The amours of the protozoa may not seem to promise much
as portraiture of modern sex appeal, but sex in the making is there, never-
theless. One can trace its course upward through worm, fish, fowl and

REPRODUCTION l6l

beast. Undeniably, when properly regarded and controlled, it constitutes
the mainspring of action in many of the most vital, romantic and sacred
relations of human kind. Yet it is only part of life in this universe of so
many interesting things and' experiences, and therefore is something that
should be kept in its proper place. Those modern advocates of "being
natural" or "getting back to nature" as they vociferously proclaim their
doctrine, may well note that through the whole realm of animal life, from
the lowliest to the liighest almost without exception, actual sex function
is paramount during only a brief period of the animal's career and there-
fore plays but a secondary role in its total existence.

Without sex the world of plant and animal life would certainly seem
very strange. There would be no flowers. In the animal world there would
be little difference in appearance among the individuals of a species since
there would be no necessity for discriminating male from female. Orna-
mentation and the displays of courtship often incident to mating would
be nil. The power of making sounds, even, might not have developed
since it is most commonly used as an aid to mating. The songs of birds,
the stridulations of such insects as katydids, crickets or cicadas, the spring
trilling of creatures like male frogs, the various calls of different mammals
have probably all arisen primarily as sex calls which insure the bringing
together of male and female at mating time, even though later such sounds
have often taken on other functions. The bellowing of bulls or the cater-
wauling of tomcats are vocal challenges more indirectly associated with
mating, while the familiar clucking and warning signals of hens and various
other female forms is an extension to the protection of young. Vocaliza-
tions of various kinds often come eventually to serve for the welfare of
flocks, herds, or other social groups. And in man, of course, voice has ad-
vanced into articulate speech and all the advantages associated with lan-
guage.

Sex is determined ordinarily by a chromosomal mechanism in the germ
cells. In man, for example, with his 48 chromosomes (24 pairs; one of each
kind from each parent) there is a special pair of chromosomes, called the
XY pair, which, unlike the others, do not match. The Y member of this
pair is smaller than the X member. In one of the last divisions of the matur-
ing germ cells the various corresponding pairs of chromosomes line up
side by side {synapsis) in such a way that in the ensuing cell division each
of the two newly formed cells receives one or the other member of a pair
but not both. Thus X would go into one of the new cells. Y into the op-
posite one. In this way each definitive germ cell while receiving only
half (24 in man) of the original number of chromosomes, gets one of
each pair; that is, one of each kind. This is called the reduction division. The
original number (48 in man) is restored at the time of fertilization: 24
being contributed by the spermatozoon and 24 by the ovum. Whether
a given chromosome of the reduced set is of maternal or paternal origin

1 62 READINGS IN BIOLOGICAL SCIENCE

is merely a matter of chance. In other words, the reduced number of
chromosomes in any germ cell is a random assortment of the original
chromosomes of maternal and paternal origin. The only necessity is that
each final germ cell {gamete) have one of each kind of chromosome, since
each kind carries special hereditary determiners and has its own particular
role to play in the development of the new individual. Thus, for instance,
if we arbitrarily represent the chromosomes of a given individual by ABC
abc, and regard A, B and C as of paternal and a,b, and c as of maternal
origin, then in synapsis only A and a can pair together, B and b, and C
and c; but each pair operates independently of the other so that in the
ensuing reduction division either member of a pair may get into a cell with
either member of the other pairs. That is, the line-up for division at a
given reduction might be any of the following: ABC, ABc, Abc, AbC.

abc abC aBC aBc
This would yield the following eight kinds of gametes, ABC, abc, ABc,
abC, Abc, aBC, AbC, aBc, each kind of chromosome required to cover the
entire field of characters necessary to a complete organism. Since ova and
sperm would be equally likely to have these eight types of gametes, the
possible number of combinations for such germ cells would be 8 X 8, or

64-
Computed on this basis, in man with his 24 pairs of chromosomes the

number of different combinations producible would be 282,429,536,481.
The fear of standardization in mankind expressed by some of our literary
folk, does not, therefore, seem very alarming. Sex makes anything like com-
plete standardization virtually impossible.

As noted, the X and Y chromosomes of man constitute a pair originally,
but after the reduction division half of the total number of sperm cells
will contain an X, the other half, a Y. Females of species such as man, how-
ever, are characterized by the possession of two X's and no Y. This means
that after the reduction division every ovum will carry an X. It is evident,
therefore, that there are equal chances of producing an XX type or an XY
type of fertilized ovum. The XX type develop into females, the XY t)^pe
into males. Thus sex is automatically launched on its course at the very
inception of development. Since there is no Y element in many species of
animal, X substance seems in some way, to be the determining factor.

Sex chromosomes are not only agents of the sex-determining mechanism;
they also carry the determiners of certain hereditary characteristics. Such
traits display what is termed sex-lmked inheritance. The form of color
blindness characterized by inability to distinguish red from green is such
a sex-linked trait. In the color-blind man the single X carries the gene of
this defect. Mated to a woman with both X chromosomes normal (XX),
their daughters although getting the paternal defective X, also get a normal
X from the mother, and this normal X is sufficient to insure normality of
vision in all daughters (XX), or in other words, the character is what is

REPRODUCTION 1 6 3

known as a sex-linked recessive. The sons of such a color-blind father
will all be of normal color vision (XY) since their single X chromosome
comes from the mother. Furthermore, they are incapable of transmitting
the defect. When the daughters marry, however, since each carries one
defective X, 50 per cent, of their ova will carry this X and 50 per cent.

will carry a normal X. Married to a man of normal color vision (XY) such
women are equally likely to have color-blind sons (XY) or sons with

normal color vision (XY), since the chances are equal for a Y-bearing
spermatozoon to meet either type of ovum. The daughters, on the other
hand, will all be of normal color vision, but 50 per cent, of them will, like
the mother, be carriers of the defect. If such a carrier (XX), however
marries a color-bhnd man (XY), the expectation is that half of the daugh-
ters will be color-blind, (XX) and half will be carriers (XX). Also, 50 per
cent, of the sons of such a mating will be color-blind (XY), the others,

of normal color vision (XY). More than twenty sex-linked traits are
known in man. Among these may be mentioned hemophilia (excessive
bleeding), various eye defects, certain skin abnormalities such as absence
of sweat glands, and several neural and mental anomalies. In the hereditary
nervous disorders, the sex-linked factor not infrequently supplements an
additional factor borne on one of the ordinary chromosomes.

Evidence of the opposite sex in normal man is seen in the possession of
nipples, a minute uterus viasculinus and other rudimentary structures. Since
each sex possess the potentialities of the other, either may, under adverse
conditions, become intersexual. Cases of intersexuality in some degree are
occasionally encountered in both man and domesticated animals. Gener-
ally it is a case of an undeveloped male in which, apparently because
of the absence of normal testicular hormone, both male and female organs
develop to a certain point so that a neutral type results.

While there is nothing novel about sex and while it will work out much
the same generation after generation in a given stock of people, there is
little doubt that many of our young folk of today know more of the true
facts of sex and have fewer absurd notions and sentimental balderdash
about it than did their more recent forebears. They are not going to look
on sex as something which, even at its best, is shameful, as something which
should be tolerated merely because of its indispensability for the continu-
ance of human existence. The chastity couch which intrigued the puritan-
ical conscience represents a vegetarian form of love that will find no re-
sponse in their marital dietary. As a result they will probably live happier,
saner, more wholesome lives than did these apostles of fleshly mortifica-
tion. If they make mistakes they will pay the inevitable penalties of lowered
ideals, blunted capacity and blighted lives, and not infrequently, of loath-
some disease and death. The latter, disease and death, is perhaps the only
penalty that will appeal to the less delicately minded of them, but even

164 READINGS IN BIOLOGICAL SCIENCE

they can surely convince themselves of the facts by a visit to almost any
clinic in the land, mental, surgical or medical.

Very often of late, our colleges and universities have come in for a
scoring at the hands of some excitable individual who, having taken pen
in hand and sex in mind, with the aid of a little fact and much fiction, paints
a lurid picture of his inner convictions. In his mind, coeducation has be-
come wholly coo-education, and he lays himself out in a heart-rending
account of how terrible the struggles of the male student are along the
thorny path of learning with a bare-kneed "babe," all waved and scented,
as his traveling companion. How much the wish is father to the thought
in such ebullitions it's difficult to say, but such writers forget that the pres-
ent generation boys have grown up with the bare-kneed sisters, mothers,
cousins, and aunts, to say nothing of grandmothers, and that as a result,
to them, unlike their palpitating mentors, bare knees are no longer "a treat."

Virtue is a matter of purity of heart rather than of the conventional
outlook of a particular age or people on the externals of life. As regards
dress, to put it bluntly, girls of the present time are probably less alluring
and therefore less dangerous to the weaklings among men than in earlier
days because there is little mystery left about them. The human mind is
so constituted that it is fascinated by mystery. The half-revealing, half-
concealing garments of former days were unquestionably more provoca-
tive to the imagination, and in matters of sex it is imaginative stimulus that
makes behavior run riot rather than the bold facts of anatomy. Our modern
woman's dress certainly leaves little or nothing for the imagination to
play around, and from the standpoint of morals it is probably better so.
Since chance revelation of the feminine form has ceased to be an excitant
to the masculine eye the whole situation makes for a more wholesome
attitude between the sexes.

For some years the problem seems to have revolved around the question
of to skirt or not to skirt — the amount of leg to expose. In earlier days,
as revealed in English poetry at least, it was apparently the breasts that
received most attention. Thus, we find such amorous clerics as the bachelor
poet Herrick rhapsodizing about this or that or the other detail of his
"Julia's breasts," and even such masters as the great Shakespeare himself
enthusing over:

Her breasts, like ivory globes circled with blue,
A pair of maiden worlds unconquered.

Whatever may have been the beauteous type of the poet's dream — and
perhaps it was mainly a dream — in the give and take of everyday living it
is probably more wholesome for man to think of these necessary mamma-
lian accessories in terms of their nutritive rather than their ornamental
functions. Here, too, with the passing of mystery, indecorous fancies
vanish,

J

REPRODUCTION 1 65

Young women may well be on guard against the flashily dressed, boast-
ful, or swaggering type of man, because he is usually a vain, self-centered,
unreliable, or overcompensating individual, who possesses few qualities
that would make him a devoted husband or father. Habits firmly estab-
lished are seldom changed much by marriage, hence to expect a man's
emotional attitudes to be reversed by such a ceremony is to flout experi-
ence. If he is not an industrious, intelligent, considerate type before mar-
riage, there is no magic that will make him such when wedded.

To the inexperienced young man perhaps the most dangerous girl is
a baby-faced, rather pretty, physically alluring, up-and-coming type, of
relatively low mentality. With our lax educational standards she not in-
frequently finds her way into the high school, or even through it and into
college, but she rarely lasts out the freshman or sophomore year. Like the
decerebrated frog of the physiological laboratory, her food-catching, swal-
lowing, and sexual reflexes, are normal, but she has little or nothing above
her ear level to make her promising material for a wife or mother. Fre-
quently such an individual is not only lacking in judgment and good taste
when it comes to the serious or finer matters of life, but sometimes she is
also wanting in the proper inhibitions which are indispensable to right
living.

But this does not mean, of course, that the little wiles of young folk,
which are usually harmless, are to be condemned. After all girls are girls
and boys are boys, and down deep in his heart every Jack wants his Jill
and every Jill her Jack. And nature has so built us that the fulfillment of
these wishes — often unadmitted to ourselves — begins the forward march
long before we recognize that it's in motion toward its matrimonial goal.
When a girl reaches a certain age it is just as natural for her to begin prac-
ticing her little coquetry toward boys as it was for her to play with her
dolls earlier, or play "grownup," and what not. How else would she find
the right matrimonial pal in this serious though glorious game of life.'
And so back of the playful coquetry of the little Dorothys and Geraldines
who challenge and intrigue a boy's attention — often (not always) un-
known to themselves — there is a deadly earnestness. And girls, from the
sheer necessities of the case, are past masters of such arts when compared
with boys, since the outcome — home, safety, provision for self and chil-
dren, love — are of so much greater fundamental importance to them.
Nature says to them, "a mate must be had and you must attract," and the
game is on.

Blame them for it? Heavens no! Bless them! Otherwise mankind would
go blundering through life missing most of its fineness; much of its worth-
whileness and practically all of its spice. Why quarrel with the way nature
insists on having things done? Who in his right senses would do away
with that judicious mixture of the sexes which gives so much tang to human
affairs?

1 66 READINGS IN BIOLOGICAL SCIENCE

Thoughtful women often ask why it is that men are so prone to select
the merely pretty woman rather than the woman of proved worth; why
some little doll-faced snip of a girl can so often mislead or make a fool
of an otherwise sensible man. Why, indeed? It has been suggested that a
pretty woman is usually a physically healthy woman and that there is an
unconscious biological tendency toward choosing a healthy mate. This
may be a factor.

Aesthetic sense, a feeling for the beautiful, is an important factor which
draws men to pretty women, although here again one can't escape the
factor of male rivalry. It is undeniable that each race or tribe of people
has its own ideas of what constitutes manly or womanly beauty, and the
standards of one race are often regarded by another as ridiculous or in-
comprehensible. For instance, an African chief of a tribe in which the
women perforate the lips and stretch them out for two or three inches by the
insertion of solid disks or rings until they resemble the beak of a duck,
was much surprised at the stupidity of an explorer's question as to why
this was done. He replied for "beauty."

It is an undeniable fact that to the more impulsive, unthinking type of
man, mere prettiness is in itself a strong lure. Yet most sensible men, even
when under the spell of beauty, know how to discount it if it is not ac-
companied by character, good sense and a self-respecting spirit. And one
sees many a man, after playing around with the free and easy, painted-
beauty kind of girl, turn to the plainer, more demure, more unselfish type,
when it comes to taking a wife. Apparently he realizes that the happiness
and sanctity of a home is likely to be more secure in such hands.

After all, physical beauty is not the only — indeed, not the main factor —
in that elusive quality called charm, and it is really charm that irresistibly
attracts a man to a woman. What is charm? Who knows? Everyone rec-
ognizes its existence and its power but no one can wholly analyze it. It
involves to a considerable degree, graciousness, tact and kindness; cheer-
fulness, or vivacity is an indispensable ingredient; evidence of pleasure
in the company of the masculine companion, tempered with appropriate
reserve, must not be missing; and through it all runs, unobtrusively, per-
haps even unconsciously, the play of sex, or better perhaps, that irradiation
of sex which takes the form of a mild and inoffensive coquetry — what men
call being feminine. To describe charm is like trying to give directions
after the fashion of the cook who tells one to take a cup of this, a bit of
that, and a pinch of something else. Charm, nevertheless, is a very real
quality and is the chief ingredient of the emotional complex which con-
stitutes the sentimental appeal of a woman to a man.

One gathers fragments of wisdom concerning sex and marriage as he
journeys through this world of divorce courts and scandals — yes to a
minor extent — but mainly, of that great army of "good sports" who know
how to give and take fairly in the intimate and complex relationship of

REPRODUCTION 1 67

wedlock. The biologist can only conclude that unquestionably the health-
iest, happiest mode of life for either normal man or woman is found in
marriage, that no career which frustrates the experiences of family life can
compensate for it. It is for this outcome that nature has prepared man-
kind from almost the very beginning of life on the earth. To insure the
most satisfactory outcome, the mutual affection of the participants should
be a matter of growth based upon repeated association. There is usually
a period before courtship, in which one is in position to learn much about
the desirability or undesirabihty of a particular individual as a marriage
mate. Only an ill-balanced person is likely to rush blindly into matrimony.
Where properly consummated the man-woman relationships of life make
for a unity of interest and ripening of emotional satisfactions as do no other
experiences, and the spirit of mutual self-sacrifice and love thus engendered
flowers into altruism and universal good will. And finally, as the fires of
life burn lower and lower, the fires of love drop down to flames of gentler
tempo, so that the happily mated pair are content to let them purr along
in a pleasant glow of mutual admiration and devotion.

■>>><<<•

>>>>>>>>>>>>>>»>>>>>>>>>■>■><<<<<<«<<<<«<«<<<<<<<«■<

V

Embryology

WE have come a long way from the viewpoint that the tgg and the
sperm contain the offspring in miniature. Our modern microscopes
have shown the absurdity of this notion. The essential parts of the gametes
are the chromosomes with their genes. The latter are chemical substances
which in some as yet mysterious way are concerned with the development
of all the characteristics of the adult.

Embryology is concerned with the development of the fertilized t^g
into a mature embryo or possibly farther. Cell division is mitosis and the
development of daughter cells into one kind of tissue or another is dif-
ferentiation. The fact that two daughter cells, presumably with the same
genes will develop into dissimilar tissues is startling and poses a problem
which has not as yet been solved. That these cells, tissues, and organs dif-
ferentiate in the right place and develop their proper function at the right
time is an even greater cause for wonderment.

There are many theories to account for these mysteries but it must be
remembered that a theory does not become a law simply by constant repe-
tition. The mysteries of the cell require much work before we can gain
a glimpse of the truth.

An attractive theory for which proof seems to be lacking is that the
genes in the nuclei of daughter cells are 7iot similar to each other but that
some mechanism is operative which changes the chemical structure of
genes to suit the future use to which the cell is to be put. This does not
imply the operation of an outside force but may be something hereditary
within the genes themselves or it may be environmental in nature.

EMBRYOLOGY *

LESLIE BRAINERD AREY

Originally 'embryology' was a term restricted to the events of prenatal
development. Only gradually was it realized that developmental proc-
esses continue long after birth. One branch of embryology traces the

* Reprinted from Developmental Anatorny by Leslie Brainerd Arey with the per-
mission of W. B. Saunders Company and the author. Copyright 1940 by the W. B,
Saunders Company.

168

EMBRYOLOGY 1 69

formative history of animals from germ cell to adult. It paints the pro-
gressive panorama of change that cells, tissues, organs, and the body as a
whole undergo in attaining their final stages. Another division attempts to
explain on the basis of experiment the way in which development works.

Although the most striking changes in the development of man and
mammals occur while the young (first called an embryo and later a fetus)
is still inside its mother's womb, yet development by no means ceases at
birth. Birth is a mere incident in the whole developmental program. The
human newborn is utterly dependent for food and care; many years of
infancy and childhood must elapse before it becomes self-maintaining in
human society. Only at about the age of twenty-five are the last of the
progressive changes complete, whereupon an individual becomes truly
adult.

All vertebrate animals are organized upon a common anatomical plan.
Similarly, their fundamental mode of development is essentially identical.
While the comparative viewpoint is indispensable for gaining a broad
understanding of embryology, it has been of special importance in supply-
ing missing pages of the human developmental story. The extent of this
reliance on related forms will be appreciated when it is stated that the
youngest human embryos known are already embedded in the uterus and
possess their three primary germ layers.

A general concept of how man and other animals develop from a single
cell by orderly and logical processes should share in the cultural back-
ground of every educated mind. From the theoretical side embryology is
the key that helps unlock the secrets of heredity, the determination of sex
and organic evolution. The body does not just happen to be arranged as
it is. Each end-result in structure is preceded by a definite, developmental
course of events. Embryology is able to interpret such rudimentary struc-
tures, variations, anomalies and 'monstrous' conditions, as well as to throw
hght on the origin of certain tumors and other pathological changes in
the tissues. Furthermore, obstetrics is basically merely applied embryology.

In the middle of the seventeenth century, it was generally believed
either that fully formed animals exist in miniature in the eg^, needing only
the stimulus of the spermatozoon to initiate development, or that similarly
preformed bodies, male and female, constitute the spermatozoa and merely
enlarge within the ovum. To be consistent this doctrine of prejorination
had to admit that all future generations were likewise encased, one inside
the sex cells of the other, like so many Chinese boxes. Serious computa-
tions were even made as to the probable number of progeny thus present
in the ovary of Mother Eve, at the exhaustion of which the human race
would end. The modern teaching, known as epigenesis, was proved cor-
rect when von Baer discovered the mammalian ovum in 1827 and later
demonstrated the three primary germ layers from which all embryos and
their constituent parts develop.

1 70 READINGS IN BIOLOGICAL SCIENCE

A multicellular embryo begins life as a fertilized egg. The fertilized
egg straightway becomes a ball of cells, which soon organizes into three
sheets known as the primary germ layers. From these the tissues, organs
and body rapidly emerge. At the end of the developmental period the
adult body may be many billions of times bulkier and heavier than the
original egg.

It seems like a long span from the egg to the trillions of cells that com-
prise the completed body of man, yet this prodigious final number can
be attained quite readily by repeated cell division. So rapid is the doubling
process that some 45 generations of mitoses are sufficient.

The first important move toward organization in a young embryo
establishes three superimposed, cellular plates, the primary germ layers.
From their positions they are termed the ectoderm (outer skin), mesoderm
(middle skin) and entoderm (inner skin). Since the ectoderm covers the
body it is primarily protective in function, but it also gives origin to the
nervous system and sense organs through which sensations are received
from the outer world. The entoderm, on the other hand, lines the primi-
tive digestive canal and is from the first nutritive; later it also becomes
respiratory. The mesoderm, lying between the other two layers and later
splitting into two sheets, naturally performs the functions of circulation,
muscular movement, excretion and reproduction; it also gives rise to the
skeletal structures which support the body. The germ layers are however,
not so absolutely specific in their potentiaUties as was once thought.

HUMAN SEX CELLS

Although always relatively large, the exact size of a mature ovum is
correlated with the amount of stored food substance and not with the size
of the animal producing it. The smallest eggs are those of the mouse and
the deer (about 0.07 mm.); the largest have a diameter measurable in
inches (birds; sharks). Most ova are nearly spherical in form and all pos-
sess the usual cell components. There is little difference in the size of the
eggs formed by the various placental mammals; mouse, man and whale
are nearly equal in this respect. The mammalian egg is small in compari-
son with many ova; yet when set beside ordinary cells it is truly big, since
it is just visible to the naked eye as a tiny speck. The diameter of normal,
fresh specimens of human ova is now known to be about 0.135 "ini. Never-
theless, all the eggs necessary to replace the present population of North
America could be placed in a cubical vessel three inches square.

At one time human sperm cells were regarded as parasites, and under
this misapprehension the name spermatozoa or 'semen animals,' was given
them. Although its length is nearly one-half the diameter of a human ovum,
the relative volume is only as 1:85,000. All the spermatozoa required to
produce the next generation of North America could be contained in a
spherical vessel having the diameter of an ordinary pinhead.

EMBRYOLOGY lyi

OVULATION AND SEMINATION

The discharge of the ovum from its follicle (in the ovary) comprises
ovulation. In primates, ovulation is periodic, at intervals of about four weeks.
The human female begins to ovulate at puberty (about the fourteenth year)
and ends with the menopause (about the forty-seventh year). Generally
only one follicle and ovum mature each month, the ovaries alternating
with irregular and unpredictable sequence. Thus from the many thousands
of potential ova provided, only about 200 ripen in each ovary during the
thirty-odd years of sexual activity.

Sometimes two or more follicles mature and expel their eggs simul-
taneously; this phenomenon is responsible for the common type of mul-
tiple births. The reason why only one follicle at a time ordinarily reaches
maturity is because of the nice balance maintained between the amount of
follicle-ripening hormone (prolan A) and the response of the ovary to it.
Hormone oversecretion brings about multiple ovulation, while under-
secretion is responsible for ovulatory failure. How long the human egg
retains its ability to receive a sperm and then start developing cannot be
stated with certainty. It is now generally believed that the fertilizable
period is not more than a day.

For many years ovulation and menstruation were supposed to take
place synchronously. But when actual data was collected, it became ap-
parent that this assumption is untrue. In reality the time of ovulation is
about midway between two menstrual periods.

The purpose of coitus is to introduce spermatic fluid into the vagina.
Spermatozoa gradually attain their full functional state, retain it for a
hmited period, and if not discharged, then slowly decHne in vigor until
death and resorption supervene. At the climax of coitus, ejaculation occurs;
involuntary muscular contractions forcibly eject the older spermatozoa,
along with the secretions of several accessory glands which discharge at
the same moment. The combined fluid mass is the seminal fluid, or semen.
The volume of the ejaculate is about 4 c.c. and in it swim some 300,000,-
000 spermatozoa. An acid environment, such as the vagina where the
seminal fluid is first deposited, is deleterious or fatal to spermatozoa; a
neutral medium, as furnished by the uterus and tubes, is more favorable.

The outstanding functional feature of spermatozoa is their lashing
flagellate swimming which resembles that of a tadpole. Forward progress
of the human spermatozoon is at the rate of about 1.5 mm. a minute which,
in relation to their respective lengths, compares well with average swim-
ming ability for man.

These innate activities, however play but little part in the transport of
sperm through the female genital tract. Passage from vagina to uterus
is the result of muscular movements of the cervix. The journey through
the uterus is similarly accomplished, in some animals at least, by muscular

172 READINGS IN BIOLOGICAL SCIENCE

propulsion.The total period required by human spermatozoa in reaching
their destination is unknown, but it cannot be more than a few hours at
the most. There is no good reason for beheving that the duration of fer-
tilizing capacity of the sperms extends beyond a day or two.

The penetration of the ovum by the spermatozoon and the resulting
fusion of their respective nuclei, constitutes the process of fertilization. In
practically all animals fertilization also supplies the stimulus that starts the
ovum dividing. The meeting and union of the human cells is believed
usually to take place in the upper third of the uterine tube.

TWINS AND TWINNING

The frequency of multiple births varies considerably among different
countries and races. Twins occur among American whites once in every
88 births, triplets have a frequency of i:(88)^ and quadruplets appear in
the ratio of i:(88)^ Six appears to be the maximum number of simul-
taneous births that is well authenticated for man.

At the outset a distinction must be drawn between true twins and a
false type that masquerades under the same name. The coincident produc-
tion of two or more individuals is most commonly due to the independent
ripening and development of an equal number of independent eggs. In
these instances ordinary, or fraternal twins are said to be produced. These
offspring may be all of the same sex, or mixed as to sex, and such false
twins have only the same degree of family resemblance as occurs in
brothers or sisters of different ages. Properly speaking, they are not twins
at all but, as in lower animals, merely members of a litter. Quite different
are the identical, or duplicate twins. This group includes those true twins
characterized by always being of the same sex and so strikingly similar
in physical, mental and pathological traits that only rarely is their diagnosis
difficult. This identity is enforced by their derivation from a single egg,
whereby each member acquires precisely the same chromosomal heritage
and hence the same genetic constitution.

Very rarely identical twins are conjoined as a 'double monster.' All
grades of union are known but conjoined twins of equal size have the
best chance for survival.

EMBRYOLOGY AND GENETICS *

THOMAS HUNT MORGAN

The stratified rocks of the earth's surface reveal the most recent part of
the long history of the evolution of the animals and plants living at the

* Reprinted from Thomas Hunt Morgan, Embryology and Genetics. Copyright
1934 by Columbia University Press.

EMBRYOLOGY 1 7 3

present time. While it took millions of years to bring about these changes,
the development of each individual from an apparently simple egg to
the visibly complex form of -the adult is now only a matter of days, or
even hours. The comparison may be misleading, however, since there have
probably been long periods when little or no change took place in the
species, and the next advance, appearing in a single individual, may ac-
tually have occurred in infinitesimal time, from gene to gene, involving
only a sudden alteration in one of the units of heredity.

The identification of the egg cells with the single-celled ancestors from
which the higher forms have evolved calls for qualification. The converse
statement may be nearer the truth, namely, that the egg of today is as
different from the original unicellular ancestor as the adult today is dif-
ferent from that ancestral adult. Both statements call for reservations, for
everything turns on what is meant by likeness and difference. In the egg
there are all the potentiahties for quickly developing the characteristics of
the adult form, and in this sense the egg differs immensely from the
original one-celled ancestor. The difference lies in the units of heredity
in the two cases: only in their visible form are the protozoon and the egg
somewhat alike. Since we know nothing about the constitutional differences
between the hereditary elements in the original protozoon and those of the
egg of today, it is futile to attempt to make any serious comparisons be-
tween the relative complexity of the two. Only superficially are they
ahke in their visible structures.

In another respect, however, we may make comparisons. The ancestral
type needed to pass through fewer visible changes from egg to adult. In
the unicellular forms, the protozoa, that multiply by self-division, each
daughter cell has little more to do than to enlarge to the original size, and
in the lower metazoa the stages, after division of the egg, are very few
compared with those of higher forms. But even then the comparison may
be misleading, for in the higher forms it is the visible changes that are
considered, and we think of them most often as changes in form or struc-
ture, while the physiological processes in the unicellular and multicellular
types are probably much more alike. In the higher forms these processes
are separated into organ systems, but they may be much the same as in
the protozoa. Descriptive embryology concerned itself entirely with
changes in form, and very little with the physiology of development. Only
recently has the latter received serious attention, although there have al-
ways been a few students interested in the physiology, especially in the
later stages, of the vertebrate embryo.

For many years — let us say between 1850 and 1900 — embryologists
were engrossed with the idea that development of higher forms reca-
pitulated the entire historical path over which their evolution had passed.
This became known as the recapitulation theory. An immense amount of
purely descriptive embryological work was carried out under the in-

174 READINGS IN BIOLOGICAL SCIENCE

fluence of this theory, and today the embryology of all types of animals
is known, often in the most minute detail. In small transparent eggs the
developmental stages may be followed under the microscope; and, even
in eggs that are more opaque, technical methods have been devised that
reveal the changes taking place beneath the surface. The perfection of
these methods — staining, imbedding in paraffin, cutting into thin slices,
mounting these in balsam on glass slides, and reconstructing the whole in
wax — occupied for a long time the attention of a great number of profes-
sional embryologists, to the exclusion of considerations dealing with the
physical and chemical events that lie behind these visible stages of develop-
ment. The historical appeal was irresistible, especially if one believed that
what he was seeing and describing was the history of "creation" — or, as
it was called, evolution. There was soon established an immense body of
information concerning the development of all the main animal forms.
Accurate observation was called for, of the same order as that of all pic-
torial art. Beautiful illustrations of the development from egg to embryo
appeared in a host of monographs. The better the artist, the more brilliant
his performance. The anatomy of development became as well known as
the older anatomy of adult structures that had hkewise called for close
observation and an artistic sense of representation in color and perspec-
tive.

During the final years of the last century and down to the present time a
new interest appeared, called experimental embryology, and sometimes
developmental mechanics. The reaction that had set in against the old
interpretation of the developmental stages as a recapitulation of the an-
cestry was in part responsible for this change of interest. New ways of
finding out something of what is going on behind the scene, the discovery
of potentialities in the egg never before suspected, the appHcation of
methods to bring about unnatural changes in the development, the emphasis
on the role of the environment in normal development, all conspired to
awaken new interest.

Into the new fields of exploration many of the young embryologists
entered with renewed enthusiasm. A great deal was revealed and many
more problems, very different in kind from those' that had fascinated the
preceding generation, appeared. Here it seemed was the possibility of
further advance in an understanding of the developmental processes; and
the idea that embryology could be placed on an experimental basis was
especially attractive to those who were familiar with the great advances
that the experimental method in chemistry and physics had brought
about. The embryologist found himself dealing with problems so different
that it did not seem possible to apply at once the laws of chemistry and
physics. He dealt with such complex materials as proteins, colloids, and
with such complex problems as surface forces, permeability, etc., that the
physical scientists themselves had not yet brought into line with the rest

EMBRYOLOGY 1 7 5

of their work. In fact, nearly all of the experimental work, so called, in
embryology remained still on the biological level. It made known many
conditions in the development of the egg that had never before been sus-
pected, but the appeal to physics and chemistry of the so-called develop-
mental mechanics was more often by analogy than by demonstration, and
even "chemical embryology" has been largely a description of the kind
of chemical compounds found in the tgg and embryo. It is true that the
transformation of some of these compounds into the other substances or
into the finished product is an essential part of the embryological problem,
but the embryologist is very largely concerned with the kinds of reac-
tions that lead to the particular changes in form of the embryo, as well
as with the origin of substances from other materials.

The extraordinary fact that an egg with little visible organization de-
velops into a complicated adult, with a vast amount of organization, had
aroused the interest of the philosophers from Aristotle to Whitehead, and
in a broad way they realized the mystery of something happening that
had no parallel in other fields of scientific interest. These thinkers were
mainly impressed with the kind of organization expressed in form as the
most important feature of development, and today this still remains as
the most outstanding feature of development. That these changes in form
might depend on chemical changes in the embryo was either taken for
granted or ignored.

The most discussed "principle" of philosophy goes under the name of
entelechy. The entelechy, supposedly the same idea under that name in
Aristotle's teachings, was postulated as a principle, guiding the develop-
ment toward a directed end — something beyond and independent of the
chemical and physical properties of the materials of the egg; something
that without affecting the energy changes directed or regulated such
changes, much as human intelligence might control the running or con-
struction of a machine. The acceptance of such a principle would seem to
make it hardly worth while to use the experimental method to study de-
velopment, since it would be directed and regulated by the entelechy. In
fact, the more recent doctrine of "the organism as a whole" is not very
different from the doctrine of entelechy, except in so far as other ways,
by which the whole might be coordinated in an ultra or supermaterialistic
way, might be imagined.

Therefore, unless it be granted that the principles involved in develop-
ment are of a different order from physical principles in the broadest and
most recent usage of this term, it would seem better to table these meta-
physical questions, and to try to discover, despite the amount of time
and labor involved, how far a knowledge of the chemical and physical
changes taking place in the egg will carry us toward an understanding of
the developmental processes. It may, of course, be found that an under-
standing of the kind of system present in the egg, sometimes still called the

176 READINGS IN BIOLOGICAL SCIENCE

organization of the egg, will require relatively new principles peculiar to
colloid systems, balanced salt solutions, semipermeable membranes, phase
boundaries, etc.; but if these "principles" are still found to follow physical
and chemical laws, whether the old ones or new ones, for large-scale phe-
nomena with \\'hich embryology appears to be concerned, the study of
embryology would still come to range itself under a broader conception
of natural processes, including in its scope both living and dead material.
If, on the other hand, it should turn out that an understanding of living
materials calls for something quite new to the physical sciences, it will then
be time to examine the nature or un-nature of this something. Meanwhile
it seems clear that the next step should be a determined effort to learn
all that we can about the kind of system or configfuration that constitutes
the tgg. This statement does not mean that we should resort entirely to
the kind of analyses which chemists and physicists have invented for the
study of their kinds of materials, but that we should not neglect any pos-
sible means of penetrating further by experimental methods, on the bi-
ological level, into the behavior of such systems.

It is unsafe to say that the physico-chemical problems are different from
the biological problem until we know more about the latter. For it must
be obvious to every student of embryology that we have only begun to
get information as to the "organization" of the egg on the biological level,
and know as yet very Httle about the chemistry and physics of develop-
ment. Should it turn out that neither the classical mechanics, nor the new
physics suffice, the ground will at least be prepared for the discovery of
some new kinds of principles that apply to living things. But until it has
been shown that what we call the property or properties of living things
are entirely out of line with what is known as non-living systems, it may
be short-sighted to resort to obviously metaphysical principles, or even
to temporize with them. It is this alternative that separates those whom the
philosophers insist on calling mechanists, and those whom the biologists
call metaphysicians. There is no need to attempt a compromise by saying
that each has his own realm, because the scientist regards mysticism as an
outmoded way of attempting to offer a finalistic solution of the problems
he studies.

Most modern biologists are not, however, so much impressed by the idea
that there is a principle of life as they are by the great variety of phe-
nomena shown by living things. It seems to them premature as well as
pretentious to discuss some imaginary ideal property of hfe when there
is abundant evidence pointing to the conclusion that there are many prop-
erties of living things of many different kinds, each crying out for solution
before attempting to synthesize them into life. Of course one may pick
out one or more of these, such as consciousness, or purpose, or free will,
and make it the si7je qua non of living things, but it should not pass un-
noticed that the selection is usually one of the most obscure phenomena of

EMBRYOLOGY 1 77

living things. Formative forces, polarity, symmetry, and purposeful regula-
tions are examples of this in the embryological realm.

The story of genetics has -become so interwoven with that of experi-
mental embryology that the two can now to some extent be told as a
single story. It is true there are still wanting many important points of
contact, but enough is known to make it possible to attempt to weave
them together into a single narrative. Although each has developed in
large part independently of the other, nevertheless today their interde-
pendence is so obvious that the geneticist takes for granted the main out-
lines of the facts of embryology, and the embryologist is coming to realize
his dependence on the evidence from genetics. For example, cell division
and the behavior of the chromosomes at maturation of the eggs and sperm
have supplied the working scheme for the theory of heredity. The
changes that take place during the maturation of eggs and sperm are con-
tributions from embryology. Conversely, genetic analysis has made it pos-
sible to go behind these visible changes into the very constitution of the
chromosomes themselves. The common meeting point of embryology and
genetics is found in the relation between the hereditary units in the chromo-
somes, the genes, and the protoplasm of the cell where the influence of the
genes comes to visible expression. Concerning the manner of functioning
of the genes during development, I have contrasted, in the following pages
whenever an opportunity arises, two possible views, and suggested a third.
The implication in most genetic interpretation is that all the genes are
acting all the time in the same way. This would leave unexplained why
some cells of the embryo develop in one way, some in another, if the genes
are the only agents in the results. An alternative view would be to assume
that different batteries of genes come into action as development proceeds.
The former view, namely, that all the genes are acting all the time in the
same way, leaves the embryological problem where it has always been
supposed to be, viz., in the protoplasm. The alternative view might appear
to give a formal explanation of development, but is inconsistent with re-
sults obtained by changing the sequence of the cleavage planes by com-
pression. Roux and Weismann attempted to explain development in some-
what this way, by assuming that the determinants in the chromosomes are
quahtatively sorted out during development. There was at the time no
evidence in favor of this view, and there is now much that is opposed to
it. The idea that different sets of genes come into action at different times
is exposed to serious criticism, unless some reason can be given for the time
relation of their unfolding.

The following suggestion may meet these objections. It is known that
the protoplasm of different parts of the egg is somewhat different, and
that the differences become more conspicuous as the cleavage proceeds,
owing to the movements of materials that then take place. From the proto-
plasm are derived the materials for the growth of the chromatin and for

178 READINGS IN BIOLOGICAL SCIENCE

the substances manufactured by the genes. The initial differences in the
protoplasmic regions may be supposed to affect the activity of the genes.
The genes will then in turn affect the protoplasm, which will start a new
series of reciprocal reactions. In this way we can picture to ourselves the
gradual elaboration and differentiation of the various regions of the em-
bryo.

-W\ ^ y y

OLD PROBLEMS AND NEW IN
EXPERIMENTAL EMBRYOLOGY *

E. G. BUTLER

Ever since man possessed the ability for correlated mental activity he
has undoubtedly speculated on the phenomenon of embryonic develop-
ment. The manner in which a living organism comes into being, takes on
definite organized form, undergoes the establishment of vital functions,
and, finally, assumes the characteristics of a complex adult body, seldom
fails to elicit the interest of intelligent human beings.

Although the study of embryology is rooted deep in antiquity, refer-
ences in pre-Grecian literature to developing organisms are, unfortunately,
somewhat fragmentary. During the rise of Greek culture, however, nearly
all philosophers devoted some attention to problems of development and
several wrote extensively on the subject. With Hippocrates, observation
began to take precedence over speculation, and he and his associates left
records indicating considerable time devoted to the study of embryos in
a variety of animals. Finally, toward the end of the fourth century, b. c,
Aristotle wrote the first book dealing solely with embryonic development,
"De Generatione Animalium."

The son of a physician, Aristotle was reared on the works of the Hip-
pocratic school and was early trained in methods of dissection. It is doubt-
ful if any of Aristotle's scientific work excelled that which he did on
embryology. His methods and tools were inadequate, his observations
often too few, and many of his conclusions far from correct, nevertheless,
he arrived at an insight into animal development far exceeding that of any
predecessor. He seems to have appreciated that embryonic development
is not a mere unfolding and growth of structures already established, and
he resorted, not infrequently, to physical or mechanical comparisons.
Referring to the developing parts of an embryo, he wrote, "It is possible,
then, that A should move B, and B move C; that, in fact, the case should
be the same as with automatic machines shown as curiosities. For the parts

* Based upon an address presented at the annual dinner meeting of the Princeton
Chapter, of Sigma Xi, May 191 1, and adapted here by permission of the author and
of the Society of the Sigma Xi.

EMBRYOLOGY 1 79

of such machines while at rest have a sort of potentiality of motion in
them, and when any external force puts the first of them in motion, im-
mediately the next is moved in actuality." ^ This cannot be called a refined
physicochemical analysis of development in the modern sense, but it marked
a beginning in the right direction. Aristotle also compared the growth of
an embryo to the effect which rennet has on milk and, likewise, to the
growth of the yeast. To paraphrase a remark by Charles Darwin, many
later embryologists have been "mere schoolboys to old Aristotle."

Aristotle's work influenced embryological thought for at least twenty
centuries, and, with the passage of time, the study of embryology had its
ups and downs. During the middle ages an enormous amount of specula-
tion regarding development teetered, often precariously, on an exceed-
ingly meagre amount of observation. At times embryology and theology
joined hands, and we find in embryological endeavors search for a nobler
concept of life. Embryology and art were sometimes associated, as in the
case of Leonardo da Vinci, who not only left in interesting drawings evi-
dence of careful dissections of the pregnant uterus, but also records of
quantitative studies on growth. On the basis of surprisingly accurate meas-
urements he compared embryonic growth with post-natal growth, in-
cluding a study of relative sizes of organs during development.

Passing rapidly over the years, let us pause for a few moments in the
seventeenth century, a period to which modern embryology is particularly
in debt. Then lived and worked, to mention a few names only, Leeuwen-
hoek, inventor of the microscope; Malpighi, with notions of preformation
within egg and embryo; Sir Thomas Browne, of singularly enquiring
mind; Walter Needham, physician and experimenter; deGraaf, whose
name is perpetuated in the Graafian folHcle of the mammahan ovary; and
William Harvey, keen observer and lucid writer.

William Harvey's book, Exercitationes de Generatio7ie A?ii?nalkmj, was
published in 165 1. It must have been in the nature of what would now be
called a scientific "best seller." After publication of the first edition in
London in 1651, three editions, all in Latin, came out during the same year
bearing the imprint of Amsterdam publishers. The first English transla-
tion appeared in 1653. The frontispiece of Harvey's book is an engraving
of Jove, holding a sphere which represents an egg. From the sphere are
being liberated all the animals under heaven, and on it is written, "Ex ovo
omnia." Although the epigram does not appear in such form in the text,
this dictum, all life from eggs, is the continuing thesis of Harvey's book
and was one of his great contributions to embryological knowledge.

A man of the abihty and versatility of William Harvey, cannot be
passed by hastily. As an observer and experimenter of the first order, he
wrote, ". . . there be one onely roade to Science, namely, that by which

1 From the translation of Aristotle's De Generatione Animalium by Arthur Piatt,
Oxford Press, 1910.

l80 READINGS IN BIOLOGICAL SCIENCE

we proceed from things more known, to things known less; and from that
which is more manifest, to that which is more obscure; . . . ." ^ Prob-
lems of growth and differentiation puzzled Harvey, and will puzzle us
in some detail in a few moments. However, he handled these problems
generally in a manner much better than his predecessors or contemporaries.
Some have held that he sought to endow developing embryos with an
imminent spirit of special sort, but as W, K. Brooks pointed out years ago,
when Harvey referred to a "vital principle," he probably meant to say
that the embryo was ahve, with no thought of implying supernatural
agencies. Parts of embryos, Harvey wrote, "are at once similar and dis-
similar, and from a small similar is a great organ made." ^ This might be
taken as a text by modern students of embryology, who discuss embryonic
localization and determination, and construct for us maps of the egg to
show the presumptive fate of each part.

Embryonic development in higher animals involves an orderly sequence
of events, including production of sex cells, the ovum or egg in the female,
the spermatozoon in the male; fertilization, which is the union of an egg
and a spermatozoon; and, following fertilization, all of those processes
concerned with growth and differentiation of the new individual. As I
have mentioned, eggs from various types of animals have long been a
subject of study. Spermatozoa were first seen by a man named Dr. Ham
and reported to the Royal Society in 1677. Knowing little about the
structure of the tgg and the spermatozoon, and less about the nature and
significance of fertilization, it is not surprising that many early embry-
ologists were led by their inaccurate observations down the easy path to
the theory of preformation. It was the simplest way — to make the deduc-
tion that all structures of the adult body were present in miniature, in
other words, preformed, either in the egg or in the spermatozoon. And,
as one would anticipate, two conflicting schools of thought arose. One
school, called the ovists, insisting that all adult structures were preformed
in the egg; the other school, called the spermists, insisting that all structures
were preformed in the spermatozoon. For the adherents to either school,
embryonic development meant an unfolding of structures already present.

1 never tire of reading the description of a spermatozoon written in 1699
by one of the zealous spermists, Dalenpatius. It is beautifully phrased
and thoroughly inaccurate. Speaking of human spermatozoa he wrote:
"They move with wonderful rapidity and by the strokes of their tails
produce little waves in the substance in which they swim. But who would
believe that in these a human body was hidden? Yet we have seen such
with our own eyes. For while we were observing them attentively, a large
one threw off its surrounding membrane and appeared naked, showing

2 From the 1653 translation of Harvey's De Generatione Animaliu7n, printed by
James Young for Octavian PuUeyn, London. (Copy in the New York Academy of
Medicine.)

3 Ibid.

EMBRYOLOGY I 8 1

distinctly two legs, thighs, breasts and arms. ... it was a delightful and
incredible sight." * (Emphasis should be, of course, on the word, incredible.)
Here we have a bold description of preformation as envisaged by an ar-
dent spermist. Other observers thought they saw microscopic horses in the
semen of the horse, similar animalcules, but with larger ears, in the semen
of the donkey, and minute roosters in the semen of the rooster.

The ovists were no less backward than the spermists in putting forward
their claims for the egg. "Emboitment," the notion that, like box within
box, all future structures were already present within the egg, presented
no particular obstacle for a dyed-in-the-wool preformationist of the ovist
school. As one (Haller) wrote: "It follows that the ovary of an ancestress
will contain not only her daughter, but also her grand-daughter, her great-
granddaughter, and her great-great-granddaughter; and if it is once proved
that an ovary can contain many generations, there is no absurdity in saying
that it contains them all."

Naturally, the preformationists did not flourish unchallenged. Opposing
theories grew up under the general title of epigenesis. In its extreme form
epigenesis was the exact opposite of preformation. The theory of epigenesis
held that the egg, for example, was a simple homogeneous structure. Ac-
cording to this view, there was not only no preformation, but, on the
contrary, no differentiation at all within the egg or spermatozoon. Ad-
herents of the most extreme views of epigenesis were under the necessity,
therefore, of explaining how heterogeneity could come from homogeneity,
how an undifferentiated egg could give rise to the complicated differ-
entiated structures of embryo and adult. And, as so frequently happens,
when obstacles such as these are encountered, recourse was often made to
some type of vital force, a vis essentialis or a nisiis formativus, which it was
easy to think, shaped the course of embryological events.

Embryologists have long recognized that neither the extreme view of
preformation nor epigenesis were correct. Yet, there were elements of
truth in each. The spermatozoon and the egg, each is far from being a
homogeneous structure. Each is a highly differentiated cell, with compli-
cated internal organization. Still, the differentiation of the spermatozoon,
the egg and the developing embryo are in no sense simply the presence in
a miniature of adult structures. Development of the fertilized egg is a far
more complicated process than any early embryologist ever dreamed. And,
only in relatively recent years has the embryologist been able to glimpse
some of the underlying mechanisms involved.

Descriptive embryology has long been concerned in following the
origin of adult structures back to their earliest appearances in egg and
embryo. Thus we have been able to recognize "anlagen" or primordia of

* Dalenpatius as quoted by Vallisneri. From Lewis and Stohr, Text-Book of Histol-
ogy, Blakiston, 1913. (English translation by Lewis from Berger's German translation
of Vallisneri.)

1 82 READINGS IN BIOLOGICAL SCIENCE

organs. It has been possible to make maps of certain eggs and in many cases
to point out, with great accuracy, the exact material that will give rise to
certain organs. We know, for example, just what materials will go into the
making of the brain, what material will form the digestive canal, the
muscles, bones, and so on.

Embryonic development is, in the main, a continuous procedure, once
fertilization has occurred. Two outstanding processes are always in evi-
dence; cell multiplication and cell differentiation. Thus, starting with the
fertilized egg, the new organism grows in size and its parts become dif-
ferentiated and specialized. The fertilized egg, which is a single cell, by
continued division forms first an aggregate of many cells. Then the many-
celled aggregate begins to undergo differentiation into special layers of
cells, in particular, an outer layer, called the ectoderm, an inner layer or
entoderm, and a middle layer, or mesoderm. Each of these three layers
has a definite significance, or fate, in normal development, and, as stated
above, maps showing the presumptive fate of different regions can be
made. For example, the ectoderm in one region gives rise to the brain,
whereas in other regions it goes into the formation of the epidermis of
the skin. The heart, blood vessels, and all bone and muscle come from the
mesoderm, and so on.

With an extensive knowledge of normal embryology, investigators
naturally began to try experiments with the developing egg and embryo,
and hence has grown up the field of experimental embryology. Experi-
ments can best be performed on eggs and embryos which develop outside
the body of the mother. Among the most favorable and most commonly
used are embryos of the amphibia, such as the frogs and newts. Eggs of
these animals are shed by the female into the water, where fertilization
takes place, and the embryo develops in its aqueous environment, shielded
only by certain protective memibranes. Hence, we have a readily available
supply of embryos. By removal of the outer protective membranes, the
experimenter can easily secure naked embryos, and, by the use of suitable
small instruments and appropriate microscopes, can perform many opera-
tions in these embryos, such as extirpating pieces of an embryo, and trans-
planting cells from one location to another.

What would happen, for example, if in an early stage of development
a group of cells, which normally would form a part of the brain, was re-
moved and cells transplanted in their place which normally would form
epidermis of the skin? In other words, suppose that presumptive brain
cells be replaced by presumptive epidermal cells. This and many similar
experiments, have been performed during recent years by experimental
embryologists in this country and abroad. From these experiments we
learn that cells which normally would form the epidermis of the skin in
the belly region of the embryo, if transplanted to the proper site at the
proper time, will develop into nerve cells of the brain. Conversely, cells

EMBRYOLOGY 1 83

which normally would become brain cells, if they are transplanted to the
belly region of the embryo, are "demoted," so to speak, and become merely
belly epidermis. Furthermore, it can be shown that, if placed in the proper
location, belly epidermis instead of becoming brain, may become muscle
tissue, or even a part of the kidney.

Such experiments command our attention. They show that, although
cells in early developmental stages may normally have a very definite
presumptive fate, this fate can be changed when the position of the cells
in question is changed. Hence, we can be certain, that in the young amphib-
ian embryo determination of parts has not, at least in all cases, been ir-
revocably established. The fate of a certain group of cells can be altered
by changing their location in the embryo. Accordingly, it appears that in
some manner the immediate surroundings of cells are of basic importance
in determining their significance in development.

It should be stated, however, that the alteration in the fate of embryonic
cells can be brought about only in young stages of development. Quite early
in embryonic development a time is reached at which the fate of the
embryonic cells becomes irrevocably determined. When this times comes,
epidermis from the belly region, if transplanted to the brain region then
"refuses" to be influenced by the new surroundings and "insists" on de-
veloping into skin epidermis. Hence, when such cells are transplanted, we
will have formed a little abnormal knot of epidermis cluttering up the
brain region. Or, conversely, if presumptive brain tissue be transplanted to
the body wall in the belly region, a bit of abnormal nervous tissue will later
be found trying to develop on the belly wall. Such results have been ob-
tained many times in amphibian embryos, and the experiments are rela-
tively easy to perform.

The question arises as to what forces are responsible for setting up this
irrevocable determination of regions in the young embryo at a certain
stage in development? This question is too large and too involved to take
up in detail in a discussion such as the present one. But, permit me to
give a few hints with regard to what is going on.

In one special region of a developing amphibian egg — a region which
biologists will recognize as the dorsal lip of the blastopore — is situated what
Professor Spemann has called the "center of organization." An extensive
series of experiments have shown that this center of organization is re-
sponsible, to a great extent, for the organization of cells forming some of
the main axial organs of the body, such as the brain, the spinal cord, and
the predecessor of the spinal column, which is called the notochord. Once
this center of organization has become active, then regions under its in-
fluence become irrevocably determined.

I shall give you just one example, of the manner in which the center of
organization appears to operate. If cells are taken from this center and trans-
planted so that they can influence presumptive skin epidermis in the ventral

184 READINGS IN BIOLOGICAL SCIENCE

body wall, leaving the local epidermis in place in its normal location, then
brain and other axial organs will develop from this epidermis. In other
words, the center of organization can assert itself, and can induce belly-
epidermis, in its normal location, to form brain tissue. In fact, the center
of organization, when transplanted to a foreign site, can induce the forma-
tion of a whole new body axis, actually a little twin embryo attached to
one side of the primary embryo.

Further research has shown that, rather than a single organizing center,
a series of such centers become operative as embryonic development pro-
gresses. The center just referred to, usually known as the primary or-
ganizer, is concerned with the establishment during normal development
of the main axial organs, such as brain, spinal cord, and associated struc-
tures. Other organization centers, the secondary organizers, have been
demonstrated which are concerned with development of parts of the eye,
the ear, mouth structures, and so on. And there are, in all probability, many
more secondary centers of organization which we know Uttle or nothing
about at the present time.

It will be well to emphasize the particularly fundamental feature of
development that has been revealed by the methods of approach and the
new operative techniques just described. That fundamental feature of de-
velopment I shall call cellular interaction. Cells in a developing embryo
realize their own special roles in development as they are acted upon, and,
in turn, act upon other cells and groups of cells.

Further evidence of interaction among cells has also been obtained from
a somewhat different type of research. My own interests in cellular inter-
action, together with those of several of my students, have centered for
a number of years around the phenomenon of regeneration. The word
regeneration, in the biological sense, refers to the replacement by cellular
multiplication and differentiation of structures lost by accident, or other-
wise removed from the body of an organism. It is well known that nearly
all animals possess the capacity for regeneration to a greater or lesser de-
gree. In higher vertebrates, such as man, the capacity for regeneration is
restricted, for the most part, to the formation of new tissue as it takes
place during wound healing. Certain lower vertebrates, however, nota-
bly the ampibia, possess a high degree of regeneration capacity. Entire
organs, such as a limb or a tail, can be completely regenerated. In a sense,
therefore, the abiUty to regenerate lost parts represents the retention of
the cells of an organism of embryonic capacities for growth and differen-
tiation. Thus, in the phenomenon of regeneration we have opportunity for
study and analysis of cellular interaction, as it underUes growth and dif-
ferentiation.

If young animals are used, such as young salamanders, regeneration
proceeds with surprising rapidity. For example, if I take a young salaman-
der and amputate a fore limb across the upper arm, a new limb will grow

EMBRYOLOGY 1 85

out from the cut stump within a period of three or four weeks. Such a
regenerated limb will be complete in every detail, including upper arm,
forearm, hand, and fingers. During this process of regeneration new skeletal
elements, new muscles, new blood vessels, and so on are formed. The re-
generated Hmb is as perfect, structurally and functionally, as the original
one.

If the processes underlying the regeneration of structure, such as limb,
were really understood we would be a long way toward understanding
many of the fundamental processes of embryonic development. We know
that, after removal of a limb, a group of cells gradually appears at the
point of amputation. These cells in many respects represent a type of
embryonic cell. From this aggregate of cells, called a regeneration blastema,
is formed nearly all new structures of the regenerated Umb. But what
governs the growth and differentiation of the blastema cells into new
structures? What determines that certain cells in the aggregate will give
rise to skeleton, others to muscle, and so on?

In an attempt partially to analyze the situation, one of my students. Dr.
Thornton, removed all of the skeletal elements from the limb stump at the
time of amputation. The method adopted was briefly as follows. Using a
young salamander, he amputated a fore limb through the middle of the
upper arm. Then the humerus was carefully exarticulated from its socket
at the shoulder joint and completely removed. Such a procedure left the
upper arm as a collapsed limb stump, made up of muscles, connective
tissue, blood vessels, and nerves, but entirely devoid of the skeleton. What
type of limb will regenerate from such a deficient upper arm?

The results from these experiments showed that such animals regener-
ated normal limbs. As the regeneration blastema formed, it was observed
that some of the cells developed into a new humerus, regardless of the
fact that none of the old humerus was present to take part in the process.
Here, then, is new evidence for the assertion, that the direction in which
cells differentiate depends somehow on their situation and surroundings.
There is evidence, that under one set of circumstances certain cells may go
into the formation of muscle, whereas under other conditions it is possible
that the same type of cells will form skeleton. In an active field of limb re-
generation, therefore, it is clear that what happens to individual cells
depends on the relation of the cells to each other and to the field as a whole,
as w-ell as on their inherent potencies.

Recently we have been able to secure still further information regarding
the manner in which cellular interaction is involved in regeneration. Pro-
fessor O. E. Schotte of Amherst and I have undertaken an investigation
of the alterations which occur in an amphibian limb rendered nerveless
and then amputated.

It has long been known that the presence of nerves is essential for re-
generation of an amphibian limb. By devising a suitable operative tech-

1 86 READINGS IN BIOLOGICAL SCIENCE

nique, it has been possible to render and to maintain the limb of a small sal-
amander totally nerveless and thus completely to prohibit regeneration.
One of the results of these experiments has been that, when a limb fails
to regenerate, because of the lack of innervation, antagonistic processes
set in which lead to regression. The situation can best be presented by
describing a single experiment,

A limb, rendered nerveless by previous operation, was amputated near
the wrist. Under these conditions no regeneration ensued, but on the
contrary, all of the skeletal elements, muscles, and other tissues of the wrist
went into regression and gradually disappeared. Then the regressive proc-
esses spread to the loM^er arm, and it, in turn, disappeared. Finally, the
tissues of the upper arm underwent the same changes. The processes in-
volved in these alterations are the opposite of growth and differentiation.
They are regression and dedifferentiation and represent, in a sense, em-
bryonic processes in reverse. It is as though a limb could say: "If I can't
regenerate, I insist on going into regression."

To complete the account of this experiment, it must also be stated that,
if nerves are permitted to grow back into a limb at any time during the
process of regression, then the tables are turned, and growth and differen-
tiation begin at once in the limb tissues. There seems to be a balance be-
tween growth and differentiation on the one hand, and regression and de-
differentiation on the other, and it appears that the nerves of the limb in
some manner control this balance.

I have now presented evidence from two different sources; first, from
the manner in which organs are established in early embryonic develop-
ment; second, from the manner in which tissues can be regenerated. These
two types of evidence have been chosen to illustrate the primary point,
namely, the cellular interaction is always in evidence and apparently of
paramount importance in the organization, differentiation, and growth
of structures.

In conclusion, it should be emphasized that, regardless of how far mod-
ern biologists have traveled beyond seventeenth century workers in im-
proving their acquaintance with problems of organization and growth,
a woeful lack of real understanding of the processes still remains. It is
evident, I believe, to all experimental embryologists that, underlying the
organization which they study in embryonic and regenerating tissues, is
a physico-chemical background. It is important to keep in mind at all
times that there is a physiological chemistry of the developing embryo,
as well as of the adult body. When we develop conceptions of cellular
interaction during embryonic development, we are dealing, I am con-
vinced, with problems of inter- and intra-cellular chemistry. And it seems
certain that investigations of cellular chemistry, as related to growth and
differentiation, offer a tremendous field for future work. It is a field, how-
ever, in which successful investigation will continue to require the devis-

EMBRYOLOGY 1 87

ing of new and ingenious techniques. As Professor Spemann once re-
marked, "we still stand in the presence of riddles, but not without hope of
solving them. And riddles with the hope of solution — what more can a
man of science desire?"

■>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<

IX

Heredity

IT is truly a long step from tall and dwarf peas to human inheritance but
the gap is being bridged slowly and painstakingly. Almost every stu-
dent is interested in the genetics of hair color, of right or left handedness, of
color blindness, of hair blazes (white areas in otherwise colored hair), of
disease, of twinning, of intelligence and of musical ability, among other
things. A comparatively few years ago the knowledge of human inherit-
ance was fragmentary, inconclusive and scattered. At the present time
it is none of these things although it should be borne in mind that many
years must elapse before we know as much about this field as we know
now about the fruit fly, the favorite of animal geneticists. Dr. Gates has
recently brought together most of our knowledge regarding human in-
heritance into a two volume work and while this is a notable contribution,
it reflects the opinion that we know only a mere fraction of the knowable.

With plants and the lower animals we are able to breed, cross-breed,
make chromosome preparations and use other intimate techniques, all of
which are impossible or difficult when using human material. Much can
be learned regarding the inheritance of human traits however by studying
pedigrees for some generations, particularly those where abnormalities
are in evidence or where the parents are of different racial groups.

Almost every layman has one or more misconceptions regarding hered-
ity. Some of the more common errors are, (i) blood will tell, or, he is
of blue blood (2) listening to good music or good literature will create
a taste for these things in the unborn child (3) peculiar markings on the
skin of the child are caused by the sight of some animal or other object
which frightened the mother (4) the blood of the mother passes into and
through the child in the uterus (5) syphilis and gonorrhea are inherited
(6) two pure white people can have a black child (7) two blue-eyed par-
ents can never have a brown-eyed child (8) that environment is not impor-
tant in the development of a person's heredity and (9) that a child always
resembles the more strong-willed of the two parents.

188

HEREDITY 1 89

GREGOR MENDEL AND HIS WORK *
HUGO ILTIS

It is 120 years since, in a small village on the northern border of what
was called Austria at that time, a boy was born in a farmer's house who
was destined to influence human thoughts and science. Germans, Czechs
and Poles had settled side by side in this part of the country, quarreling
sometimes, but rnixing their blood continually. During the Middle Ages
the Alongolic Tatars invaded Europe just there. Thus, the place had been
a melting pot of nations and races, and, like America, had brought up fi-
nally a splendid alloy. The father's name was Anton Mendel; the boy was
christened Johann. He grew up Hke other farmers' boys; he liked to help
his father with his fruit trees and bees and retained from these early ex-
periences his fondness for gardening and bee-keeping until his last years.
Since his parents, although not poor compared with the neighbors, had
no liquid resources, the young and gifted boy had to fight his way through
high school and junior college (Gymnasium). Finally he came to the con-
clusion, as he wrote in his autobiography, "That it has become impossible
for him to continue such strenuous exertions. It was incumbent on him to
enter a profession in which he would be spared perpetual anxiety about
a means of livelihood. His private circumstances determined his choice of
profession." So he entered as a novice the rich and beautiful monastery of
the Augustinians of Bruenn in 1843 and assumed the monastic name of
Gregor. Here he found the necessary means, leisure and good company.
Here during the period from 1843 to 1865 he grew to become the great
investigator whose name is known to every schoolboy to-day.

On a clear cold evening in February, 1865, several men were walking
through the streets of Bruenn towards the modern school, a big building
still new. One of these men, stocky and rather corpulent, friendly of coun-
tenance, with a high forehead and piercing blue eyes, wearing a tall hat,
a long black coat and trousers tucked in top boots, was carrying a manu-
script under his arm. This was Pater Gregor Mendel, a professor at the
modern school, and with his friends he was going to a meeting of the
Society of Natural Science where he was to read a paper on "Experiments
in Plant Hybridization." In the schoolroom, where the meeting was to be
held, about forty persons had gathered, many of them able or even out-
standing scientists. For about one hour Mendel read from his manuscript
an account of the results of his experiments in hybridization of the edible
pea, which had occupied him during the preceding eight years.

Mendel's predecessors failed in their experiments on heredity because
they directed their attention to the behavior of the type of the species

• Reprinted by permission of the Scientific Monthly, American Association for the
Advancement of Science, Copyright 1942.

190 READINGS IN BIOLOGICAL SCIENCE

or races as a whole, instead of contenting themselves with one or two clear-
cut characters. The new thing about Mendel's method was that he had
confined himself to studying the effects of hybridization upon single par-
ticular characters, and that he didn't take, as his predecessors had done,
only a summary view upon a whole generation of hybrids, but examined
each individual plant separately.

The experiments, the laws derived from these experiments, and the splen-
did explanation given to them by A4endel are to-day not only the base of
the modern science of genetics, but belong to the fundamentals of biology
taught to millions of students in all parts of the world.

Mendel had been since 1843 one of the brethren of the beautiful and
wealthy monastery of the Augustinians of Bruenn, at that time in Austria,
later in Czechoslovakia. His profession left him sufficient time, and the
large garden of the monastery provided space enough, for his plant hybrid-
izations. During the eight years from 1856 to 1864, he observed with a rare
patience and perseverance more than 10,000 specimens.

In hybridization the pollen from the male plant is dusted on the pistils
of the female plant through which it fertilizes the ovules.* Both the pollen
and the ovules in the pistils carry hereditary characters which may be alike
in the two parents or partly or entirely different. The peas used by Mendel
for hybridization differed in the simplest case only by one character or,
better still, by a pair of characters; for instance, by the color of the flowers,
which was red on one parental plant and white on the other; or by the shape
of the seeds, which were smooth in one case and wrinkled in the other; or
by the color of the cotyledons, which were yellow in one pea and green
in the other, etc. Mendel's experiments show in all cases the result that all
individuals of the first generation of hybrids, the Fi generation as it is called
to-day, are uniform in appearance, and that moreover only one of the two
parental characters, the stronger or the dominant one, is shown. That means,
for instance, that the red color of the flowers, the smooth shape of the seeds
or the yellow color of the cotyledons is in evidence while the other, or re-
cessive, character seems to have disappeared. From the behavior of the
hybrids of the F^ generation, Mendel derived the first of the experimental
laws, the so-called "Law of Uniformity," which is that all individuals of
the first hybrid generation are equal or uniform. The special kind of in-
heritance shown by the prevalence of the dominant characters in the first
hybrid generation is called alternative inheritance or the pea type of in-
heritance. In other instances, however, the hybrids show a mixture of the
parental characteristics. Thus, crossing between a red-flowered and a white-
flowered four o'clock (Mirabilis) gives a pink-flowered Fi generation.
This type of inheritance is called the intermediate, or Mirabilis, type of
inheritance.

• What is meant here is that the eggs in the ovules are fertilized bv the sperms in
the pollen grains. — Ed.

HEREDITY 1 9 1

Now, Mendel self-fertilized the hybrids of the first generation, dusting
the pistils of the flowers with their own pollen and obtained thus the second,
or Fo generation of hybrids. In this generation the recessive characters,
which had seemingly disappeared, but, which were really only covered in
the Fi generation, reappeared again and in a characteristic and constant pro-
portion. Among the Fg hybrids he found three red-flowered plants and one
white-flowered plant, or three smooth-seeded and one-wrinkled-seedcd
plant, or three plants with yellow cotyledons and one with green ones. In
general, the hybrids of the F2 generation showed a ratio of three dominant to
one recessive plants. Mendel derived from the behavior of the F^ generation
his second experimental law, the so-called "Law of Segregation." Of course,
the characteristic ratio of three dominant to one recessive may be expected
only if the numbers of individuals are large, the Mendelian laws being so-
called statistical laws or laws vaUd for large numbers only.

The third important experimental law Mendel discovered by crossing
two plants which distinguished themselves not only by one but by two or
more pairs of hereditary characters. He crossed, for instance, a pea plant
with smooth and yellow seeds with another having green and wrinkled
seeds. The first, or F^, generation of hybrids was of course uniform, show-
ing both smooth and yellow seeds, the dominant characters. Fi hybrids
were then self-fertilized and the second hybrid, or F^, generation was
yielded in large numbers, showing all possible combinations of the parental
characters in characteristic ratios and that there were nine smooth yellow to
three smooth green to three wrinkled yellow to one wrinkled green. From
these so-called polyhybrid crossings, Mendel derived the third and last of
his experimental laws, the "Law of Independent Assortment."

These experiments and observations Mendel reviewed in his lecture.
Mendel's hearers, who were personally attached to the lecturer as well as
appreciating him for his original observations in various fields of natural
science, listened with respect but also with astonishment to his account of
the invariable numerical ratios among the hybrids, unheard of in those days.
Mendel concluded his first lecture and announced a second one at the next
month's meeting and promised he would give them the theory he had elab-
orated in order to explain the behavior of the hybrids.

There was a goodly audience, once more, at the next month's meeting.
It must be admitted, however, that the attention of most of the hearers was
inclined to wander when the lecturer became engaged in a rather difficult
algebraical deduction. And probably not a soul among the audience really
understood what Mendel was driving at. His main idea was that the living
individual might be regarded as composed of distinct hereditary characters,
which are transmitted by distinct invisible hereditary factors — to-day we
call them genes. In the hybrid the different parental genes are combined.
But when the sex cells of the hybrids are formed the two parental genes
separate again, remaining quite unchanged and pure, each sex cell contain-

192 READINGS IN BIOLOGICAL SCIENCE

ing only one of the two genes of one pair. We call this fundamental theo-
retical law the "Law of the Purity of the Gametes." Through combination
of the different kinds of sex cells, which are produced by the hybrid, the
law of segregation and the law of independent assortment can be easily
explained.

Just as the chemist thinks of the most complicated compound as being
built from a relatively small number of invariable atoms, so Mendel re-
garded the species as a mosaic of genes, the atoms of living organisms. It was
no more nor less than an atomistic theory of the organic world which was
developed before the astonished audience. The minutes of the meeting in-
form us that there were neither questions nor discussions. The audience
dispersed and ceased to think about the matter — Mendel was disappointed
but not discouraged. In all his modesty he knew that by his discoveries a
new way into the unknown realm of science had been opened. "My time
will come," he said to his friend Niessl.

Mendel's paper was published in the proceedings of the society for 1866.
Mendel sent the separate prints to Carl Naegeli in Munich, one of the
outstanding biologists of those days, who occupied himself with experi-
ments on plant hybridization. A correspondence developed and letters and
views were exchanged between the two men. But even Naegeli didn't ap-
preciate the importance of Mendel's discovery. In not one of his books or
papers dealing with heredity did he even mention Mendel's name. So, the
man and the work were forgotten.

When Mendel died in 1884, hundreds of mourners, his pupils, who re-
membered their beloved teacher, and the poor, to whom he had been al-
ways kind, attended the funeral. But although hundreds realized that they
had lost a good friend, and other hundreds attended the funeral of a high
dignitary, not a single one of those present recognized that a great scientist
and investigator had passed away.

The story of the rediscovery and the sudden resurrection of Mendel's
work is a thrilling one. By a peculiar, but by no means an accidental, coin-
cidence three investigators in three different places in Europe, DeVries in
Amsterdam, Correns in Germany, Tschermak in Vienna, came almost at
the same time across Mendel's paper and recognized at once its great im-
portance.

Now the time has arrived for understanding, now "his time had come"
and to an extent far beyond anything of which Mendel had dreamed. The
little essay, published in the great volume of the Bruenn Society, has given
stimulus to all branches of biology. The progress of research since the be-
ginning of the century has built for Mendel a monument more durable and
more imposing than any monument of marble, because not only has "Men-
delism" become the name of a whole vast province of investigation, but all
living creatures which follow "Mendelian" laws in the hereditary transmis-
sion of their characters are said to "Mendelize."

HEREDITY 1 93

As illustrations, I will explain the practical consequences of Mendelian
research by two examples only. The Swede, Nilsson-Ehle, was one of the
first investigators who tried to use Mendelistic methods t» improve agricul-
tural plants. In the cold climate of Sweden some wheat varieties, like the
English square-hood wheat, were yielding well but were frozen easily.
Other varieties, like the Swedish country wheat, were winter-hard but
brought only a poor harvest. Nilsson-Ehle knew that in accordance with
the Mendelian law of independent assortment, the breeder is able to com-
bine the desired characters of two different parents, like the chemist who
combines the atoms to form various molecules or compounds. He crossed
the late-ripening, well-yielding, square-hood wheat with the early-ripen-
ing, winter-hard, but poor-yielding Swedish country wheat. The resulting
Fj generation, however, was very discouraging. It was uniform, in ac-
cordance with Alendel's first law, all individuals being late-ripe and poor-
yielding, thus combining the two undesirable dominant characters. In pre-
Mendelian times the breeder would have been discouraged and probably
would have discontinued his efforts. Not so Nilsson-Ehle, who knew that
the Fi generation is hybrid, showing only the dominant traits, and that the
independent assortment of all characters will appear only in the F^ genera-
tion. Self-fertilizing the Fi plants he obtained an F2 generation showing the
ratio of nine late-ripe poor-yielding to three late-ripe well-yielding, to three
early-ripe poor-yielding, to one early-ripe, well-yielding wheat plants.
The desired combination of the two recessive characters, early-ripe, well-
yielding, appeared only in the smallest ratio, one in sixteen — but because
recessives are always true-breeding, or as it is called "homozygous," Nilsson-
Ehle had only to isolate these plants and to destroy all others in order to ob-
tain a new true breeding early-ripe and well-yielding variety which after a
few years gave a crop large enough to be sold. Thus, by the work of the
Mendelist, Nilsson-Ehle, culture of wheat was made possible even in the
northern parts of Sweden and large amounts heretofore spent for imported
wheat could be saved.

Another instance shows the importance of Mendelism for the under-
standing of human inheritance. Very soon after the rediscovery of Mendel's
paper it became evident that the laws found by Mendel with his peas are
valid also for animals and for human beings. Of course, the study of the laws
of human heredity is limited and rendered more difficult by several obsta-
cles. We can't make experiments with human beings. The laws of Mendel
are statistical laws based upon large numbers of offspring, while the number
of children in human families is generally small. But in spite of these difficul-
ties it was found very soon that human characters are inherited in the same
manner as the characters of the pea. We know, for instance, that the dark
color of the iris of the eye is dominant, the light blue color recessive. I
remember a tragi-comic accident connected with this fact. At one of my
lecture tours in a small town in Czechoslovakia, I spoke about the heredity

194 READINGS IN BIOLOGICAL SCIENCE

of eye color in men and concluded that, while two dark-eyed parents may
be hybrids in regard to eye color and thus may have children both with
dark and blue eyes, the character blue-eyed, being recessive, is always pure.
Hence two blue-eved parents will have only blue-eyed children. A few
months later I learned that a divorce had taken place in that small town. I
was surprised and resolved to be very careful even with scientifically
proved statements in the future.

Even more important is the Mendelian analysis of hereditary diseases.
If we learn that the predisposition to a certain disease is inherited through a
dominant gene, as diabetes, for instance, then we know that all persons
carrying the gene will be sick. In this case all carriers can be easily recog-
nized. In the case of recessive diseases, feeblemindedness,* for instance, we
know that the recessive gene may be covered by the dominant gene for
health and that the person, seemingly healthy, may carry the disease and
transmit it to his children.

With every year the influence of Mendel's modest work became more
widespread. The theoretical explanation given by Mendel was based upon
the hypothesis of a mechanism for the distribution and combination of the
genes. To-day we know that exactly such a mechanism, as was seen by the
prophetic eye of Mendel, exists in the chromosome apparatus of the nucleus
of the cells. The development of research on chromosomes, from the obser-
vations of the chromosomes and their distribution by mitosis to the dis-
covery of the reduction of the number of chromosomes in building the sex
cells and finally to the audacious attempt to locate the single genes within
the chromosomes, is all a story, exciting as a novel and at the same time one
of the most grandiose chapters in the history of science. A tiny animal, the
fruit fly, Drosophila, was found to be the best object for genetical research.
The parallelism between the behavior of the chromosomes and the mecha-
nism of Mendelian inheritance was studied by hundreds of scientists, who
were trying to determine even the location of the different genes within
the different chromosomes and who started to devise so-called chromosome
maps.

Correns, Baur and Goldschmidt in Germany; Bateson and his school in
England; Devries in Holland; Nilsson-Ehle in Sweden, are the outstanding
geneticists of the first decade after 1900. But soon the picture changed. The
Carnegie Institution for Genetic Research in Long Island, under the leader-
ship of Davenport and later under Blakeslee, became one of the world's
centers of genetic research. In 19 10, T. H. Morgan, then at Columbia Uni-
versity, later at the California Institute of Technology, started his investi-
gations with the fruit fly, Drosophila, and founded the largest and most
active school of geneticists. The U.S. Department of Agriculture with its
network of experimental stations connected with more than a hundred agri-

• Not all feeblemindedness is inherited. Some cases are due to accidents or falls,
some to disease. — Edt

HEREDITY 1 95

cultural colleges became the most admirable organization for breeding of
better crops and farm animals based upon the principles of Mendelism. The
ideas developed by Mendel have found a new home here in the new world.
From 1905 to 19 10, 1 tried by lectures and by articles to renew the mem-
ory of Mendel in my home country and to explain the importance of A4en-
delism to the people. This was not always an easy task. Once I happened to
be standing beside two old citizens of Bruenn, who were chatting before a
picture of Mendel in a book-seller's window. "Who is that chap, Mendel,
they are always talking about now?" asked one of them. "Don't you know?"
replied the second, "it's the fellow who left the town of Bruenn an inherit-
ance!" In the brain of the worthy man the term "heredity" had no mean-
ing, but he understood well enough the sense of an inheritance or bequest.

^ ^ \r %% TT

HUMAN HERITAGE *
CARROLL LANE FENTON

Man has been inheriting for a million years, but his study of the process
dates back a scant half century. At various times during the former period
he has lost color from skin, eyes, and hair, has reduced the thickness of his
jaw, enlarged the capacity of his skull, and improved his brain. The half
century of study, however, has been largely devoted to clearing away
ancient treasures of misconception. Much of this still remains to be done
before human beings will admit the results of their own genes and chromo-
somes.

SIMPLE CHARACTERS MAY SEEM COMPLEX

Our most obvious inheritance is sex, controlled by two X chromosomes
in women but an X and a Y in man. Much simpler, however, is tanning, a
character developed when sunshine causes cells of the skin to pile up grains
of brown pigment just beneath the surface. Though such grains are not in-
herited, the power to make them is controlled by one dominant gene in each
of two paired chromosomes. The opposite is a recessive gene that seems
to do nothing; fair-skinned whites who get two of these sunburn endlessly
since their cells cannot make protective pigment.

If a fair-skinned recessive marries a person who is pure for tanning, their
children will get one gene of each kind, as any hybrid must. These children
are sure to tan, for one dominant gene can control the skin cells about as well
as two.

It is not clear how many characters exist which involve one pair of genes.
They undoubtedly include certain types of nearsightedness and clubfoot,

* From: Our Living World by Carroll Lane Fenton, copyright 1943 by Carroll
Lane Fenton, reprinted by permission of Doubleday & Company, Inc.

196 READINGS IN BIOLOGICAL SCIENCE

and at least one kind of dwarf appears as a simple Mendelian recessive.
Short fingers are produced by a dominant gene which also makes the whole
body short and stocky. Those of us who lack these defects are "pure" for
the normal recessive gene, which lets bones, especially those of the fingers,
develop to full length.

There seems no doubt that human albinism, like that of guinea pigs, is
a recessive character that appears only when a fertilized egg receives two
appropriate genes. One gene has no effect, for it is hidden by normal color-
ing of skin, eyes, and hair. Since albinos frequently do not marry, this re-
cessive character affects only about one person in ten thousand, or a total
of about thirteen thousand people in the entire United States. On the other
hand, a white patch of hair above the forehead is caused by one or two
dominant genes whose action seems to be regulated by age, and perhaps by
other factors. As a result, the character sometimes appears in small children,
but may be delayed until those who possess it are twenty or thirty years
old.

HAIR COLOR INVOLVES SEVERAL GENES

Since World War I we have heard a great deal about the Nordics, a
tall and supposedly superior race whose narrow heads are covered with
yellowish or straw-colored hair, which may be so pale as to look almost
white. Studies of heredity show that these blond hues depend upon one pair
of recessive genes which seemingly appeared as mutants and replaced
darker genes among folk who wandered into northern Europe some five
thousand years ago. These genes combined with other recessives control-
ling great height, fair skin that does not tan, and blue eyes.

After becoming racially distinct the Nordics spread far and wide through
western Europe, interbreeding with other peoples whom they met or con-
quered. Nordics grew darker and darker as they intermarried until their
racial traits survived only in shape of skull and other obscure characters.
But their genes for hair color did not vanish. Today the heredity of Eu-
ropean races is as mixed in this respect as it is in most other characters.

GENES MAY CO-OPERATE

Skin color, which differs from the power to make sun-tan pigment, is
complicated. When whites and pure negroes cross, their children are mu-
lattoes of intermediate type. This suggests partial dominance, but the chil-
dren of mulattoes are too varied for any 1:2:1 ratio. Indeed, they show
almost every conceivable gradation between the pale skin of one grand-
parent and the "black" one of the other.

These gradations have long puzzled scientists, especially of the United
States, where racial color is the subject of strong prejudice. After col-
lecting an enormous number of records these investigators conclude that
both whites and negroes have four pairs of contrasting genes that control

HEREDITY 1 97

skin color and behave with all the independence of those determining hue,
sleekness, and shagginess of coat in guinea pigs. Each "negro" gene con-
tributes a substantial quota of dark brown pigment, while each "white"
one produces a small amount of the same or a closely related substance.
When the two races cross, these genes combine equally in fertilized
eggs, so that mulattoes (the F^ generation) are intermediate in color.
Among offspring of the mulatto generation, however, there are bound to
be all sorts of combinations. Though the majority will have some black
and some white genes, a few will receive only one t)'pe and a few the other.

Such sorting explains why, after generations of racial crossing, there
still are some six hundred and fifty thousand pure negroes in the United
States — people without a trace of white color genes. It also lays an old
sob story, the one of a white girl who married a man who seemed to be
white, only to find that her first baby was "as black as coal." Since all
black genes are dominant, a person who seems white almost certainly is
SO; many persons whose color genes are as pure as those of their distant
white ancestors emerge every year from matings between part-negro
parents. Second, no person who is light enough to pass for a white can
carry enough genes for negroid color to make his children coal black or
even a healthy brown. Each gene produces its quota of pigment, and all
blacks are dominant.

Multiple series of genes controlling one character are very important in
man. Several pairs control human height, those for shortness being domi-
nant. As a result, two tall parents are likely to have tall children, though
some youngsters may violate this rule by receiving all genes for shortness
from both father and mother. Short parents, however, are likely to have
hidden genes for tallness which combine in their children.

SOME CHARACTERS ARE LINKED WITH SEX

Baldness is variously blamed upon disease, worry, hats, mental work, and
failure to anoint one's scalp with the latest brand of hair tonic. Instead
it is hereditary. Disease can only hurry it a little, while no tonic on earth
can prevent it if the right genes are present in a member of the proper sex.

There actually are three types of baldness, each a distinct character
with its own determiners. They are inherited like other genes, but their
power to act is controlled by secretions of the sex glands. In males these
secretions enable the genes to dominate. Ovarian secretions give the genes
so little chance to act that they almost seem to be recessives.

Common color blindness, which makes red and green look gray, is a
sex-linked character, linked to the X chromosome. A man who has received
one gene for this trait is color-blind, since his Y chromosome cannot con-
tribute the normal dominant. A woman, however, cannot become color-
blind unless she inherits the proper recessive genes from both her father
and her mother. Since this does not happen very often, few women show

198 READINGS IN BIOLOGICAL SCIENCfi

the defect. Yet many women carry the recessive gene and so transmit
color bHndness to at least half their sons.

Four sex-linked characters are known in man at least, and others may
be discovered. The most serious is haemophilia, or bleeding, a recessive
trait which somehow keeps the blood from clotting and so from sealing
wounds. A male bleeder who marries a perfectly normal wife cannot give
the defect to his children, nor can his sons pass it on. But his daughters,
though healthy throughout their own lives, will give one gene for bleed-
ing to half their sons.

The majority of man's characters are determined by genes in forty-six
other chromosomes, most of which are longer than the X, while all are
longer than the Y. Since chromosomes are chains of genes or gene capsules,
it becomes obvious that the bulk of human heredity depends on sorting,
pairing, and dominance that takes place without reference to sex.

SOME DISEASES ARE HEREDITARY

Most of US have been taught that disease is not inherited, since germs
cannot be transmitted by way of sperms and eggs. The latter statement
seems to be true, but the former is not. Mankind suffers from many
diseases caused by defects or faulty operation of human tissues and organs,
and of these an increasing number are known to be hereditary.

Bleeding of the kidneys is a dominant character, as are albumin in the
urine and a type of diabetes which causes excessive urination, wdth
equally excessive thirst. A form of anemia in which red blood cells become
sickle-shaped is a dominant character. Pernicious anemia also is inherited
in some families, though in others it seems to develop without any help
from genes.

Most familiar of all hereditary ailments are those grouped as allergy.
They include hay fever, asthma, hives, eczema, ivy poisoning, indigestion,
sick headaches, and other disorders, all caused by abnormal sensitivity
to foods, pollens, dust, smoke, medicines — even to heat and cold. One
authority says that asthma is a dominant trait, while another thinks it reces-
sive. Hay fever has been called a dominant that sometimes skips genera-
tions, but it also has been diagnosed as a straight dominant. One author
believes that each sort of allergy is the product of multiple dominant genes.
This would explain much variation, but the genes also seem to be con-
trolled by age and other factors. Thus a child was allergic to milk at
birth, but his mother developed sensitivity to wheat at the age of seventy-
two.

MENTAL DEFECTS ARE INHERITED

Mental qualities are even more problematic than those involved in
disease. Thanks to tedious but careful collection of data, we know that at
least two kinds of feeble-mindedness are hereditary. Thus one group of

HEREDITY 1 99

families in which both parents were defective produced 470 feeble-minded
children but only 6 who were normal. When only one parent was defec-
tive the proportion was 193. to 144. Other matings, as well as gradations
from idiots to morons, seems to show that the common type of feeble-
mindedness is controlled by a small set of multiple genes which also are
recessive.

Some mild types of epilepsy are allergic, being caused by such foods as
wheat; others are results of accidents or infections, and so cannot be in-
herited. But at least one tenth of all epilepsy is a distinct hereditary char-
acter, apparently being determined by multiple genes. Insanity, too, is a
hodgepodge; a variety of mental ailments that may or may not be related.
Some types are caused by accidents or genes, others by worry or extreme
unhappiness.

MENTAL INHERITANCE IS NOT SIMPLE

Family superiority is not traced to a single ancestor. One good parent
may produce a sporadic genius, but it takes two superior parents in gen-
eration after generation to keep a whole family notably above par. Con-
versely one bad ancestor is not enough to explain a defective family that
lasts and proliferates for generation after generation. We have no means
of knowing how much superior ability is helped by wealth and family
training; how effectively genius as well as mere normalcy can be swamped
by lack of money, broken homes or other demoralizing conditions.

>> s 't ^vv_.

THE STUDY OF HUMAN HEREDITY *
LAURENCE H. SNYDER

One of the most interesting biological developments of the past decade
has been the increasing realization of the importance of a knowledge of
human heredity in everyday life. Of course a certain respect has been paid
to heredity for a long time. The considerations given matters of birth,
family background and race testify to this fact. It is only recently, how-
ever, that we have had any exact knowledge of the transmission of factors
for diverse characteristics from generation to generation in human beings.

When the laws of heredity were discovered, tested and finally under-
stood in experimental plants and animals, it was inevitable that the atten-
tion of the geneticist should be drawn to the study of similar phenomena
in man. Gradually a body of knowledge on the genetics of man has been
built up, and, as always happens when sufficient basic facts are accumulated,
a series of practical applications has appeared.

* Reprinted by permission of the Scientific Monthly, American Association for the
Advancement or Science. Copyright 1940.

200 READINGS IN BIOLOGICAL SCIENCE

The first of these practical applications involves the physician, who may
find a knowledge of human heredity of value in diagnosis, especially early
dia^osis. Instances are on record in the medical literature involving
telangiectasis, polycythemia vera, spina bifida, orthoglycemic glycosuria,
multiple exostoses and others, where the proper diagnosis was not made
until the genetic background was taken into account.

A second practical appHcation of a knowledge of human heredit\' con-
sists in the outlining of preventive measures as a result of the examination
of the family histor\- of the patient. Tests for pre-clinical and laboratory
si?ns of a disease which has a genetic basis may be made in the relatives
of affected individuals, and proper preventive measures instituted where
indicated, before the condition becomes acute. This is being done by
many physicians in cases of pernicious anemia and its antecedent achlor-
hydria, in certain t\-pes of cancer, in hemolytic icterus, in hypertension,
in diabetes and in other cases where a genetic background is known.

A third practical application involves the lawyer. In recent years the
heredit\- of several substances (antigens) found in human red blood cells
has been carefully worked out. On the basis of this knowledge a man
falsely accused in a paternity- case may be cleared of the charge in cer-
tain instances.

As a fourth practical application of a knowledge of human heredity,
such knowledge may furnish the basis for advice on prospective mar-
riages. It is a common experience for the geneticist to be asked, "\^^hat
are the chances that this trait which is in my family background will ap-
pear in my children?" Sometimes it is a trait which the individual may
be desirous of having in his children, such as musical ability, intelligence
or red hair. At other times it may be an unwanted trait such as feeble-
mindedness, dementia praecox or deaf-mutism. When such questions are
asked, the geneticist must call on his knowledge of the trait concerned, the
possible genetic basis, the variabilit\' caused by different environments,
and from this composite picture reach some ans^ver. Frequently the
answer must be vamae and unsatisfactor\' because there is not enough
exact knowledge concerning the parts played by heredity and by en-
vironment in the production of the trait. Sometimes, however, where
such knowledge is at hand, valuable information may be given.

In a recent case a hemophilic patient with a tj'pical family history- of
the disease stated that his three daughters had not been told the nature of
his affliction, nor were they to be told, since he was ashamed of the
hereditary* blemish, as he considered it. Yet if these daughters marry, half
their sons will be expected to have hemophilia, a condition which proves
fatal in childhood in the majority of instances. Advance knowledge of the
chances of hemophilia in these families would at the ver\* least make it
possible for the mothers of sons to have every-thing in readiness for an
emergency transfusion at any time.

HEREDITi" 201

In another case, a girl blind from aniridia was amazed to leam, upon
consulting a eeneticist, that half of her children of both sexes would be
expected to have the abnormalirv*.

Fifth, a knowledge of human heredity- mav furnish the basis for ad-
\nce on prospective pregnancies. A voung man recentlv came to us for
adnce on a family histor\- of psoriasis, a skin disease. His father and grand-
father had the disease, as did several brothers and sisters and some nieces
and nephews. The young man's \^ ife was then pregnant. After becoming
pregnant she had learned of and seen the skin affliction of her husband's
relatives, which in the case of the girls and women, prevented the wearing
of sleeveless or low-necked gow ns. The voung wife became obsessed with
the idea that her child would have psoriasis. It preved on her mind to
such an extent that she was in danger of a nervous breakdown. Close ex-
amination of the familv histon* revealed that in this family the psoriasis
never appeared in a child unless one of the parents showed it. Onlv cer-
tain members of each familv showed it, although ail came in contact with
it. It was apparently behaving as a dominant character. Since the young
man in question was entirely free from the disease, it was possible to assure
his %\"ife that there was no danger of the child's inheriting: the condi-
tion.

SLxth, a generic knowledge can provide the necessan* information for
setting up eugenic and euthenic programs for the protection of societ\%
a problem in which every citizen should be able to take an intelligent part,
based upon experimental data, not on opinions, prejudices or the exag-
geration of the uncertainties.

Seventh and last, there is even' indication that with the discovery- of
more test factors of the sort exemplified by the blood agglutinogens, the
taste deficiencies and others which can be determined in early childhood,
we shall evenraaUy be able to predict in children the probabilit\- of the
occurrence of latent genetic diseases and abnormalities which may prove
to be closely linked in inheritance with such test factors.

The various kinds of hereditary behavior now known are so compli-
cated that their undersranding requires a certain amount of study. This
means that no one is justided in stating on his own responsibilirv that a
given trait in man is or is not conditioned by hereditar\- factors unless:
(i) He is thoroughly familiar with the known kinds of hereditary* be-
havior. (2) He is familiar with the character under discussion in all its
varving manifestations. (3) He has carefully investigated the character in
a scientific manner from a genetic standpoint. This often involves the
cooperation of geneticists, physicians, dentists and ps\'cholcgists.

As in other sciences any h\"pothesis of heredity, tiesides accounting for
the facts at hand, must stand the acid test of predictive value.

In order to apply a knowledge of heredirv" to practical problems in
human beings, certain fundamental conclusions must be srranted. Among

202 READINGS IN BIOLOGICAL SCIENCE

the conclusions taken for granted in the application of genetics to man
are the following:

(i) The biological basis for the dozen or more major kinds of hereditary be-
havior has been adequately established by experimentation in animals and plants.

(2) Man fulfills the biologic requirements for being subject to the same laws
of heredity as other organisms. (Among these requirements are sexual reproduc-
tion, a chromosome mechanism in which the chromosome number is reduced to
half in the sperms and eggs, physiologic processes similar to those of other organ-
isms, etc.)

(3) Hereditary factors are associated with the chromosomes. The evidence
for this now amounts to what is practically a complete proof.

(4) Mental traits have their basis in physico-chemical structure, and are sus-
ceptible to the same laws of heredity as other characters.

(5) Heredity and environment are cooperative in the production of any
finished character. One or the other influence may in certain circumstances ap-
pear neghgible, but the dual nature may always be demonstrated.

Let us turn for a few moments to the principles involved in the analysis
of human pedigrees.

The transmission of diverse hereditary factors from one generation to
the next involves a series of phenomena resulting finally in the visible
expression of characters in observable ratios. Most of the events in this
series develop in direct consequence of the laws of probabihty, the prob-
abilities being exactly determinable, thus making genetics more readily
amenable to mathematical analysis at the present time than any other
biological science. The included phenomena are as follows:

( 1 ) The segregation of factors into germ cells. Segregation involves the
separation of the two members of a pair of factors when germ cells are
formed so that one member of the pair goes to one of the resulting cells,
the other member to the other. Thus half the germ cells will normally
contain one factor of the pair, half the other. If the two members of the
pair of factors are different, so that the individual is said to be heterozygous
for that pair, the germ cells will be of two sorts, in equal numbers, in re-
gard to that pair of factors. Thus the probability that any given germ cell
of a heterozygous individual will contain a particular factor is one half.
However, abnormal segregation is known, in which certain factors do
not separate from each other, thus changing in these instances the prob-
ability of a given germ cell containing a particular factor.

(2) The assortmejit of factors during segregation. If an individual is
heterozygous for two or more pairs of factors, the factors segregate at
random if they are located on different pairs of chromosomes. Thus, in
regard to two pairs of factors, four kinds of germ cells will be produced in
equal numbers; in regard to three pairs of factors, eight kinds in equal
numbers, and so on. The chance of a given cell containing any two par-
ticular factors is therefore one fourth, any three particular factors, one
eighth, and so on. However, if the factors are located on the same pair of

HEREDITY 203

chromosomes (in which case they are said to be hnked) these probabilities
are altered, roughly in proportion to the relative distance bervveen the two
pairs of factors on the chromosomes. This distance determines how often
the factors may assort at all, the assortment approaching a random one
as the relative distance increases.

(3) The type of mating. When a population consists of various sorts of
individuals, there will be, of course, various sorts of mating possible. The
kinds and proportions of germ cells available for fertilization in any
particular mating will depend upon the genetic composition of the indi-
viduals involved in the mating. Mass matings in a population may be at
random or may be assortative (that is, certain types of mating tending to
occur to the exclusion of others). The probabilities for various kinds of
offspring depends among other things on the type of mating.

(4) The freqiievcies, in the population, of the genes concerned. The
two members of a pair of factors may be equally distributed in a popula-
tion, or one may be common and the other rare. The relative proportions
can be determined by the use of certain mathematical technics, and are
of importance wherever mass matings are concerned. Moreover, the fre-
quencies of the two members of a pair of factors may have reached an
equilibrium in the population, or they may not yet have done so. This too
may be deduced by special methods. Gene frequencies and equilibria be-
come of especial importance in the modern analysis of human pedigrees,
and will be further discussed later in this paper.

(5) The union of the germ cells. Fertilizations normally occur at ran-
dom, that is, any sperm has an opportunity equal to that of any other sperm
of fertilizing a particular tgo^; conversely, an tg^ has a probability equal
to that of any other available tg^ of being fertilized by a particular sperm.
Here again, however, exceptions occur, and cases of selective fertiliza-
tion are known. In such cases the probabilities are of course shifted.

(6) The ijiter action of factors, during development, zvith each other
and with the environment, residting in observable characters (phenotypes).
The characters finally produced and the proportions in which they are
produced will depend upon this and the preceding five phenomena. These
phenomena, serially taking place from generation to generation in specific
environments, give rise to the phenotypic expressions of characters in
definite ratios, from the analysis of which the laws of heredity have been
deduced.

The type of inheritance involved in any particular case, the number
of pairs of factors concerned, the mode of interaction and other relevant
conclusions have long been determined from the study of the phenotypic
ratios derived from specific types of mating. The classical genetic analyses
of animals and plants have necessitated the scrutiny of at least three gen-
erations (parents, F^ and Fg). Often additional generations (back-crosses,
F3, etc.) have been required. As long as such planned matings were readily

204 READINGS IN BIOLOGICAL SCIENCE

made, there was no necessity of searching for other types of analysis. With
the growing interest in the study of human inheritance, however, it was
increasingly realized that the classic methods could not serve in this
field. It became imperative to devise technics which would obviate the
necessity of knowing the precise genotypes of the parents, and which
would eliminate the need for the study of Y^ generations, back-crosses, etc.

Once the need was felt, the technics were not long in appearing. In gen-
eral, such technics are based primarily on derivations of the frequencies of
the genes in the population, the derivations being made from the fre-
quencies of observable phenotypes. On the basis of such gene frequencies,
the results of various mass matings may be predicted. The many methods
now available have originated in scattered laboratories. Contributions to
this field have been made in England by Fisher, Haldane, Hogben, Pen-
rose and others; in Germany by Bernstein, Lenz, Wellish and others; and
in America by Burks, Wiener, Wright, Cotterman, Rife, Snyder and
others. In the course of the development of methods for analyzing hu-
man inheritance the number of generations required for the analysis has
been reduced first to two, and finally to but one, while the requisite knowl-
edge of the precise genotypes of parents has been gradually reduced and
finally eliminated entirely.

It must not be thought that methods which lessen the required number
of generations available for study or which minimize precise genotypic
knowledge concerning parents are more desirable or more efficient than
the classic methods. It is merely that they must serve, as efficiently as pos-
sible, in a field in which test matings of precisely known genotypes are
not available.

It will be readily seen that no single method can answer all the questions
about the genetic bases of human characteristics. Various technics are con-
cerned in solving the problems as to the number of pairs of factors in-
volved, whether these factors are acting as dominant, recessive, blending,
sex-linked, sex-influenced, lethal or multiple factors, whether or not epi-
static relationships are present, and whether the factors are linked or in-
dependent. In predicting the proportions of different types of offspring
to be expected from various mass matings involving specific phenotypes,
complications arise in that a single phenotype often includes several dif-
ferent genotypes. In linkage studies a heterozygous genotype may include
both coupling and repulsion phases. Hence it is necessary to provide suit-
able statistical corrections and allowances, since in human data such com-
plications can hardly be avoided.

One of the points most frequently overlooked in the study of human
heredity is the matter of equilibrium in gene frequencies. It should now be
a commonplace that equilibrium in regard to the genotypes resulting from
a pair of autosomal factors exists when the homozygotes for one allele,

HEREDITY 205

the heterozygotes and the homozygotes for the other allele are in the
relative proportions p-, ipq and q\ respectively, where p and q are the
frequencies of the two alleles so that p -{- q= \ and p or ^ may have any
correlative value from o to i. Moreover, if anything occurs to displace the
equilibrium, a new equilibrium is reached after a single generation of ran-
dom mating. For sex-linked genes, epistatic interactions and other com-
plicated cases, equilibrium may be reached more slowly.

Self-evident as these propositions would appear to be, misunderstandings
of them and of their implications are all too frequent in discussions of hu-
man heredity. It is often said, for example, that a dominant character in-
creases in the general population at the expense of its recessive counter-
part until it stands in the ratio of 3:1. This statement has no basis in fact.
A recent text states that "albinism is due to a recessive factor, which ex-
plains zvhy it is so rare'' (italics mine). Another book, a treatise on handed-
ness, proclaims that "left-handedness occurs in 25 per cent, of the popu-
lation, which indicates that it is a Meiidelian recessive''' (italics mine). Each
of these statements shows a complete lack of understanding of the prin-
ciples of equilibrium.

A recessive character may be common or rare in a population, depend-
ing upon the relative abundance or scarcity of the hereditary factor de-
termining the character. Split hand, or "lobster claw," in which the hand
has only two large fingers, is due to a dominant factor, the normal comple-
ment of five fingers being due to its recessive allele, yet the recessive char-
acter is the common condition. Recessive characters may occur in various
populations in any frequency whatsoever from o to 100 per cent.

A recent prize-winning essay of the Eugenics Research Association con-
tains this remarkable pronouncement: "We are indeed lucky that the men-
tal disorders or psychoses are not dominant traits, or we would all be
insane by now, according to the laws of heredity." In a recent manuscript
on fingerprints which I was requested to read and criticize appeared the
following paragraph:

"Here we have a pattern (arches) which when crossed with another of
the same classification, produces its own kind, plus loops and whorls. This
reaction seemed to fit the requirements of a character heterozygous in
the parents and segregating in the 1:2:1 ratio. A check on the frequency of
arches in the general population quickly invalidated such a supposition,
however, for it was found that only about 5 per cent, of all patterns are
arches. Support for such an idea would require 25 per cent, loops, 50 per
cent, arches and 25 per cent, whorls. Some other explanation was there-
fore necessary." Here again we have examples of complete misunderstand-
ing of gene frequencies and equilibria.

I have belabored this point because the lack of attention paid to these
important considerations has greatly retarded the progress of the study of

206 READINGS IN BIOLOGICAL SCIENCE

human genetics. The necessity for a thorough understanding of the unique
problems involved in the genetics of man must be appreciated before
further progress can be made.

Among the problems facing the student of heredity in man, are the
following: to test the linkage relations of known human genes and to con-
struct maps of the human chromosomes by the use of the newly elaborated
paired-sib technic; to search actively for new genes in man; to further
elaborate the gene-frequency technics and other statistical methods for the
analysis of hereditary human factors; to determine the phenotypic fre-
quency of various traits in the population — in other words to take a census
of human traits; to establish and maintain twin chnics in qualified hospitals;
to study intensively the genetic and environmental influences interacting
in the production of "mental" characters; to obtain relevant facts about
the genetic and environmental backgrounds of socially significant traits
of all sorts; and finally to create an awareness of the importance of the
genetic viewpoint among physicians, social workers and the general public.

It is the hope of the student of human genetics that such a coopera-
tive line of research may eventually give rise to a social edifice, the founda-
tion of which is made up of substantiated facts about the development,
both from a genetic and an environment standpoint, of human character-
istics, and the superstructure of which is a tower of eugenic strength
which can be defended against any attack. To this end we bespeak the
cooperation of biologists, physicians, anthropologists, psychologists, soci-
ologists, legislators and social workers, and we ask the continued faith and
support of the pubUc.

WHAT WILL YOUR CHILD LOOK LIKE *
AMRAM SCHEINFELD

Given certain facts about you and your mate, we can make some fairly
accurate predictions as to w hat your children would look like.

Were we able to breed people as the geneticists breeds flies, we could
make many more predictions, with greater accuracy. By constant breed-
ing and inbreeding, geneticists have established strains of Drosophila,
ranged in rows of bottles in their laboratories, whose genes they know
almost as well as the chemist knows the make-up of his various com-
pounds. In fact, with almost the same precision that the chemists mix com-
pounds, the geneticist can "mix," by mating, two flies of any strains and
predict the types of off^spring that will result.

We cannot, of course, ever expect to do anything like that with human

• From You and Heredity. Copyright 1939, by Amram Scheinfeld. Published by
J. B. Lippincott Co.

HEREDITY 20J

beings. Pure strains of humans cannot be produced, like flies, by long in-
breeding of parents with children, brothers with sisters, etc. And where
flies have 300 offspring at a tfme and three generations to a month, human
couples do not average more than four offspring to a marriage, and only
three or four generations to a century.

So, genetically, in most respects we humans are unknown quantities.
With regard to your own genes, you can only make guesses, but in this
you will be helped considerably not merely by the characteristics which
you yourself reveal, but by those which appear in your parents, grand-
parents, brothers, sisters, and other close relatives. If you are dark-eyed,
the chances of your carrying a "hidden" blue-eye gene increase according
to the number of your relatives who have blue eyes, and their closeness
to you. Going further, if you marry a blue-eyed person and have a blue-
eyed child then you know definitely that you carry a blue-eye gene. On
the other hand, if two, three, four children in a row are all dark-eyed, the
presumption grows that you haven't a blue-eve gene.

Likewise, where both parents are dark-eyed, the appearance of a blue-
eyed baby is proof conclusive that both carry "hidden" blue-eye genes.
But if all the children are dark-eyed, it still might mean that only one of
the parents has no blue-eye gene.

These qualifications hold for every case where persons have some char-
acteristic due to a dominant gene (dark hair, curly or kinky hair, thick
lips, etc.) and wish to know what chance they have of carrying a "hid-
den" gene which might produce a different trait in their child.

But before we try to make any predictions these facts should be clear:

All forecasts as to the types of children people w'ill have are based on
averages determined by the laws of chance.

Wherever dominant and recessive genes are involved, it is like tossing
up coins with heads and tails. Toss up coins long enough, and the number
of heads and tails will come out even. So if you are carrying one dominant
and one recessive gene for any characteristic, were it possible for you to
have an unlimited number of children, you'd find that exactly half would
get the dominant and half the recessive gene.

With two parents involved, the results will be like those obtained in
"matching" coins. This, of course, conforms to Mendel's laws.

When we think in terms of the characteristic produced, the result in
"mixed" matings will be that the dominant characteristic (dark eyes, dark
hair, etc.) will show up three out of four times, the recessive only one in
four, as it requires a matching of the recessive genes.

Of course, where one parent carries two dominant genes, all the chil-
dren will show the dominant trait. Where one parent carries a dominant
and a recessive, and the other parent two recessives, half the children will
show the dominant trait, half the recessive.

But here is something else to bear in mind:

208 READINGS IN BIOLOGICAL SCIENCE

Wherever it is a question of a child's getting one gene or another, or
having such and such a characteristic, the odds for every child are exactly
the same.

Some gamblers might dispute this, but if you toss up a coin one time
and it comes up heads, that does not mean that the next time there is any
better chance of its coming up tails. There is the same fifty-fifty chance
on each toss-up. Even, if through an unusual "run," there would be ten
heads in succession, on the eleventh toss there would still be an exactly
even chance of either "heads" or "tails." (This applies to dice, roulette,
or any other game of chance. Many a gentleman has lost a fortune trying
to disprove it.)

So, let us say, if the odds are even for your having a blue-eyed child,
and your first one is brown-eyed, that does not mean that the odds are any
better that the next one will be blue-eyed. Even if four or five children in
a row are born with brown eyes, there is still that same fifty-fifty chance,
no more or no less, that the next child will have either brown or blue eyes.

But perhaps we need not have gone into all this. In the "boy or girl?"
question we say that there is a io6 to loo chance that the child will be a
boy. And yet, authorities like Eddie Cantor will tell you that the fact of
their having had two, three, or four girls in a row in no way bettered the
odds that the next one would not be a girl!

In "boy or girl?" however, it is a simple question of one or the other.
But in the case of features or form — in fact, of any detail in the body —
there are innumerable variations to contend with. If you and your mate
conform to the average, you will find that the forecasts here presented are
fairly dependable. Always, however, allow for exceptions and — whatever
happens, do not blame us (or the geneticists on whose studies these tables
are based) if the baby does not turn out the way the forecast indicated.

And now to Sir Oracle!

HOW TO USE THESE "CHILD FORECAST" TABLES

First: If this is to be your first child, find out as much as possible about what
genes you and your mate may be carrying by studying other members
of your families.* A4ake allowances for all characteristics influenced
by environment.

Second: If you have already had one or more children, also study each child for
additional clues as to your genes.

Third: Remember that no matter how many children you have had, or what
they look like, the odds that your child will receive a given character-
istic are exactly the same as if it had been the first.

Fourth: In consulting the tables, look for your own characteristic in either of
the "parents" columns. (They each apply equally to father or mother.)
If you and your mate are of different types, look first for the type most
pronounced — the darkest coloring, the most extreme hair form, etc.

• "Family" refers not only to parents, brothers, and sisters, but also to grandparents
and other close relatives.

HEREDITY

209

Fifth: Remember that these "forecasts" are based on averages in large num-
bers of matings. With just one child, that child might be the exception.

Sixth: Wherever age is a factor, make due allowances for its future effects or
changes that may be expected to take place.

E\TI-COLOR FORECAST

If eyes of one parent
are:

If eyes of other parent are:

Child's eyes will be:

BROWN (or black)
Type I. If all this
parent's family were
dark-eyed

Type 2. Where some
in this parent's
family have lighter
colored eyes (gray,
green, blue)

X NO MATTER WHAT COLOR

X BROWN, Type 2

X GRAY, GREEN, BLUE

Almost certainly dark

Probably brown, but possibly
some other color

Even chance brown or lighter
color (usually like that of
lighter-eyed parent)

GRAY or GREEN

X GRAY, GREEN, BLUE

Probably gray or green but
possibly blue, rarely brown

BLUE

X BLUE

Almost certainly blue.
(Rarely a darker shade, the
possibilities being less if
parent's eyes are light-blue)

ALBINO (Colorless)

X NORMAL-eyed parent of
any eye-color

X ALBINO

Normal, leaning to shade of
normal parent's eyes, unless
this parent carries hidden
"albino" gene, when i in 2
chance of child being albino
Definitely albino

width:

slant:

lashes:

EYE-SHAPE FORECAST

Where just one parent has wide eyes, child will be quite likely to have
them.

If one parent has slant eyes (but not of Chinese type) child will not be
likely to have them unless slant eyes also appear in the family of the
other parent. If, however, the parent's eyes are of the Chinese, or Mon-
golian type, there is great likelihood that child will have them.
Where just one parent has long lashes, child may be expected to have
them.

STATURE FORECAST

Both parents tall. The child on maturity will almost certainly be tall, or taller
than average.

Both parents short. The child will probably be inclined to shortness, but may
possibly be taller than the parents, and even very tall.

One parent tall, one short. The child will incline toward shorter parent.

BUILD

If both parents are slender, the child will be more likely to be like them than
if both parents are fleshy. But build is a highly variable characteristic dependent
on so many conditions and genes that it can hardly be predicted.

210

READINGS IN BIOLOGICAL SCIENCE

HAIR-COLOR FORECAST

If one parent's hair
color is:

Other parent's hair color:

Child's hair color will be:

DARK (brown or black)
Type I. Where all in
this parent's family had
dark hair

Type 2. Where there
are lighter shades
among others in
this parent's family

'

X No matter what
X DARK, Type 2

X RED
, X BLONDE

Almost certainly dark

Probably dark, possibly lighter

About equal chance (a) dark
or (b) red-brown or red, with
(c) slight possibility of blonde
Probably dark but possibly
blond, rarely red

RED

X RED
X BLOND

Most probably red, and occa-
sionally light-brown or blond
Even chances (a) red or (b)
light-brown or blond

BLOND

Type I. If medium
shade

Type 2. If flaxen or
white

X BLOND

X BLOND-fllaxen or white

Fairly certain blond, with
rarely brown. (Red possibly if
this shade is present in either
parent's family)

Certainly blond, but with shade
of darker parent apt to prevail

HAIR-FORM FORECAST

If one parent's hair is:

Other parent's hair:

Child's hair will be:

CURLY

Type I. If all in this
parent's family are
curly-haired

Type 2. If some wavy
or straight in this
parent's family

: Any form, except kinky
or wooly

x CURLY, Type 2

X WAVY
X STRAIGHT

Almost certainly curly

Probably curly, possibly
wavy or straight

Even chance (a) curly or
(b) possibly wavy or straight
Probably curly or wavy, possi-
bly straight

wavy

Type I. If no straight-
haired persons in this
parent's family
Type 2. If there are
some with straight hair
in this parent's family

X WAVY or STRAIGHT
X STRAIGHT

Almost certainly wavy, rarely
straight

Even chance wa\'y or straight.
(Rarely anything else).

straight

X STRAIGHT

Almost certainly straight

KINKY

Type I. Where all in
this parent's family are
kinky-haired

y

: No matter what hair
fonii

Almost certainly kinky

HEREDITY

211

If one parent's hair is:
(cont.)

Other parent's hair:

ico?it.)

Child's hair will be:
(cont.)

Type 2. Where other
hair forms appear in
this parent's family

X CURLY, or WAVY
X STRAIGHT

Even chance (a) kinky or (b)
curly or wavy; rarely straight

Almost like above, greater pos-
sibility of being straight

wooly: While fairly frequent among Negroes, it is rare among Whites. Where,
however, it appears in even one parent half the children will have wooly hair.

FORECAST OF FACIAL DETAILS

NOSE

(Nose-shape is not inherited as a unit. Different characteristics of the nose
may be inherited separately, one detail sometimes from one parent, another
from the other parent. Environmental factors also have great influence.)

Generally: Where both parents have about the same type of nose, a child on
maturity will have a similar type.

But: If just one parent has a broad nose, a long nose, or a prominent nose, and
the other parent a moderate nose, the child's nose will very likely be of the
most extreme type (on maturity).

Where any nose peculiarit)'^ has appeared for several generations in either
parent's family there is an even chance that the child will inherit it.

EARS

Large. If just one parent has large ears, the child will very likely have similar
ears.

Affixed lobes. Where only one parent has affixed lobes or absence of lobes,
and the condition does not appear in the other parent's family, there is little
likelihood that the child will have such ears.

MOUTH

Lips. If just one parent has thick lips, the child will probably have them.
If just one parent has a heavy or protruding underlip (Hapsburg type) the
child has an even chance of inheriting it.

>■>■><<-<•

WHAT BLOOD TELLS

*

DAVID C. RIFE

A few years ago, in a large city hospital, the nurses mixed the identifica-
tion tags of two new born babies. Both sets of parents, the Smiths and
the Browns, claimed one of the babies while no one wanted the other. Vari-
ous tests were made in order to determine which baby belonged to the
Smiths and which to the Browns. Foot prints were compared, as well as
head shape and general appearance, but they gave no conclusive evidence.
Finally someone suggested a comparison of the blood groups of the babies
with those of the parents.

• Reprinted from The Dice of Destiny by David C. Rife with the permission of
Long's College Book Co. Copyright 1945.

2 12 READINGS IN BIOLOGICAL SCIENCE

It was found that one baby belonged to group O and the other to group

A. Both of the Smiths were of group O, while one of the Browns was O
and the other A. This proved conclusively that the baby of group A be-
longed to the Browns, as two O parents can produce only children of
group O.

Your blood group depends upon the presence or absence of two sub-
stances in your blood stream, known as antigens. The four blood groups,
AB, A, B, and O depend upon the presence of both, or of either alone, or
of neither of these antigens. The antigens are known as A and B. People
of group O possess neither antigen, those of groups A and B possess the
corresponding antigens, while those of group AB possess both antigens.

An individual's blood group is determined by heredity. It is estabhshed
within the individual months before birth, and cannot be altered by any
known environmental circumstance. Age, disease, and climate do not
change one's blood group. Even transfusion from one of another group
does not permanently alter one's group.

Three different genes are responsible for the four blood groups. One,
which we shall represent by A, results in the formation of antigen A,
Another, which we shall represent by B, results in the formation of antigen

B. The third gene, which we shall represent by O, produces no antigen.
Two of these genes, possibly A and B, mutated from the original one,

which would have been O. As all three genes are of the same origin only
two of them can be present within any individual. In other words, they
occur in pairs, as do the genes determining whether or not one can taste
P.T.C. (a certain chemical.) Their behavior is a Httle less simple, however,
because three instead of two different kinds of genes are involved. The
blood groups are determined by three alleles, A, B, and O whereas only
two are involved in the determination of whether or not you can taste
P.T.C.

Genes A and B are each dominant to gene O. But A and B show no
dominance to each other. People of group AB are heterozygous for genes
A and B, and each antigen is present to as marked degrees as in those pos-
sessing only one of the antigens. People of groups A and B may be either
homozygous, or heterozygous for O. As O is recessive, people of blood
group O are always homozygous.

Knowledge of the mode of inheritance of the blood groups is now
widely recognized as of great practical importance in cases of disputed
parentage, as well as in other types of identification, such as the baby mixup
we have cited. If we know the blood group of the mother and child, we
can tell to what group or groups the father had to belong. This is, of
course, negative evidence in that it tells only to what groups the father
had to belong, and clears a man who does not belong to those groups. If
the accused man happens to belong to one of the possible groups of the
father, we have no evidence one way or the other as to his guilt.

HEREDITY 2 I 3

Blood is always typed, if possible, before a transfusion. People of group
O have two substances in their blood stream known as antibodies a and b.
These react with antigens A- and B in such a manner as to cause clumping
of the red blood cells. Such a reaction is called agglutination. If a per-
son of group O should receive blood from any one of the other three
blood groups, antigen-antibody reactions would result in agglutination
of the red cells taken in. Likewise those of group A cannot donate to those
of group B and those of group B cannot donate to those of group A.
Those of group AB cannot donate to those of any other group. Stored
plasma can be given to those of any group as the red cells, which contain
the antigens, have been removed.

Different races show significant variations in the percentages of the four
blood groups (see table below). North American whites show approxi-
mately the same percentages as do northern Europeans. Generally speak-
ing, Asiatics show higher percentages of B and less of A than do Europeans.
Most American Indians appear to have very low frequencies of both
antigens. These variations are of great interest to physical anthropologists,
as they serve to suggest common origins and migrations in the evolution
of human populations.

Distribution of the Blood Groups Among Various Racial Groups. (After Weiner)

Racial Group

North American Whites

Peru Indians

Navajo Indians

Arabs , . .

Chinese ,

Natives of India

Negroes, West Africa . .

Negroes, U.S.A

Russians

Spanish

Swedes

0

%

A
%

B

%

AB

%

45.0

41.0

1 0.0

4.0

lOO.O

0.0

0.0

0.0

70.8

28.6

0.3

0.1

34.1

30.8

28.9

6.2

30.0

25.0

35.0

lO.O

337

24.6

3^-5

9.2

52-3

21.5

23.0

3-2

47 -o

28.0

20.0

5.0

32.0

38.5

23.0

6.5

43.6

51.2

3-9

I.I

37-9

46.7

10.3

5-1

The anthropoid apes have four blood groups, corresponding to those
in man. This suggests that the blood group mutations may have occurred
among the common ancestors of such apes and man. Different blood
antigens have been shown to be present in many mammals. In domesti-
cated rabbits, strangely enough, there are four blood groups whose heredi-
tary behavior corresponds exactly to the blood groups in man and apes.
Recent work shows a tremendous variation in cattle in regard to blood
antigens and their inheritance.

Two other blood antigens, known as M and N, occur in man quite in-
dependently of the blood group antigens. The antibodies for the M and
N antigens do not occur in man, but are prepared from the blood of

2 14 READINGS IN BIOLOGICAL SCIENCE

rabbits. The M and N blood types are of no consequence in transfusions.
They are used in the same manner as the blood group antigens in cases
of disputed parentage. Only two genes are involved in the M and N types.
One results in the formation of antigen M and the other in the formation
of antigen N. Like the blood group antigens, M and N show no dominance
with respect to each other. Unlike the blood groups, however, everyone
possesses two genes for the production of antigens. No individuals have
ever been found corresponding to blood group O, that is, lacking both
M and N antigens. People are of three genotypes; homozygous for antigen
M, homozygous for antigen N, and heterozygous for antigens M and N.
There is only one genotype for each of the three phenotypes. The table
below illustrates how both the blood groups and the M and N types may
be of value in cases of disputed parentage.

Examples of How the Blood Groups and Types may be Used in the Determination

OF Paternity

mother

CHILD

FATHER

MUST BE

Group

Type

Group

Type

Group

Type

O

M

O

M

0,A,B

M,MN

O

M

A

MN

A,AB

N.MN

o

N

B

MN

B,AB

M,AIN

A

MN

A

M

M,MN

B

MN

A

MN

A,AB

AB

MN

A

MN

Lines in columns 5 and 6 signify that the father could belong to any group or type.

As the M and N types are independent of the blood groups, it is pos-
sible by testing for both blood reactions to greatly increase the efficiency
of tests for disputed paternity. Twelve combinations of blood groups and
types are possible within individuals.

Significant racial variations are manifested in the occurrence of the M
and N types although they are less marked than in the blood groups (see
table below). The knowledge and techniques of the M and N types are
more recent than for the blood groups, and the available data are cor-
respondingly less extensive.

No other hereditary traits in man have as yet been discovered which
are as universally satisfactory to work with as are the blood groups and
types. They are established before birth and remain constant throughout
hfe. The tests for them are objective and clearcut, much more so than
for P.T.C. Moreover they show considerable variability and none of the
genes involved are rare.

Boyd recently tested the blood groups of over one hundred Egyptian
mummies. His findings indicate that the distribution of the blood groups
among the ancient Egyptians five thousand years ago was apparently
about the same as among modern Egyptians.

HEREDITY

215

Distributions of the M and N Blood Types in Various Racial Groups

(After VVeiner)

Racial Group

M

N

MN

North American Whites

Indians, U.S.A.

Australian aborigines

Ainu ,

Chinese ,

Danes

Egyptians

Eskimos

Germans

Negroes (New York) . .
Russians

29-0%
60.0
3.0
17.8

33-2
29.1

28.3

66.2

30.2

28.4

32.2

21.0%

4-9
67.4

31.94
18.2
21.4
23.1
2.9
19.7
21.0
21.2

50.0%

35-1
29.6
50.2
48.6

49-5
48.6
31.0
50.1
49.6
46.6

In recent years several other blood antigens have been discovered. All
of these appear to be inherited as simple dominants. Of especial interest
is the Rh antigen, which has recently been found to be of considerable im-
portance. If a developing embryo develops the Rh antigen, and the mother
lacks the antigen, she may develop the corresponding antibody. This may
diffuse through the placenta into the blood stream of the embryo, sometimes
with fatal results. In such an event the father must have been either homo-
zygous or heterozygous for the Rh factor. Approximately 85% of North
American whites possess the Rh antigen. Considerably higher percentages
are found among Indians, Chinese and American Negroes.

Knowledge of the inheritance of the blood antigens is not only of value
in cases of disputed parentage, but has also thrown considerable light on
racial variations and origins. And there is every indication that in the
future blood will tell more and more.

■>>><<<■

THE INHERITANCE OF DISEASE *
PAUL A. LEWIsf

Considered in a broad and untechnical sense, an individual's inheritance
means all those attributes both actual and potential received at or before
birth from the parents. This usage has of late years been given up by scien-
tific men in favor of a more circumscribed one, namely, that the in-
heritance consists of those attributes actual and potential acquired at the
moment of conception due to the intrinsic properties of the germ cells.

* Reprinted from Human Biology and Racial Welfare, edited by Edmund V.
Cowdry with the permission of Paul B. Hoeber, Inc. Copyright 1930, by Paul B. Hoe-
ber, Inc.

t Died of yellow fever at Bahia, Brazil, on June 30, 1929, while investigating the cause
of the disease. — Ed.

2l6 READINGS IN BIOLOGICAL SCIENCE

This distinction is of real importance to a clear understanding of the
relations between inheritance and disease. The biblical dictum that the
sins of the fathers are visited on their offspring for generations has been
considered in recent times to be particularly appUcable to one contagious
disease, syphilis. Children suffering severely from this disease are fre-
quently brought into the world at or before the normal birth period. It
is now considered a certainty that in these cases the child is infected at some
point in its fetal life definitely subsequent to its conception. In any event,
it is infected with an extraneous microorganism carried by one or both
parents. On the other hand, it is known, by animal experiment at least, that
the offspring of an immune mother are apt to show more than the usual
resistance to certain diseases for some time after birth. This, it is recognized,
is due to the transfer of protective substances in a passive way from the
mother either through the membranes separating the fetal from the ma-
ternal circulation hi utero or in the milk during the first days of life. Under
the older definition, these instances would be considered to be cases of
inherited disease or inherited immunity respectively, but are not so re-
garded under the more rigid definition of inheritance.

Even the circumscribed definition of inheritance as here given may not
be wholly accurate. There is much reason to believe that injury to the
parents by long-continued exposure to certain poisons such as alcohol or
lead may affect the offspring unfavorably and it is also probable on the
basis of animal experiments that exposure of the parents to roentgen rays
may, under certain conditions, result in altered if not abnormal descendants.
In so far as these influences may be manifest through action on the male
parent it can only be by some affection of the germ cell itself and it would
probably be impossible to frame an entirely adequate definition of in-
heritance in which these preconceptual influences are justly accounted for.
These may for purposes of definition be recognized and passed over.

The outstanding achievement of genetic study has been to show that as
a broad biological principle the most diverse general characters can be
analyzed into an infinity, almost, of combinations of less inclusive specific
unit characters which are inherited independently in principle. Actually
they are inherited either separately or in small and apparently "chance
constituted" linkage groups. There is every reason to suppose that the
mechanism of human inheritance completely conforms to this "A4en-
delian" scheme. That it does so has been demonstrated for a considerable
number of characteristics.

"Disease" is a general concept sufficiently defined for many purposes
as any condition of body or mind which departs from "perfect health."
A precise definition which shall be more critical than this and cover all
the manifestations of morbid processes is extremely difficult to formulate.
It is well to recognize this clearly at this point because there is a very
general assumption or belief that people are quite definitely divided into

I

HEREDITY 2 1 7

two classes, those who are born healthy and of sound constitution, and
those who come into the world otherwise. All such conceptions, it should
be clearly seen, are in fact untrue. A healthy person is one who has no
gross anatomical or physiological defects and enough normal general
health to get on with.

In fact the great progress made by medicine as an art and a science from
the dawn of civilization down to today is based on the steadily developed
recognition of the infinite complexity and relative nature of the phe-
nomena included in the general term "disease." And especially the re-
markable progress of the last two centuries is due to the extension of this
general principle into the study of particular diseases. Even the most simple
(apparently) of abnormal conditions is found on closer scrutiny to be of
the utmost complexity. A common boil is spoken of in scientific terms as
a simple inflammation and even moderately informed lay people know it
as the result of some "germ" getting into an insignificant scratch. In
reality the processes are complex far beyond our present understanding.
Essentially the same process in the lungs gives rise to the acute and often
fatal disease, pneumonia. But when pneumonia is examined, even in the
light of our present imperfect knowledge, attention being paid to the
particular germ giving rise to the infection, and the qualities and distri-
bution of the reaction material in the lungs, it is easy to discriminate more
than ten essentially independent kinds of extensive and severe inflamma-
tions of the lungs, which would be properly designated by the practicing
physician as pneumonia.

It will readily be understood, therefore, that when an attempt is made
to deal with the points of contact and mutual influence of two such all-
inclusive and infinitely complex assemblies of phenomena as those of in-
heritance and of disease, it cannot profitably be done solely with reference
to general principles. Nor would it be useful in this place to attempt a
very detailed account of what is known. The plan adopted is to try to
give an outline of principles where these are discernible and to illustrate
them vv^ith such concrete examples as may be most informing to the general
reader.

INFECTIOUS DISEASES

As previously pointed out there is in the rigid sense no such thing as the
positive inheritance of an infectious disease. This lies in the nature of the
case since the impelling incident in such a disease is the entry of an agency:
germ, bacterium or protozoan, from the environment. None the less, the
inheritance is of very vital significance and within certain limits absolutely
controls the prevalence of these diseases. This is true when we approach
the question from a wide biological viewpoint, regarding species lines. It
then becomes in truth a matter of common knowledge. It is probably
quite correct to state that each distinct species of animal or plant has

2l8 READINGS IN BIOLOGICAL SCIENCE

certain diseases which are peculiar to it, and neither naturally nor arti-
ficially transmissible to any other species. Influenza and malaria are fair
examples of such diseases of human beings. Asiatic cholera is another.
Many cases may be cited in which species lines are not rigidly respected
and are yet very influential. Smallpox is such a human disease. It may
spread to milch cattle under suitable conditions, but in them produces a
modified type of disease similar to the naturally occurring cowpox. Rabies
is widely disseminated among the domestic animals, is very frequently
transmitted to man but is not known as a disease of birds.

The questions at issue really become debatable when we consider the re-
lation of the racial, familial or individual inheritances within the species.
It is now clear that here the lines are much less rigid. There are very cer-
tain instances, particularly among plants, where families or strains within
the race are quite immune to a particular disease from which the race as a
whole suffers most severely. The rust-resistant varieties of wheat and
asparagus are familiar cases. Similar cases can be made out among animals.
There is no certain instance of an infectious disease affecting one or more
race of the human species and leaving another untouched. There are a
number of instances when it seems that certain races are less susceptible
than others to particular diseases but even here it is impossible in the
present state of knowledge to be sure of the significance of the cases. Racial
habits as to diet, for example, and the continued state of contact with the
disease are apparently influential factors about which there is as yet in-
sufficient information.

When we turn from the race to the individual, vision apparently be-
comes clearer, for there can be no doubt that with reference to most in-
fectious diseases there are wide individual variations in resistance.

But if we go back for a moment to an earlier period we find a fixed and
universal opinion that certain infectious diseases follow family lines to
a considerable extent. This is not true of measles or smallpox. It seems con-
spicuously true of tuberculosis. Most of us can doubtless call to mind
families in w^iich severe illnesses and deaths from tuberculosis have been
common, and other families in which they have been rare. Large groups of
family histories have been collected and submitted to the best available
mathematical analysis and these have also given evidence of some differ-
ence in the inheritance. But it is also known that under conditions of uni-
versal exposure as in crowded cities, practically all individuals have some
tuberculosis at some time or other. The disease is one which often lasts in
individual cases for years or even through a long lifetime. There is ob-
viously unusual opportunity for infection to follow a family in which it
is established. In the face of such considerations on the contrary side, it
cannot be maintained that such studies of human family histories as have
been made absolutely decide the matter. They do give evidence, however,
that familial differences in resistance exist.

Heredity 2 1 9

The studies of human material from the pathological standpoint show,
as has been said, that most individuals become infected with tuberculosis
at one time or another and it may therefore be concluded that neither in
kind nor degree are the inherited factors capable of preventing infection.
They must, therefore, be exerted on the progress of the disease after the
body is invaded by Bacilhis tuberculosis * The direct evidence at present
available from human sources does not carry us beyond this point.

In the guinea pig it is found that there are inherited factors which in-
fluence the quantity of antibodies (antitoxic substances) which are pro-
duced in response to a given stimulus. There are other inherited factors
which influence the severity and precise quality of the ulceration which
the tubercle bacillus and some other irritating agents produce in the skin,
and in the character of the tuberculous inflammation in the lymphatic
vessels and glands. There is also an indication of another group of sepa-
rately inherited factors affecting the nature of the reaction to dietary de-
ficiencies.

Granted that there are inheritable factors influencing the character of
tuberculosis in the individual, any clue as to their dominant or recessive
quality is a matter of great interest. Unfortunately the human material
lacks the precision of detail necessary for an answer to such a question.
The guinea-pig material suggests that where all of the characters favor-
able to resistance are combined in a family it presents a dominant com-
bination. The first generation crossbreds are as resistant as the most re-
sistant family. In the actual observations they somewhat surpass this mark,
indicating the operation of those forces which make for heterosis or hybrid
vigor. Where crosses are made between families of less than the maximum
resistance the result varies. Some crosses produce offspring as resistant as
the better family, another produces an intermediate resistance. In gen-
eral, dominance of resistance prevails but it is imperfect.

With the coincident and tremendous improvement in hygienic condi-
tions and nutritional well-being in Europe and especially in America,
tuberculosis and the minor infections referred to have a greatly diminished
prevalence.

A generation ago the general conception of the fundamental nature of
inheritance was that it was a blending or fusing of the parental character-
istics, stronger characters being diluted by weaker. The cases which such
a blend did not explain were regarded as unaccountable exceptions. Then
the work of Mendel was revived and it was seen that when inherited
qualities were sufficiently analyzed into their component parts the blended
was rather the exceptional occurrence. But instances of blending inherit-
ance could not be gotten over or disregarded and it seemed to some
students that there must be two principal forms of inheritance. These
views have been quite completely harmonized by further study. In the

• Now known as Mycobacterium tuberculosis. — Ed.

i20 READINGS IN BIOLOGICAL SCIENCE

obvious Mendelian case a particular character, which to familiar scrutiny
is simple and definite, is controlled by the presence or absence of a single
inheritable unit known as the gene. Color in animals, eye color in man,
taliness or dwarfness in the garden pea are such characters and their study
clearly defined the Mendelian principle in inheritance. Skin color in man
if albinism is contrasted with the presence of any pigment is similarly con-
trolled.

But skin color among the pigmented of the human species, taliness or
shortness in the human race (excepting particular types of dwarfism),
the weight or ear length in rabbits and innumerable other conditions are
at first sight not so controlled. The result of a cross between individuals
of widely diff^erent character is usually a "blended" or intermediate state
in the ofl^spring. While it was difficult at first, as has been said, to fit these
cases to the Mendelian hypothesis it is now apparent that blended in-
heritance means that the character as expressed in the individual is the re-
sultant of the combined and overlapping functional expression of the
action of two or more genes. It now is the consensus of opinion among stu-
dents of heredity that this is the true significance of blended inheritance.
Mendelian principles are as strictly appUcable as in the more obvious in-
stances but more than one, often many, unit characters are involved in the
make-up of the observable quality. This is evidently the condition under-
lying the inherited factors in resistance to tuberculosis.

CANCER AND OTHER MALIGNANT TUMORS

In general the state of our knowledge of the factors underlying the
occurrence of malignant tumors is not dissimlar to that with regard to
tuberculosis. The evidence from human sources is of about the same order
but less significant on the whole. Tumors have been alleged to frequent
occasionally certain families while others remain quite untouched. In the
mass there is the sporadic, occasional appearance of a tumor case in most
family histories. Cancer is not believed by most authorities to be an in-
fectious disease although the fact that it can apparently be initiated in
man and animals by chronic irritation with various substances, even by
various parasites, creates many resemblances between tumors and infec-
tions. If the tum.ors classified as sarcomata are included there are cases
in which the utmost consideration of detail fails to reveal any precise
reason why they should not be accepted as infections; and yet because
of that fact that these appearances suggesting infection are the exception
rather than the rule, most scientists hold in reserve the thought that even
in these cases it is more than possible that some other explanation will be
found, that eventually it will appear that all the true malignant tumors
(including most forms now classed as such) will be found to originate
in causes resident within the body.

Tumors bear a certain resemblance to infection in that those which orig-

HEREDITY 2 2 I

inate in animals are often transferable to other animals of the same species
by a succession of transplantations of the tumor tissue, or in some instances
by extracts of this tissue containing no intact body cells. The conditions
governing the transplantation are such as to make the influence of in-
heritance very apparent. These tumors are never transferable outside the
species of animal in which they originate. For instance, mouse tumors can
only be propagated in mice. Within the species they are transferable with
great difficulty when at all, from one race to another.

This variation in resistance has been the subject of thorough genetic
experimentation and analysis in certain instances. When the Japanese
waltzing mouse and the common tame mouse were compared it was found
that their differences with respect to tumor transplantability across the
race hne must be under the influence of at least twelve separately inherited
unit characters. The reasoning applied to the case of tuberculosis in the
preceding paragraphs holds here. We should expect the familial evidence
for inheritability in the human race to appear only very occasionally.
Even less is known about the fundamental nature of the inherited char-
acters in tumors than in tuberculosis.

There is also a great deal of evidence that the incidence of spontaneous
malignant tumors in animals is quite dependent on the inheritance.

DISEASES BASED ON ABNORMAL SENSITIZATION

A number of disease conditions, all troublesome and some very serious,
asthma, hay fever, and various "idiosyncrasies" against particular articles
of food or particular drugs have been found to have certain features in
common. They are alike in that they are all unusual reactions to partic-
ular substances found in the environment which do not affect most people
in any harmful way. Of those suffering from the condition some react
only to a single substance, others are affected by many substances. The
diseases are so common as to be familiar to most people and place need
not be given here to any detailed description of them. The simplest, and
in many ways most characteristic, is urticaria, or hives. Most people suffer
at one time or another from this trouble. Some people always have it as a
consequence of eating a particular food, e. g. strawberries, eggs. The skin
becomes blotched and irregular wheals are raised above the general level
of the skin surface by reason of the fact that the skin in these areas is
swollen. The sweUing is due to fluid in these areas having left the blood
vessels and stagnated in the tissue spaces. In asthma the same general proc-
ess occurs but the area affected by the swelling is the smaller air tubes
in the lungs and these are partly closed, making breathing difficult. In hay
fever it is the mucous membranes of the eyes and nose which are affected.

Inquiry has disclosed a well-marked familial influence in these condi-
tions. They are in some measure inherited. The inheritance seems to be
based on recessive characters in the Mendelian sense. There is a certain

222 READINGS IN BIOLOGICAL SCIENCE

difficulty in this interpretation, however, in that not all the offspring of
matings with both parents diseased are afflicted. This is susceptible of
alternative explanations. It may be that the inheritance is dependent on
multiple factors in which case the line between dominant and recessive is
not necessarily clean cut. Some characters may be dominant, others re-
cessive and the actual behavior of the individual is the result of a kind of
balance.

Another possible explanation is that the disease itself is not inherited but
only the liability to contract it. That is to say, an individual potentially sen-
sitive by reason of inheritance may escape the influence of the environmen-
tal factor and never reveal his latent tendencies.

DISORDERS AND DEFECTS OF THE CENTRAL
NERVOUSSYSTEM

Popular interest in inheritance, alike of normal and abnormal qualities,
naturally reaches its highest when the nervous system is considered. From
the medical point of view we are here dealing with the diseases referable
to a single organ. Gross defects of development occur and are likely to
be lethal before their general effects on function can become manifest.
Finer defects in structure may well be common but may escape recogni-
tion. The brain and spinal cord are affected in the course of infectious dis-
eases which are to be considered as general infections, and also are the
seat of infections primary in or affecting, chiefly themselves, e. g. polio-
myelitis, encephalitis lethargica, and cerebrospinal meningitis. With ref-
erence to these what has been said with regard to the inheritance of im-
munity or susceptibility to infectious disease generally doubtless has some
application in principle but we have no specific knowledge of inherited
influences in the particular cases. The functional disorders of the nervous
system are manifest in almost infinite variety and the study of them has
gradually become a very intricate specialty. From our present point of
view only certain outstanding selections can be considered for purposes
of illustration.

Feeblemindedness has a peculiar interest. The condition (one, it may
be supposed, of limited development) rests in some instances on an in-
herited basis as made evident by careful and competent scientific investi-
gation. Is feeblemindedness a disease? Obviously it may be so regarded in
the social sense, since on a purely practical basis a highly developed society
is forced to maintain large institutions for the care of such of its offspring
as are unable to maintain the pace. From the pathological standpoint it
is hardly to be looked upon as a disease except in the most extreme or
particular instances. But when one begins to discriminate on a quantita-
tive basis all the standards must be arbitrarily chosen. The question clearly
becomes an academic one when purely practical standards are disregarded.

HEREDITY 223

The same may be said of many types of insanity. The discrimination be-
tween sane and insane in general is possible on a legalistic and practical basis,
however difficult decision in particular cases may be. A perfectly sharp
borderline in the scientific sense can hardly be drawn.

But insanity presents another aspect, in that there are certain disorders
of the nervous system characterized by definite symptomatic behavior
which clearly define them without reference to their severity or, in other
words, whether the sufferer is incapacitated or not. The most widely
illustrative perhaps is the disease known as essential epilepsy. Those most
slightly affected may not only be not incapacitated but may be mentally
quite normal or unusually brilliant people. Those most severely affected
are or frequently become unquestionably insane. In its mildest forms or in
its most severe, the symptomatology is characteristic. The difficulties of
recognition in the mild cases are due to the fact that the slight symptoms
long pass unnoticed. This disease is inherited in many cases, and apparently
usually as a Alendelian recessive. There are indications of sex linkage in
some instances and it sometimes appears as a dominant. Multiple factors are
probably involved. Other forms of insanity equally well characterized
are recognized and some are probably inheritable.

LONGEVITY

It has been increasingly recognized of late that the length of life of the
individual is a measurable biological phenomenon, the analysis of which
might uncover very interesting facts. It is, of course, a common impression
that length of life is determined in considerable measure by inheritance.
Some families are thought to be notably long lived. That the condition
is counter-balanced by equally well-marked short lived families is possible
but this is in the nature of the case less easy to be sure about. When an
individual lives a long time we think naturally of his constitution as a
responsible factor and when his ancestry and immediate relatives also
survive, the constitutional factor becomes more and more apparent. But
when an individual dies young, the disease of which he died or the accident
of fate which carried him off is the impressive feature. Suffice to say that
observations on selected families of animals, fruit flies and guinea pigs
particularly, have shown that length of life whether short or long is a defi-
nite family characteristic and have given us some clues regarding its
hereditary transmission.

Hypothetically if the human race were comprised exclusively of those
we know as long lived such diseases as tuberculosis and typhoid fever would
be unknown or would be recognized as disorders, disturbing but not es-
pecially dangerous to hfe. Whereas if the population were exclusively of
the short lived, cancer, arteriosclerosis and many other diseases would be
practically unknown.

2 24 READINGS IN BIOLOGICAL SCIENCE

ASSEMBLAGE OF CHARACTERS AND QUALITIES

Throughout this presentation it has been evident that the essential charac-
ters on which the inheritance of disease depends are separately transmissible
units of an almost endless variety. In some few instances one such unit may
completely control a disease condition. But in most cases not only is the
disease itself only partly influenced by the inheritance but even that part
is controlled by a number of separately inheritable unit characters. Our
present knowledge fails completely in so far that in no single instance does
it furnish a perfect insight into the fundamental nature of even one of
these inheritable units. The task for the future is obviously enormous if
we are to gain a usable understanding of the inheritance of disease on the
basis of rational knowledge. We require to know for the different dis-
ease conditions the precise part played by the inheritance m toto; the
number of unit characters involved for each case, and their structural or
functional nature. It may well be, however, that the obstacles which inter-
vene between our present understanding and a much more perfect and
useful one are lessened by some favoring circumstances which may be
sketched.

While it is considered fundamental that unit character is distinct in
inheritance, certain definite instances are known where diverse characters
are usually inherited together. This is termed linkage. Thus in hemophilia
(which is manifest by failure of the blood to clot, so that those aft'ected
are "bleeders,") the disease condition is hnked with the factors determin-
ing the sex. It is also true that a single unit character is sometimes known
to be concerned with a variety of structures or functions although the
author is unable to point out an example of this nature with reference to
any disease condition.

From the point of view of pathology, also, there are rather clearly out-
lined associations between certain structural pecuUarities and disease condi-
tions, excluding cases previously outlined where the disease is directly
dependent on a particular fault of structure. There are also recognizable
tendencies for individuals and families to suffer from or be relatively im-
mune to groups of diseases. Thus the tall, thin, flat-chested type of man is
believed to be more liable to acquire tuberculosis. People who suffer from
rheumatism and gout are believed to be less liable than the average to ac-
quire tuberculosis. Most of these relationships are, as at present recognized,
of the uncertain order resting on the impressions of successive generations
of physicians. Yet recent approaches to the subject on the basis of careful
measurements, accurately recorded case histories and adequate statistical
analysis lend credence to the belief that there is a real and traceable set
of associations here which it will be worth while to develop by further
studies. Up to now the interest had chiefly centered on recognizing certain

HEREDITY 2 25

anatomical types of people and trying to correlate with these the diseases
from which they have suffered. The recent work of Draper who ap-
proached the question by taking typical cases of certain diseases and study-
ing the physical conformation seems to promise more definite results. Of
similar import and carrying even greater suggestion of future interest are
observations indicating that the blood grouping, a functional inheritable
manifestation developed under definite conditions between the blood cells
and the blood serum, is associated in the inheritance with the natural im-
munity to diphtheria toxin or with the capacity to be immunized against
this poison.

Our general culture, our freedom from certain infectious diseases may
alike be immediately and largely a matter of social inheritance. Our lia-
bility to those diseases, defects, and discomforts which are controlled by
the physical inheritance must always be based directly on the qualities of
the germ plasm transmitted from father and mother to their children and
so to their grandchildren.

We can perhaps sterilize certain obvious defectives and so minimize
the economic burden imposed by the maintenance of institutions for their
care. But we cannot so durably solve the problems imposed by the fact
that disabling defects, diseases and tendencies to the development of
disease are inherited. The faulty germ plasm considering the multitude of
distorted conditions is too widespread for this. The ancients when they
wished to completely subjugate a conquered enemy people "decimated"
the population. This seems to be the ultimate which cold-blooded im-
mediate destructive human purpose can achieve. It is doubtful if we shall
ever be persistent enough to interfere radically with the propagation of
lo per cent, of the defectives even in cases where there is complete agree-
ment as to the need for such measures.

Recognizing the wide distribution, the completely individualistic char-
acter of the faults in the germ plasm, it seems that most rapid progress can
be made through the development of the individual understanding and
conscience. The appeal to family pride has been a most potent force in the
past, and one which it may be feared the present unduly loses sight of.

Family pride is likewise regarded as undemocratic. But in terms of gen-
erations we can pass to our descendants as we choose a democracy of the
unfit or one of the highest personal and social accomplishment. To the
development of this end the study of the detailed manner in which dis-
eases or the influences controlling disease incidence are transmitted in in-
heritance is likely to prove an increasingly useful and stimulating force.
At present and doubtless in the end the practical guide to individual judg-
ment would appear to lie in the stem of longevity. A short lived strain may
be fundamentally healthy, a long lived one must be at least superior. When
this complex of physical attributes is balanced with the knowledge of the

2 26 READINGS IN BIOLOGICAL SCIENCE

presence or absence of certain particular diseases in the strain and the
whole weighed with a rating for success with the business of life, the
basis for the intelligently prideful propagation of the family may be well
laid.

>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<

El

ufentcs

'g

EUGENICS is the science which has for its aim the improvement of the
human race. The cabbage has been developed from the scraggly chff
cabbage of Europe, the carrot has been selected and reselected from a
worthless plant known as Queen Ann's Lace, high-powered hens have
appeared by the efforts of man from a tough jungle fowl of low t^<g pro-
duction and the improvements in dairy and beef cattle are familiar to all.
Man is, of course, making great efforts to improve himself mentally and
culturally but the great and important problem dealing with the control of
certain mental illnesses, and other hereditary defects has not been attacked
with nearly the same vigor.

There are probably over five million feebleminded individuals in the
United States and, in addition, several million having other inherited defects
such as Huntington's chorea, insanity, and epilepsy. Of course, not all feeble-
mindedness and epilepsy are inherited. Over tw^enty states have laws per-
mitting the sterilization of people with these defects thus preventing them
from passing the defects along to the offspring. Cahfornia is probably the
only state which makes any attempt to enforce these laws adequately.
Sterilization is not a panacea and will not eradicate these defects from
the population but it will reduce the number greatly and also the cost of
caring for the children of these people.

Segregation of all the feebleminded is just about prohibitive from the cost
standpoint. California segregates defectives as much as possible and the
idea is to sterilize them before release. In this way they may marry and
become a part of normal society but cannot procreate any defective chil-
dren.

An interesting possibility is that through our present knowledge of tis-
sue culture the sperm-producing tissue of great men can be kept alive for
an indefinite time and a family may then decide to have a child in the
family sired by a superior person, by artificial insemination of course. This
plan would be only a novelty unless such superior germ plasm was used in
superior females to produce a group of superior children, in a favorable
environment.

227

2 28 READINGS IN BIOLOGICAL SCIENCE

SOME BEARINGS OF GENETICS ON
HUMAN AFFAIRS *

OTTO L. MOHR
INTERMARRIAGE AND CROSS-BREEDING

A series of fundamental problems has, thanks to our modern knowledge
of heredity, come into an entirely new light. This applies, for instance, to
the old question of inbreeding. There is a widespread popular belief that
intermarriage, e. g., marriage between first cousins, is to be advised
against, since occasionally unfavorable results are seen. On the other hand
there is ample evidence, also in human material, that intermarriage has no
harmful effects at all. As historical examples of very close inbreeding in
man, the brother-sister marriages among the Ptolemaic family of old
Egypt as well as among the Incas of Peru and the Aztecs of Mexico may
be mentioned.

The question is of foremost importance, and an enormous amount of
experimental work has been devoted to its solution. The results of these
investigations may be summarized thus: inbreeding as such has no harmful
effects at all. On the contrary, the astounding progress within animal
breeding has been mainly based upon close inbreeding among the off-
spring of a limited number of prominent sires. In this way we are able to
"recapture" as many valuable genes as possible of those carried by the
prominent sire in question. Valuable genes, this is the nub of the problem.
If an undesirable recessive gene happens to be present within the family
strain beforehand, then inbreeding will favor the occurrence of indi-
viduals that receive the undesirable gene in double dose, in which case the
corresponding harmful character will come to light. The unfortunate re-
sults sometimes seen in consanguineous marriages are in other words not
due to inbreeding as such, but to the presence of undesirable recessive
genes in heterozygous condition in the antecedents of the family. Con-
versely, if the hereditary factors in the family are good, then even close
inbreeding will give valuable offspring.

THE BLUE BLOOD

Some people are proud when they are able to trace their pedigree back
to the portrait of a remote ancestor. From a genetic point of view such
"pedigrees" are rather comic. Disregarding possible cases of intermar-
riage, we have already 64 ancestors in the sixth generation. What does it
matter to know one of these, when the rest, the 63 unknown ones, are
genetically equally important? If we go the other way, trying to con-

* Reprinted from Heredity arid Disease by Dr. Otto L. Mohr by permission of
W. W. Norton and Co., Inc., New York. Copyright 1934, by the publishers.

EUGENICS 229

Struct family trees comprising all our ancestors, we do not get far back
until we meet persons who, both in personal and social respects, would
be regarded as rather undesirable relatives by the present bearers of the
family name. Such an investigation is not apt to promote our respect for
the so-called "blue-blood."

On the whole, persistent misconceptions are wide-spread in the fields
with which we are dealing. Some of them even have nothing to do with
heredity. This applies for instance to the belief in telegony, after-ejflFect,
which even Darwin shared. Dog-breeders have been particularly prone
to this belief. It is thought that a bitch that by accident has been mated with
a male dog of another breed is spoiled, useless for future pure breeding.
Now when we know the mechanism of fertilization it needs no explana-
tion that this belief is entirely absurd. Mating, and the fact that a litter
of mixed breed has stayed temporarily in the uterus of the bitch has of
course not the slightest influence on the germ cells present in her ovary
and the genes which they contain.

MATERNAL IMPRESSIONS

More serious in its consequences is the old deep-rooted belief in "ma-
ternal impressions" which has caused much unfounded self-reproach
among conscientious mothers. Everybody has probably met with the
popular conviction that if a pregnant woman happens to see the head of
a hare, there is imminent danger of the coming child developing harelip,
or even cleft-palate. Birth-marks are traced to burns acquired by the
mother, in corresponding locations, and temperamental deviations in a
child are attributed to the mother's distress or loss of temper during
pregnancy. Conversely, I know of a case in which the husband sys-
tematically took his newly married wife to fine concerts in order that the
expected child might be musical in contrast to the parents. No wonder
that he was badly disappointed at the results of the treatment.

One might expect that it would be comparatively easy to persuade
people that external influences of this sort do not penetrate deeply enough
to produce changes in the child, which, as an independent individual,
happens to spend the first nine months of life as a parasite within the
mother's body. But as a matter of fact, according to my experience, it is
exceedingly difficult to persuade the parents that the fate of the child in
these respects is irrevocably determined already at fertilization, when the
two germ cells meet.

STERILIZATION

In the United States, up to 1933, about 16,000 persons had been sterilized
because they were for difi^erent reasons considered unfit for propagation.
But an American committee estimated that no less than 15 million persons
ought to be sterilized up to 1980, starting with 100,000 a year and increas-

230 READINGS IN BIOLOGICAL SCIENCE

ing the number up to 400,000 annually. Lenz in Germany regards 10 per
cent, in each generation as a by no means too high percentage of steriliza-
tion. But he even regards "ausgesprochene Hasslichkeit," translated ugli-
ness, as a proper indication for this procedure!

The effect of sterihzation is at best very, very slow. To take a single
actual example (after Hogben): One of the best known recessive patho-
logical traits in man is ordinary albinism, lack of pigmentation of skin and
eyes. This anomaly has an incidence of less than Yioo per cent. If steriliza-
tion of all albinotic individuals was carried out in every generation, it
w^ould require a period about equivalent to the Christian era to reduce
its incidence to one-half of its present dimensions, a simple consequence
of the fact that the heterozygous carriers continue to transmit the gene.

These examples are not quoted as arguments against sterilization proper.
Its application is advisable not only in the relatively few cases in which
by this method we may prevent dominant defects from being transmitted
to the offspring, but also because irresponsible defectives like imbeciles
or schizophrenic individuals are entirely unfit to serve as parents and
educators of children, even though we cannot predict that their children
will be similarly affected. It should also be remembered that in several cases,
as for instance in schizophrenia, the fecundity of the affected is by itself
so reduced that, as Nissen's statistics from Norway show, we must assume
repeated mutations of the causative genes in order to account for the
fact that schizophrenia has not been ehminated by nature's own virtual
sterilization of the affected. On the whole, those who are affected with
really serious hereditary abnormalities do not propagate at a rate that is
sufficient to keep up their number.

BIRTH CONTROL

It is frequently stated that the widespread application of contraceptive
methods will lead to "race suicide" by lowering in a selective way the
productivity of the best germinal material. The advocates of this view
simply take it for granted that the best germinal material is represented
by the "good families," the upper social strata, among which birth con-
trol, as is well known, has been most generally applied.

If this view is correct the upper classes would, so to speak, have attained
their favored position by natural right, by virtue of their superior geno-
typical quaUty, a conception that has been illustrated by the following
metaphor: The population is compared to a container filled with milk, a
fluid in which larger and smaller fat drops are dispersed. After a while
these drops of fat will float to the surface, and the largest, fattest drops of
fat will form the upper layer of the cream, the creme de la creme of the
French.

From a biological point of view this metaphor is entirely misleading.
Let us assume that a particular individual, due to his superior genotypical

EUGENICS 2 3 I

equipment, has been able to fight his way from the proletariat to the prop-
ertied class. Here he marries. There is nothing to guarantee that his wife
will be on an equally high level genotypically. Moreover, when his germ
cells ripen, segregation, the very principle of Mendelian inheritance, in-
sures that this valuable combination of genes is again dissolved, and his
genes will enter new combinations in his children. These children may
very well be quite ordinary as regards their genotypical quality.

But, thanks to better nourishment, better opportunities and training, it
is much easier for individuals born in an economically independent class
environment, even though genetically mediocre, to remain on the social
level of their parents, than it is for an individual of superior genotype
to overcome the handicap involved in an unfavorable environment with
limited opportunities.

If this is true, this argument against birth control loses its weight. At any
rate, an appeal to the intelligent and responsible circles to efTectively in-
crease their number of children is futile. The only way open in order to
counteract an assumed selective birth rate is accordingly to spread the
same information among the poor because every child ought to develop in
a good environment. And this goal cannot be attained if we give natural
fertility its free course.

THE ATTITUDE OF THE PHYSICIAN IN QUESTIONS OF

HEREDITY AND DISEASE

The individual medical practitioner is most frequently consulted as to
the possible consequences of marriage in cases where one or even both
partners belong to a family in which the pathological hereditary traits
occur. He may, by aid of one of the now existing text-books on the known
pathological hereditary traits in man, give valuable advice in quite a few
cases. But his judgment should always be given with the reservation in-
volved in the fact that genetics primarily deals with probabilities.

A frequent question is whether a normal person belonging to a family
in which a recessive pathological trait occurs may be expected to beget
affected children if he marries an unrelated individual. This must of
course be answered in the negative. As regards serious dominant ab-
normalities we have presented quite a few cases where affected heterozy-
gous carriers should be advised against propagation, even though the
chance of begetting an unaffected child is i: i. If such an individual never-
theless takes the chance and begets a normal child, then further propaga-
tion should be prevented.

Intermarriage in famihes where dominant pathological traits occur is
generally inadvisable. In families where serious recessive pathological
traits are met with, such as extreme eye abnormalities and hereditary types
of deafness, the risk involved in an intermarriage of two normal, but pos-
sibly heterozygous family members should be made clear to the consultants.

232 READINGS IN BIOLOGICAL SCIENCE

If they prefer to take the chance, which is at worst 3:1 in favor of be-
getting a normal child, I advise against further propagation if the first
child is normal.

As regards serious sex-linked anomalies, as for instance haemophilia, I
think affected men should be strongly advised against propagation, since
their normal daughters are sure to transmit haemophilia to half their sons.

HEREDITY AND ENVIRONMENT

It cannot be denied that the estabhshment of the fundamental fact that
the genes are virtually unchangeable by external agencies is somewhat
disillusioning. All the valuable acquirements which conscientious parents
may accumulate in the course of life are genetically a dead investment.
Conversely, however, the same fact involves considerable consolation.
Neither are our evil acquirements visited upon our children genotypically.
Irrespective of the parent's dissipated manner of life the children may
nevertheless in genetic respect get a good start, this start only depending
upon the genes which the parental germ cells contained.

It is quite another matter, however, that the evil acquirements of the
parents create a bad environment for the children. It is here that their
fatal consequences are to be sought. Alcoholism creates a bad environ-
ment, a bad milieu, for the children in almost every respect. Grave in-
fections in the parents may lead to contamination of the children. The
same holds true for moral dissipation.

We finish as we started by emphasizing that each individual is a product
of two sets of influences, the genes on one hand, the environment on the
other. Valuable genes may in a bad environment be hampered in their
manifestation. Conversely, a good environment may in many cases counter-
act and eventually suppress the influence of undesirable genes, and effec-
tively accentuate the manifestation of the valuable genes.

>>><-<-<■

THE ROLE OF EUGENICS *

EDWIN GRANT CONKLIN

Millions of human beings are born so defective in organization that they
cannot survive and leave offspring, and although we may attempt by every
means in our power to preserve them we cannot do it. Other millions not
so seriously defective we do manage to preserve, with the result that
modern society is burdened with multitudes of feeble-minded, epileptic,
insane, deaf, blind, and deformed, some of whom at least transmit these
defects to their children. It is because of the weakening of natural selection

* Reprinted from Man, Real and Ideal by Edwin Grant Conklin, by permission of
Charles Scribner's Sons, Copyright 1943.

EUGENICS 233

that the human race contains so many defectives. Galton ^ said, "Our hu-
man stock is far more weakly through congenital imperfection than any
other species of animals, whether wild or domestic."

Unquestionably this greater imperfection of modern man is the result
of nullifying the law of natural selection, so far as that is possible, and of
failing to replace it by intelligent human selection. Throughout the course
of past evolution, the perfecting principle by means of which animals and
plants have been prevented from deterioration, and have been adapted to
changing environments, has been the continual elimination of the less fit
and the perpetuation of the more fit, that is, the Darwinian principle of
natural selection. But by means of his intelligence and inventiveness, mod-
ern man has often succeeded in preventing the elimination of the unfit,
and by the most extraordinary efforts has preserved the lives of the dis-
eased, defective, delinquent, and insane, and has permitted them to breed
as freely as they can, with the result that, whenever any of these defects
are hereditary, they are passed on to future generations. Thus arise fam-
ilies and stocks characterized by hereditary feeble-mindedness, epilepsy,
dementia, deaf-mutism, some types of blindness, haemophiha, muscular
atrophy, and numerous other defects of practically every organ-system of
the body.

To eliminate such defective stocks by their ruthless destruction, as
occurs in nature and as was practiced in ancient Sparta, would violate our
social sentiments of mercy, compassion, and charity. But the preservation
of the hves of the unfit does not necessarily require that they should be
permitted to leave offspring and thus to perpetuate hereditary defects.
It is right and proper that society should care for those of unfortunate
inheritance and thus set aside the hard rule of the elimination of the unfit,
but it should replace the ruthless process of natural selection by the hu-
mane method of intelligent human selection of those who are permitted
to procreate their kind. This is the program of eugenics, and although we
hear less about this now than we did a few years ago, there is much evi-
dence that it is making progress, not merely in legislation providing for the
segregation or sterilization of defectives, but much more in the general
and serious concern of prospective parents that their children shall be
"well born." The increasing burden of caring for defectives will surely
lead to increasing efforts to protect society from this burden, and to more
rational customs of preventing the propagation of hereditary defects, and
thus to more scientific methods of population control.

This is a program which is already in force in many enlightened socie^
ties. Persons showing the most serious hereditary defects are in many states
prevented from passing these on to offspring by segregation of the sexes
in public institutions, or more rarely by sterilization. But those enthusiasts
who think that a new and better race can be produced in this way do not

1 Francis Galton, Essays in Eugenics, 1909.

2 34 READINGS IN BIOLOGICAL SCIENCE

consult reality or reckon with statistics. No breeder of domestic animals
or cultivated plants would ever expect to improve his stock by such feeble
methods. They are necessary to prevent further deterioration but they
offer little or no hope of great improvement.

The difficulty, or rather the impossibility, of any more radical program
of eugenics than is involved in the gradual reduction of the fecundity of
the worst human types and the encouragement of greater fecundity in
the best types makes it extremely improbable that any great or rapid im-
provement in the inherited nature of the human race can be produced by
eugenics. It is relatively easy for the breeder of animals or plants to choose
the types which he wishes to propagate and to make new combinations
of desirable traits, but the case is far different in man where in the main
restrictions on reproductions must be self-imposed, where there is little
uniformity of opinion among different peoples and in different times as
to what is the best human type, and where social and moral customs are at
variance with the best methods of the breeder.

Alexander Graham Bell,^ inventor of the telephone, was a skillful
breeder of sheep and was also greatly interested in human eugenics. He
had found that he could by selective breeding produce a breed of sheep
in which twins were produced at almost every birth, and then by further
selection, ewes with four functional teats, instead of two, were produced.
But he pointed out the differences in the technique of sheep-breeding as
compared with the social conditions governing human reproduction,
by supposing that the sheep breeders were compelled to observe the cus-
toms which prevail in the most advanced human society, namely (i)
all must be allowed to breed and none must be sterilized, (2) weaklings
and deformed individuals must receive special care and must be permitted
to propagate, (3) polygamous and consanguineous unions must not be
permitted, (4) every individual must be allowed to choose its own mate
and for hfe. Under such conditions, he says, no improvement in a flock
would be possible, and as long as these social conditions prevail among men
no hereditary improvement in the human stock will be possible. But al-
ready the first and second of these social customs are being abolished or
changed in the most enlightened societies, either by sterilization, segrega-
tion of the sexes in public institutions, or by the less drastic method of the
social taboo. It does not seem probable that in a free society the third and
fourth of these social customs will be abolished, even for the purpose of
breeding a race of supermen. Methods of negative eugenics, that is, the
prevention of the breeding of defective stock, offer no hope of race im-
provement, but only prevention of further deterioration.

A much more potent means of race improvement, indeed the only
means of improving inherited traits, is by the positive method of breeding

2 A. G. Bell, How to Improve the Human Race, ]our. Heredity, 5, 1-7, 1914.

EUGENICS 235

from the best stock. So far as the human species is concerned this is a
counsel of perfection, but at least a gain would be registered if the fashion
could be established in society that leaders in thought and action would
be expected to have large families, and that, when they do not, it would
be generally recognized that they carry some secret hereditary defect.
That such a social consciousness or fashion can be established is shown in
many countries of the East, where the continuance of the family is held to
be the highest social and even religious obligation, but where too little
attention is paid to hereditary quality.

A radical system of both negative and positive eugenics was introduced
by the Nazi regime in Germany in the 1930's. It was based on the best
technique of animal breeders and with little regard to social traditions or
moral considerations. In so far as it provided for the legal sterilization of
the most defective human beings it was not unlike methods proposed, but
rarely enforced, in other countries, but in the field of positive eugenics
it showed all the faults and dangers of prejudice, intolerance and ignorance
that might be expected in a dictatorship. There is no reason to think that
the ideals of such dictators, as to what constitutes the best human types,
are progressive, wise, or just. There are too many unknown factors as to
what may be needed in the near or distant future, even if their ideals were
the very highest possible at present. Furthermore good and bad hereditary
traits are so mixed in all men and the possible permutations of these in
offspring are so numerous that their transmission is wholly incalculable.
Add to this the well-known fact that slight and incalculable changes in
environment and training have profound influences on development, and
we see that no one is wise enough to foretell what the physical, intellectual,
or social worth of his own children may be. Who would have been able
to predict from their hereditary antecedents and their early environment
and training the development of such men of genius as Beethoven, Schu-
bert, Keats, Faraday, Franklin, Lincoln? And when we add to all these
impossibilities of predicting who will be the fittest to inherit the earth,
the prejudices of family and class, or race pride and arrogance among
those who would attempt to control the breeding of men, we may be
thankful that nature has so successfully concealed her methods of pro-
ducing genius.

Long ago Darwin ^ expressed to Galton his doubts as to the feasibility
of any satisfactory method of selecting the best human stocks, and Huxley *
pointed out the difficulties and dangers of permitting any individual or
class of individuals to decide which human families are the most fit. He
wrote:

8 Charles Darwin, More Letters, Vol. "2," p. 43. Appleton, New York, 1903.
*T. H. Huxley, "Evolution and Ethics, Prolegomena." Collected Essays, Vol. 9,
p. 39, Appleton and Co., New York, 1898.

236 READINGS IN BIOLOGICAL SCIENCE

I sometimes wonder whether people, who talk so freely about extirpating the
unfit, ever dispassionately consider their own history. Surely one must be very
fit indeed, not to know of an occasion, or perhaps two, in one's life when it
would have been only too easy to qualify for a place among the unfit.

In the present temper of the world the human species would not be im-
proved by the wholesale sterilization of those persons, nations, and races
that conquerors and tyrants may proscribe — even if such a thing were pos-
sible. When class, national, and racial hatreds are rampant, there is no
possibility that a scientific program of eugenics can be wisely enforced.
Instead of intelligent mate selection and ethical education aimed at produc-
ing the best physical, mental, and moral qualities, we see at present in cer-
tain countries a return to the law of the jungle, with natural selection
operating on the lowest plane of physical strength, cunning, cruelty. This
is "Nature red in tooth and claw," for those distinctively human and
civilized qualities of reason and altruism. It is a return to conditions of
savagery and barbarism which prevailed in the early history of human
society, survivals of which still persist. In the modern world, competition
has led to the seizing of the best parts of the earth by the most aggressive
and powerful types, such as Arctic areas, desert wastes, tropical jungles,
and barren mountains: or, within a single society, to slums, ghettoes, and
marginal lands. It has led to the enslavement or exploitation of certain
races, tribes, or classes by others, in accordance with what has been called

Nature's simple plan
That those should take who have the power
And those should keep who can.

Whether all mankind can ever become really civilized is a serious ques-
tion. Certainly it will not be accomplished by breeding perfect brutes,
nor, on the other hand, by eugenical sterilization. Of course science rec-
ognizes the importance of good environment as well as of good heredity.
All that heredity contributes are genes, factors, potentiaHties. These po-
tentialities become realities only in the process of development and devel-
opment is controlled not only by genes, but also by all the environmental
conditions under which genes function. Thus environment, no less than
heredity, enters into the results of development. This is especially evident
in the later development of human beings, when example, instructions, hab-
its, the desire of approval and fellowship are potent factors in shaping char-
acter. New-fangled eugenics will never replace old-fashioned education,
but each should supplement the other.

■>>>■<■<■<-

>>>>>>>->->>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<

XI

Evolution

THE question of man's origin is as old as man's reason. Our main method
of attack seems to be an ever-intensifying search for ancient men
and missing hnks. Comparatively speaking only a handful of men are en-
gaged in the search. Whereas many skeletons of early man have been
turned up in various parts of the world we still do not have a clear picture
of man's ancestors.

Speaking broadly, the old controversy regarding the fact of evolution
is dying down. However the method of evolution is still a subject of much
debate. Whatever the name of the theory, the mechanism seems to be
gradually centering about the hereditary units, the chromosomes. The
genes themselves are apparently subject to change or mutation thereby
producing new effects. Chromosomes may become changed in number
in individuals through failures in the reduction cycle or through hybrid-

ization or crossing.

The layman is often heard asking the question "is evolution going on
today and if so where?" As Darwin correctly pointed out, evolution is a
slow process and it is as difficult to observe as the gradual descent of the
glaciers in the ice age was to the animals of that time. However, plant and
animal geneticists have started interesting lines of research here and have
found that they can hasten the natural process considerably by species
crossing, genera crossing, x-rays and other methods. Actually several score
of new species of plants and animals have been "created" in this way,
many of them perfectly fertile. This is rather a new avenue of approach and
the future is very bright indeed for an increase in our knowledge of ev-
olution.

THE AGE OF HOMO SAPIENS *

W. W. HO WELLS

It is customary to speak of the time since the beginning of the Ice Age,
or the last million years, as the Age of Man, because its geological deposits
are embellished with the stony fruits of human handiwork as well as with

* Reprinted by permission of the Scientific Monthly, American Association for the
Advancement of Science. Copyright 1941.

237

238 READINGS IN BIOLOGICAL SCIENCE

the fossilized fragments of man's own frame. But this is otherwise a loose
term. What kind of a "man" is meant?

As an erect animal newly distinct from an ape, with a growing propen-
sity to reinforce his hands with rocks and sticks, man is probably older
than this, by far. De Terra, it is true, believes that the advent of the ice
itself, shifting climatic zones southward in Asia and causing a dispersal of
the once flourishing ape family into nev/ and varying environments, was
the indirect stimulus to the emergence of man from the anthropoids, so that
this event, he thinks, must have happened within the Pleistocene period
itself. But many students, Hooton being the most articulate, feel that man
must have been evolving for several million years at the end of the pre-
ceding Tertiary age, using tools of stone which can not even be recognized
to-day before getting to the stage of physique and culture which we see
in the earliest known remains. Man's age, in other words, is doubtless sev-
eral times as great as the "Age of Man."

On the other hand, we ourselves, in our present form, constitute one
particular and definite species of man, the species Homo sapie?js, which
must have arisen later on within this total limit of time. He is an advanced
type and is distinct from various other known human forms. However,
almost all these forms seem to be well above, and therefore later than, the
earUest imaginable stage of true humanity, and all may be thought of as
lines, gradually separating, which descended from the original human
stem. Homo sapiens appeared somewhere as such a line but how old he
is, as a species, we do not know. Curiosity as to his age is not simply the
mark of a fond antiquarianism, for information on the pace of recent
human development would give us a better perspective for the possibilities
of future change in mankind. How old, then, is Homo sapiens?

We really can not say, taking the remains alone. If we dutifully repeat
only what paleontology has revealed so far, it would seem as though Ho?no
sapiens were very recent. (Actually, we know somewhat more about the
age of our nearest neighbor in time, the species of Neanderthal Man.)
There is, however, some imperfect evidence that indicates Hovio sapieiis
as being fairly ancient, and there are various abstract considerations and
deductions which bear this belief out.

Put purely in terms of skeletal evidence, this is what we know. /. There
is archeological proof of human existence apparently throughout the
Pleistocene, running back a milHon years, to use a figure, or 1,000 millen-
niums. 2. There are remains of the species Homo sapiens, and Homo sapiejis
only, going back some 30 millenniums (more or less, actual dates not being
certain) to the Cro Magnons, who appeared at the beginning of the Upper
Paleolithic, the last portion of the Old Stone Age. 5. In the previous 950
or more millenniums (the disproportionately long Lower Paleolithic, com-
prising i%oths of the whole Pleistocene) there were various types of fossil
men, but no finds have been made which would prove, with the finality

EVOLUTION 239

of a theorem in geometry, the presence of Homo sapiens. Thus there is a
break, at the beginning of the Upper Paleolithic, with no indisputable men
of our own species earlier, and no men of any other species after it. The
situation is such that only the captious would deny that Homo sapie?is
existed before the Cro Magnons, who are his first clear manifestation; but
on the other hand it is not such that any anthropologist can ring general
agreement from his colleagues as to a particular time, whether relatively
late or going back toward the beginning of the Ice Age, when Homo sa-
piens might be said first to have become a distinct species.

Through the long reaches of the Lower Paleolithic there is sprinkled
a corporal's guard of human fossils. The Neanderthal species is well rep-
resented by finds, especially in the west, which can be referred to the
last 100 millenniums or more of this time. Equally well known (for the
cranium at least), thanks to recent discoveries, are the Java and Peking
types, obviously related to one another and probably dating from the
lo\\er middle part of the Pleistocene. Aside from these, the main species
are largely single specimens or scraps; the Heidelberg (an early forerun-
ner of the Neanderthals) and Piltdown men, and the undatable Africans —
the Broken Hill skull of Rhodesia, and Africanthropus, from the Lake
regions. Of all these and certain others none is assigned to Homo sapietis.
This gives a picture of several species of man, some of whom at least must
have been contemporaneous, though differing considerably. The question
is: Did Homo sapiens also overlap any of them in time, or did he, appearing
late, arise from one of them, and if so, from w^hich one?

The possible representatives of our own species during the Lower Pale-
oHthic are not many. (There are reasons, however, for not expecting them
to be. For example, Homo sapiens has a thin skull, which is less likely to
survive in fossil form.) One is the Galley Hill skeleton of the Thames Val-
ley, whose physical type is fully sapiens but whose geological claims to
antiquity are impaired by the confusion and carelessness which attended
its discovery in 1888. There are a few other modern looking skulls with
similarly sullied credentials. Otherwise the skeletal evidence of early
Homo sapiens rests on two finds. The first is the very important Swans-
combe skull, also of the Thames valley, whose parts were found in an ab-
solutely certain connection (a rare thing) with glacial deposits and arch-
eological tools which are believed to belong to the second interglacial, in
the first half of the Pleistocene. It is thus very ancient, but its establishment
as an actual specimen of Homo sapiens has to rest on the crow^n and back
of the head, all else being gone. This is not entirely satisfactory. Most are
inclined to accept its validity, and to believe that it legitimizes Galley
Hill at last, but some would regard it with acute suspicion, remembering
that the back of the ape-jawed Piltdown skull would seem almost equally
modern. The other main find comprises skeletons from two caves at Mount
Carmel in Palestine, excavated ten years ago and dating apparently from

240 READINGS IN BIOLOGICAL SCIENCE

the later part of the Lower Paleolithic. In the Tabun cave was found a
Neanderthal-like woman with some sapiens characteristics, while the skull
cave contained several skeletons of a practically sapiens type but with
Neanderthal-like features. The interpretation of all this is likewise in doubt.
The discoverers believe that they have found what is perhaps the actual
moment of appearance of Homo sapiens, while others think the skeletons
represent a mixture of the two species, in which case Homo sapiens must
already have been in existence, and probably for some time.

This is not much with which to reconstruct the trail of Homo sapiens
into the past after the visible part of it disappears abruptly with the Cro
Magnons, or at best becomes pocketed in the mysterious case of the Mount
Carmel skeletons. Even if we provisionally accept the Swanscombe skull
as a specimen of Ho?no sapiens, there remains a large gap in time between
it and the Cro Magnons, bridged only by a moral certainty. Consequently
there is a flourishing diversity of opinion in the whole matter — notice that
even regarding the Mount Carmel skeletons alone there are currently two
quite different explanations, logically leading to equally different con-
clusions as to the age of our species. In general there are two schools of
thought. One holds that the development of Hoino sapiens was inde-
pendent of that of other species, all of them being considered as a con-
stellation of different descendants of a common source placed well back in
Tertiary time. At the other extreme are those who would graft him onto
some one of the known non-sapiefis forms of man, at some period well
along in the Pleistocene.

Neanderthal Man supplies a case in point. Becoming extinct less than
50 millenniums ago, he seems to have ruled Europe for the preceding 100
millenniums at least. A few students think that during his career he gave
rise to, or influenced, Homo sapiens. Others feel that this is not so; that his
physical unlikeness, in his low, massive head and huge face, is too great,
and that he had developed definite pecuHarities of his own which are not
to be found in modern man and which would therefore exclude him from
our ancestry. In spite of all the racial variety of the latter, and a consider-
able variety of the Neanderthal species as well, there is no actual over-
lapping of the two stocks in physical form.

Now if there has not been any important connection between the two
species in recent times, then it would appear that Homo sapiens existed
somewhere outside of Europe, and that his line goes back, parallel to but
not connected with that of the Neanderthals, for many thousand years.
Does it go back to the Java and Pekin types, or is the same situation re-
peated here? Probably it is. The Swanscombe skull shows, if it shows
nothing else, that a high, vaulted brain case of the sa^piens type, whether
actually parental to that of our species or not, had been evolved in the
human family long before the known period of the Neanderthals, and
almost certainly as early as, or earlier than, the backward Java-Pekin

EVOLUTION 241

family. And the always-mysterious Piltdown skull, in spite of its extremely
ape-like jaw, has a very human brain case which indicates the same thing.

It is possible to disregard the limitations of the fossil evidence and to
take a fresh view of the problem by considering the living races of Hoiiio
sapiens as they have probably been in the past. To-day two biUion people
are spread thickly upon the earth. They are divided somewhat unequally
into the conventional White, Yellow and Black, with infinitely weaker
representations of American Indians, Australian blackfellows, South
African Bushmen, and so on. They constitute different races but all be-
long, from a zoological standpoint, to a single species. None of these races
alone is the type of the species, which is made up of all of them together.
In other words the most advanced is not necessarily the most typical. It
would indeed be more proper to represent Homo sapiens as a whole by
his most primitive manifestation, the native Australian, or by an imaginary
form of this sort, which could have become the parent of all living races,
as a sort of greatest common denominator.

The picture of the present suffers from lack of depth, because our col-
lections of skulls of various ethnic origins do not go back far enough to
tell much of history on a grand scale, and the older remains give us only
the barest of indications as to race. Nevertheless, it is clear that before we
even begin to trace races back we must modify this picture because of
violent changes which must have taken place in the very recent past, in
the time since culture really began to develop.

A mere ten thousand years ago, toward the end of the Paleolithic, man
knew only the art of hunting. Since then, with the onset of the Neolithic,
he has progressed to agriculture, opening a vast food supply to himself;
later on, in the Bronze Age and classical times, he has benefited by town
life and artisanship, and still later, in the last few centuries, by the subjuga-
tion of natural forces to the purposes of transportation and manufacture.
These things have occasioned an almost incredible increase in the popula-
tion of the world. Throughout his previous existence, man could never
rise in numbers above what the stable animal population in any region
would feed. It can be estimated, from the little that is known about the
recent rate of increase, and the population density of present-day hunting
peoples, that there can have been only something like ten million beings in
the then-inhabited world, compared to the two billion of today. (For ex-
ample, the New World, most of whose people were relatively advanced in
culture, had a population of roughly eight million at the time of dis-
covery.) Now in this tumultuous upsurge of some two hundred fold, it is
plain that those peoples who participated in the progress of culture would
increase and monopolize the world, while those who remained hunters
would continue to be few in numbers and sparse in distribution, or would
even face extinction on encounter with a people more advanced.

Ten millenniums is a very short time, being only one hundredth of the

242 READINGS IN BIOLOGICAL SCIENCE

"Age of Man," yet it has produced this revolution, this amazing upheaval
in numbers and in attainments, which is in vivid contrast with the long
previous span of man's existence during which culture had plodded ahead
at a barely perceptible pace. Very few Bushmen remain in South Africa,
or blackfellows in Australia, and these have probably survived by grace
of living in a desert and a remote island respectively; but in those days
of the end of the Paleolithic the races we distinguish to-day must have
been more equal in numbers. The point of this effort to ignore the present
scene, and instead to restore that of 10 millenniums ago, is to give these
now negligible races their proper significance. When they and possible
others stood on more equal terms with those which dominate to-day, the
whole species would have presented an appearance of even greater di-
versity than at present, and this very diversity is an index of the age of
the species itself, because races can not have appeared overnight.

Races seem to have formed almost entirely as the result of random evolu-
tion. It is conceivable that the tropical sun was an influence in establishing
dark skin in the possessors of that feature, and woolly hair as well. If so,
it was certainly a long process, too gradual a one to have affected the
Indians of tropical America over many thousand years. But geographic
isolation, the simple separation of groups descended from the original
Ho?no sapiens, was probably the most important factor. Such groups
changed slightly but continuously, by nature's laws, and being separated
geographically, they tended to drift aimlessly apart in physical form as
well, becoming racially diverse. Bagehot, the economist, once suggested
that when man was new his meager culture allowed natural selection to
act powerfully upon him, leading to the rapid development of races. This
is a poor hypothesis all around; natural selection would affect the func-
tional development of his legs, etc., but selection would actually tend to
prevent racial differentiation. There is no real reason to think that there
was irregularity in the speed of racial development, or anything except
an even increase in diversification, which reached a maximum about ten
thousand years ago.

The process probably took a long time. The only sighting point by
which we can judge its pace is the beginning of the Upper Paleolithic. The
first unquestioned Homo sapieris, the Cro Alagnons, demonstrate; (i) that
there has been no progressive racial development, as far as can be seen, in
some 30 millenniums, and (2) that the men of that time were hardly more
primitive in an evolutionary sense. In Europe, the Cro Magnons and re-
lated types were purely "white" in character, showing that this racial
stock, at least, was fully developed and by no means in any embryonic
stage. And there is some evidence from other skeletons of comparable
age that the Negro and Mongoloid stocks were equally well established.
Furthermore, the native AustraUan of to-day is definitely more backward

EVOLUTION 243

in form than were these ancient Caucasians; indeed the fact that the
most primitive branch of the species that we know of should be found in
a living race rather than an ancient fossil emphasizes again our ignorance
of early stages of Homo sapiens development.

Now, if no material change in the degree of racial differentiation can
be observed in the time from the present back to that which immediately
follows the disappearance of the Neanderthals, then it can hardly be denied
that the development of all the races out of a common stem must have
taken a period several times as long as this one. Even the time when the
now archaic Australian, chinless and small-skulled, and with beetling
brows and protruding face, represented the forefront of sapiens, develop-
ment must be relatively remote. (Galley Hill and the other geological
hoboes were more advanced than he.) So from this consideration alone, it
would appear that Homo sapiens must go back as a distinct species to the
middle of the Pleistocene at least, and probably much further. This being
so, it is difficult to believe that the Swanscombe skull can have belonged
to some other species. And certainly if for these additional reasons the
Galley Hill man, who has about the same putative date, can finally be
accepted, then the age of Homo sapie?is must be really great indeed.

>■>><<<

man's long story *

LEWIS G. WESTGATE

We live in a time in which human values, built up slowly through cen-
turies with untold sacrifice, are threatened with destruction; when nations
at either end of the old world have set out on a career of world conquest
with the intention of exploiting and enslaving the conquered peoples, and
are pushing that aim with sub-human brutality; when our own country is
fighting for its life. It is a time of fear and uncertainty. It is a time of hu-
man tragedy, when for millions the future is black indeed. Can science
help us to an understanding of what has taken place, or give us a perspec-
tive with which to judge the present, or point to any hope for the future?

We need perspective, the perspective of a long past. Swept along in the
rapids of present-day happenings, we are in no position to judge them.
We need to stand on the bank, watch the river's rush, get some notion
of its whence and whither. It were well to turn to the history, American
history, European history of the last six millenniums. We have gone far

* Reprinted by permission of the Scientific Monthly, American Association for the
Advancement of Science. Copyright 1943.

244 READINGS IN BIOLOGICAL SCIENCE

since neolithic man started civilization on the flood plains of the Nile and
in Mesopotamia. Other times have been worse than this, bad as it is. On
the whole there has been advance.

We need a longer perspective even than that of the last six thousand
years, a perspective that science alone can give. The master historian is
the geologist; he deals with time on a scale which dwarfs ordinary history.
To him, as to the Creator, a thousand years are but as yesterday when it
is past and as a watch in the night. He speaks of a hundred million years
with the same nonchalance that the ordinary historian displays in handling
centuries; and if he misses by a million or even ten millions when he is
talking big, he sees no need of apologizing.

That the earth is old, very old, has been known for the last two centuries,
ever since the birth of geology as a science. But how old in years? Re-
cently the discovery of radioactivity has led to a new and apparently
reasonably accurate method of estimating geological time. Uranium by
the loss of helium passes into lead. The rate of such loss has been deter-
mined in the laboratory. By comparing the amounts of uranium and
uranium-derived lead in certain granites we can find the age of the granites,
and a minumum age for the sedimentary rocks in which they have been
intruded. Thus are obtained the data for the following table, which shows
the periods into which the geologist divides the past history of the earth,
with their respective lengths:

Period

Length

Length of time to beginning
of (in inillions of years)

Cenozoic (time of re-
cent animal life)

60

60

Mesozoic (time of
medieval animal life)

130

190

Paleozoic (time of
ancient animal life)

300

490

Pre-paleozoic

1300

1790

These figures are approximations at best; still, we shall probably not go
far wrong in fitting our thinking to this schedule. It gives us some two
billion years for the age of the earth as recorded in the rocks. Back of
that is an indefinitely long, early planetary period of which the geologist
has no record.

II

Time as mere duration is uninteresting. It is what happens in time that
matters. The length of geological time has been emphasized not on its own
account, but because probably during the whole of that time there has
been life on the earth, slowly, very slowly developing into the variety

EVOLUTION 245

which we see about us to-day. Thne is the background for the story of
life.

The ancestry of man is a long one. It goes back beyond Neanderthal
man; beyond the ape, the early mammal, the fish; beyond whatever in-
vertebrate ancestor the fish had; back to some single-celled form in pre-
Paleozoic seas nearly two billion years ago. A long time for man to be at
school. Progress has been slow, for Nature is a severe school mistress.
Failure in her school means more than just waiting over a grade; the
organism is thrown on the discard. She insists that her lessons be so learned
that they become part and parcel of the organism, and she takes all the
time necessary to secure that end.

Somewhere in the pre-Paleozoic sea existed single-celled ancestors of
man, possibly like the amoeba. It could eat, assimilate, breathe, move,
reproduce, all in very simple ways; but these were the essential functions
of life. It was perfectly adapted to its environment; so perfectly that some
of its descendants, still amoebae, are with us to-day. It is no newcomer
into that early ocean; it had been at school for tens, perhaps hundreds of
millions of years, and the lessons of that infantile grade had become a
part of its very structure and function. We came along perhaps a thou-
sand million years to the mid-Paleozoic, the Devonian, the age of fishes.
Our ancestor is now a fish, admirably adapted to its medium, doing the
same things the amoeba had been doing, but in a more elaborate way. And
there were those milHons of years of schooling between. Some of the
Devonian fish, certain ganoids, were ready for a higher grade. In these
the swim-bladder opened into the throat, and in extremis could be used
for gulping air, that is, breathing. The fins were stout, and again, in
extremis could be used for crude walking. Imagine these ganoids, caught
season after season in time of drought in muddy pools on the Devonian
flats, gulping air and floundering about, half in and half out of water. It
was hard schooling, but some graduated; the air bladder developed into
a lung, the fins into legs; and these ganoids were the ancestors of all the
higher vertebrates. In the monotonous uniformity of the sea, evolution
of the higher types of life would have been impossible; that required one
variety of the land surface. The coming to land of these Devonian fish
has been said to be "the most momentous step in the whole advance from
amoeba to man."

Two hundred million years further down the line we are in the mid-
Mesozoic. Great reptiles rule the air, the sea and the land. It looks as if
their future were secure, that their reign would last forever. It did last
for more than a hundred million years. But the future lay not with the
reptilian giants, but with certain small primitive mammals, an offshoot of
the line of reptiles. They had been waiting their chance for some tens of
million years. At the beginning of the Cenozoic, Nature took them in hand
for training for the higher grades; sixty million years of schooling it was

246 READINGS IN BIOLOGICAL SCIENCE

to be. One group, the primates, came in for a special education of body
and brain that had a more direct human trend. The early anthropoids,
man's line, were tree-dwellers. Toward the middle of the Cenozoic our
direct progenitors came down out of the trees, adapted themselves to the
ground, spread beyond the forest, and assumed an increasingly erect
posture.

The Cenozoic was sixty million years long. Its last division, the Pleisto-
cene or Glacial, was one million. Through this past period, which includes
four glacial stages with long intervening interglacial epochs, man was
slowly straightening up, increasing in brain capacity and intelligence, de-
veloping speech, inventing tools. His prolongation of infancy, far beyond
that of other mammals, carried with it increasing teachableness, and the
lengthening of the period in which offspring were dependent on their
parents led to the beginning of the family with its accompanying in-
tensification of the altruistic sentiments, to the growth of the qualities
which we consider most distinctively human.

Early in the Pleistocene, forms recognized as man and not ape are
found (Java, Peking and Piltdown man). Neanderthal man {Homo
?ieanderthalensis) made his appearance in the last interglacial epoch; but
it was not until the last glacial epoch, perhaps 50,000 years ago, that Cro-
Magnon man appeared in western Europe, the first that is admitted to the
present species {Homo sapiens), and whose descendants are doubtless
with us to-day. Erect, with prominent chin, high forehead and brain as
large as that of modern man, he was skilled in the use of simple tools, and
his carvings and drawings and polychrome paintings are the admiration of
anthropologists. Cro-Alagnon man stands at a pivotal point in the world's
history. He is the climax of two billion years of animal evolution. Man's
long preliminary education is now completed. The stage is set for a new
act in the drama of life; whether comedy or tragedy we do not yet know.

The purpose of this emphasis on the length of life on the earth is to
show that the race enters manhood with an immense animal momentum.
The Roman Catholic Church is said to hold that if it can have the teach-
ing of its youth for the first seven years, it will guarantee them to the
Church for life. Nature is man's teacher, and she has had his early educa-
tion for a vastly longer time proportionally than the Catholic Church asks
for its youth. Man has been in the distinctively human school less than
a million years. He was in the primate (not primary) division throughout
the Cenozoic, sixty times as long. He began his primary education as some
single-celled form in the early pre-Cambrian ocean, possibly two thousand
times as far back as the day when he was promoted to the human grade.
Nature has insured that he learn his lesson well; that the animal is so in-
wrought in him that he can never get away from it. His human nature is
a recently acquired and uncomfortably-worn garment.

EVOLUTION 247

III

The first inference to be drawn from man's long animal inheritance is
that he is primarily a creature of instinct. His driving forces are hunger,
sex, fear, crowd, combativeness. No one who has honestly looked into
himself or around at his neighbors can fail to see this. He is not a fallen
angel, god-descended, mixed with animal clay. On the contrary he has
risen from the animal level. Let us hope he is still rising, and has his eyes
at times fixed on the stars. Unless we keep his animal origin and bias in
mind, we can neither judge him fairly nor plan wisely for his future.

A second inference, indeed the obverse of the first, is that man is not
a creature of reason. The zoologists when they named the human species
called it Hovio sapiens; man the wise! Whether they did this from egotism
or wishful thinking or just for a joke, they were in error; wisdom is not
his outstanding characteristic. Reflective thought is a late acquisition and
few have it in any large measure. The eighteenth and nineteenth century
confidence in reason is now seen not to be justified by the reality. For most
people, even for the best of us most of the time, reason is the servant of
instinct, finding excuses for what one wants or has already decided to do.
It is rationalization, first cousin of wishful thinking, which is not thinking;
it is merely wishing. Here again honest introspection will give us the
evidence; also observation of neighbors. If one wants proof in public life,
he can follow the doings of the United States Senate, the resolutions of
Chambers of Commerce, or the propaganda of nations at war. If he looks
for it in the rarefied air of abstract thought, he can dip into any book on
astrology or even theology.

However, man's being primarily a creature of instinct furnishes a needed
conservative and conserving factor. His animal inheritance keeps him on
the track, keeps him from going off into all kinds of wild disintegrating
experiment. But had this been the only force at work, man would still
be on the animal level; progress would be impossible. Sane human history
is a balance between the conservative instinct we inherit from our animal
ancestors, and the use of reason to guide that instinct.

Again, a clear appreciation of the strength of man's animal inheritance
shows us that it serves to qualify both our hopes and our fears. It works
against optimist and pessimist alike. The optimist expects that evil can
be overcome, and that, speedily; that some sort of golden age or millen-
nium is coming in the not distant future. The pessimist is sure that evil is
Math us to stay, and that to fight against it is a hopeless adventure. Both to
the extreme hopes of the optimist and to the extreme fears of the pessimist
the long biological-historical view is a corrective. The momentum of an
age-long inheritance is not easily changed. The animal in us, often at odds
with our idealism, will carry on indefinitely. But other forces are at work.

248 READINGS IN BIOLOGICAL SCIENCE

We are told that we can not change human nature. But human nature can
change. It has changed. We are what we are because it has. There is no
good reason to suppose that it has ceased changing. But the process is
extremely slow. Further, whatever may be said of human nature, human
behavior can be changed, both in the individual and in the mass, and it is
behavior that counts. Recent events in Germany may not be proof of any
change in the human nature of the Germans; but they certainly bear wit-
ness to a change in German behavior; and it is German behavior that the
rest of the world has to deal with. It is equally possible to shape human be-
havior to good ends.

IV

Organisms must adapt themselves to their environment as the very condi-
tion of survival. If a satisfactory adjustment has been achieved and then
the environment changes, a new adjustment must be effected; and that is
always difficult. The course of geological history is strewn with the relics
of species that, faihng in adjustment, perished. The application of this
principle to man is this: man's body and mind reached its distinctly hu-
man state in one type of environment, and he has lived on into a radically
different type, which he has himself created, and he is having tremendous
difficulty in making the necessary adjustment.

The environment of early man was that of forest, or forest and plains,
suited to hunting; or, if he was near the sea, to hunting and fishing. It was
an active life in the open. He needed neither golf course nor gymnasium.
He got his food from plants that grew wild, or from animals of the chase;
at any odd time, not thrice daily o' the clock. It was one continuous strug-
gle against cold and hunger. Eternal watchfulness was necessary that he
get the animal before the animal got him, for both were out for a meal.
Strength of limb, keenness of eye and ear, accurate knowledge in a narrow
field counted for more than familarity with Plato or the calculus would
have done. On them hung the issues of life and death. Dense population
was impossible; there was not food enough. If population crowded on
food supply, then war, starvation or infanticide kept it down. It was a
life close to elemental nature, a life in which every normal adult could and
did share somewhat equally, had his chance, and was on the whole equal
to the situation.

All that is a matter of far away and long ago. Some thirty thousand
years separate us from Cro-Magnon man. Two great environmental
changes have taken place. The first, to a settled agriculture, we see already
accomplished at the beginning of recorded history, some six or seven thou-
sand years ago. Man at that time possessed domestic animals and cultivated
grains; and on this basis he had established permanent agriculture on the
rich, level, well-watered flood-plains of the old world. This permitted the
accumulation of wealth, the growth of dense population, commerce by

EVOLUTION 249

land and sea, together with arts and industry, and the development of
social classes. It permitted war, conquest and slavery. Still, the great mass
of the people, the farmers ox peasants, lived an out-door life not greatly
different from that of the earliest hunters.

The second change, a revolutionary one, the greatest of all in man's
environment, began some five hundred years ago. We find ourselves today
in the very rush of it. Our age has been called, not wholly accurately, the
age of science; the age of technology would be the better term. Technology
has been slowly growing, as a process of trial and error, from the very
earliest times. The pyramid builders in 3000 b. c. had a high degree of
technical skill. Man has not been so stupid that he has not been able through
the centuries to improve the old ways, to find both new things to do and
new ways of doing them. Invention, quite apart from scientific research,
has made great advances in the last two centuries. Mere enumeration is
all that is necessary: iron and steel, fuels (coal and oil) for power, trans-
portation, the factory, mass production; all this culminating in crowded
peoples and overgrown cities. For a while industry and new-born the-
oretical science followed separate paths. There was nothing in the early
experiments in electricity to suggest the gigantic electrical developments
of to-day. Science was largely the experimenting of individuals working
alone. Slowly it became clear that science could be of use in human affairs.
It was first pity, then endure, then embrace. Governments began to see
the advantages of subsidizing geological, agricultural and medical re-
search. To-day most large industrial corporations support their own re-
search staffs. Science and big business have entered into partnership, and
technology advances by leaps and bounds. It is reported that $235,000,000
were set aside by industry for scientific research in the United States in
one depression year. Whether in the end this union of business and science
will be for the world's good, it is too early to say. It has made possible mass
production and the modern city. Following, as it has, the discovery of new
continents, it has led to commercial rivalry, the exploitation of weaker
peoples, the demand for new markets and new sources of raw materials,
race antagonisms and world wars.

It goes without saying that man himself has produced this new environ-
ment. Nature with no help from man shaped the environment in which he
acquired his mind and body. But to a large degree he has taken over from
Nature the building of his environment, has already tremendously changed
it, with what results we are beginning to see. Fle must no\\^ \\ork out his
destiny in a world amazingly different from that of any epoch of the past.

This change to a technological environment is inevitably accompanied
by maladjustments which reach into every aspect of life. The dwellings
in which we live, whether the tenements and shacks of the poor or the
air-conditioned apartments of the well-to-do, are a sharp contrast to the
open-air life of man's formative period. The specialized and monotonous

250 READINGS IN BIOLOGICAL SCIENCE

work of the miner or factory hand is slavery compared with that of the
early hunter, which, if strenuous at times, lacked neither variety nor in-
terest, and was a real education. The deep-canyon streets of the city, filled
with noise, gas, dirt and rush, or the drab surroundings of the factory
town, are a sorry alternative to the open country. Two views of lower
Manhattan, taken more than three centuries apart, would symbolize the
change. One, to-day, would show the wonderful sky-Hne of high build-
ings, the other the wooded island Hudson saw when he entered the upper
bay in 1609.

The human element in the environment has changed no less than the
material. The pace of modern life and the intellectual level on which it
is carried on, make demands beyond any that were made on early men,
demands which many can not meet. Modern industry finds many unem-
ployable persons. It requires more from those it takes on, and scraps those
it can not use with the same lack of consideration with which it scraps
outworn machinery. It imitates Nature in her harsher moods.

The results? Before the war, between five and ten million unemployed
in the United States, facing the choice between public support, starvation
or crime; worse, unemployables; poverty, economic insecurity and recur-
rent depressions. Clearly the economic system is not working satisfac-
torily. Sickness; the medical bill of the United States is some three billion
a year, and large numbers get no medical care. Defectives and insane;
mental cases in hospitals rose from 63.7 per 100,000 in 1880 to 263.6 in
1934. The total annual cost of crime, direct and indirect, in our country
runs into the billions. This tremendous load; unemployment, including
the idle rich, crime, sickness, waste, class struggle, and worst insanity of
all, war; all this is loaded on the backs of the actual workers on farm, in
factory and office. This is the "white man's burden," not his egotistically
assumed overlordship of races of another color.

What of the future? Physical conditions alone considered, there is
every reason to believe that the earth will be a suitable home for men
for a long time to come. There is nothing in the geological past to suggest
any speedy wind-up of mundane affairs. If some wandering star ap-
proaches our sun and upsets things, or if the sun blows up, as suns (novae)
have been known to do, or if in the far distant future our central sun be-
comes cold, that will end us. But such contingencies are almost infinitely
remote, and the scientist, as a student of earth's history, is justified in ignor-
ing them.

Chmatic conditions will continue to be favorable. When the extent of
the continental glaciers of the northern hemisphere was first appreciated,
it seemed as if the earth might be cooling down; that we were about to
enter upon a long period of refrigeration, in which human life would be-

EVOLUTION 2 5 I

come increasingly difficult, and finally end. We have since learned that
glaciers are no new thing in the earth's history. There was extensive glacia-
tion at sea-level in India, South Africa and South America at the end of
the Paleozoic, perhaps two hundred million years ago. Another extensive
glaciation occurred twice as far back, before the beginning of the Paleo-
zoic. Climatic changes seem to have been rhythmic instead of progressive;
swings from warm to cold, and back again; from wet to dry and dry to
wet; but at all times of a character to permit human life, had it been in
existence. There is no reason to suppose that conditions will not continue
much the same in time to come. The weather prediction for the future is
"favorable." Today's climate, like all weather everywhere, is "exceptional."
We are still in the fag end of a glacial period, with immense ice-sheets in
Greenland and Antarctica, and abundant mountain glaciation. There have
been four generations in the Pleistocene. It is quite within the realm of
the possible that another ice sheet may develop in Canada, push south into
the United States, and overwhelm New York, Cleveland and Chicago; the
last ice sheet reached that far. The next, if there is a next, may do the same.
It will not be a glacial blitzkrieg, however. There will be plenty of notice
in advance. And it will be exceptional. Through most of the past the
climate has been mild and uniform, and it will probably be so through most
of the future.

The environmental aspects just mentioned are exempt from interference
on the part of man. Others are not. Man cuts the forest, plows the grass-
lands, and plants his corn and wheat. He digs or drills the ground for his
fuels and his metals. These are his resources for food, for industry. How
is it faring with these natural resources?

First, as to the food supply. There will be enough to eat, if . . . There
have been times in the past when a land animal hke man would not have
found enough to eat, enough of the right kinds of food. When the lung
fish of Devonian times came ashore to become the ancestor of vertebrate
land hfe, he found an abundant vegetation. But it did not contain our
present foods. None of the plants which fill the spring seed catalogues
were then in existence. Flowering plants did not come until late in the
Mesozoic, nor were grasses and grains, man's basic foods, abundant until
the Cenozoic. But now they are with us. Nature has done her part. "Be-
hold I have given you every herb yielding seed, which is upon the face of
the earth, and every tree, in which is the fruit of a tree, yielding seed; to
you it shall be for food." What man is doing at improving this endow-
ment is told in the splendid story of modern scientific agriculture.

But plants require soils; aye, there's the rub! We are waking to the fact
that soils are being destroyed in this country at an alarming rate. They
are being washed to sea by the rivers and blown away by the winds. Al-
ready from one quarter to all of the top soil has been eroded from 59 per
cent, of the United States. They are being impoverished by cropping with-

252 RE-\DrNGS rS BIOLOGICU. SCIEXCE

out any retnm of the fssfntia] eloDencs takoL Soil loss is a serious nati<»al
diieat; sod coasemdon a great natJooal pix>bkm and need. The soil is
a icsoorcc wfaicfa can be used and kept. Soil eidiaustion is not necessan'.
Sooie sckils have retained their ferTilit\' after thousands of veors of use,
but it has been intelligent use.

Resoorces such as sral and water, if pioperlv handled, can be used and
k^id \Mth them you can eat vour cake and have it too. It is different -with
most mmeial resources. The fuels — coal, oil and gi5 — ire stored supplies
ol organic origin which have come down from ihe c^e j : ? i5t. If thev
arc f ornm^ anWhere today- it is at a rate which is infir : . ■ 1^^
son with that with which thev are bein? used tq>. The ^ -: ~ -\ and

qQ are Imiited in amount, and \hiien dilate used up: : e e

is a certain coal tonna^ still in the eardi. Its amount 15 :
How many years it wiD fast d^iends on so m2nv fac: . r : - : r : , , j.:i-z
forecast can be made. Those already z.iie 5 : l): not of decades, nor mil-
lenniums; but of centuries. The storv of ever\~ oil field is cme of discover^'
and oploftation, followed bv slow decline to exhaustion. There ire 2
definite mm^ber of oil fidds in existEnce. ScMne are known, others are yet
to be discovered, \llien the last field has been discovered and exhau5Te i : > e
suj^ity of petroknm will be gaoc forever. Then, unless someir rr = --
vented to take its place, we shsl! be driven to the disr^i^riAa 01 Ou. iioir.
oBsfaak.

Coal anc :l ire :;si^ iir^^r : '~z n- f e-;:j : :;: iz :v plants of
the geok>e.:i- ri5t. Plant life 5 Ttr : ::r : ire : ::.z fin's energv. It
mar be : i: ;;: :ie -.rtit .111 .t it e i_ ::i 1: :: :i and chemists
HHV hit on stmie wav :: 1 tcriv catching : t 5:- f er :hat futiuje

housewives m: ;:" :" _ -.? with pe;: tf in : - i: :r for winter

siq^phr. Or w:„ zr.t :" r _ : ^ panv of A t . : e : : lish a monopoly?

If we tAe : t irz r - ir "ould seer : e ; 1: :ne ccmdosion
that we ; - ;:: :: : :r z ..r .-.zi irr^' t: ~-.-.z:i\ : t :-;! metak, and
that is : :: : ::i J : :^ ;t ; : ;: : 1 ;;: : : ; :rt : : - : : ": 1? we now
know I : A :iit::. lit :: 1: ri'm^ :r- :;tf : : i: -. "e. oer-

hapsfc: 1 :t :- : ::i- 1 t::f :- 1 f _: 5:.r_:ef : ;: :/ ; :; ::: 5 ... :.;.: Bur
iclotdcf : : z - :t :- : : r : it ii; irv to return to conditions
fike tb: I .1 ireitii: : t -r:tr-:- :e-:i.- . Doubtless some would
look 00 such a chai^ with re^naticMi. Tfaer s^e liking whether the
Sondav paper, movies and radio, battleships, tanks i-.i 1 :~es. and much
of the rest of modem {woductkMi. have realhr n t: : - -\ level.

Were not manjr men m ShakesTjesre's dav livnig n :_ ^ e^ - - v of us

now-

T: vi~ ir Niriie 11 : "e her srizt : r ::e 1 rivoring it A:
— 1- " ; 1- - :th-.::. ."z :_7ire. If :i_'ii 1: - :: so well, r.t i_i ; .:

EVOLUTION- 253

y I

Will man himself change; in bodv c r — - : - And if so, in what direction?
These are questions impossible to ai^ ;j T'.tre seems to have been no
significant change in his body since die bcgir r ' 1 : :b€ historical period.
But in considering his foture we have to do v . . ' . : ' .oosands bat niil-
iions of vears; tens, possibly hondreds of milli<His. T : ; was immense
evolution along manv mammalian [Ir.ts during the sixtv million vears of
the Cenozoic; great changes took z'.i'-t :r. :-.e homi- : ioring the
last million, sL". : e "t '.rr. r'2;:i' itr :. 1.

In the past, icrr:.: :'z'. 7:: e : rowiy specialize: " e! -.— rf :: 1
particular environrr.:' "i t- : 1: environmoit : : .t: : t :;

unable to adapt rher. .t t: : rr.t "rv cmditions. ;' : i:: : re: i"
is a generalized i<'..r\. 1 .:' : - - - -: : tr. He ;i" r_r ; _: r r

the deer; climb, but not like : t r :- t r : - e :- r :- :

he can fiv. But he has what birds, bei:: ;- : - - - ^ r,: - : i

superior brain. He can think; and by:' r t i : . :t:

body and hands and with the tools his :: have made, devisee rrtir.:
for beating each of the others at their r. ::7:i2ity. It is pre" 1: ^ :ri:
man v^iil continue much as he is now, iisirg f_i :_-::eil^eiice to seci-rc -is
adjustment and his contin-zed life

That man has advances ~er:i. Jiiring historic times ~_r": stt— :o
be a good bet; but it is one :i::: :^:: - :: be collected on. _.::; -.: z:z - j
wav of establishing the facrs. Certainhr the eminenne oi d^e G:; Tt-
lectuals proves nothing. A^ .: 1. : eir abilitv the Git. i tit r :: t ::<
weld tosether the ^rri.'. Greek states and prevait their over:i-_- : r
Macedonia and R:~e. And it is i ii:: i-Jercnce that Xewron. E
and Einstein, Shakespeare and Goethe, and those ^rho are orgi~ : :j ::;
complex industrial life of to-dav, are at kast the e:::ii of the g^oiy zi^i:
was, for a short time, Greece.

\Mth man a great chai^ has coir.e - ::: f^Oxiizh:- ~ :>rocess. i- ::;
past, evolving forms have been ouite -: riiTi^is o: ::r_r jwri ce ; :-
ment-Formanthisisnoloncer :r":e H: :^ r ::: . 7Z : — "?e :e r:5 :;— r.
he discovers the factors at wo:i: - ris own hereditv i- : t- : :~:-:- re
can look into the future; and ft : ; ^ ma degree : : :: ;t : r :: : :: :
direct his own evolution. He is alreadv directing the ev: : : :rt

animak that are useful to him; die rest he exterminates. A^ : : : r.e

in producing different breeds of cattk, swine, sfaeep : : : rr.-. a visit
to anv state fair will show. After such a visit one mav j "^ ' " s

just as welL in vie\r of his presoit ignorance, that r-i- r
to exfjerimenr in this wav on himself. But the iv???:: _r. _^ :~^re.

O

2 54 READINGS IN BIOLOGICAL SCIENCE

V I I

Man's evolution now is primarily social and cultural. It has been going
on since earliest man; its description is the burden of histors'. And in spite
of the wails of the pessimists its progress has not been slight. So it will con-
tinue to be throughout the immediate future, sav for the next ten or hun-
dred millenniums. x\s in biological evolution, there is variation (by the
introduction of new ideas), heredity (in the sense of transmission by tradi-
tion), and struggle for survival, both within and between groups. That
struggle is ever^'where present in current American Hfe, and is now going
on on a world scale with furious intensity in the present war. As with
biological evolution, cultural evolution has been mainly unconscious and
altogether unplanned; but here, too, man has reached a stage when he
could in a measure take it in charge.

One important aspect of social evolution is the development of con-
sideration for others, of the idea of right and wrong, of moralit^^ Animal
nature is non-moral. The question of right and wrong does not exist when
the wolf drass down the deer. Consideration for others besran with the
early family. The long period of human infancy, close-spaced births over
the woman's bearing period of thirty- years or so, held the family together.
In such soil thought for others had a chance to grow. Alan's susceptibihty
to the favorable or unfavorable opinion of others helped. As a result there
has come that slow gro^^•th of sympathy for others which has raised the
strucrale for existence above the animal level. It is these and other distinctly

DC ^

human traits which make life worth while.

VIII

What are some of the first steps that should be taken in planning for
the future? The foremost need is a clear-cut human ideal, the envisaging
of "the highest human values realizable on earth through human effort"
(Max Otto). This comes close to the democratic ideal, namely the fullest
development of the possibihties of every individual, both on his own
account and for the service he can render the world, the state being
guardian, not master or slave driver. Each man to have his chance. It means
the end of race discrimination. The claim of superiority by Europeans
over non-Europeans has done immense harm to both.

In giving content to this aim, science, that is, knowledge, must help.
Science, some sav, has brought us to the mess we are in. True, technology
rests back on science, but science is not responsible for technology', nor
is technology responsible for the uses made of it. For that we are all
responsible, through our stupidirv^ and selfishness. We need to know vastly
more about man, his heredirv, the effects of his environment, the way
his mind works. Millions are spent for research in technology, for im-
proving glass, rubber, com and hogs; very little for the study of man

EVOLUTION 255

himself. One sickens at the bilhons now necessarily given for war. all of
which would be unneeded in a decently ordered society; and thinks whar
tremendous advances the wide use of a fraction of that wealth would brinij
about if devoted to the problem of man. Just one hundred years ago Long-
fellow wrote:

Were half the power that fills the world with terror,
\\'ere half the wealth bestowed on camps and courts,

Given to redeem the human mind from error,
There were no need of arsenals or forts.

We must revamp our economic system. We have the resources for a
decent life for all. Povert\' is no longer a necessitv^; it is a curable disease,
and it is our shame that it is still with us. Our resources must be used for
the good of all and not for the profit of the few. We need a new com-
mandment, "Thou shalt not waste!" And we need to put new content
into that old one, "Thou shalt not steal." This reconstruction will have
to be done on a world basis, for science and technolog\' have so drawn
the world togrether that what is harm to one is now hurt to all.

Education must help, but it must be an education fitted to our present
needs, not one that is an inheritance from an ahen and aristocratic past.
It must be an education that fits for jobs, trains leaders and gives a satisfy-
ing philosophy of life. An education that makes it forever impossible for
one to forget that all that he has comes to him not through his own efforts,
but because of the sacrifices of those who have gone before; and that he
is not only a citizen of a national state, but a member of a world society.
Above all separate groups is mankind.

WHAT WE DO NOT KNOW ABOUT RACE *

WILTON MARION K R O G M A N

We are, in this discussion, going to focus upon race and problems of
race purely from a biological angle. The approach may be illustrated by
an experience the writer had some dozen years ago. In 1930-31 it was his
privilege to study in the Galton Laborator>^ of AppUed Eugenics at Lon-
don Universirs'. On the first day, as he ascended the stairs to a second-floor
classroom, he saw on the landing-wall in front of him a huge illustration, an
enlargement of a cartoon that had appeared in Punch. Tv.o EngHsh coun-
try srentlemen were standing beside a blue-ribbon buU, and one gentle-
man said to the other, "We know about breeds in animals, but what about
ourselves?" The theme of this discussion is, then: What about breeds in

* Reprinted by permission of the Scientific Monthly, American Association for the
Advancement of Science. Copyright 1943.

2^6 READINGS IN BIOLOGICAL SCIENCE

our biological selves? We shall discuss these selves not in individual, but
in group terms. In a very real sense what we do not know about human
biological groupings may become positive knowledge if it outlines future
avenues of research. If we recognize a darkness we also recognize a need
for light.

The first "don't" is simply this: we are not sure — at least we do not
agree — what actually constitutes a biological race in man. In 1871 Charles
Darwin, in "The Descent of Man," expressed the problems of racial clas-
sification quite clearly:

"Every naturalist who has had the misfortune to undertake the descrip-
tion of a group of highly varying organisms, has encountered cases . , .
precisely like that of Man, and if of a cautious disposition he will end by
uniting all the forms which graduate into one another, under a single
species; for he will say to himself that he has no right to give names to ob-
jects which he can not define."

Darwin represents one extreme: there is but one race, the human race.
One may study the literature on human racial classification and go to
the other extreme, wherein no less than 150 species, each with sub-races,
are postulated.

In 1735 Linnaeus, the great Swedish naturalist, gave Man the scientific
name he to-day still bears — Hovw sapiens (the "wise man"). Let us ana-
lyze ourselves biologically; an expanded cerebral cortex that makes of us
a reasoning animal; a protracted period of infancy and childhood that en-
ables us to be a learning animal; a facial skeleton reduced in size so that we
have a physiognomy instead of a snout; a forelimb that is freed from loco-
motion so that a forepaw has become a hand; a spinal column, viscera,
a pelvic girdle, and a hind limb, that are reasonably well adapted to an
upright posture and bipedal locomotion. In this general morphological
pattern all mankind is truly one; one genus, one species. In all important
and major bodily details we are one — in brain, in peripheral nerves, in
heart, in blood and blood vessels, in all viscera, in muscles, and in skeletal
architecture.

But there do exist differences which are, as it were, superimposed upon
this basic ground-plan. There are differences in skin color, in eye color,
in hair color and hair texture, in head shape, in nose and lip shape, and
even in limb proportions. These differences are obvious, they are external,
and we have recognized them for thousands of years. On the basis of skin
color, principally, we subdivide Homo sapiens into three major groups:
White, Yellow, Black. Scientifically we may designate these as H, s.
caiicasoideus, H. s. jnongloideiis, H. s. 7iegroideiis, respectively.^ Each of
these groups — in practice we often call them "stocks" — is a sub-species,
and each has certain distinctive morphological features which, taken
singly, are not necessarily mutually exclusive, but which, taken in com-

1 Some anthropologists feel that these merit specific ranking.

EVOLUTION 257

bination or complex, do tend to set the groups apart. Actually, this same
general conclusion applies to sub-species in lower forms as well.

So far, so good. Now let us observe one of these stocks — the Caucasoids
— in greater detail. Within this sub-species, in Europe, there are groups
which, originally on a geographical basis, precipitate out as more or less
recognizable entities: Northwest, Central, Southwest, Northeast, South-
east. To these types — and we here use a simphfied terminology — have
been applied the names Nordic, Alpine, Mediterranean, Baltic and Dinaric,
respectively. They fall into place in our scheme as follows:

H. s.

caucasoideus nordiciis
" alpinus

" mediterraneus

" balticus 2

" Dinaricus ^

In this stock break-down we come, finally, to the groups that the
anthropologist generally terms race; they are, in taxonomic fact, sub-sub-
species, or varieties. Do they exist today? The answer must be a qualified
affirmative; that there may be local, isolated, probably highly inbred
groups of Alpines, for example, in certain Swiss valleys. Similarly there
may be small regional groups of the five Caucasoid varieties we have
named. But there are no peoples or nations in Europe who are pure Nordics,
pure Alpines, or pure anything else. In substance, there are no pure races:
there are only populations in which two or more varieties are intermixed,
and that intermixture began before the dawn of European history. There-
fore what we term races in Man are poorly defined, because they are not
— as in races in lower forms — homogeneous; they are intermixed, hy-
bridized, diffused. That is why one man says "no races," the other "many
races." The first is appalled at the difficulty of disentangling intermingled
varieties; the second holds that secondary or composite groups warrant
racial status.

The problem of mixture above mentioned — of hybridization so that
"racial purity" is non-existent — renders it impossible to ascribe genetic
homogeneity to the races we have set up. Suppose we took ten persons
classed as Nordics (five males, five females), and ten persons classed as
Mediterraneans (five males, five females) and bred within each group;
we could not guarantee, and we would not expect, that the oflFspring would
be all Nordics and all Mediterraneans, respectively. In the Nordic X
Nordic we might get some short, brunet, long-heads; in the Mediterranean
X Mediterranean we might get some tall, blond, long-heads. About all we
might reasonably expect is that the Nordic off^spring would tend more to
tall blondness, and the Mediterranean off'spring to brunet shortness. In other
words, the groups we call races are genetically heterogeneous; they include

2 There is reason to believe that these were originally variant combinations of the
three preceding, basic types,

258 READINGS IN BIOLOGICAL SCIENCE

genes that are generalized, and that are also shared more or less equally
by one another.

Actually, how have we in practice set up a racial classification? The first
method is that of somatological inspection: we look at a group and find
that, on the average, they are short, slender, dark-complexioned, long-
headed, wavy-haired, and their habitat is circum-Mediterranean; thus
H. s. caucasoideiis mediterraneiis comes into being (Italians, Spanish,
southern French, etc.). The second method is by biometric analysis. Here
a certain portion of an entire group — a random sample — is measured and
described precisely. If mathematical investigation shows that this sample
(and hence the group) is statistically homogeneous and significantly dif-
ferent from all other groups, then the group under consideration is termed
a race. "A biometrician's concept of race of man is derived primarily from
the statistical study of samples. . . . His methods are essentially descrip-
tive and they do not presuppose any particular theory of individual or
racial heredity." ^ The end result of both of these methods is the Vhonnne
moyen, or type, the hypothetical individual who represents the averages
of all the individuals in the group (e. g., John Bull, Alphonse, Hans, Uncle
Sam are caricatured types of an Englishman, a Frenchman, a German, an
American).

In summary, our first "don't" recognizes that the groups we call human
races are, taxonomically, sub-sub-species. As in lower forms the differ-
ences which set these races apart — at such a taxonomic level — are not
clear-cut and precisely defined. As far as Man is concerned, we focus upon
a relatively few apparently stable characters and then accept them as hav-
ing a definitive and diagnostic value. In doing this, however, we do not
diverge radically from accepted zoological principles at sub-sub-specific
level for lower animal forms generally. At species level distinctions are
quite clear; below that they are dim in the haze of variability.

The second "don't" is found in the fact that we are uncertain how stocks
and races arose, i, e., when in human evolution they appeared and the
mechanism involved in their emergence. We are pretty well satisfied that
Man, as a primitive hominid, probably arose some five million years ago,
more or less, as the result of a divergence from a generalized anthropoid
form which gave rise to Man and the Anthropoids as we to-day know
them. But that accounts for Alan as Man — how about the White Man?
The Yellow? The Black? Well, we are not really sure. There are sugges-
tive finds, but nothing more. The first White Man may possibly be seen
in Galley Hill man, resident in England some 400,000 years ago; the first
Yellow Man is suggested by Weidenreich to date to Sma?nhropiis, the
man of Peking, China, of about a million years ago; the first Black Man
may date to Rhodesian man in Africa, 100,000 (?) years ago — certainly
he was present in southern Europe at Grimaldi, some 25,000 years ago. We

3 G. M. Morant, in Race and Culture, p. 24, 1934. Royal Anthropol. Inst., London.

EVOLUTION 259

repeat, we are not sure of the import of these finds in terms of the time-
appearance of stocks. Two things must be borne in mind: first, the finds
are random and inconclusive because we do not have sufficient numbers
to know range of variation; second, the characters commonly diagnostic
of stock or race are those of soft parts not preserved in the fossil record.

If stocks, or sub-species, be of doubtful origin, how about races, or
varieties? Here we are more in the dark than ever. We can answer only
that Mediterranean-type crania are found well defined by the opening of
the Neolithic, about 10,000-15,000 years ago; Nordic-type crania are re-
ported in the Swedish Neolithic. The time element in stock and race emer-
gence is approximate, nothing more.

Now that we have considered when they arose, let us take up how they
arose. One of the most intriguing theories is that of Sir Arthur Keith,^
who feels that the endocrines may have played a role: "The transforma-
tion of man and ape ... is determined by a common growth-controlling
mechanism which is residual in a system of small but complex glandular
organs." As Keith surveys the role of the pituitary in acromegaly, the
thyroid in achondroplasia, the adrenals in pigmentation, the gonads in
secondary sex characters, he sees analogies with certain statural, osteologic,
cranio-facial, skin conditions in the stocks of mankind; e. g., the big-boned,
rugged-skulled Caucasoid shows a possible pituitary dominance; the flat-
faced Mongoloid shows a possible thyroid dominance; the dark-skinned
Negroid shows a possible adrenal dominance.*^ Keith offers these endocrine
associations more as suggestions than as absolute statements. They un-
doubtedly exist as factors, but to-day we recognize the endocrines as so
complex, so interrelated, that any statement of uniglandular dominance
must be taken with tremendous reserve. The exact role of the endocrines
in human evolution and in the appearance of stocks and of races is in the
realm of conjecture.

In our present knowledge of human evolution we assume that sometime,
somewhere, there existed a generalized proto-human or hominid species
that had, potentially at least, all of the morphological characters found
to-day in all of mankind. This species must have been genetically fairly
homogeneous, though probably inherently variable.

From this species there arose through mutation, recombination, selec-
tion, migration and isolation, the stocks and races as we now recognize
them.

The third "don't" resides in the inadequacy of our knowledge con-
cerning heredity in Man. Specifically, we do not know the precise mecha-
nism \\hereby traits diagnostic of stock and race are transmitted.

* A. Keith, "The Differentiation of Mankind into Racial Types," Ann. Rep.
Smith. Inst., pp. 443-53. Washington, D.C., 1921.

5 About 1775 John Hunter concluded that the original skin color of Man was Black,
and in 192 1 Keith reaffirmed that statement.

l6o READINGS IN BIOLOGICAL SCIENCE

One of the most obvious methods employed by the physical anthro-
pologist in studying human heredity is to analyze the effects of race mix-
ture." Here it is assumed that the traits that "show up" or persist in a cross
are "dominant." For example, when a long-head is crossed with a broad-
or short-head it is apparently the broadness or shortness that dominates;
similarly, nasal breadth thickness over lip thinness, and so on. But all this
is not genotypic (genetic constitution) it is phenotypic (physical ap-
pearance). We do not know the exact genetic pattern involved; we know,
for the most part, only what the end-result "looks like." Moreover, we are
observing the operation of only a dozen or so parts of thousands of pairs
of genes in Alan. It is this dozen or so for hair, eyes, nose, hps, skin, and
a few other traits, that we rely upon for stock and racial diagnosis; all the
others are presumably constant for all groups.

Strandskov has given us an excellent summary of known gene distribu-
tion in Man.'' Color blindness is a sex-linked recessive, with gene (cb) on
the X-chromosome; color blindness is present when normal color vision
(Cb) is absent. Ability to taste the chemical phenyl thiocarbamide is an
autosomal recessive with (T) for tasting, (t) for non-tasting. In the A-B
blood groups we find inheritance by triple allelomorphs, as follows:

Blood group Gene Combination

AB
A
B
O

In the M-N blood groups we find the following:

Blood group Gene Combination

MM Am hP-

MN , A°> An

NN A° An

Biologically the knowledge of these few genetic patterns is important
because the mechanism is identical for all human beings; the inherited
traits cut straight across stock and race; e. g., all blood groups and their
genes are found in Whites, Yellows and Blacks, though in varying per-
centage combinations. It is possible that these combinations may have
some value in racial distinction, just as does skin color, etc., but as far as
transfusibility is concerned (allowing for blood groups) all human blood
is alike.^

6 T. W. Todd, "Entrenched Negro Physical Features," Human Biology, i ( i ) : 57-
69. 1929; W. M. Krogman, "The Inheritance of Non-Pathological Physical Traits in
Man," Eugenical News 21 (6): 139-146, Nov .-Dec, 1936.

■^ H. H. Strandskov, "The Distribution of Human Genes," Sci. Mon., 52: 203-215,
March, 1941; "The Genetics of Human Population," Am. Nat., 76: 156-164, 1942.

8 It is implied in the phrases "blood-relation" or "blood will tell" that somehow
blood is a carrier of familial relationship. The blood group is itself inherited, but blood,
per se, is not a vehicle of genetic transmission.

I-^

F

I-^

JA or I^i

IB

P or Pi

I

EVOLUTION 261

We are certain that physical characters diagnostic of race and stock are
hereditary: they arose genetically, via mutations and subsequent isolation;
they have been perpetuated genetically in varying combinations. We
know, for example, that there is an average of "one mutation for every
50,000 individuals per generation" (Strandskov), and that most of these
mutations are of indifferent or even negative survival value. The few that
are positive are transmitted and over a long period of time have entered
into complexes and combinations which differ from stock to stock, and
within stocks from sub-type to sub-type, from variety to variety. We are
slowly but surely learning the genetics of Mankind in terms of his many
physical-type variants.

A fourth "don't" is really a corollary of the third, namely, we realize
that discrete traits have a hereditary basis, but we are still not sure which
of these traits are relatively stable and which are easily modifiable, so
that the first set is useful in classification, the second extremely limited in
use.

In studying problems of racial analysis Hooton ^ has outlined three cate-
gories of physical traits in Man: those that are non-adaptive, those that
possess an acquired stability, and those that are easily modified. We may
summarize these three categories as follows:

There are certain features which appear to act as heritable entities, either
as unit characters or with multiple factors. These comprise in general
hair-color and eye-color, form of hair, eye-fold, nose, lips, ear, incisor
teeth and vertebral border of scapula, head breadth, face length, chin
prominence and prognathism, and limb proportions, including intra-
membral, inter-membral and trunk-limb ratios. These physical characters
are non-adaptive, stable, fixed, and may quite reasonably form the basis of
the assessment of racial distinctions. Furthermore, certain combinations of
these traits, varying within natural boundaries, result in the establishment
of subgroups within each major classification.

We come now to several traits which have in the course of time been
functionally modified and by selection have become more or less stabilized;
at least their variability is of intra-racial rather than inter-racial magnitude.
Here we may include skin color, shape, size, and proportion of the molars
and the palatal arch, head height and brain volume, and possibly certain
calcaneo-gastrocnemic relationships. The list is small and its import un-
certain; the farther we go in our study of individual growth patterns and
their probable relation to presumed racial criteria the more we must allow
for modifiability. It may be that the stability is spurious, merely a transi-
tory phase in the creation of an ultimate pattern dictated by constitutional
vicissitudes.

Finally, there are a number of bodily features so directly susceptible to
health, diet and food habits, climatic factors, gait, exercise, occupation

^E. A. Hooton, "Methods of Racial Analysis," Science, 53: 75-81, 1926.

262 READINGS IN BIOLOGICAL SCIENCE

and other miscellaneous influences as to render them useless as racial cri-
teria. Here must be mentioned height, weight, thoracic dimensions and
proportions, nasal proportions, facial width, proportions of forearm and
hand, relationship of vertebral column and pelvic girdle, and shaft propor-
tions of femur and tibia.

It may be finally emphasized that we must, in problems of racial inter-
pretation, pay general attention to the sum total of all bodily traits, but
specific and critical attention to the nonadaptive bodily characters, for
these are transmitted regardless of the multifarious and complex extraneous
factors of the environment. All things equal, it is not one, nor two, but
the majority or all of the traits, in unique combination, which really con-
stitute racial or group differences. But until we know more of the heredity
of the several traits, of the effect of the growth-pattern upon these traits,
we can not truly assess them in terms of non-adaptivity, acquired stability,
or modifiability.^°

For the last thirty years we have had reason to doubt the stability of
certain morphological features, as in the cephalic index studies of Boas and
his students, wherein significant generational differences were observed
when foreign-born parents and American-born Jews and Sicilians were
studied. In recent years Shapiro " has suggested that instability is char-
acteristic of a majority of Man's physical racial traits. He studied three
generations: (i) "sedentes," native parents born and still resident in Japan;
(2) Japanese-born (of these parents) who migrated to Hawaii in their
late 'teens; (3) Hawaiian-born children of these immigrants. The anthro-
pometric battery comprised twenty-eight measurements with twenty-one
derived indices and twenty-two observations. When the first two genera-
tions were compared it was found that they differed significantly in all
traits measured and observed as follows: male, 72.4 per cent.; female, 67.9
per cent. As between the second and third generations the corresponding
differences were 55.2 per cent, and 42.9 per cent., respectively. These dif-
ferences are progressive from sedentes, to immigrants, to Hawaiian-born,
but whereas between sedentes and immigrants disproportionate changes
occur, between immigrants and Hawaiian-bom proportionate changes are
the rule. The progression is apparently a real one, relatively unaffected by
age-changes or changes in occupational status. The causes of the changes
are twofold; the immigrants probably constituted a sub-group of the
sedentes population from which they are drawn; the new environment
(of Hawaii) provided a stimulus toward change and some inbreeding in-
tensified the variant exemphfied by the immigrants. But the changes are of
course, limited in extent — the Japanese in Hawaii, as long as they marry
within their own group, will always be Japanese; biologically they will

low. M. Krogman, op. cit. pp. 144-145.

11 H. L. Shapiro (with F. S. Hulse), "Migration and Environment," Oxford Uni-
versity Press, N.Y., 1939.

EVOLUTION 263

not, can not, become Hawaiians, even though there might be some en-
vironmental convergence.

We now regard human races as much more plastic than we formerly
did. But our concept of plasticity is basically a genetic one. There are a
multitude of genes which encompass the entire range of human physical
characters. Plasticity resides principally in recombinations of these char-
acters. Recently Mills ^- has shown that there is another phase to this
plasticity, an environment (diatetic) aspect. He found that vitamin B re-
quirements (thiamin, pantothenic acid, and pyroxidene at least) are much
higher in the tropic than in a temperate zone and that growth and de-
velopment are inhibited by inadequate B intake under tropical living
conditions. Here is an example where growth-pattern and hence adult con-
figuration (taken as a racial criterion) is modifiable by the food environ-
ment. We are just beginning to learn how a temperate-zone White man
may possibly adjust to a subtropical or tropical habitat, but for one fact
we know there are 100 questions that are still to be answered.

The fifth "don't" is found in the functional aspects of Man: we know
little about the physiology of race-types. We have studied racial metabo-
lism, pulse-rate, respiration-rate, and so on, but these analyses are not so
much tests of race-groups per se as reflections of conditions under which
they live. There is no reason, really, to assume difference in kind, rather
only differences in degree. If we relate body-type to body-function then
distinct group differences can not be expected, for body-type cuts across
stock- and race-lines. ^^

There is another phase of the functional problem which requires clas-
sification, viz., so-called "racial susceptibilities." For example, the peoples
of North Europe are said to be prone to whooping cough, resistant to
goiter and cretinism; the peoples of Central Europe fall prey to goiter
and cretinism, but withstand pulmonary diseases; the American Negro
succumbs to tuberculosis, diseases of heart, lungs and kidneys, and more
successfully combats malaria, yellow fever, measles, scarlet fever and
diphtheria.^^ Are these really racial difi^erences? Probably not. The answer
is more likely to be found in problems of relative isolation and exposure,
and most certainly in considerations of socio-economic standards. There
are, so far as we know, no genetico-racial biological differences in the
organs which will conduct to, or inhibit, organic breakdown under the
onslaught of disease. The problem, however, is still one to be explored.

The sixth and final "don't" is that we do not know of any characteristics,
either biological or psychological, that in a given race-cross are superior

12 C. A. Mills, "Climatic Effects on Growth and Development, with Particular Ref-
erence to the Effects of Tropical Residence," Avier. Anthropol., 44: 1-13. 1942.

13 F. Weidenreich, "Rasse und Korperbau," Springer, Berlin, 1927.

1* A. Hrdlicka, "Immunity as the Chief Task of Future Aledicine," Lit. Digest, Dec.
9, 1933 (see p. 14); see also J. H. Lewis, "The Biology of the Negro," University of
Chicago Press, 1942.

264 READINGS IN BIOLOGICAL SCIENCE

or inferior. On the biological side tliere may be one exception, viz., the
sickle-shaped erythrocyte which is an autosomal dominant trait (Si)
found only among Negroes, to the extent of 4 per cent.

Much is being made these days of "race superiority" and "race inferi-
ority." In words of one syllable there is no such thing." One hears of the
woodsman who, on a crowded city street, heard a cricket; he can be
matched by the mechanic who in the turmoil of a machine-shop hears a
bearing-knock in an engine four rows removed. Again there is the savage
whose keen eye sees vast distances or detects a faintly-trodden blade of
grass; he can be matched by the scientist who under the microscope sees
a new world in a drop of water. I'he ear and eye are common human pos-
sessions as far as morphology is concerned — it is the degree of their train-
ing that differs. This type of reasoning can be applied to any phase of
Alan's activities: how he learns and how much he learns is dependent upon
his cerebrum and upon the cultural framework within which he learns;
the cerebrum is the constant factor, the cultural framework, the variable.
The same holds true for "intelligence," however it may be defined and
assessed. We repeat that biological superiority and inferiority in the stocks
and races of man do not exist, and that biologically there is no valid bar to
stock- and race-mixture. The first generation hybrids are not biologically
inferior — it is Society and not Nature that stamps the brand of unde-
sirability.

In recent years German anthropologists have, as we know, advanced
preposterous claims of Nordic or "Aryan" superiority (Das Herrenvolk).
Such claims have no basis in fact. They have also claimed that widespread
race-crossing ("race bastardization") will have a dysgenic effect ("gene
chaos"), leading to various bodily abnormalities and asymmetries. This,
too, is far more fanciful than real, though Fleming,^^ an English anthro-
pologist, has found some shght evidence of dento-facial disharmonies in
Negro-White hybrids crossed with Negro-Chinese and Chinese-White
hybrids. But this evidence is not conclusive, for there is no guarantee that
growth inadequacies rather than genes are to blame, i. e., that malnourish-
ment has not modified a genetic pattern. As matters now stand the crossing
between sub-species or stocks is socially so unacceptable that only lower
social strata are involved. It is precisely here that environmental impact
and modification — in terms of insufficient and incorrect foods, improper
hygiene, health hazards — are at their maximum. We have no adequate
basis, therefore, for a true assessment and interpretation of the solely bi-

15 Otto Klineberg, "Race Differences," Harpers, N.Y., 1935-, W. M. Krogman, "Is
There a Physical Basis for Race Superiority?" Sci. Mon., 51: 428-434, 1940; AI. F. Ash-
ley Montagu, "Problems and Methods Relating to the Study of Race," Psychiatry, 3
(4); 493-506, 1940.

18 R. M. Fleming, "Physical Heredity in Human Hybrids," Annals Eugen. 9: 55-81,

1939.

EVOLUTION 265

ological effects of stock-crossing. As far as we know the genetics of stocks
and races, we need not, a priori, expect any biological maladjustment.

This discussion has been. pretty much on the negative side — a sort of
"hit parade" of scientific uncertainty with respect to race biology: we
are not agreed what a race is, we are not sure when and how races arose;
we do not know the precise hereditary mechanism in race; we are not sure
which physical traits in race are stable, which modifiable: we do not know
physiological and immunological features of race-groups; we can not
assess race in terms of superiority and inferiority. In very truth we know
little about the bio-genetical aspects of race.

Despite the foregoing avowal of inadequate knowledge we venture to
present a definition of race that is sufficiently generalized to include the
variables of physical type, heredity, environment and habitat:

A race is a sub-group of peoples possessing a definite combination of
physical characters, of genetic origin; this combination serves, in vary-
ing degree, to distinguish the sub-group from other sub-groups of mankind,
and the combination is transmitted in descent, providing all condi-
tions which originally gave rise to the definite combination remain rela-
tively unaltered; as a rule the sub-group inhabits, or did inhabit, a more
or less restricted geographical region.

Certainly the physical anthropologist is not so dogmatic about the
clarity of distinction between racial groups as he once was. Indeed, there
are those who would deny the existence of human races, and who ad-
vocate dropping the term entirely. If the term race is purely genetic, and
if we do not know the genetic make-up (the genotype) of a presumed
race-group, then it follows that we can not define the group genetically,
and therefore it does not exist as a homogeneous genetic entity. This argu-
ment, as the present writer sees it, while biological on the face of it, stems
more from a cultural misinterpretation of the term ("racism"), wherein
race and nationalism are confused, than from considerations of presumedly
diagnostic morphological characters.

There do exist certain groups which may be put into categories; i. e.,
there are groups which tend to precipitate out when defined by a cer-
tain physical trait-complex. The trouble resides in the fact that the trait-
complex has been too rigidly defined, with too little allowance made for
variability. The physical anthropologist freely admits that his classifica-
tion has been based on the phenotype — the few external features used in
diagnosis. We are prepared to reclassify upon the basis of the genotype —
the basic genetic constituency. In both instances we will have groups called
races: in the first instance — the present-day method — groups are classified
by what they look hke physically; in the second instance — the emerging
bio-genetic method — groups will be classified by what they are genetically.

The term race as we use it to-day is a recognition that group differences

266

READINGS IN BIOLOGICAL SCIENCE

do in fact exist. It does not imply, scientifically and biologically, a homo-
geneity such as demanded by geneticists. When our knowledge of human
heredity enables us to classify the peoples of the world genotypically we
will gladly accept that classification — we will substitute it for the one
we now have. Until then, and with full and complete recognition of all
of its many inadecjuacies, we will use the system at hand.

<fc S '^ ^ ^ ^

>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<

II

Ecology

ECOLOGY deals with the action of the environment on plants and animals
and their reaction, in turn, to the environment. These patterns have
been built up through thousands of years of evolution and one should
realize that not only have plants and animals evolved but so also has the
environment.

When one considers parasites such as the tapeworm or the hookworm,
it is impossible to believe that they were always parasites. Sometime, in
the long dim past they were probably free-living. Organisms however can
change in man's memory too. The Colorado potato beetle was not always
a potato pest but fed on many western plants which were of no economic
importance. Not very many years ago it switched its diet and, using the
potato fields as highways, spread far and wide over the United States.
When plants and animals move to or are moved to different environments
they show startling responses in some cases. The English sparrow was' not
particularly numerous in the British Isles in the iSoo's but when brought
here to this country and released it increased enormously. The same
phenomena took place when the daisy, the dandelion, chicory, milfoil,
and devil's paint brush were introduced here from Europe. The Mongoose
became a pest in Australia and the muskrat became obnoxious in England
when introduced there.

In regard to the changes in the environment, it seems to be well known
that the sea covered large areas of what is now dry land. Wherever we
find marine fossil shells or other remains in rock on dry land we have the
right to assume that the immediate area was once ocean bottom. We also
know that the climate of many regions now cold was mild if not sub-trop-
ical. In the rocks of Greenland for example one can find fossil leaves of
trees now found only in warmer places. We know that the Great Lakes
region was once covered with a thick sheet of glacial ice and this certainly
made a great difference in the kinds and amounts of organisms there.

One of the chief studies in the science of ecology is the construction
of food chains. For example, the combustion of gases in the sun sends
waves of heat and light earthward. In the sea one finds tiny one-celled
green algae. These minute organisms absorb part of the light rays in their
green coloring matter or chlorophyll and with the use of carbon dioxide
and water they fix this light energy into the form of a sugar. This sugar

267

2 68 READINGS IN BIOLOGICAL SCIENCE

the algae 'burns' in respiration. Minute fish, however, happen to feed on
algae and the stored sugars; also vitamins pass into the systems of the
fish where they are utilized. These small fish are eaten, in turn by larger
fish and so on until they find their M^ay to the table of man or die in some
other way. Other organisms may enter into this chain and change its di-
rection. Animal life is dependent upon the sugars made by green plants
and the latter could not exist without light, heat, minerals, gases and water.
Thus we see a chain of dependence stretching throughout the realm of the
living. This is the chain of life.

INTERDEPENDENCE OF PLANTS AND ANIMALS *

A . S . PE ARS E

Since life began plants and animals have developed together. A plant
and an animal are more or less interdependent. The activities of one result
in waste products which are necessary for the syntheses of the othej*.
Photosynthesis, the process which gives rise to nearly all the organic foods
which are used by plants and animals, requires carbon dioxide which is,
in turn, liberated by the breaking down of the substance of living or dead
animals or plants. Decay is commonly brought about by bacteria and other
fungi. All living substance forms carbon dioxide as a result of its activities.
With a few exceptions, both plants and animals require a continual supply
of oxygen, and oxygen is an end product of photosynthesis. Carbon dioxide
in large amounts is injurious to living substance, and its presence may make
a particular locality unfit for life. On the other hand, the fact that it is
necessary for photosynthesis makes it a continual necessity for green plants.

Chlorophyll is the remarkable, life-supporting green substance which,
when given a supply of water and carbon-dioxide and energy in the form
of light, can manufacture simple starches and sugars. These in turn can
be built up by living things into simple protein substances if nitrogen and
a few other chemical compounds are available. Although nitrogen makes
up a large proportion of the atmosphere it cannot be used by living things
in its simple, gaseous state, but must combined with hydrogen, oxygen,
and carbon before it can be made a part of living substance. The only

Water J 2 hydrogen

contains \i oxygen These in the

presence of -
Carbon f chlorophyll

dioxide -i i carbon and light

contains U oxygen

The Manufacture by Plants of Organic Food from Water and Carbon Dioxide.

simple fi carbon
Will form — sugar •{ 2 hydrogen

•-I oxygen
Will se^f'^ree {' ^^^S^"

* Reprinted from Envirorifnent and Life by A. S. Pearse, by permission of Charles
C. Thomas, publisher. Copyright 1930.

ECOLOGY 269

living things which are capable of combining gaseous nitrogen with hydro-
gen and carbon are certain bacteria, especially those often associated with
the roots of leguminous plants, such as peas and beans.

Chlorophyll is not generally present in animals, but there are certain
of the simplest of Hving things which can live either as plants or animals.
For example, one microscopic organism, Chlamy domonas, when in light
manufactures its own food by using the chlorophyll in its own body, but, if
the same organism is kept continuously in the dark, it will lose its green
color and die if it cannot devour organic food, such as bacteria or other
minute things. Chlorophyll is not only essential as the machinery with
which organic foods may be manufactured, but it is of great importance
to animals in other ways. Some animals, such as certain protozoans,
sponges, corals, and flatworms, contain small green plants within their
bodies. These serve as little slaves which work to make food for their
captors, and in turn receive protection and the essential materials for such
synthetic activities. Chlorophyll is also known to be the source of pigments
which serve important functions in animals. Even haemoglobin, which
in blood is so essential for carrying oxygen to the tissues in man and other
animals, is believed to be derived from the chlorophyll which is taken into
the bodies of animals as food.

Plants, then, manufacture practically all the organic food in the world
and animals must obtain it from them. They are also the chief factors, as
bacteria and other fungi, in reconverting the bodies of dead plants and
animals into simple substances, such as water, carbon dioxide, and ammonia,
which may again be used in the synthesis of foods. Somewhere in their
substance plants also contain vitamins, which though they occur in minute
Quantities, have lately been shown to be of vast importance for the proper
nutrition of animals.

The dependence of animals on plants for organic foods brings about
certain general relations between the two. Animals that eat plant food
usually do not restrict their diet to particular species or parts of plants.
However some of them are very specific in their food preferences. For
example, the boll weevil eats only cotton and the pronuba moth feeds on
certain parts of the yucca flower. Animals that are non-specific in their
food habits act more or less as regulators in nature. They tend to keep
down the most abundant plants, which might otherwise become pestifer-
ous. Vegetarian animals are of course always much more numerous in any
district than the carnivorous species which prey upon them. There is a
series of dependencies in regard to food. Plants must be present in sufficient
numbers to support vegetarian animals without being seriously depleted;
carnivores can never be so abundant as to eat all the herbivores on which
they depend for food. In any locality the plants and animals are so adjusted
that their rates of growth and reproduction keep conditions fairly stable

270 READINGS IN BIOLOGICAL SCIENCE

year after year. Without the influence of man there is seldom any over-
grazing or famine.

Various animals have attempted to insure a stable food supply by storing
food or raising crops. Certain ants, squirrels, beavers and other animals
in times of plenty regularly gather appropriate foods which they store
away for unfavorable seasons. The ancestors of ants appear to have been
generally carnivorous, but certain desert species have gradually developed
habits of gathering, husking, drying and storing the seeds of certain grasses.
Other desert ants gather honey from flowers and store it away for use dur-
ing the dry season in certain peculiar individuals of their worker caste.
These remain within the nest, become greatly distended, and serve as
living bottles for their fellows. Some species of termites make httle beds
of wood, the dead bodies of their comrades, and excrement. On these
they plant and rear the fungi which they use as food. The leaf-cutter ants
have progressed to an even more specialized type of agriculture. They go
out along beaten paths and bring home bits of leaves. Some of these they
use to thatch over their nest, but others are chewed up and arranged in
beds on ^^■hich a peculiar type of fungus is grown. This is not eaten in
its natural state, but is first carefully pruned with the mandibles of the
ants. In this way pecuHar growths, which were called "kohl-rabi clumps"
by MuUer, are produced. These growths constitute the sole food of leaf-
cutters. When a young queen is ready to start a new nest she takes a little
of the material from an old fungus bed and places it in a little pouch at the
back of her mouth. She then makes her nuptial flight, breaks off her wings,
digs a burrow, cuts a few leaves and prepares a little bed. Then she takes
the fungus from the back of her mouth and plants it. She lays eggs and
carefully rears a few young. When these mature, they begin to care for
her and she then has nothing to do for the rest of her hfe but eat and lay
eggs. Aside from a few insects, man is the only animal which has practised
agriculture systematically. The assurance of a continual and adequate food
supply among insects and men has been important in making the develop-
ment of social life possible.

Plants are important factors in regulating climate and in making condi-
tions in any locality suitable for animals. They cover the bare soil and thus
conserve moisture. When there is a growth of plants over an area, winds
cannot dry out the soil so readily and deep-growing roots bring water to
the surface. Water is continually lost through the leaves of plants and by its
presence in the atmosphere tends to make temperatures more equable.
During the heat of the day water evaporates and thus cools the air. At
night its condensation gives up heat and its presence as vapor serves as a
blanket which prevents radiation of heat from the earth. Thus when plants
cover the soil they help to furnish water to keep air temperatures more
uniform.

Plants continually shed leaves which fall to the surface of the soil below

ECOLOGY 271

and serve as a ground cover. Such accumulations retard evaporation from
the soil, prevent rapid changes in soil temperatures, and exert other useful
functions. They furnish shelter and food for many animals and fungi. As
they decay, they produce heat which may be taken advantage of by many
animals. For example, the brush turkeys in Australia depend largely on
the decay of plant remains for the incubation of their eggs. These birds
scratch together great piles of leaves and twigs and place their eggs within.
They watch their rubbish heaps jealously and on warm, sunny days re-
move some of the material above their eggs, but during cold, wet weather
they pile on more. Certain centipedes, salamanders, lizards, and insects take
advantage of the heat generated by the decay of fallen logs to keep their
eggs and young warm.

The vegetation cover over a tract of country also conserves and holds
water in a more general way. The accumulation of living and dead roots,
stems and leaves, serves as a great sponge which retains water after rains.
In various countries where forests and other vegetation have been thought-
lessly removed, disastrous floods have followed. Of course floods do not
always result from denudation, but the removal of vegetation is perhaps the
most important factor.

There are many remarkable relations between flowers and animals.
Flowers offer various "inducements" to attract visitors. Bright colors and
characteristic odors make them easy to find; "rewards" to visitors take the
form of nectar, pollen, and other foods. In return for such "favors" animals
carry pollen from one flower to another and cross fertilization between
different plants is thus insured. Some flowers show a high degree of adapta-
tion for particular visitors. They furnish convenient landing stages, post
color signals which indicate the shortest routes to the gifts of food, and
have complicated entrances which prevent the stealing of "offerings" by
unwelcome visitors. Some flowers depend largely on small birds for pol-
hnation and show corresponding adaptations. They are usually red in color
and have long trumpet-shaped corollas. Other flowers possess special
features which fit them for "fertilization" by bees, wasps, flies, butterflies,
moths, beetles, or other animals. Avocado trees have two different types
of blossoms on a single tree. The male flowers on a particular tree may
open only in the morning, but on a nearby tree they open in the afternoon.
On the same trees the female flowers will be open on the first in the after-
noon and on the second in the morning. Insect visitors are thus pretty
certain to carry pollen from one tree to another, and not between flowers
on the same tree. The blooming of many flowers occurs at a particular time
of day, and the insects which best carry their pollen are active at such hours
but quiet at others. Flowers are often protected from creeping marauders,
such as ants, by having separate "offerings" of honey exposed below the
flowers; by isolation in or above water; by sticky secretions; by slippery,
smooth or waxy surfaces; and by other means.

272 READINGS IN BIOLOGICAL SCIENCE

Flowers have developed with animals. Millions of years ago there were
no flowers. The first plants which "crept" from the ocean and freshwater on
to land had none. Then plants began to develop pollen and seeds which
contained stores of nourishment. The developing land animals soon took
advantage of these concentrated and rich foods, especially during dry or
cold periods when other foods were scanty. As animals formed habits of
visiting particular plants, the latter gradually "responded" and various mu-
tual benefits were derived from such associations. Finally the plants came
quite generally to offer food, and advertised the fact; in return, animals
carried pollen and distributed seeds. Fruits were developed which fur-
nished luscious food about a hard or inedible seed. Today, a robin which
swallows a cherry regurgitates the "stone," and thus these seeds are scat-
tered about where they may find favorable places for growth. Burrs and
little beggar-ticks take firm hold on the hairy coats of mammals and are
widely distributed.

There are a variety of simple green plants, bacteria, and other fungi
which live in the bodies of animals and serve various beneficial functions
or cause diseases. Some of these aid in the digestion and assimilation of
food. In fishes certain luminescent bacteria live in special cavities and pro-
duce light when stimulated by the host in which they reside. There are
various fungi and bacteria which live in the skins of animals and cause
diseases. In man these are most frequent in dark-skinned races. There are
also bacteria which live within the body and cause diseases that are familiar
to all: typhoid, typhus, cholera, tuberculosis, leprosy, influenza, etc.

Plants frequently furnish shelter or permanent homes for animals. The
fibrous and woody portions of land plants are especially suited for such
purposes. The paper-making v/asps chew up fibers and shape them into
nests which show characteristic forms and considerable architectural
complexity. In the tropics bromeliads, which are all more or less like pine-
apple plants, harbor a great variety of animals, some of which are greatly
flattened or otherwise especially adapted to live in the spaces between the
leaves. Leaf-rollers, web-worms, and certain ants fasten leaves together
to make nests. There are even a few insects that habitually take shelter
within pitcher plants, which entrap and devour most types of insects.
Natural or artificial cavities in trees are used as homes by bees, beetles,
woodpeckers, owls, hornbills, squirrels, and other animals. Wood, on ac-
count of its flexibility, strength and durability is an excellent material for
the dwelling places of animals. It is also a good insulator and therefore
protects animals against the extreme heat of summer and the cold of winter.

Among the most interesting of the relations between plants and animals
are those furnished by ant plants. Most of these plants "provide" shelter and
food for their guests and in turn the ants protect them from browsing
animals and plant-eating insects. In America the ant plants are largely
acacias and cecropias. The former usually have hollow thorns at the bases

ECOLOGY 273

of the leaf-stalks. These serve as dwellings, and glands near the tips of the
leaves furnish food. The ants which inhabit acacias are very pugnacious
and have very potent stings. They drive away leaf-cutter ants and other
enemies. The cecropias provide many small chambers for dwellings within
their stems. They also supply food along their leaf stalks, but many of their
ants procure their food largely from plant lice which are kept in the cham-
bers inside the stems. The ant plants in Asia are usually somewhat sponge-
like, with intercommunicating spaces within a fleshy body and many
small openings on the exterior. In British Guiana, Wheeler studied an ant
plant which had about fifty species of animals associated with it. These
included twenty-eight species of ants, besides beetles, crustaceans and
other things.

The various associations between plants and animals not only show the
interdependence between the two, but also add to the evidence concern-
ing the high degree of adaptation that all animals show to the particular
environments in which they live. Animals are just as strikingly adapted to
the living things which surround them as to the non-living.

>>><<<■

SOME ADAPTATIONS TO THE ENVIRONMENT *
HORATIO HACKETT NEWMAN

"The adaptation of every species of animal and plant to its environ-
ment," says Jordan and Kellogg, "is a matter of everyday observation. So
perfect is this adaptation in its details that its main facts tend to escape our
notice. The animal is fitted to the air it breathes, the water it drinks, the
food it finds, the climate it endures, the region which it inhabits. All its
organs are fitted to its functions: all its functions to its environment. If it
were not so fitted, it would not live. But such fitness on the vital side leaves
large room for variety in characters not essential to the life of the animal."

So long as the environment remains uniform, a given species will remain
unchanged, except for minor fluctuations and occasional mutations; but
if the environment changes, sometimes even slightly, the development of
the individual responds in such a way as to give a radically different end
product.

If the organism fits the environment, no less certainly must the environ-
ment fit the organism. Professor Lawrence J. Henderson points out that
the environment, no less than organisms, has had an evolution. There is
hardly an element of the effective environment that could be changed
without causing the extinction of life or at least the transformation of it
so profound that it might not be hfe at all as we know life. Water, for ex-

* Reprinted from Evolution, Genetics, and Eugenics by Horatio Hackett Newman
by permission of the University of Chicago Press. Copyright 1925.

2 74 READINGS IN BIOLOGICAL SCIENCE

ample, has a dozen unique properties that condition life. Carbon dioxide
could not be replaced by any other substance. In brief, given the environ-
ment ns it is, life could not be other than it is. The evolution of the environ-
ment and the evolution of the organisms have gone hand in hand.

In the case of plants the action of the environment is remarkably direct;
for the plant cannot get away from a fixed environment. If the environ-
ment undergoes material change, the plant's only response is a structural
one. For example, if plants that are accustomed to a relatively humid cli-
mate are grown in the desert they develop numerous xerophytic adapta-
tions such as small leaves with greatly diminished transpiration surface,
a thick epidermis, hairs, or spines, small stature, deep-root system, and
other similar protections against the inimical desert conditions. Similarly,
plants accustomed to grow in relatively dry soil, if grown in soil that is
covered over with water, will produce aquatic leaves and roots and un-
dergo appropriate changes in epidermis and loss of supporting tissues, for
plants that are buoyed up by water need little support.

Animals, on the other hand, are for the most part not so intimately
related to a local environment as are plants. They are characteristically
mobile creatures with varying capacities for wandering about and select-
ing the habitat that best suits them. "Animals select their habitats. By this
we do not mean that the animal reasons, but that selection results from
regulating behavior. The animal usually tries a number of situations as the
result of random movements, and stays in the set of conditions in which
its physiological processes are least interfered with," according to V. E.
Shelford.

Many special adaptations may be explained through habitat choice.
Thus animals such as the duckbill platypus, the lung-fishes, and others
whose teeth are replaced by bony or chitonous plates that are used for
crushing the hard shells of molluscs and crustaceans, may not confidently
be said to have developed these crushing appUances in adaptation to a habit
of feeding upon hard-shelled prey; but rather it seems more likely that the
loss of teeth and the development of crushers occurred through a degener-
ative process incident to racial senescence and that the possession of the
crushing equipment enabled them to avail themselves of a new type of
food, formerly unavailable to them.

SOME SPECIAL ADAPTATIONS

The mammary glands of mammals are skin glands usually with well-de-
fined ducts leading to the surface and terminating in teats. In the lowest
mammals, the monotremes or egg-laying mammals, these glands are rela-
tively poorly developed and difi^use; also they are known to be developed
through a regional specialization of sweat glands. In the true mammals the
glands are modified sebaceous or oil glands and may be seen to develop
from the same embryonic rudiments as the latter.

ECOLOGY 275

The marsupial pouch of the kangaroo and its allies is a pocket-like fold
of the integument, folded forward or backward over the region of the
abdomen in which are located the mammary glands. Hartman has recently-
described a very striking pie'ce of behavior in connection with the birth of
young opossums. The young are born in an exceedingly immature state
and looking like tiny pink grubs. They crawl under their own power, by
means of a swimming-like motion, through the hairs of the mother's
abdomen, till they reach the pouch. This they enter unaided and each tiny
"larva" finds for itself a slender tubular teat, which it swallows and holds
in place by a specially adapted hold-fast mouth. The young remains
attached fixedly to this teat for several weeks, feeding almost constantly
on milk. After a long interval the teat is released, the mouth metamor-
phoses into the adult form and the young feeds only at intervals, as do the
young of other mammals. This complex of adaptive structures and instincts
is among the most remarkable in the annals of biology.

Nest-making instincts in birds represent, on the behavior side, adapta-
tions of extraordinary perfection. Some nests are built with the greatest
care and precision, others represent a relatively crude and slovenly per-
formance. Some nests are made of tvvigs, fibres, and mud, others of mud
alone, still others are hollowed out in clay or sand banks, and some are
made in holes in the ground. In any case, the type of nest is highly specific
and due to a hereditary instinct; for birds receive no instruction in nest
building.

A vast number of animals and plants have given up the active search
for food and have taken up the relatively easy habits of parasitism. In
adaptation to this life certain structures have developed and many of the
characters found in independent, free-roving creatures have disappeared
or become reduced to mere vestiges. Thus the more completely dependent
or parasitic an animal becomes, the more completely does it lose its organs
of locomotion and its sense organs such as eyes, auditory organs, tentacles,
etc. Some animals are free-living when young or in the larval condition
and only settle down to a parasitic life when near the end of the life cycle;
other animals are parasitic only when young or larval and become inde-
pendent in the adult condition; still others are parasitic throughout the
entire life-cycle and pass from host to host without any interval of in-
dependent life.

The classic case of extreme parasitic degeneration is that of SaccuUna,
a crustacean. The young larva swims about and leads a free life for a time,
but soon attaches itself by means of its antennae to a hair pit of a crab. The
internal tissues of the larva then undergo degenerative processes and are
reduced to an almost fluid mass of embryonic cells, which flow through
the hair pore of the crab and into the latter's lymph spaces. The small mass
of cells then rounds up and is carried about with the circulation of the
crab's blood until it comes to a favorable place of lodgment. Here it flattens

276 READINGS IN BIOLOGICAL SCIENCE

out and sends rootlike branches almost all over the crab's body, like a
malignant tumor. The unbranched part of the parasite is little more than a
sac of reproductive organs, and these produce eggs and sperms, which
unite to form larvae. By this time, the host is killed, and with the decay of
its body, the larvae escape into the sea water ready for a period of free life.

Commensalism may be defined as an association in which two organisms
exist in close association without any positive detriment to either. In some
cases the claim is made that the association is mutually beneficial, but as a
rule the relation is relatively one-sided.

Some of the most remarkable cases of commensalism are found in con-
nection with elaborate colonies of ants. In some cases two species of ants
live together in the relationship of master and slave. The master species is
unable to perform any of the ordinary duties of the colony, such as se-
curing food, taking care of the young, etc. In extreme cases the masters
are only soldiers, specialized for fighting and marauding, and cannot even
feed themselves unaided. The slave species would be able to carry on to
some extent if not captured, but thrives exceptionally well under the pro-
tection of the soldier species.

One of the weirdest environments the world affords is the bottom of the
sea at great depths. There it is dark and cold and almost devoid of oxygen,
while the pressure is almost unbelievably high. Yet in these vast and for-
bidding abysses there dwell in apparent comfort representatives of most of
the animal phyla. We do not at all understand the nature of the adaptive
mechanism that enables these animals to withstand with their frail bodies
the steel-crushing pressures that prevail at all such depths. We do know,
however, how some of the deficiencies of the environment are made good
by these denizens of the deep. Thus many abysmal forms produce their
own light by means of phosphorescent organs placed at advantageous
points of their bodies. Not only fishes of the depths, but some mollusks
possess forms of artificial lighting equipment.

Equally highly adaptive to life in a world of darkness are the strange
eyes of some of the abysmal fishes. Sometimes these eyes are enormously
large, and thus adapted to bring to the perception of the animal the weak
light of the depths, or again they may be modified still further in a strik-
ingly peculiar manner, each being drawn out into a cylinder and projecting
from the side of the head like a telescope. Such eyes are in fact not tele-
scopes, but are merely adaptations for concentrating the lights of low in-
tensity and making the environment visible.

Other creatures of the darkness live strange lives in caves, such as the
Mammoth Cave of Kentucky. Most cave dwellers are blind or nearly so,
and usually have a pale and ghostlike appearance because of their lack of
pigment. AH grades of defective eyes are found, ranging from those that
are merely somewhat smaller than normal to those that remain deeply
imbedded in the head in a relatively undifferentiated state. It goes with-

ECOLOGY 277

out saying that such animals are better adapted to life in caves than they
would be outside. One pressing problem of biology is: How did the cave
animals become blind? Did' they wander into the caves as normal animals
and become blind because their eyes were disused, or did they become
blind outside through no fault of their own, as a result of a mutation, and
by chance find safety in an underground stream or cave? The first explana-
tion is Lamarckian, the second Darwinian.

Adaptations are characteristic of all living organisms and must be ac-
counted for by any evolutionary theory that is to be acceptable. Any
theory that claims to account for new species but does not account for
adaptations is at best only a partial explanation.

BEES RAISE QUESTIONS *
HENRY S. CONARD

In many ways, the behavior of bees suggests our own ways. Old bee-
keepers always attribute to their pets the will, the motives, the emotions
that they recognize in themselves. Bee-keepers speak of bees in the lan-
guage of human conduct.

In comparing bees and men certain factors should be borne in mind.
From the evolutionary standpoint, we are of course very distantly related
to bees, but our common ancestry is not nearer than the segmented worms
or perhaps the Cambrian Eurypterids which lived 100 or perhaps 1,000
million years ago. A common origin of our protoplasm explains perhaps
the similarities between bees and men in their cruder chemical and physical
structure, and even in the muscles, nerves, skin, digestive tracts and body
fluids. Both man and bees are made up of proteins, fats and carbohydrates;
our active tissues are all protein in nature; we store excess food in our
bodies as fat (insects are very oily); we consume carbohydrates and oxi-
dize them for release of energy. We all get our protein and carbohydrate
from the plant world, and give it back to the plants during life, as water,
carbon dioxide and nitrogenous wastes, and at death our bodies return to
dust. There is little reason to think that our common ancestor was capable
of experiencing any of the appetites or emotions that we know in ourselves,
although Jennings does assert that if the amoeba could be seen and known
as we see and know dogs, we should attribute to the lowest animal organism
known to science "states of pleasure and pain, of hunger, of desire, and the
like, on precisely the same basis as we attribute these things to the dog."

Man and the honey-bee are, however, so profoundly different in most
respects that we might almost regard them as inhabitants of different

• Reprinted by permission of the Scientific Monthly, American Association for the
Advancement of Science. Copyright 1940.

278 READINGS IN BIOLOGICAL SCIENCE

planets. Where the two creatures resemble one another, we often seek some
other explanation than that of common ancestry. Usually it is due to adjust-
ment on the part of the bee to the same world as that in which we live and
to which we are adjusted. For life is adjustment, and any serious lack of
adjustment quickly leads to death.

Our common ancestor was without any means for breathing air or for
motion on land or for resistance to the desiccating effect of dry air, or for
terrestrial hearing or smelling or seeing. It follows therefore that the ad-
justments of men and bees to terrestrial Hfe have been achieved quite inde-
pendently of each other.

As to breathing, we "draw air" into our lungs, there load the blood with
oxygen and then pump it throughout the body to carry oxygen to the
tissues. The insect has a system of fine air tubes whereby the air itself is
carried to every part of the body. For motion the bee has six limbs to our
four, and surpasses us completely by the possession of four wings. But her
limbs so closely resemble ours — made up of two long pieces and a set of
small pieces at the foot — that we not only speak of the legs and the feet of
the bee, but we call the parts femur, tibia and tarsus. Obviously this re-
semblance is strictly superficial. It is not due to common ancestry, but to
the mechanical nature of the world we inhabit.

The skeleton of the bee consists entirely of her hard outer shell, which
serves in place of bones. This shell also serves to prevent desiccation. Our
bones are inside us, and consequently we must have a special waterproof
skin to keep us from drying up. The powerful muscles of the bee are at-
tached to prongs and bars of the shell, which often project far into the
insect's body. That this method is adequate is proven by the legs of the
grasshopper and the wonderful flight of many higher insects. Once I saw
a worker bee grasp a dead bee by her legs and fly up as high as the house
and over a neighbor's lot before dropping her load. The muscles of the bee
are "striped" exactly as are the voluntary muscles of the vertebrates. No
worms have such muscles.

The eye of the bee is too complex to describe in detail, but it depends
upon the lens-shaped bodies of dense refractive material which focus the
rays of light. Of course, this is an adjustment to the nature of light-waves
in relation to solid bodies. The food of the bee consists of nectar, or honey,
and pollen, the latter being the richest bit of protein that plants produce.
Why has man never found a way of eating pollen? I have tried it but with-
out success; it didn't taste good. The nectar of flowers is mostly a very
thin solution of cane sugar which the bee sucks up and swallows into a
special pouch called the crop. The crop connects with the throat of the
bee, as our lungs connect with our esophagus. In the crop later, the cane
sugar is partly inverted or predigested, becoming dextrose and levulose.
This is exactly the effect of human digestion upon cane sugar.

I

ECOLOGY 279

In the hive, the bee regurgitates the thin solution of sugar which is
received and placed in a cell of the honeycomb by a house servant. The
water is evaporated by currents of air, set up by fanning by the wings of
the bees. During this process the honey is tongued and tested by another
class of workers. When a cell is full of sufficiently concentrated honey, it
is capped over with wax and sealed. Now this honey, or nectar, serves as
the carbohydrate ration for the bee, but pure cane sugar syrup does just as
well. Consequently we may take away from the bees all the honey they
make and feed them during the winter on a sugar syrup. At this point their
digestions are very much like our own, but the inversion of cane sugar
in both cases is due primarily to the nature of the sugar molecules, not
to the relation between bees and men. Nor should it be assumed that all
protoplasms can use the sugars interchangeably. Many bacteria can use but
one or a few kinds of sugar and will absolutely starve if given only some
other kinds.

Well-finished honey is about 20 per cent, water. A colony of bees will
consume from 20 to 40 pounds of honey during the winter months when
they can not leave their hives. For each pound of honey consumed, at least
three quarters of a pound of water and one half a pound of carbon dioxide
will be exhaled by the bees. That is, a hive of bees generates seven to ten
quarts of water during the winter, all of which must be expelled from the
hive. It is a delicate matter to get enough ventilation to eliminate the mois-
ture, and yet not take in enough cold air to freeze the bees. Sometimes the
water does condense on the inside walls and top of the hive. If it drips down
and freezes at the entrance to the hive, completely stopping the entrance,
the colony will quickly die for lack of air.

The production of carbon dioxide by bees, as by other animals, increases
with the temperature and the activity of the animals. When cold and at
rest, bees produce but little carbon dioxide and need but little air. One cold
evening in early winter, I moved two hives, disturbing the bees and setting
them in motion. For some hours afterward it was necessary for them to
keep up a vigorous fanning with their wings at the entrance of the hive
in order to expel the vitiated air and to draw in enough fresh, cool air. On
moving one hundred hives of bees one autumn, we packed the entrances
tight with soft snow in order to keep the bees from emerging. But the bees
directed a current of warm air against the snow and melted holes through
it in from three to five minutes.

In winter, or at any time of rest, the bees cluster together in a solid mass.
Those at the center are constantly working out to the surface of the mass,
while those at the surface are working in. A neighbor undertaking to kill
a small colony by freezing, uncovered the hive, spread the combs apart,
and left them overnight. The next morning, with the temperature at io°F.,
all the bees were still alive. By remaining in a compact mass and continually

2 8o READINGS IN BIOLOGICAL SCIENCE

ex'changing places they were kept warm by their own body heat (com-
bustion of sugars). The healthy cluster maintains a temperature of 57° or
above.

Bees can not void their excrement except when flying; at least it is be-
lieved they do not. During the winter their abdomens become greatly dis-
tended with waste matter. If their stores are of inferior honey, this condi-
tion will be intensified and may prove fatal. If wintered out of doors, bees
usually find days in Januar)^ or February when they can fly out. Hence,
wintering out of doors with sufficient protection is better than wintering
in a cold cellar, for in the latter case so-called cleansing flights are impos-
sible. Since bees can live all winter with only honey, i. e., water and carbo-
hydrate for food, during these periods they use protein sparingly in their
life processes, and they must be in a state of extreme protein starvation
when spring comes. There are in honey, usually, a few grains of pollen,
and some pollen is commonly stored in the hive in the cells separate from
the honey. Perhaps from these sources bees get a sufficient protein ration,
but I think they eat only honey in winter.

The personnel of a colony of bees consists of three castes or classes:
drones, workers and queen.

Drones are male bees. They are much larger than the workers, and are
present in a hive by tens or hundreds. The drones can not gather honey or
pollen and can not even feed themselves, but are fed by the workers. They
buzz very viciously but have no sting. Their sole contribution to a colony
of bees is to mate with the queen, and since a queen mates but once in
her life, very few drones ever mate. Drones are reared from June into
summer. In September the workers drive them out from the hive and pre-
vent their return. So they starve to death or die of cold.

Drones are the product of unfertilized eggs laid normally in the larger
cells of the comb. All drones, therefore, are fatherless, though they have
grandfathers and stepfathers, because queens and workers develop from
fertilized eggs, and have a male parent. And a drone which mates with a
queen will be the male parent of hundreds of workers and a dozen or more
queens.

Beekeepers always think of drones as lazy, happy-go-lucky louts, with
nothing to do but eat, sleep and buzz about on sunny days, waiting for an
occasion for mating. But for the drone, the mating is a serious matter, for
the act is fatal. The queen returns to the hive with the end of the abdomen
of the male torn off and hanging to her.

There are from 20,000 to 50,000 (some say 80,000) workers in a strong
colony. The worker is an unsexed female, with only rudimentary ovaries,
but in a queenless colony one or more of the workers may acquire the ca-
pacity to lay eggs. Probably this condition is brought about by the exces-
sive feeding of selected young bees. Such "laying workers" never leave the
hive and never mate. Hence they never lay fertilized eggs; their eggs are

ECOLOGY 2 8 1

fatherless and hatch out only drone bees or males. Such a colony soon dies
out, since no new workers can be raised and the life of a busy worker in
summer is only five or six weeks. Workers hatched late in autumn live
over winter, and do a few weeks' work in spring. To get rid of laying
workers, one has only to shake all the bees out of the hive in a grassy place,
a hundred or more feet from the original position of the hive; the regular
workers will easily find their way back to the old stand; the laying workers
never having been out of the hive, can not get back and will perish. Then
the helpless, eggless colony will accept a new queen, if one is offered to it.

Workers alone have mouths for collecting nectar and the honey-carrying
crop. They also have combs on their front legs especially suitable for comb-
ing pollen off their bodies. The second pair of legs has a notch through
which the first legs can be pulled, to gather up the pollen; and the hindmost
legs have each a little basket in which the pollen is placed and carried home.
Workers differ greatly in their use of this natural equipment. Some return
home all dusty with pollen, and let their sisters clean them up. Others enter
as neat as a pin, with huge sacks of pollen on their legs.

Last summer a loaded worker entered an observation hive and presently
walked along one side of the comb, then went over to the other side,
rambled about over and through and under a cluster of bees, looking into
various cells here and there and, finally, after several minutes, settled on
a place to unload. She put her hinder legs deep into a cell, and remained
for about a minute; then she pulled them out, leaving her two lumps of
pollen loose in the cell. Immediately, another worker went in head first
and remained for about a minute. When she came out, the pollen was
tightly and smoothly packed in the bottom of the cell. The bee which lost
the time in deciding on a place for depositing her pollen was t)*pical, for
most bees seem always to be just milling around aimlessly over the comb.
Do not send the sluggard to the busy Httle bee to learn a lesson in efficiency.

Observers remark the same characteristic when the bees are building
their marvelous comb. They run about without any semblance of order
or continuirs' of work. A bee bites at the comb here, sticks on a bit of wax
there, and runs on while others follow. But meanwhile the marvelous comb
grows up before our eyes! The wax is secreted in scale-like pieces on the
under side of the abdomen of the workers. To produce the wax they eat
vast amounts of honey and hang in characteristic clusters over night. The
wax appears in a few hours. Bees consume about twelve pounds of honey
to make one pound of wax, but one pound of wax will build enough comb
to contain sixteen pounds of honey. The cell of the comb is not only
hexagonal — a response to the nature of the space in which we live — but
its axis slopes upward, so the honey will not drip out. There is, therefore,
a very definite right side up for honeycombs.

There are three sizes of honeycomb cells. Most of the cells are almost
exactly one fifth inch in diameter. As long as the queen lays eggs in the

282 READINGS IN BIOLOGICAL SCIENCE

cells as fast as they are ready, this size cell is made. If the workers get ahead
of the queen, they build larger cells one fourth inch across. For storage
of honey, even larger cells may be made. But all this variety is produced
in an apparently disorderly, helter-skelter manner by a host of workers,
running about over the comb. We have absolutely no conception of how a
precise piece of work can be turned out in this way. Nor can we believe
that the method is economical or efficient. Apparently it succeeds merely
by dumb persistence — by force of numbers and in defiance of time.

The workers are custodians of the hives; it is they who fly out and sting
the intruder. But the different varieties of bees differ greatly in irritability.
The gold-banded Italians sting only after rough handling, but a black bee
will probably sting you if you simply stand within five feet of her door-
way. This reaction is changed by puffing smoke into the hive or upon the
bees. Certain it is that smoke induces the bees to rush to the combs and
gorge themselves with honey without stopping to sting the intruder. After
smoking the bees, one can open the hive, lift out the combs one by one, and
inspect them minutely. Sometimes not one bee will attempt to sting; at
other times, however, a half dozen will leap on one's hand at once and
sting with great energy. Why the calming influence of smoke?

Animals and plants respond to natural stimuli in a manner that has
proven, in the last million years of experience, to be useful and profitable.
A new and strange stimulus will call forth one or another of the reaction
patterns that have been established by age-long experience. Is smoke a
new experience, and the reaction fortuitous, or is it a very old stimulus
with an adaptive reaction? Since bees have lived for ages in hollow trees,
the smell of smoke may indicate to them that their tree is on fire and that
the colony should move. So the bees load up with honey and get ready.
It is probably possible so to smoke a hive that the workers will leave it,
taking their queen along, but usually the queen simply hides among the
bees or in some corner of the hive. This hiding of the queen is doubtless a
reaction to the stimulus caused by opening the hive. In all the pre-human
period bee hives have never been opened up and the combs removed ex-
cept by predatory animals. And the combs were never put back in as I do
it until the invention of the movable frame in 1852. Under such conditions
the preservation of the colony depended upon the queen being hidden
among the mass of the bees, or tucked away in some deep crevice. Then
when the marauder had gone, she could come out and join the remnant of
her family to reestablish a home in the same or another hole in the tree.

So when I smoke my bees, and proceed to tear open their hive, I turn
loose two ancient behavior patterns — the behavior suited to a burning tree
and that suited to an attacking animal. For the first, the bees fill up with
honey and do not sting; for the second, they sting violently and hide
their queen. The business of the beekeeper is to keep enough smoke in the

ECOLOGY 283

air to hold the insects to the burnt-tree type of reaction. Even so, why the
difference in irritability of the several varieties of bees?

The ability of bees to make long journeys — two to four miles — and re-
turn unerringly to their own hive is remarkable. The feat becomes more
interesting when we see the bee yard containing 50 to 100 hives, all made
as nearly alike as modern machinery and paint can make them, and packed
so closely that there is just room for the beekeeper to pass between them.
But interest culminates when we learn that this skill is the result of careful
training. A young bee first emerging from the hive suns herself on the
front porch. Later she flies out a foot or two and buzzes about facing the
hive. Then she goes farther and farther, still facing the hive — say to ten
or fifteen feet. Finally she makes a real collecting trip.

Last summer I placed a comb of bees in an observation hive, fastened
them in, placed them in the cellar to cool off. They settled down at once.
Twenty-four hours later I found they were humming in a tone that indi-
cates mild excitation. (One can tell what a bee is likely to do next by the
tone of her humming, just about as well as you can predict the next act
of a dog or a person by the tone of his voice.) I took my bees out to a new
location and opened the little doorway. It was six p. m., just growing dusk.
In a few minutes one bee found the open door. She crawled out, made
sure of her freedom, and then stood by the door and buzzed till you couldn't
see her wings. Soon another came, and she buzzed too. Then they all made
for the door and poured out in a stream, mostly taking wing at once. For
several minutes they made quite a swarm within 3 or 4 feet of the little
hive, milling about in the air, all facing the hive. Then they spread out
farther and farther, to 100 feet or more. I thought they must all be gone.
But while I thought it, the crowd gathered again by the door, and all poured
in as eagerly as they came out before. In a trice all were in and quiet. Had
they been studying the location? Ordinarily, when collecting, they run
out of the hive and take wing without a look behind; and returning, swoop
out of mid-air directly into the doorway.

When it is necessary to move a colony, one should place a board or net
in front of the hive in its new location, so the bees will be compelled to take
notice as they come out. The obstruction can be removed after a day or
two. There is no doubt that bees can learn to find a certain location, both
for their home and for their collecting grounds. A good collecting ground
is revisited until its resources are exhausted. Then a new place is sought
and similarly worked. Ability to do this is essential to the life of the bee.

I do not see in this any general ability to learn. It is only an adaptation to
the peculiar life of bees — gathering nectar from the successive fields of
flowers from season to season — and the change of abode when swarming.
It does not indicate any ability to learn in any other realm of knowledge.

When bees are much agitated by a disturbance in the hive or by the

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excitement of stealing made-up honey from whatever source ("robbing"),
the bees do not usually settle down until nightfall; they have to sleep it
off. The length of time for relaxation depends on the intensity of the
stimulus. So it is with a person. When he is greatly excited, he gets a large
dose of adrenalin poured into his blood from those little glands in his back.
And he simply can not settle down until that disturbing hormone is oxi-
dized or eliminated or sent back to its place. Ritter suggests that the human
organization is unified by hormones. Does the bee have hormones? Does
a puff of smoke let loose in her body fluids some guiding substances from
some hidden gland? And when I open the hive, do I stir up some other
hormone, which keeps Miss Bee literally on pins and needles until the hor-
mone works itself out?

Speaking of robbing, whenever bees find a chance to gather real honey,
ready made, they go for it and carry it away with the utmost haste and
energy. They often tear a comb to pieces, a thing they never do in their
own hives. They fight one another while gathering the loot. They are
unusually irritable and Hable to sting. Once about noon I left a lot of combs,
wet with honey, exposed in my shed. On getting home at five o'clock, I
found the air full of bees buzzing around the shed and the shed crowded
with bees. A neighbor down the street called my attention to the great
numbers of bees buzzing around his house, my bees stirred up by the experi-
ence of robbing. Were I a Maeterlinck, I could describe them as exhibiting
all the passions of a madhouse or an army. With nightfall, the bees mostly
came home. I put the exposed combs under cover by candle light, and
next day all was quiet.

Bees sting in different ways at different times. If one alights quietly
on one's face or hand, she means no harm, and soon flies away. If she gets
into one's hair by accident, she hurries down and stings. Why? because
among the hairs she feels caught; the reaction is to injure and drive away
the enemy. If she alights on one's arm and one's sleeve presses down on
her, she stings. A drop of ammonia cures it. If her hive is disturbed she
comes out with a shrill whistle of the wings, and the intruder is in for it.
She alights on his glove, bends down her abdomen and gives a thrust. It
misses its goal in the soft fuzz of the gloves. She thrusts again, with a violent
contortion, — she misses. Again she thrusts, with a violence that nearly
bends her double, and draws her abdomen into a sphere. One is obliged to
think of it as an expression of baffled rage and savage bitterness. She looks
and behaves like a veritable little fury.

The queen fulfils the Christian admonition that he who would be greatest
must be servant to all. (That is the only Christian virtue about bees.) She
has absolutely no freedom of action whatever. She can not feed herself,
but is fed by her daughters. When she lays too many eggs, the workers
withhold food and she lays fewer. If she lays too few, they feed her up. So
do beekeepers. If that doesn't bring results or if she lays only unfertilized

ECOLOGY 285

drone eggs, she is carried out and killed, and a new queen is raised. If she
lays eggs in small wax cells, and she is young, she lays fertilized female
eggs; if the cell is a large one,- she lays unfertilized drone eggs. It seems to be
simply a matter of the size of the cell. When the bees are moved to swarm
out and leav^e the hive to start a new colony, the queen goes along with
them. If she doesn't go, a guard of workers goes in and gets her. Two sum-
mers ago a swarm came out of one of my hives. I caught the queen with
difficulty and awkwardness, put her in a cage after much fingering, and
gave her and her flock a new hive. Next morning I found her lying dead
in front of the hive, with a few bees crawling over her. Authorities tell me
I handled her too much; she got a strange smell and the workers killed her.

When a hive is opened on a rainy day and rain falls into the hive, the
workers are hkely to kill the queen. These are reactions for which it is not
easy to see an explanation. Once a colony was left queenless by such mad-
ness and without hope of ever getting a queen. Left to themselves they
would have died out. But they were given the makings of a new queen,
which they accepted, and raised a queen and produced 15 pounds of good
honey.

Queens and workers come from exactly the same kind of eggs. Queens
are raised in very large cells, as big as the end of one's little finger, and are
fed as larvae upon very rich food called royal jelly. If one takes a young
worker out of her cell and places her in a big cell with a bit of royal jelly,
the bees will go and make a queen of her. Or, if the queen is removed, the
bees will make several queens from the recently laid eggs. When, in 16
days, those new queens are hatching there are exciting times.

A queen emerges pom her cell with a number of complete behavior pat-
terns. One day a worker came by just as a queen emerged. She jumped on
the worker and was about to give the death blow with her powerful sting
when she suddenly stopped and got off. My informant remarked that "she
discovered her mistake." Did she? Soon she met a newly hatched queen.
Again she leaped on and this time she plunged her sting into the abdomen
of her victim between the plates of armor, and the victim curled up and
died.

After killing all her immediate rivals, the young queen lives quietly for
a day or so, and then goes out on her mating flight. A few workers go with
her. They fly up into the air and are gone a few hours in the middle of the
day. She meets the drone in flight and receives into a little sac enough sperm
cells to supply her egg-laying for two, three, four or even five years — 200,-
000 to 1,000,000 male sperms. She returns to the hive with a high degree
of certainty. Whether she finds her own way back or is guided by her more
experienced attendants we can not say. Having returned, she is groomed
by her maids, and in two or three days more begins her career of egg-
laying. On occasion a vigorous young queen caji lay 2,500 eggs a day, jnore
than twice her own weight!

2 86 READINGS IN BIOLOGICAL SCIENCE

For various reasons we often want to give a new queen to a colony — a
queen of our own selection, which is quite possible if done correctly. First
we must remove the present queen and be sure that no laying worker is
at hand. It is well to wait three or four days until the bees have themselves
built queen cells and begun to raise new queens. Then destroy all these
beginnings, and the colony is hopelessly queenless. There are many ways
of introducing new queens. Of course, the situation is absolutely new and
strange in the experience of bees. They have no behavior pattern for such
a situation. It can only call out some kind of behavior that has been de-
veloped for some other circumstances.

Sometimes in adding a new queen to a queenless colony this colony is
joined with another. Now there are only two natural situations where a
large number of bees enter a colony: First, where a swarm settles in a hole
that is already occupied; in this case there is a strange queen as well as
strange bees — hence some of the behavior towards strange queens. And,
secondly, where the strangers come in to rob and carry off honey. In
either case, the rightful owners do all in their power to drive off and kill
the invaders. This, then, is the natural reaction when two colonies are
united. Last summer I put a small group with a bigger one, and next day
the ground in front of the hive was littered with dead bees. Apparently
every stranger was killed. To obviate this difficulty, some beekeepers turn
in a quart or two of strange bees into the hive and then sprinkle in a quart
or so of water. The water changes the type of reaction. One old man tells
me: "Oh, no trouble at all. If they get to fighting, just get a spoonful of
flour and dust it into the hive all over the bees. Then they get so busy clean-
ing each other off that they forget all about their quarrel." Why does it
work?

I have spoken of the bee as a combination of hereditary structures and
behaviors. But it must be remembered that the parents of worker bees are
drones and queens, and these parents do not have the characteristic struc-
tures nor the industrious or warlike habits of workers. How can workers
inherit characteristics which their parents do not possess? Only, as some
wag said, by inheriting from their maiden aunts.

While this inheritance has been considered a problem, it is really not
so. Or, rather, it is a commonplace problem, and part of all considerations
of heredity. Bees are improved by breeding from those queens whose off-
spring are most productive and least irritable. And nature too has certainly
bred from those queens whose offspring best fitted themselves to their
surroundings.

It is very easy for me to believe that the bee is a kind of automaton — a
complex of physico-chemical reactions bound by and leading to a com-
plex of behavior patterns — and that all is dependent on the nature of the
materials and forces of our world and the million-year-old inherited ex-
perience of bees. But if that conception of the bee is true, what am I? If

ECOLOGY 287

the bee could observe me as objectively as I observe her, would she not
define man in exactly those same terms? Can she do otherwise? Can I do
otherwise?

>■>-><<■<

HOW DANGEROUS IS THE JUNGLE? *
C. SUYDAM CUTTING

A good way to improve one's knowledge of natural history is to look
into some of the misconceptions that have arisen about the character of
wild animals. For misconceptions, like bad pennies, keep cropping up in
daily conversations, and our knowledge of animals must stand that test
before we can go further. I refer not to wild animals seen along the length
of a rifle barrel but wild animals as they exist under natural conditions. Our
discussion will be limited to some simple observations, for I have never
undertaken an exploring trip for the prime purpose of studying wildlife.
But I have always been as much interested in the natural behavior of the
wild animals I have hunted in Africa and Asia as in the actual sport.

For all the danger to the lesser animals, the jungle is a more tranquil spot
than the romancers make out. The man who enters it for the first time may
expect to see a congress of frenzied animals with a symphonic background
of roaring lions, barking jackals, hissing snakes. Instead, he is surprised to
find a vast silence, broken only by the cries of birds and the stridulations
of insects. If he stays long enough, he may, depending on the region, hear
a lion roar before starting off on a hunt, a hyena growling as if the sounds
came from the depths of his bowels (the hyena's growl, contrary to legend,
does not resemble laughter! ), or a jackal barking his Hght, sharp note. Many
animals will probably maintain a discreet silence.

The quietest time of all in the jungle is high noon, when the glare of
the sun and the heat reach their greatest intensity. Most of the animals are
probably sleeping. Even the birds and insects relapse into dead silence. Only
the bees are inspired to greater noise and activity by the bright sunlight.

Late in the afternoon life begins to stir. Toward their various water
holes, animals of all kinds begin their cautious descent. Whereas the rumi-
nants want only a drink, the meat-eaters are yearning for dinner. The
mortality curve rises at this hour.

The lion, tiger, or leopard will probably start his prowling toward the
watering hole of lesser animals. The big cats are extremely agile but at
the same time they are not in the market for any long distance runs. They
first stalk their victims and then make a rush. When they get near enough
to strike, it is all over for the victim.

* Reprinted by pennission of Natural History Magazine and the author. Copyright
1941.

2 88 READINGS IN BIOLOGICAL SCIENCE

Having killed, the big cats do not proceed to eat the entire carcass im-
mediately. They eat a little starting from the rear, and return later. A car-
cass left for 24 hours in the jungle is likely to become carrion. And carrion
is what the big cats like.

Now and then a big cat rushes his prey and misses. In this event he is
usually disinclined to give chase. Racing through the jungle or across the
open plain is not to his taste. If he bides his time he will find something
later with less effort.

Offhand one would think that the habit of leaving game for the morrow's
meal would result in thefts and hence lead to fights among the big cats
themselves. But the instinct of these animals is usually to eat their own
kills and let the property of others alone, and they usually lie up near their
kills.

THE VULTURE "GRAPEVINE"

When the beasts have consumed their prey, the vultures take their turn.
It has taken a great deal of observation to discover the secret spying methods
of these birds. At the moment a beast makes a kill, the human eye is often
unable to discover a single vulture either in the sky or in the surrounding
trees. Yet within a few minutes, scores, sometimes a hundred birds, come
wheeling down from the sky, to fall on their game — what is left of the
animal.

Their system is simple. Spaced far apart in the sky beyond the range of
binoculars, they are able to survey a wide stretch of territory. If one de-
tects something promising, he swoops lower to have a look. One bird sees
another swooping down, and curiosity moves him to follow. The signal
spreads for miles around. The sky patrol, too high for human vision, oper-
ates very efficiently.

With possibly the single exception of the leopard, big cats are not in the
habit of killing more than they can eat. This acts as a sort of safeguard for
the lesser animals, for all can tell the difference between a hungry cat and a
sated one. Once when I was in a machan (a high platform in the trees from
which one observes game), I heard a sambar deer get near enough to a tiger
to bell at him. The tiger in the neighborhood of his latest kill seemed in
no hurry to start feeding. This reassured the deer, who kept up his belHng
for quite some time and then moved off.

In discussing life in the jungle I have said that the danger for a man is vastly
exaggerated. Others have said this before me, and some have gone far
enough to say they preferred a jungle, from a safety standpoint, to Fifth
Avenue, New York, in the rush hour. I wouldn't go that far.

If there were no other reason to fear most jungles, there would be ma-
laria. There are also scorpions, centipedes, stinging ants, and wild bees.

In Kohima, Assam, a swarm of wild bees once appeared on a tennis court

ECOLOGY 2 89

while I was in the middle of a game. My partner called across in a peremp-
tory tone, "Stand perfectly still! Don't budge!"

I obeyed, standing breathless for several seconds while the bees whizzed
by only a short distance above. The queen was in the center, of course,
and any gesture indicating danger to her might have brought the vast cloud
closing in around our heads.

We have said a great deal to deflate the common romantic idea of the
jungle and the habits of wild beasts. But the fact remains that man-eating
animals do exist. When lions, tigers, and leopards acquire a taste for man,
they are terrible, relentless enemies. When a big cat shows a tendency to
attack man, he is, of course, an abnormal animal, and it is often difficult to
say with any degree of finality' what caused him to become abnormal.

Many explanations have been given. A big cat, once wounded by a man,
may develop an inclination to attack men without further provocation.
By example the young may be taught to become enemies of man. Aged
or disabled cats that find difficulty in slaying other animals may take to at-
tacking human beings. Cats that have tasted human flesh seem more dan-
gerous than those that have not. Many are the theories and difficult are the
proofs. Case histories of wild animals, it stands to reason, are difficult to
procure.

A distinction should be made between animals in the jungle and animals
that wander afield near human habitations. When one reads that 3000 peo-
ple lost their lives to wild animals in India during a single year and that
1600 of these were tiger casualties, there seem to be grounds for the notion
that the jungle is as dangerous as the romancers make out. Actually the
figures prove no such thing. Few of the casualties occurred in the jungle.
The miscreant beasts were prowling near villages, many doubtless bent
on stealing domestic animals. Their encounters with man certainly altered
their natures. It is impossible to say how many of the attacks were un-
provoked.

Selous, the most famous of big game hunters, who was killed in the Great
War, said, "Any man who invites the charge of a lion is an idiot."

Tigers have a better opportunity than lions for declining further ac-
quaintance \\ith man. Whereas a green hunter, starting off in real lion
country with the proper guidance, feels reasonably sure that his chances
are good to get a lion, the tiger hunter has no such assurance. He may, as
a matter of fact, undertake many shooting trips and never see a single
tiger. Bigger and stronger than the lion on the average, the tiger is also
more elusive. He is never seen in large numbers. His habitat is dense jungle
and high grass. All in all, man and tiger meet less frequently than man and
lion.

The density and height of vegetation in the Asiatic tiger country defies
a hunter's vision. If he is on foot, views of the tiger are momentary and re-

290 READINGS IN BIOLOGICAL SCIENCE

quire a quick sliot with very little time for a careful aim. Facing a wounded
tiger in a jungle is a truly hazardous position. For this reason tigers are
shot from the back of an elephant or from a machan which is set 20 feet
or more above the ground. Natives of the tiger and hon country erect
thornbush palisades to protect their cattle.

What has been said of the tiger applies also to the craftier and more
courageous leopard. The same land usually harbors both animals.

Two ruminants who can be very dangerous because of their size are the
bison and water buffalo. These animals, if wounded, may charge a man.

I learned something about the water bufTalo during a shoot with Theo-
dore Roosevelt, Jr. We were stalking a large herd in a vast, open dry swamp
in French Indo-China. Because there were no trees and the grass was too
short, we had inadequate cover. The herd sighted us. Instead of moving
away or stampeding, they turned and faced us, with their leader out in
front. At that time we were shootings with a Frenchman named De Fosse
who had lived in Indo-China for a long time and knew the habits of the
water bufTalo. Instantly he perceived danger. "If the leader makes for us,"
he said, "the whole herd will charge at us blindly. They have no purpose
of their OM'n, a mere blind impulse to follow the leader. All of us must
fire at the leader."

We lifted our guns. We fired. Two animals fell. There was a breathless
pause while we waited to see if there would be a charge. But the noise of
the guns terrified the entire herd. They stampeded away from us.

In South India I had an experience with the bison, or gaur, of that coun-
try. Once a solitary bull was wounded and he escaped into the jungle. We
had to follow him for more than a day before finishing him off. My com-
panion on this pursuit was Randolph Morris, a coffee planter, with whom
we were staying. He knew the habits of the bison, and it was under his
direction that we moved forward with infinite care from tree to tree.
Twigs, dry leaves, and clumps of earth were daubed with the bloody foot-
prints of the wounded beast. The jungle interfered with our vision. While
we could always follow the animal's path, we could not gauge his proximity.
From time to time we threw stones into the dense thicket in order to lo-
cate him.

Hour after hour we followed the bloody track. Once we got within 50
yards of the animal. Morris had decided it would be too dangerous to in-
vite the frontal attack of an animal weighing almost 2000 pounds. A way
had to be found to divert its attention.

When we found ourselves in a tiny glade not far from the animal, Morris
tossed a knife, hoping the enraged bison would charge it and give us an aim.
He threw it too far. The knife landed in thick jungle out of our sight. But
suddenly we heard a snort, a bellow. The 2000-pound beast was crashing
through the jungle. Our native servants were terrified and clambered up
the nearest trees. Just at this minute I looked up. An enormous red and black

ECOLOGY 291

squirrel, four feet long, went springing from tree-top to tree-top with such
speed that he seemed to be flying. Then there was silence once more.

This failure meant many, more hours of stalking. It was not until the
next morning, as a matter of fact, that the bison was brought down.

These instances prove but one thing, that the bison and water buff"alo
are disposed to charge, given sufficient provocation. The word "provo-
cation" is important. These two ruminants, along with the big cats, have
been taxed with a fundamentally hostile attitude toward man. But often
it is man that starts the trouble.

ATTACK WITHOUT PROVOCATION

I can name t\vo animals, however, that will attack a man without provo-
cation. They are the Asiatic sloth bear and the rhinoceros. Up to the mo-
ment no mitigating circumstances have been found for them. The king
cobra is also supposed to attack without provocation. But on the whole
snakes are much maligned.

We have named three out-and-out aggressors. But this is not such a for-
midable list when we consider the legends of evil behavior in the animal
kingdom.

In American folklore a great deal of mischief has been imputed to the
wolf and the eagle. Let us consider the wolf's case. The United States
Biological Survey disposes of two legends. American wolves do not hunt
in large packs and they do not attack man. The most they achieve in the
way of communal organization is the hunting of smaller game in small
groups. Man they let alone. On the other side of the wolf ledger there
are plenty of cases where Asiatic and European wolves have attacked men.

The stories about the eagle's exploits usually spring from an exaggerated
idea of the bird's strength. It is true they will swoop down and snatch rab-
bits, hares, and even young lambs. But eagles which seize children belong
in mythology. Among the natives of northern Chinese Turkestan, inci-
dentally, the eagle is sometimes used for coursing. The bird is let loose at
gazelle. Left to his own choice, he would not ordinarily attack such a big
animal since he could never hope to carry it back to his aerie. But he has
been well trained. He knows that if he can knock down or impede the
animal in his flight, mounted sportsmen will soon ride up to dispatch it.

By this time it has become reasonably clear that in most conflicts be-
tween man and beast, man is the aggressor. From earliest times man has
hunted — as a means of procuring food and for skins to protect his body
against the elements. He has left a legacy of fear with the animals, and the
fact that some of them when injured or menaced will fight back is not in
the least surprising.

One curious phase of man's relation with the animals is the process of
domestication. Although all the domestic animals we know today were
originally wild, the transformations all took place in prehistoric times.

292 READINGS IN BIOLOGICAL SCIENCE

There is no written record of any animal's being domesticated in modem
times, except the African elephant. And whether we are to call the African
elephant a domestic animal is a moot point.

We have seen that wild animals are inclined to flee from man. Certain
animals enjoy special advantages, such as speed and cunning, in avoiding
human contacts. Others are well protected because of their isolated habitats.

In my experience the most exhausting kind of hunting is provided by the
anoa of Celebes, the panda of Chinese Tibet, and the ibex of northern
Ethiopia and of the Tien Shan Mountains of China.

Even to approach the Simen Mountains of Ethiopia or the Tien Shan
range requires tremendous effort. Crags and precipices at lofty altitudes
are the habitats of the goat. The chances are against the hunter's even
seeing game, to say nothing of shooting.

The panda inhabits a mountainous region, dense with dwarf bamboo.
Not only is visibility bad but the ground is usually covered with mud so
that the hunter must constantly guard against falls. Silent stalking is out
of the question: the bamboo cracks and breaks so that the panda is fore-
warned.

The anoa or dwarf buffalo of Celebes lives in steep, hilly country, pro-
tected by dense jungle. Merely to cut one's way through this jungle re-
quires terrific labor. Thorns reach out to scratch the face and tear the
clothes. Visibility is usually limited to a green wall a few feet away.

TIGER HUNT

I should like to tell of a tiger hunt carried out in Nepal, in the district
of Kheri. This hunt, to which I was invited by Kunwar Dillipat Shah,
brother of the Maharani of Kheri, was interesting because it showed some-
thing of the tiger's characteristics and emphasizes the trait I have stressed
— the desire of the big cats to avoid trouble.

The first step was to tether native cattle to trees in the jungle. The
forest officer was aware of the approximate number of tigers in the dis-
trict, having acquired the information from native forest rangers, who
seemed to know everything going on in the jungle. When a tiger or leopard
had made a kill, the facts were reported to us the next morning by the
ranger. Preparations were immediately made for a hunt. The tiger or
leopard, after killing a calf, would invariably drag it a short distance away,
sample it, and then go away for a while. Until he felt disposed to return
and finish his meal, he would in all likehhood remain in the vicinity of the
kill.

There were two periods of the day when hunting was feasible. One was
the early morning shortly before sunrise, when there was barely light to
see one's rifle sight. The other was in the heat of the day, when the animal
would be lying in some thick, densely shaded spot and could be driven
out by a line of elephants. The middle of the day was the better time be-

ECOLOGY 293

cause it gave us better visibility for shooting. (We hunted both tigers and
leopards in exactly the same way.) It was not necessary to hurry, for we
knew the tiger would probably be somewhere in the vicinity of his kill all
day.

We had twelve elephants in the line, which gave us a beat of considera-
ble breadth. The breadth varied so much depending on the nature of the
terrain and the proximity of the tiger, that it was difficult to estimate its
mean. Perhaps it was never less than 1 50 yards or more than 300.

The beat moved through high ratwa and nurtle grass, which sometimes
grows as high as the howdah (the commodious railed, canopied seat on the
elephant's back). Should a tiger sleeping in the grass be startled by our
beat, his natural tendency would be to move on ahead of us. But cases have
occurred where a tiger, driven out of his refuge, broke back through the
line of elephants. Great precautions had to be taken to keep the elephants
close enough together to frustrate any such move; for swinging around
to shoot from an elephant's rear is difficult.

As long as we could drive the tigers in front of us we had no fear that
they would disappear "into the blue" like deer or antelope. Tigers, like all
big cats, will not run far. They have a short temper and no running en-
durance. It is true one may lose them, but the explanation then would be
that they had turned or doubled and were again secreted in a spot where
the beat would just miss them.

The tiger as a species was originally a cold weather animal. The Indian
tigers of today are supposed to have descended from Korean, Manchurian,
and Central Asiatic stocks. The reason for the migration seems to have
been the more plentiful game afforded by the hot countries.

The tigers in our area were not fond of heat. As soon as the sun was
fairly well up from the horizon, they chose a densely shaded spot wherein
to lie down.

With twelve elephants in line, a considerable area could be covered;
and since we continued beating as long as the light permitted, our chances
for discovering a tiger were excellent. All during the beat the line tried
to comb those places where the grass was highest and the jungle thickest.

This difficult and highly technical show was managed by the Kunwar
with consummate ease. He used gestures. He spoke in a soft, gentle voice.
Occasionally he whistled. Men and elephants were instantly responsive to
his signals.

There were no dull moments during the hunt. We never knew when a
tiger might appear. But we did know that a bad shot might cause the tiger
to charge at an elephant and maul him. An elephant cannot abide the smell
of a big cat. Seeing a tiger, he will always trumpet and raise his trunk and
curl it over his head, for he knows how vulnerable he is to a tiger's claws.
Because a tiger can leap very high, accidents do happen. However, keep-
ers always take great care to dress their elephant's wounds.

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Although we had twelve elephants we did not have a rifle on each. Three
or four rifles among the lot was considered a fair number. Each of the ele-
phants carrying a rifle also carried a howdah. The other elephants, merely-
assisting in the drive, each carried the mahaut (keeper) and one or more
other natives.

The mahaiit always sat forward of the elephant's shoulders. His knees
were curved around the animal's ears, and his feet dangling downward gave
the signal for every movement. The other natives sat on a large pad fas-
tened to the elephant's back by ropes. These ropes provided them with a
grip when the going was rough.

Shooting from a pad elephant is not uncommon. The hunter, sitting di-
rectly behind the mahaitt and facing due forward, has two means of travers-
ing his rifle, right and left. For general shooting, however, the howdah is
preferable. This is a comfortable perch and is large enough to accommo-
date an extra kit of guns. For the sake of steadiness one usually stands up
to shoot from a howdah. Hunters find it better to lean against the front
rail for greater steadiness. Before any shooting is done, the elephant is
brought to a halt, but even so there is apt to be some motion for he may
suddenly shift weight from one foot to another. Even his breathing may
make the bead on the front sight a little wavy.

One morning word was received that two tigers had been spotted. One
had made a kill the night before. We started oft" immediately. After an
hour's beat we arrived at a dry swamp covered with nurtle grass. This grass
was so high it covered the heads of all our elephants.

The morning was well advanced. It was very hot. The grass gave the
tiger an excellent shelter against the sun. Advancing slowly, we roused
many wild pig and hog deer from their noonday rest. Everyone was
tense. Those with rifles were standing at the rails of the howdahs, staring
straight ahead.

In a situation like this the first intimation that a tiger is near comes
from the trumpeting of one or more elephants who have winded him. Al-
though tigers and elephants are not natural enemies and usually leave each
other alone, elephants, particularly females, are always afraid of tigers and,
therefore, quick to sense their presence.

One of our elephants trumpeted. Soon after, we were able to locate our
quarries. Their path could be traced by a ripple along the tops of the grass.
Shooting was, of course out of the question till the tigers could be driven
out of the grass and into the bordering jungle where a proper view could be
obtained.

The tigers advanced at first in a short series of slow movements. Then
one of them broke to the left and passed safely beyond the elephant at the
farther end of the Hne, No one saw it emerge from the grass. It was never
seen again.

We concentrated on the other. Finally we saw him emerge at the end

ECOLOGY 295

of the grass bordering on the jungle. One yellow-striped flash and he was
gone. But we were sure he would not run far. If we were persistent in our
driving, we would soon see him again.

It was slow work. The jungle vegetation, streaked with light and shade,
made it difficult to pick out the tiger. But shortly before the light began
to fade, we spotted him. A heavy rifle roared just once, and the tiger lay
dead on the ground.

There were several days of the hunt when we received no reports of
tiger or leopard. All hands then went out on the elephants to shoot what-
ever they could. The game on such days included swamp deer, black buck,
alligator, chital, hog deer, partridge, pheasant and peacock. We never shot
at these when we were out after the big cats, for at such a time the sound
of shooting might have frightened them away.

No one could say that comforts and conveniences were lacking on the
hunt. We lived in large, firm tents. One pad elephant carrying our lunch
always traveled along with us. Out in the open, in the bright sun, it was
very hot, but with the jungle always at hand and clumps of trees about,
one could easily find shady retreats in which to rest. Our luncheon hour
varied greatly, because on the tiger or leopard days we never stopped till
we had bagged the quarry or lost it for the day.

All in all our shooting trip netted two tigers, two leopards, and a croco-
dile, besides the smaller game already mentioned.

One last word about elephants. In our hunt they were so careful of their
footwork, so indomitable in pushing through difficult spots of the terrain,
that we were able to scour the tiger country quite thoroughly. Their bulk
was, an aid rather than a handicap in plunging through the jungle. Their
great trunks tossed logs aside, pulled saplings up by the roots, and tore
boughs from trees. In dealing with any impediment, their trunks showed
almost manual dexterity. A sure and subtle understanding existed between
every elephant and its mahaiit. As a matter of fact, the inahaut's language
is a special dialect incomprehensible to the layman.

In return for their services, the elephants were given particular care by
their keepers. They required, for instance, one bath a day in order to keep
their skins healthy. The bathing and scrubbing in the stream near the camp
was a regular ritual. It was an engaging sight to watch the great beasts lie
down docilely and allow the natives to give them a thorough scrubbing.
For a brush the natives usually used a good brick which was not too rough
for the elephant's thick hide.

This tiger hunt belonged to an elaborate type that takes place at rare
intervals. The average man in India does not possess twelve elephants; if he
did, he would find more productive uses for them than tiger hunting.

A tiger district, as I have indicated, is not precisely overpopulated with
tigers. One does not hunt them in a random way as one might hunt deer.
A machan is erected only when tigers are known to be in the immediate

296 READINGS IN BIOLOGICAL SCIENCE

vicinity. If a tiger leaves a natural kill, the machan is put up nearby. If no
natural kill has been discovered, a bait is provided in the form of a live
domestic animal. In any case, when hunters climb into a machan they
must be prepared for a long and tedious wait.

Alachans are designed to provide a maximum of safety for the hunter.
Tigers have been known to jump higher than fifteen feet, so the average
machan is around 20 feet above the ground. Tigers, in common with other
animals, seldom look up. They find nothing of interest in the skies and
treetops. If their attention is drawn to the machan by the slightest noise,
it is another story.

When man meets tiger, or for that matter any wild animal, it is usually
man who takes the initiative.

>>><<<■

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XIII

Health and Disease

No topic is of greater or more immediate concern than that of bodily
or mental health. Everyone wants to live to a ripe old age and none
wish to be considered as eligible for admission to an institution for the
mentally-ill. Death seems to be a certainty for all of us, however and mil-
lions in our present population are destined for institutional care. The
problem seems to be to avoid or cure serious illnesses and so postpone con-
finement or death. The articles in this section are all thought-provoking,
timely, and helpful.

There are many kinds of diseases and the causes are equally varied. The
bacterial diseases such as tuberculosis, pneumonia, diphtheria and scarlet
fever are well-known. Poliomyelitis or infantile paralysis, smallpox,
mumps, and rabies are the result of infection by tiny particles known as
the viruses. Syphilis is due to the action of a spirochaete, a one-celled or-
ganism. Amebic dysentery is caused by a tiny, one-celled animal. Diabetes
and goitre are due to the malfunction of the pancreatic and thyroid glands
respectively. Pellagra, rickets and beri-beri are the result of vitamin de-
ficiencies. Trichinosis is due to the effects of a pork roundworm. Then
there are those diseases which are due to none of these but are inherited
such as some kinds of feeblemindedness, hemophilia or excessive bleeding,
and Huntington's chorea.

The conquest of disease is an inspiring chapter and more honor should
be paid to the research workers in all branches of science who discover
the causes and cures. Too often these men and women are forgotten and
the public is prone to think that university scientists are never engaged
upon anything of practical importance.

Penicillin, streptomycin and the sulfa drugs are three of the powerful
weapons with which we are combatting disease germs. Although people
still die of bacterial diseases, the number has been reduced dramatically.
Vitamin therapy is being used successfully in pellagra and rickets, among
others. Thyroxin and insulin help those suffering from thyroid troubles
and lack of natural insulin. All along the line new drugs are appearing
which cut severely into the numbers of deaths from the above causes.
However, as these foes have been beaten back to a respectful distance, the
degenerative diseases such as arteriosclerosis, and heart troubles are noticed

297

298 READINGS IN BIOLOGICAL SCIENCE

more and it is on them and the always-troublesome mental diseases that
science has now turned the bulk of its attention.

ENTER LOUIS PASTEUR *
E. C. LARGE

In 1 86 1, Albert, Prince Consort of England, died of typhoid fever. There
was then no knowledge of the real nature or cause of typhoid fever, and,
a fortiori, no knowledge of the hygienic or prophylactic measures by
which his regrettably early decease from this cause might have been pre-
vented. If anyone had suggested that the good Prince died because of the
multiplication in his intestinal tract of a microscopic fission-fungus, nour-
ished by the royal juices and brewing virulent poisons in them, that person
would have been considered mad. A very great deal more was known about
the Potato Blight by 1861 than about typhoid fever. The fungal organism
that caused the Potato Blight was known, at least in part; the bacillus of
typhoid was not even identified until 1884.

That typhoid was an infectious disease was apparent to everybody; in
epidemics it spread among men almost as fast as the Blight spread in the
potato fields, but the agency by which it was communicated from one
person to another was a mystery. There might be pernicious "miasmas"
or the Disease itself might have "germs" — much as one might speak of the
germs of an idea. The "germs" might even have a material existence, for all
kinds of notions of germs had been the playthings of the philosophers for
about as long as there had been any philosophers in the world. But in 1861
the notions about germs were even more nebulous than those about "atoms"
before Dalton. Nobody seriously imagined that the germs of typhoid fever
would ever be seen, measured, counted, and cultivated in dishes and test-
tubes.

One very good reason why knowledge of the bacteria — a few species
of which were subsequently found to cause infectious diseases of man —
lagged so far behind that of the micro-organisms associated with the prin-
cipal diseases of plants was that the bacteria were of a second order of
smallness, and of deceptively-insignificant appearance when seen with even
the highest powers of the microscopes available. The spore-bearing hyphae
of the Potato Blight fungus, the summer and winter fruits of the common
Powdery Mildew of the Rose, the germinating spores of the Bunt fungus
of the wheat — they all appeared comparatively large when magnified some
three hundred and fifty diameters, and they were easy to recognize as
organized vegetable growths. But even yeast cells appeared very small at
that magnification, and the several forms of bacteria were smaller still,

* From The Advafice of the Fungi by E. C. Large, Henry Holt and Company, New
York.

HEALTH AND DISEASE 299

some of them at the extreme limit of visibiHty. They were mere single
cells, quivering and swimming about, or congeries of such simple cells,
often colourless, and in the detritus of organic matter amongst which they
were commonly found, it was by no means easy to say what they might
or might not be.

These "bacteria," or "bacteridia," for they were called by many names,
had been known to science since the time of Leeuwenhoek, who in 1683
first described one of the larger species, which he had seen by squinting
through his rudimentary microscope — a single tiny lens mounted in a
strip of brass — at some remains of food scraped from his own teeth. In-
numerable observations had been made upon them since that time, and by
1838 Ehrenberg distinguished what he took to be sixteen distinct species
assignable to four genera. After 1844 the study of the bacteria was facili-
tated to some extent by DoUand's oil-immersion lens for the microscope
which enabled a magnification of one thousand diameters to be obtained.
But until a way was found — with the Abbe condenser of 1870 — of con-
centrating an intense beam of light upon the minute objects under obser-
vation, the scene in the microscope was very dim and ways were not then
known of picking out the bacteria by means of stains. Later, when the use
of differential stains revealed that the bacteria had distinct cell-walls, some-
what resembling those of other plant cells, and that they multiplied by
simple fission, the bacteria were claimed by the botanists as Schizomycetes
or fission-fungi. A few of the great naturalists, whose comparative studies
led them to believe that the law of life would hold down to its lowest mani-
festations, were convinced, as Spallanzani had been in the eighteenth cen-
tury, that the swarms of bacteria found in infusions of decaying organic
matter had their origin in living spores which drifted in the air. That like
all other living things they grew from "seeds" or "eggs." For the rest of
the world, however, it seemed very plausible that such minute bodies could
well be animated by little sparks of life set at liberty when the stuff of
larger organisms died or that the processes of fermentation and putre-
faction, then regarded as purely chemical, could originate such trifling
living things by the way — and this was "spontaneous generation." By 1861,
resort to the ancient theory of spontaneous generation to account for the
appearance of parasitic fungi on the crops had been thoroughly discredited,
but for the smaller organisms, the bacteria, such notions still held sway,
and the idea, put forward from time to time, that there might be as many
distinct species of bacteria as there were flowers of the field was regarded
as an extravagant pleasantry or a precious piece of nonsense.

As the microscope was improved, and as botanists paid more and more
attention to the smallest things in their weird gardens, the fission-fungi
might have been admitted quietly into the vegetable kingdom, in the course
of twenty years or so, and most people might have taken their biogenesis
for granted, but for one historic circumstance — in 1859 Darwin's Origin of

300 READINGS IN BIOLOGICAL SCIENCE

Species was published. Darwin's cautious hypothesis, that some species
were evolved from others in the course of time, was thoroughly respecta-
ble, it was an illuminating idea, by no means new, and it was of profound
and special interest to the botanists and zoologists, as it provided them with
a better basis for the classification of living things than they had ever had
before. It introduced a fourth dimension — Time — into Taxonomy, as into
morphology, and it enabled the naturalists to make most interesting mu-
seum arrangements illustrative of a hypothetical Tree of Life, out of their
bundle of sticks. The break-away from the dogma of original creation had
its roots in a long-repressed desire on the part of some people to spit in the
eye of the Church. The ultimate clash was between vitalism and material-
ism; it divided the scientific world into two camps; started as it were, two
great and opposing tidal waves of passionate thought which irrigated with
violence every province of the biological sciences. The wealth of eagerness
and hard-thinking that went into attempts to establish the theory of evo-
lution did much for the advancement of knowledge; but the determination
of those of another mind that the theory of evolution should not be pushed
to the absurdity of its logical conclusion, led to advances which were per-
haps of even greater practical moment.

It could easily be seen why the resurrection of a dwindhng belief in the
possibility of spontaneous generation was regarded as a philosophical neces-
sity by those who sought to explain away the Creation by wild extrapola-
tions and extensions of Darwin's hypotheses. So long as it was possible to
regard the production of living organisms of any kind, no matter how
small, as a result of purely chemical and physical processes, it was (just)
possible to imagine the evolution or elaboration of life-forms, stage by
stage, through successive geological epochs, all the way up from a unicellu-
lar organism to a blessed Queen Victoria herself, or even a Thomas Henry
Huxley. If the smallest living cell could still be brought into being only
through the reproduction of its kind, by the passing on of life from like
to like, the farthest-flung train of Evolutionary speculation brought no
ultimate balm. There would be no ha'p'orth of reason to suppose that the
first amoeba could ever have crawled spontaneously out of the primordial
slime. If it was still necessary to imagine some super-natural occurrence
or act of Divine intervention to account for the first animalcule, one might
just as well believe that God created Adam in his own likeness, and leave
it at that. The materialists put Dirt before Life; it pleased them to think of
all life as born of the inanimate dirt. The vitalists, on the other hand, men
for whom Christianity was a faith essentially humane, along with most
of the men of science who studied living things, alive, instinctively put
Life before Dirt: a living God before the first dawn on earth, biology be-
fore chemistry, and human desires and passions before Gold.

Enthusiasms for the Grand Darwinian Theory was conspicuously lack-
ing in France, and it was by no manner of accident that Louis Pasteur, in

HEALTH AND DISEASE 30I

1 86 1, was attacking the doctrine of spontaneous generation. He was dig-
ging the supposedly fecund Dirt away from the very base of the evolu-
tionists' precious Tree of Life, and leaving that Tree suspended as an eter-
nal mystery in the Divine air. Pasteur's investigations into the disease of
silkworms in the south of France were not begun until 1865, he did not
turn his attention to anthrax in sheep until 1877, and it was 1885 before
the first child was inoculated against hydrophobia. In 1861, Louis Pasteur,
too good a Catholic, and much too good a chemist, to tolerate materialistic
doctrines against the evidences of his senses, was attacking the "philosophic
necessity" of spontaneous generation.

As a young man, in 1848, when he was only twenty-six, Pasteur made
his first, brilliant scientific discovery, and happily it received immediate
and full recognition by the greatest savants in France. This success fired
in him a consuming passion for research, and started him on his course
with an unbroken youthful ambition. His maiden discovery meant so much
more than an addition to knowledge of the properties of tartaric acid. A
minute difference, which he was the first to perceive, among the crystals
of the acid, the right and left handedness of certain of the crystal facets,
was associated with the power of their solutions to turn polarized light
to the right or to the left. What did it mean? It meant that some at least
of the molecules of which the whole universe was composed had the power
of assembling in tvvo ways, one of which was the mirror image of the
other.

While the crystals of tartaric acid were still sparkling for Pasteur, with
all the magical brilliance of first discovery, he had not only traveled about
Europe collecting specimens of tartar from many sources, poking about in
the dregs of the wine vats where the tartar was found, he had also sought
for the phenomenon of optical dissymmetry in other substances. Pasteur
was happy when his appointment at Lille in 1854 took him into a district
where there were many distilleries. He would have to prepare lectures on
the chemistry of fermentation for the apprentices and technical workers of
the district, but, alongside his teaching work, he would be able to continue
his researches, and perhaps find some more dissymmetrical substances. The
distillers' vats were good places in which to look for them.

He had not been studying fermentation for very long before he began
watching the yeast cells in the fermenting worts and liquors, with a very
particular attention. Under the microscope they appeared, normally, as
small globules, often with a smaller globule budding out at the side, like
a "dolly" on a potato. They multiplied in this way, by budding. In fer-
mentation that went well and gave good brews, the cells were all of this
kind: but in those that went wrong, and produced sour wine or inferior
beer there were present cells of a different shape, not globular, but elon-
gated or sausage-like. Could that abnormality make all the difference in
the brew?

302 READINGS IN BIOLOGICAL SCIENCE

The numerous groups of simple unicellular fungi associated with various
fermentative processes — of which ordinary yeast in alcoholic fermenta-
tion was only one — thus began to receive the attention of an exceedingly
astute observer. Pasteur's thought, from the very first, was that the yeast
globules and smaller, elongated bodies were the cells of living organisms,
and as they had life so they would require food. Not only were the cells
of yeast and other simple organisms taking their nourishment from the
solutions of sugar and other substances in which they lived — they were
also, of necessity, transforming it. They were using part of it to build up
their own substance and rejecting the rest. Hence the chemical changes
that took place in fermentation.

This realization led Pasteur to a number of discoveries of great industrial
value. He discovered that the process of making vinegar from wine de-
pended upon the grow^th of a particular kind of fungus — "the vinegar plant"
— on the beach-wood chippings over which the wine was allowed to flow.
Where the wine would not "turn" to vinegar, he put in a little of the living
fungus and the vinegar-makers' troubles were at an end. He showed that a
souring of wine was due to the growth of an undesirable organism in it
after it had been bottled, and he showed the wine-makers how to over-
come the trouble, very simply, by heating the wine, to kill the cells of the
organism, before it was bottled. An early instance of "Pasteurization," al-
though, indeed, the Romans had been familiar with this dodge for preserv-
ing wine. The very idea that fermentation was brought about by any life-
process was rank heresy for the chemists at that time and Pasteur was
scornfully accused of attempting to put back the clock of up-to-date
nineteenth century progress.

Pasteur's researches on "so-called spontaneous generation," which con-
tinued from 1859-1S65, arose directly out of his work on fermentation.
He had discovered that fermentation and putrefaction were dependent
upon the growth of Hving organisms. Where did those organisms come
from? Pasteur knew the answer before he began. The organisms came from
the air, in which their imponderable "spores" were always floating about,
as the grosser seeds of some of the flowering plants drifted in the wind.
But the apparently spontaneous appearance of minute organisms in in-
fusions of fermenting or decaying material was the very "fact" upon which
the last behef in spontaneous generation now depended. Pasteur set him-
self to prove experimentally what he knew beforehand must be true. As
the truth would be most unwelcome, and he would be challenged at every
step of the way, he had to contrive a series of experiments which would
give unambiguous results, and yet be of such simplicity that no one could
pretend to misunderstand them.

He did not succeed in routing the materialist's belief in the possibility
of spontaneous generation. It was, in truth, impossible to prove that it never
occurred in nature. But Pasteur did show that the postulation of spontaneous

HEALTH AND DISEASE 303

generation was wholly unnecessary to account for anything that happened
in his experiments, and as his experiments were expressly designed to cover
all the instances in which the phenomenon was supposed to occur, he left
his opponents with nothing to put forward but unverified suppositions.

Pasteur made up a number of broths and infusions of organic matter
that very quickly fermented or went bad when left exposed to the air. As
Spallanzani had done before him, he put the infusions into small glass
flasks, heating them to destroy any spores or cells of living organisms and
then sealed the flasks. But this time he sealed them positively — by drawing
out the narrow necks and fusing the glass with a blowlamp. The infusions
kept clear and "good" indefinitely. When he broke the seal, thus permitting
a few cubic centimeters of air to rush in, the preparations promptly went
bad, and in a few days they were teeming with living organisms, all of
which had arisen from the multiplication and growth of the few micro-
scopic cells and spores let in with the air. He repeated the experiments,
sterilizing the air before admission by passing it through a red-hot platinum
tube. There was then no growth of organisms in the preparations and they
kept good.

By 1863, both Pasteur and Ferdinand Cohn had reached the conclu-
sion that putrefaction of organic matter was a process of the same na-
ture as fermentation, also consequent upon the growth of living organisms.
The suppuration of surgical wounds was regarded as an instance of putre-
faction, and by 1865, Dr. Lister in England was excluding air-borne
germs from wounds with filter pads of cotton wool, and kilhng the germs
which settled on the skin, on instruments, and on exposed tissues during
operations, with carbolic acid as an antiseptic.

The plant doctors were concerned with these new developments no less
than the medical profession. When plant tissue was cut or wounded, hosts
of smaller organisms, yeasts and bacteria, would get in from the air or the
soil and complete the work of decay. They could, for example, rot blighted
potatoes in the ground, reducing them to skinfuls of slime. The "vegetable
pathologists" would now have to study not only the moulds and mildews,
but the yeasts, the myxomycetes and the bacteria.

Assuredly, those early researches of Louis Pasteur left the plant patholo-
gists with much to brood over, and their suggestiveness had not been ex-
hausted by 1947.

304 READINGS IN BIOLOGICAL SCIENCE

PESTILENCES AND MORALISTS *
HOWARD W. HAGGARD

Most civilizations are willing to accept protection from pestilence when
the measures involved require only the eradication of insects, quarantine,
the draining of swamps, and similar general measures. But when the con-
cepts of morals are involved in the prevention, fanaticism is aroused even
in the highest civilization. There are two pestilences which thus unfor-
tunately involve moral conceptions. They are the plagues of syphilis and
gonorrhea. Against them medicine has developed methods of control. They
could be eradicated. But as yet civilization has not advanced entirely be-
yond the ancient belief that disease is imposed by God in vengeance for
sin.

Those who today still look on syphilis and gonorrhea as punishment for
sin have not progressed beyond the ideas of medieval Europe. There was
an excuse for the Emperor Maximilian when he issued his edict in 1495 de-
claring syphilis to be an affliction from God for the sins of men. Cotton
Mather declared syphilis was a punishment "which the Just Judgment of
God has reserved for our late Ages. . . ." His ignorance was as great as his
religious bigotry which led him to drown helpless old women for witch-
craft.

The reason that syphilis and gonorrhea are not viewed as pestilences lies
in the fact that they are involved in one of the greatest problems of civiliza-
tion— the relation of the sexes. The veneral diseases are involved in that
great sex problem about which the ideals and ethics of Christian civiliza-
tion center. A true perspective on sexual matters is lost because the facts
are obscured with secrecy and distorted in the imagination.

A continuous epidemic of syphilis has lasted now for at least five cen-
turies. Its origin is a question over which the historians argue. Some main-
tain that syphilis occurred in Europe at an early date and was known to
ancient civilizations. Others maintain that syphilis was a new disease
brought into Europe from the island of Haiti by the sailors of Columbus.
The preponderance of evidence points to America as the source of the
disease; but the evidence is not absolute.

Syphihs often attacks the bones and leaves definite marks by which
it can be recognized after death. Skeletons of ancient peoples in China,
Egypt, and Europe have been examined with this point in view. Thus far
no prehistoric or even pre-Columbian skeleton found in Eurasia shows
evidence of syphihs. There are marks on them which have been mistaken
for those of syphilis, but these marks are now definitely proved to have

* Reprinted from Devils, Drugs and Doctors by H. W. Haggard with the permission
of Harper and Brothers. Copyright 1929, by Harper and Brothers.

HEALTH AND DISEASE 305

occurred post mortem through the action of insects and fungus growths.
Many of the early references to venereal disease, as in the Bible or other
ancient writings, have been bejieved by some observers to indicate syphilis,
but they were more probably gonorrhea. There is no question about the
antiquity of gonorrhea in Europe and Asia.

If syphilis was brought into Europe by the sailors of Columbus, cer-
tainly conditions were ideal for its reception. In 1493 Charles VIII of
France claimed the kingdom of Naples as his by hereditary right on the
death of Charles, Count of Main. His claim was disputed by the Neapoli-
tans, and Charles VIII gathered an army of mercenaries to take the king-
dom by force. In August of 1494 he led his army into Italy and entered
Naples in the following February. Toward the end of May King Ferdinand
broke a treaty he had made some years before with Charles VIII and sent
an army into Naples. In this army there were a number of men who had
been to the West Indies the previous year and who were still infected with
the disease they had contracted there.

In 1496 the army of Charles VIII fell into factions and was expelled from
Naples. Those that remained of the mercenaries ultimately scattered to
their own countries. Their various routes were marked by the spread of
syphilis. It appeared in France, Germany, Switzerland, Holland and Greece
in 1496, in Scotland in 1497 and in Hungary and Russia in 1499. Vasco da
Gama carried it on his ships to India in 1498, Europeans brought it to
China in 1505, and by 1569 it had been smuggled into Japan. It has been
truly said that civilization and syphihzation have advanced together.

The age in which syphilis made its appearance in Europe was one of ex-
treme laxity in matters of sexual behavior. The new disease at first involved
nothing derogatory to a gentlemen's reputation. It was said at one time that
a man who had not had the disease at least once was to be reg-arded "as
boorish and no gentleman." The mother of Francis I of France said that
her son was punished where he sinned. According to the story, Francis
was infected by the wife of a Parisian tradesman. Francis solicited her
favors, but was repulsed. After consulting with the court lawyers he de-
cided to exercise his royal prerogative and notified the lady to that effect.
With her husband's assistance she acquired a syphilitic infection and re-
venged herself on the king. He is said to have died of the disease.

The appearance of syphilis in Europe gave rise to a series of speculations
as to the cause of the disease. As the part played by bacteria and other or-
ganisms in infectious diseases was not established until the middle of the
nineteenth century these early speculations were somewhat far fetched.
Both a divine and a cosmic origin were given to syphilis. The conjunction
of Saturn and Mars and the rainy weather in Italy were both blamed for the
disease. The disease was also attributed to the radical innovation of wearing
linen shirts which were coming in at that time to replace woolen or leather

3o6 READINGS IN BIOLOGICAL SCIENCE

garments. The physician to Pope Clement attributed the disease to poison-
ing. The idea that syphilis was a venereal form of leprosy was frequently
brought forward.

In 1905 Schaudinn and Hofmann found the organism of syphilis "swim-
ming in the blood." It is known today that the symptoms of syphilis are
due to these organisms. The search for the organism of syphilis started
when bacteria were discovered by Pasteur to be a cause of disease — a little
more than half a century ago. The organisms causing the infectious diseases
were discovered in rapid succession, but that of syphilis stayed hidden.
Metchnikoff failed to find it but in 1903 he demonstrated that syphilis
could be transmitted to the higher apes. This discovery furnished a means
for studying the disease experimentally. The higher apes are the only ani-
mals which, when inoculated, develop syphilis resembling the disease in
man. The fact that calves cannot acquire syphilis is of more than passing in-
terest, for the opponents of vaccination have on occasion talked of "bovine
syphilis" which they claim is transmitted by vaccination.

The organism of syphilis could not be made visible under the microscope
by means of staining. Most bacteria absorb dyes readily and the color
thus imparted to them allows them to be differentiated from the material
containing them. The organism of syphilis does not absorb dyes, but re-
mains colorless and transparent and hence invisible under the microscope
as it is ordinarily used. Two German investigators, Schaudinn and Hof-
mann, working at the University of Berlin in 1905, sought for the elusive
organism by another method of using the microscope. They used what is
known as dark stage illumination. Schaudinn and Hofmann placed a black
background under the microscope to cut off all light coming through
the material they were examining. They moved their source of illlumina-
tion to one side and brought its beams horizontally across the field. With
the light thus shining in a direction at a right angle to that in which they
were looking they could see only such light as was reflected from objects
which the rays struck. Under this method of examination the organism
of syphilis could be seen. It was a spirochete, that is, an organism spirally
shaped. It was, in fact, like a very tiny but a very perfect corkscrew, usually
with fourteen turns. The organism was named Spirochaeta pallida (now
called Trepone?Ha pallidimi) .

The Spirochaeta pallida is a frail organism. It has a relatively short life
outside the body; under ordinary circumstances it dies in less than six
hours. Moreover soap and water serve to destroy spirochetes that may be
deposited on such articles as drinking-glasses. If the spirochete had the
resistance of the tubercle bacillus, syphilis would be a vastly more preva-
lent disease than it is. The spirochete is passed from the syphilitic only
during those stages of the disease when there are sores on the skin or mucous
membranes, but as such sores, particularly on the mouth and lips, may be

HEALTH AND DISEASE 307

SO small as to escape detection, there is little satisfaction to be gained from
this fact. The stage of the disease during which the sores appear lasts from
a few weeks to two or three years, depending on whether the disease is
properly or improperly treated. After this stage, the disease, although it may
persist, can no longer be transmitted in the usual manner.

The spirochetes cannot force their way through the unbroken skin or
mucous membrane. They can enter only through a break in the surface.
Although theoretically the invasion may occur at any point on the body,
it rarely does so outside of the genital organs and lips. About 5-10 per cent,
of all cases start from the lips and such cases are usually caused by kissing.

When infection occurs, events follow a characteristic order. The spiro-
chetes at first show none of the aggressive characteristics which mark their
later activity. These they develop about a month after infection has oc-
curred. The invading spirochetes are so slow^ in gaining a foothold that
during the first twelve hours they can be eradicated and the disease pre-
vented. This fortunate opportunity^ for preventing syphilis makes possible
an effective prophylaxis. It is an opportunity afforded by very few diseases.

Syphilis is a mild disease, but, paradoxical as it may seem, the mild diseases
are often the most persistent. Mild diseases do not eUcit an acute reaction
on the part of the body. Consequently, they persist, and in persisting they
become chronic diseases. There are no acute stages in the progress of
syphilis. Its duration is marked by years rather than days. The first symp-
toms of syphilitic infection is a chancre, a round ulcerated area which ap-
pears at the point of infection. The margin of this ulcer is swollen and
feels hard under the touch. It is painless, is associated with no feeling
of illness, and gives no indication in itself of the serious nature of the in-
fection. It persists for three or four weeks before it shows any tendency
to heal.

During the primary stage of syphilis the spirochetes are mostly in the
area about the chancre and for the first week the disease cannot be de-
tected by testing the blood with the Wassermann reaction. Nevertheless,
an examination of the material from the chancre under the miscroscope
with dark field illumination shows the spirochetes in great numbers. Under
proper treatment applied early in its primary stage the disease can be
stopped so quickly that no manifestation other than the chancre develops.
The treatment of syphilis becomes more difficult and the results of the
treatment less certain as the disease advances through the secondary and
into the tertiary stage.

From their focus in the chancre the spirochetes spread into the blood
and are carried throughout the body. The general manifestations of the
disease develop and give rise to the secondary stage of the disease about
two months after the original infection and at about the same time the
chancre is healing. An eruption appears on the skin and the mucous mem-

3o8 READINGS IN BIOLOGICAL SCIENCE

brane of the mouth becomes raw in places. Even without treatment the
secondary stage of the disease passes away in time; it may last a few months
or it may persist for a year or two.

If syphilis produced no effects except its primary and secondary stages
it could almost be ignored, for there is little inconvenience or physical
suffering. The serious nature of the disease appears years later. Insanity,
paralysis, and disease of the heart and blood vessels and other conditions
of the so-called tertiary stages develop. The lack of suffering during the
early stages of syphilis is one of the most dangerous features of the disease.

The most distressing consequences of syphilis occur when the late de-
structive action of the spirochetes is centered on the nervous system. The
tissue of the brain and spinal cord is destroyed and replaced with scars. It
can no longer function normally. If the brain is involved, insanity results;
in its most pronounced form this insanity is called paresis.

In locomotor ataxia the syphilitic changes occur in the spinal cord. The
feet lose their sensation of position; the gait becomes awkward. The legs
become paralyzed. Finally the man is helplessly bedridden but his mind
remains clear.

Syphilis is often spoken of as a hereditary disease, but in reality it is not
hereditary. Syphilis can be transmitted to the child during pregnancy if
the mother has syphilis. That is not hereditary; it is contact infection. To
be hereditary the characteristic thus designated must be a part of the germ
plasm and be carried in the sperm of the male or the ovum of the female.
Children with syphilis are born only of mothers who themselves have the
disease.

A child which acquires syphilis from its mother during the early stages
of her pregnancy frequently dies before birth. Syphilis is one of the great-
est causes of miscarriages and of stillborn children of which there are at
least 100,000 annually in the United States. Those children who do not die
soon after birth can be treated and frequently cured.

The origin of gonorrhea is lost in antiquity. The germ which causes it
is even more frail and delicate than the spirochete of syphilis; under ordi-
nary conditions it cannot exist outside of the body for more than a few
minutes. No animal other than man can acquire the disease. Among adult
humans it is transmitted by sexual contact. Like syphilis, it strikes at infants
— and blinds them.

In the female the symptoms of the infection may be so mild as to escape
detection, but the subsequent effects are serious. For women gonorrhea
ranks with cancer as a cause for operations and invalidism.

The bacterium which causes gonorrhea belongs to that large group of
germs known as cocci because of their round or oval shape. It is shaped
like a coffee bean and two germs are usually found together.

Gonorrhea, unlike syphilis, cannot infect the skin, but only mucous
membrane. The gonococci burrow into the deeper layers of tissue. An

HEALTH AND DISEASE 309

acute local infection results in two to five days. Pus streams from the in-
fected surface. In the male the infection occurs in the urethra, the passage
leading to the bladder. The raw and inflamed surface gives rise to intense
pain during urination. The infection may travel into the generative ap-
paratus or even up to the kidneys.

In women the infection starts in the vagina and from there extends to the
uterus. It spreads further and passes into the Fallopian tubes and through
them to the peritoneum lining the abdominal cavity. The inflammation
of the tubes causes them to be closed by the formation of scars; sterility
results.

Gonorrhea, like syphilis, may be transmitted from the mother to the
baby. The transmission is effected only during the birth of the child. As
the baby passes down through the vagina the infected pus is forced into its
eyes. At one time about a quarter of the blindness throughout the world
resulted from gonorrheal infection. There is a prophylactic treatment by
which gonorrhea of the eyes can be prevented. Most states in this country
require by law that this prophylactic treatment shall be given as a routine
part of post-natal care. The laws designed to prevent venereal blindness
are enacted for economic reasons; the blind are in most cases dependent
upon the state for support.

-^ s ^ ^ ^ ^

ANIMAL PARASITES TRANSMISSIBLE TO MAN *

BENJAMIN SCHWARTZ

INTRODUCTION

Practically all vertebrate animals serve as hosts to parasites, and Homo
sapiens is not an exception to this general rule. Actually man is an excellent
host for various protozoan, helminth and arthropod parasites, the species
adapted to live on or in human beings totaling several hundred. There is
hardly an organ, tissue or cavity in the human body that is immune to the
attacks of one kind of parasite or another. Such vital organs as the liver,
spleen, lungs, heart, brain, eyes and others too numerous to mention are
susceptible to invasion by parasites that are capable of inflicting serious
damage to the parts of the body that are invaded.

Human beings acquire parasites through some form of contamination,
usually traceable to soil pollution, through the consumption of raw food
of animal origin, and in other ways. In parts of the world where sanitation
and hygienic standards are far below the levels that are accepted in most
civilized countries, parasites that are acquired through contaminated food

• Reprinted by permission of the Scientific Monthly, American Association for the
Advancement of Science. Copyright 1938.

3IO READINGS IN BIOLOGICAL SCIENCE

and water constitute an important health factor; in tropical countries they
are usually one of the most important health factors. In countries where
the level of sanitation is high and where the standards of hygiene are exact-
ing, parasitism that spreads ordinarily through soil pollution tends to dis-
appear, more particularly in urban communities. In rural sections, how-
ever, including those of this country, there is always a greater or lesser
residuum of parasitic infection of one kind or another, and urbanites who
visit the country for rest and recreation may acquire a few unwelcome
guests, such as hookworms, ascarids, whipworms, dysentery-producing
amoebae and other parasites, which occur as infective eggs, cysts or larvae
in contaminated soil.

By and large, however, human beings hving in cities and towns are
in most cases adequately protected from acquiring parasitic infestations
to which rural inhabitants may be exposed as a result of contact with the
soil. The nation-wide campaign against soil pollution, undertaken in this
country on a large scale in the beginning of the twentieth century, has
done much to reduce the danger of acquiring parasitic infestations, even
in rural areas. Several years ago the annual report of the Rockefeller
Foundation contained the statement that hookworm disease, for years an
important factor in the physical and mental retardation of the population
of rural areas in certain parts of the South, had been practically eradicated.
While this statement was open to challenge at the time that it was published
and was challenged vigorously, the fact remains that the hookworm in-
cidence and intensity in the United States have been greatly reduced, thanks
to the activities of such agencies as the U.S. Public Health Service, the
Rockefeller Foundation, the state boards of health and local health units in
the South.

While progress in the control of human parasitic infestations traceable
to soil pollution has been steady and on the whole satisfactory, that relat-
ing to the control of parasites of man that are acquired from consuming
animal food still leaves much to be desired. Actually, the available evidence
shows that one human tapeworm infestation acquired from certain species
of fresh-water fish is spreading in the United States, although its distribu-
tion is still rather limited. Trichinosis, a serious, painful and sometimes a
fatal disease of man, is apparently gaining headway. Whether the increase
in the number of cases of human trichinosis is only apparent because of the
greater vigilance on the part of physicians in making a correct diagnosis,
or whether the increase in the number of such cases is real, is difficult to
determine on the basis of available evidence. The extent of beef tapeworm
infestation, in so far as this can be determined from the data on the preva-
lence of the larval stages of these parasites in cattle slaughtered under federal
inspection, shows that during the past ten years or so this parasite has been
holding its ground, although the data of previous years showed a down-
ward trend.

The parasites mentioned, namely, the fish tapeworm, the beef tapeworm

HEALTH AND DISEASE 31I

and trichina, are the most important parasites of man in the United States
that are transmitted through the consumption of animal food. The pork
tapeworm, though only of slight importance in this country, must be added
to the list. We shall briefly consider each of these parasites and its bearing
on human health.

THEFISHTAPEWORM

The so-called fish tapeworm, Diphyllobothrhim latum, is really a human
tapeworm that spends part of its early hfe (plerocercoid stage) in certain
species of fresh-water fish. According to Wardle the following species
of fish in North America are known to be intermediate hosts of the tape-
worm under discussion: Pike, Esox estor; pickerel, Stizostedion vitreum;
sauger or sand pike, Cynoperca cajiadejjse; and perch, Perca flavescens.
Prior to getting into fishes this parasite occurs as a larva in fresh-water cope-
pods or so-called water fleas, that constitute a part of the microscopic and
near-microscopic aquatic life — plankton — which is an important item in
the food of fishes. The life cycle of the tapeworm is rather complicated and
is briefly as follows:

The tapeworm, which may attain a length of about twenty-five feet and,
in exceptional cases, a length of sixty feet, in the human intestine, produces
eggs which are microscopic in size and which are eliminated from the ripe
or gravid tapeworm segments into the lumen of the host's intestine. Oc-
casionally long chains containing as many as one hundred or more segments
may be passed with the excreta of infested animals, including dogs, cats
and wild carnivores, such as bears and foxes, that also serve as hosts of this
tapeworm. The tapeworm eggs passed with excreta and those which be-
come liberated from the passed segments, as a result of the disintegration
of the latter, hatch in water following their normal development. The
newly hatched larvae, provided with cilia, may be swallowed by copepods
which are usually found teeming in fresh-water lakes. When swallowed
by suitable intermediate hosts the larvae undergo further development but
do not become infective to man and other definitive hosts unless they reach
the body of a second intermediate host, namely, a suitable species of fish, as
already noted, and develop there to the plerocercoid stage that is infective
to mammals. Fishes become infested by swallowing the infested copepods,
and human beings acquire the fish tapeworm as a result of eating raw, or
nearly raw, or cold-smoked or salted fish that harbors the stages of the
parasites infective to man.

According to Magath the Finlanders, as well as other northern Europeans
in iMinnesota, have retained their native fondness for raw fish, and the
more nearly raw the fish is the better the Finlanders like it. Magath makes
the following statements: "One Finlander remarked that he was in the
habit of not carrying a luncheon on a fishing trip, being satisfied with the
raw fish he caught. A common dish is fish which has been salted in brine

312 READINGS IN BIOLOGICAL SCIENCE

for twenty-four hours and cut up with green peppers, cabbage and cu-
cumbers, while some bury the raw fish for a few days to ripen it, then eat
it with salt."

At one time there was considerable discussion among parasitologists as
to whether the fish tapeworm could complete its life cycle in North Amer-
ica, some investigators taking the position that infested persons in this
country must have acquired this parasite abroad. It has been definitely
established, however, that the fish tapeworm has become endemic in North
America and many cases of infestation of native origin have been traced.
Fishes from the Great Lakes region of the United States have been found
to be naturally infested, and species of copepods that are capable of serving
as the first intermediate host have been shown to be susceptible to experi-
mental infection. Thus, the entire hfe cycle of this tapeworm can take
place in North America, and this parasite, originally introduced into this
country by immigrants from northern Europe, is now definitely established
in the United States. According to Ward the belt of infection stretches
across the Great Lakes, includes the upper Mississippi basin, even reaching
out into Iowa, crosses the height of land into Manitoba and embraces lakes
almost to the Rockies.

Once having gained a foothold, it is easy to see how this parasite estab-
lished itself solidly, since untreated sewage from cities and towns is com-
monly emptied into lakes. Infested immigrants coming to North America
from countries along the shores of the Baltic and from other areas where
this infestation is common, polluted the lakes in some of our North Central
States and other regions.

In parts of Scandinavia, Finland, Russia and Germany, bordering on
the Baltic and connecting waters, the local population shows an incidence
of infestation up to 50 per cent, or more. Even a few infested immigrants
could have greatly polluted our fresh-water lakes, since it has been esti-
mated that an infested person may discharge at least one million tapeworm
eggs a day. The fondness of certain people of European origin for raw fish
or portions thereof raw, or lightly salted or pickled, has served to propagate
this infestation in this country. The susceptibility of the dogs, cats and
various wild carnivores to this parasite has added a further complication
tending to increase the spread of this tapeworm.

Persons infested with the fish tapeworm may exhibit nervousness, loss
of sleep, experience creeping feelings and occasionally show a voracious
appetite. The symptoms manifest themselves particularly after a person
discovers that he or she is infested, this indicating that the symptoms, at
least in part, are probably mental rather than physical. Of special interest
in connection with this parasite is the occurrence in a very*small percentage
of infested persons of an anemia that is indistinguishable from pernicious
anemia. However, precise information is still lacking with regard to the

HEALTH AND DISEASE 313

causal relation of the parasite to the cases of pernicious anemia observed in
infested subjects.

The prevention of infestation with the fish tapeworm is simple and ab-
solutely effective. Fresh-water fishes should not be eaten raw, semi-raw,
cold-smoked or lightly cured in salt. Thorough cooking of fish is an abso-
lute prevention and can be relied upon as being a one-hundred per cent,
prophylactic measure.

THE BEEF TAPEWORM

The beef tapeworm, Taenia sagmata, occurs in its adult stage solely in
the human intestine where it may attain a length of about thirteen to forty
feet. Usually an infested person harbors but a single tapeworm, the oc-
currence of one worm in the intestine apparently excluding others from
developing.

The life cycle of the beef tapeworm is similar to that of the fish tape-
worm, except that but one intermediate host, namely, a bovine, is required.
Human beings become infested solely as a result of eating raw or rare beef
containing the larval stage of the tapeworm infective to man, and cattle
become infested with the larval or cystic stage as a result of swallowing
the tapeworm eggs with feed or water that has become contaminated in
one way or another with the excreta of a tapeworm carrier. The life history
of the beef tapeworm involves, therefore, an alternation between two
hosts, man and the ox.

Ranson pointed out years ago that a single individual with a tapeworm
is a peripatetic center of infection. Each gravid segment of a tapeworm
contains several thousand eggs, and several segments may become gravid
and expelled every day during a period that may extend over several years.
Thus hundreds of cattle might become infested from a single tapeworm
carrier, if this person happens to live in a rural district where cattle are
raised.

The control of infestation of cattle M^ith the larval stages of this tape-
worm will inevitably result in the control of the beef tapeworm infestation
in man, and vice versa. Reduced to simple terms, improvement in con-
ditions as regards the disposal of human excreta in rural sections will pre-
vent cattle from becoming infested, and this in turn will tend to reduce
and ultimately eliminate the infestation in man.

As an example of the unsanitary conditions that prevail in some rural
sections of the United States, particularly as regards the disposal of human
excreta, an outbreak of larval tapeworm infestation in cattle, technically
known as cysticercosis, was investigated by the Bureau of Animal Industry
a number of years ago with the following results:

Following the detection under federal meat inspection procedure of
a heavy infestation of cysticercosis in 3 lots of cattle which came from the

314 READINGS IN BIOLOGICAL SCIENCE

same locality, 105 out of 523 cattle, or 20 per cent, being infested, it was
determined that about 1,500 cattle, of which the 523 were a part, had been
fed during the winter and spring in the yards of a cottonseed oil mill. These
animals were later marketed at various live-stock centers and data were
obtained on the 523 animals already referred to. The remaining animals
were not traced to the point of slaughter.

The investigation made at the yards of the mill disclosed that the regular
water supply for the cattle was taken from a river 75 yards below a sewer
outlet. The river was wide and shallow, had a sluggish current, and the
banks, which formed a portion of tract of land designed for a public park,
were strewn with human feces. The investigation disclosed further that
the cottonseed hulls used for feeding the cattle were stored in a building
where tramps commonly slept during the feeding season. Evidence was ob-
tained which indicated that the cottonseed hulls had become more or less
contaminated with human excreta, the hull house being used evidently
by the tramps and mill employees as a place for defecation, especially dur-
ing very cold weather. An inspection of the 3 outhouse toilets intended
for the use of the mill employees showed that the structures were of poor
design, the excreta falling directly on the ground or in boxes set on the
ground level. As many of the mill employees using these outhouses were
transients, it was estimated that about 200 persons used the three poorly
constructed and unsanitary outhouses during the cattle feeding season.
At the lower end of the feed yards there was a stagnant pool which drained
a watershed that included a portion of the town and cottonseed oil mill
with its three primitive outhouses. The cattle were occasionally forced to
drink from this stagnant pool as a result of frozen pipes which shut off the
regular water supply. The 1,500 cattle fed at the yards were therefore ex-
posed to the following sources of infection with tapeworm: (i) The out-
houses which drained into the stagnant pool; (2) the regular water supply
from the sewage-laden river; (3) the cottonseed hulls, which were more
or less subject to contamination, and (4) a portion of the town's waste
which drained into the stagnant pool. That fully 20 per cent, of the cattle
that were fed under these unsanitary conditions became infected, as shown
by the data obtained, is not surprising considering the four possible
sources of infection.

Two recent outbreaks of cysticercosis in cattle, investigated by the Bu-
reau of Animal Industry, showed conclusively the important role of a single
human tapeworm carrier as a spreader of this parasitic infestation to bo-
vines. The facts in these cases are as follows:

Following the receipt of information that 166 out of 252 cattle carcasses
were retained in an officially inspected establishment at Fort Worth, Texas,
because of infestation with tapeworm cysts, an investigation was made
of the premises where these cattle had been fattened for market. It was de-
termined that the bovines in question were kept in a feed lot to which feed

HEALTH AND DISEASE 315

was hauled by an individual who later was found to be responsible for the
outbreak of cysticercosis. When the owner of the cattle was informed of
the retention of a number of beef carcasses, as already noted, from the
particular lot of cattle in question, all men on the ranch that were con-
nected in one way or another with the feeding of these animals were exam-
ined by a physician, and the individual referred to was found to be infested
with a tapeworm. According to the information furnished "about 20 feet
of tapeworm" were removed from the person following the administra-
tion of a taeniacide. Upon being questioned, the tapeworm carrier admitted
that he did not hke cooked meat and, therefore, "ate all his meat raw."

The premises to which this and other persons connected with the feed-
ing of the cattle had access had no toilet facilities, and the infested person
was seen, on numerous occasions, to defecate in the feed troughs.

In an officially inspected establishment in Oklahoma City, Oklahoma,
twelve out of thirty-seven cattle carcasses were retained recently because
of infestations with cysticerci. In tracing the origin of these cattle, it was
determined that they came from a farm that had no toilet facilities, the barn
and chicken house being used as places for defecation by a man and his
wife who had charge of the cattle-feeding operations. The only source of
water supply for the cattle was a small pond located about a hundred yards
from the farm house; all the drainage from the dwelling, barn and chicken
house ran directly into this pond. Through the assistance of the State Board
of Health, it was determined that the wife of the cattle feeder, who com-
plained of being sick, was infested with Taenia saginata. Considering the
primitive conditions under which this couple lived, it is not surprising that
one third of the cattle that were fed on this farm became infested with
tapeworm cysts.

While the consumption of raw or slightly cured fish will probably strike
the readers of this article as a freak habit of certain northern European im-
migrants, the consumption of raw and rare beef is certainly a well-estab-
lished American custom. Steaks cooked rare are frequently raw in the
middle, and rare roast beef is certainly a common American dish. It is not
surprising, therefore, that infestation with the beef tapeworm is quite com-
mon in the United States. No adequate statistical information is available
on this point, since there is no agency in the United States for collecting
this sort of information. Several physicians with whom the writer of this
paper has discussed this point stated that cases of human tapeworm infesta-
tion are encountered by them, sometimes several times a year in routine
practice. That tapeworm infestation in man is not more common in this
country is due entirely to the protection that is afforded to the consumer
by the vigilant federal meat inspection service and competent state and
local meat inspection units.

Beef tapeworm infestation in man occurs in all parts of the world where
beef is used for food. In Abyssinia, where beef is regularly eaten raw, prac-

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tically the entire population is infested; in certain parts of Syria, one third
of the population is infested. In countries where beef is commonly cooked
the extent of the infestation is more limited.

Under federal meat inspection beef carcasses showing an excessive in-
festation with tapeworm cysts are not passed for human food, thus cutting
off the most fertile source of infection. During the past five years, the
total number of beef carcasses condemned on account of tapeworm in-
festation was somewhat under i,ooo out of a total of over 50 million cattle
slaughtered under federal inspection. During the same period, however,
over 135,000 beef carcasses were retained on account of infestation with
tapeworm cysts. Under federal meat inspection the retained carcasses which
contain only one dead and degenerated cyst are passed for food following
the removal of the cyst and adjacent parts, and a careful inspection to make
sure that no other cysts are present; carcasses showing a moderate infesta-
tion are not passed until after the removal of all visible cysts and subsequent
refrigeration of the carcasses for a period of not less than six days and at a
temperature definitely known to be fatal to the vitality of these parasites,
or such carcasses are cooked at a temperature that is known to be destruc-
tive to the vitality of these tapeworm larvae. Carcasses showing a heavy
infestation, or a pathological condition of the muscles indicative of such in-
festation, are condemned.

It should be borne in mind, however, that only about two thirds of the
food animals slaughtered in the United States are subject to federal inspec-
tion or under imperfect inspection. Slaughtering done on the farm for
home consumption is not, of course, subject to any official inspection.
Actually, however, even the best kind of inspection can not guarantee per-
fect results so far as the detection of tapeworm cysts in beef is concerned,
because in most cases the degree of infestation is slight and a large propor-
tion of slightly infested carcasses necessarily escape even the most careful
inspection. The actual number of cases of infestation in cattle with larval
tapeworms is probably much greater than that shown by the figures cited.
From a practical viewpoint, however, it seems scarcely possible to effect a
more thorough inspection for tapeworm cysts than is done under existing
requirements. The inspection that is made eliminates most of the carcasses
that are likely to transmit tapeworm infestation to human beings; the car-
casses that are passed without detecting these parasites probably have only
slight or almost negligible infestations.

As in the case of the fish tapeworm, the beef tapeworm in many cases
may produce no noticeable symptoms. This is particularly true of cases
involving robust individuals. Delicate and nervous persons and children
may show, at times, rather alarming symptoms, including severe gastro-
intestinal disturbances, nausea, and vomiting. Nervous persons may show
convulsions and even some severe reactions that are suggestive of epilepsy.
Sometimes tapeworm infestation gives rise to emaciation and anemia. On

HEALTH AND DISEASE 317

the whole, tapeworm infestation does not produce serious illness, the se-
vere symptoms mentioned being the exception rather than the rule. Ef-
fective treatments for the removal of tapeworms from man have been
established, and persons affected should seek the advice of a physician.

Prevention is simple and effective. To avoid tapeworm infestation cook
beef until it is well done.

THE PORK TAPEWORM

Aside from being somewhat shorter, as a rule, the pork tapeworm, Taenia
solium, bears a very close resemblance to beef tapeworm. Like the beef
tapeworm, the pork tapeworm lodges in the small intestine of human be-
ings, its head being provided with hooks that afford the possibility of a
firmer anchorage to the intestinal wall than in the case of the beef tape-
worm, which lacks this armature. Ordinarily the pork tapeworm is from
about two and one half to five feet long, but it may attain, at times, a length
of about twenty-five feet. Its life cycle is essentially similar to that of the
beef tapeworm, except, of course, that the hog serves as the intermediate
host. Human beings become infested with the pork tapeworm by swallow-
ing infested raw or insufficiently cooked pork, and hogs in turn become
infested with the cystic stage by swallowing feed or water that has become
contaminated with human excreta passed by infested persons. The life his-
tory of the pork tapeworm thus consists in an alternation between two
hosts, man and swine. The reduction in the incidence of infestation in swine
necessarily leads to a reduction in the incidence of infestation in man, and
vice versa.

Actually the pork tapeworm is very rare in man in this country; the
rarity of this parasite in human beings is directly correlated with the rarity
of the cystic stage in swine. This is a very fortunate situation, because from
the view-point of its bearing on human health, the pork tapeworm is far
more dangerous than the beef tapeworm. So far as the production of in-
testinal disturbances and nervous symptoms in infested individuals is con-
cerned, the two species under consideration are on a par. Unfortunately,
however, man is also capable of serving as an intermediate host of the pork
tapeworm and thus becoming infested with the cystic or bladderworm
stage. Since the cysts may lodge in such organs as the heart, the brain and
the eye, an infestation in man with the cystic stage of pork tapeworm may
lead to serious consequences and often does. Persons harboring the pork
tapeworm in the intestine might accidentally contaminate their hands with
the tapeworm eggs. It requires but little imagination to see how the hands
thus contaminated might transfer the eggs to mouth and thus pave the
way for an infection of the muscles and of such vital organs as the heart,
brain and eyes. Several years ago a medical officer of the British Army re-
ported the pork tapeworm as a rather common cause of epilepsy in British
troops returning from abroad, presumably from places where the cystic

3l8 READINGS IN BIOLOGICAL SCIENCE

Stage of the pork tapeworm was of rather common occurrence in swine,
the epileptiform symptoms being due, of course, to the lodgment of the
cysts in the brain and other parts of the central nervous system.

Under federal meat inspection swine carcasses showing a light infestation
with tapeworm cysts are passed for sterilization, which means thorough
cooking at a temperature more than adequate to destroy Uf e in these para-
sites; if the infestation is moderate or excessive the carcass is condemned.

For many years it was assumed that the rarity of the pork tapeworm in
man and swine in this country was due to the fact that the American people
were not in the habit of eating rare or raw pork, a habit which is well
established among the people of certain countries of Europe. Unfor-
tunately, in the light of the evidence to be presented in connection with
the next and final topic, trichinosis, this assumption does not appear to af-
ford the entire explanation. Federal and other competent meat inspection
offer the public the greatest measure of protection against the pork tape-
worm. The importance of cooking pork thoroughly will be discussed in
connection with trichinosis. Thorough cooking of pork will absolutely
preclude the possibility of infestation with a tapeworm that is very dan-
gerous to human health.

TRICHINOSIS

Trichinosis is a disease of human beings, swine and other animals. The
parasites which produce this disease are small cylindrical worms, known
to zoologists as Trichinella spiralis and commonly known as trichinae;
these parasites occur in a great variety of carnivorous and omnivorous
mammals. So far as human trichinosis in this country is concerned, only
swine need be taken into consideration, since practically all the known
cases of human trichinosis in the United States that have been definitely
traced to their source were shown to have resulted from the consumption
of raw or undercooked infested pork or to the consumption of inade-
quately cooked or cured meat food products containing infested pork
muscle tissue. A few cases of trichinosis have been traced in this country
to the consumption of jerked bear meat, and in Germany this food was
responsible for a serious outbreak of trichinosis several years ago.

Unfortunately, pork that is infested with trichinae does not differ in
appearance or in taste from uninfested pork. The trichinae that occur in
the flesh of hogs are very small, measuring only about one twent)'-fifth
of an inch in length and about one eight-hundredth of an inch in width.
The individual worms are spirally rolled and enclosed in capsules which
are somewhat less than one fiftieth of an inch in diameter and hence, micro-
scopic in size. The capsules do not stand out in contrast to the meat, except
in infestations of long standing. Considering the minute size of encapsuled
trichinae, it is impossible, of course, under meat inspection procedure, to
detect their presence in pork with the naked eye. Microscopic inspection

HEALTH AND DISEASE 319

of pork for trichinae is practiced in some European countries. Such in-
spection, however, is inherently imperfect, many infected carcasses, espe-
cially those moderately or hghtly infected, being overlooked. Knowledge
of the existence of a microscopic inspection of work would tend to create
a false sense of security in the minds of persons who are fond of raw pork,
and this would tend to promote rather than discourage the unhygienic
custom of eating pork in a raw or semi-cooked state. In the United States,
microscopic inspection for trichinae of pork intended for home consump-
tion has never been undertaken. Consequently, pork that is passed under
federal and other meat inspection as being fit for human food may be in-
fested with trichinae, and for this reason pork should always be cooked.
If infested pork is eaten raw or insufficiently cooked, serious consequences
are apt to follow and sometimes do.

During the year 1937 three serious outbreaks of trichinosis were reported
in the press. Through official correspondence, the Bureau of Animal In-
dustry ascertained the facts in each outbreak from the health officer of
the community concerned or from the physician who treated the patients.
These three outbreaks illustrate how trichinosis may be contracted and
afford information on the seriousness of this disease.

Early in December of last year, a farmer, Mr. X, living in Flathead
County, Montana, a Russian by birth, and the father of eighteen children,
prepared a lot of smoked sausage which contained venison mixed with
pork obtained from hogs slaughtered on his own premises.^ These sausages
were eaten by X and his immediate family. Some of these home-made
sausages were distributed by the kindly father to his married sons and
daughters, and they in turn, partook of these home-made products and,
with characteristic western hospitality, distributed the surplus products
to their friends and neighbors. The available evidence indicates that the
immediate family of X, and some members of the families of his sons and
daughters and those of some of their friends ate these products without
cooking or only after slight cooking or warming. As a consequence thirty-
eight persons became ill, Mr. X and members of his immediate family being
the first ones to show symptoms of illness.

The first symptoms shown by the members of the stricken family were
a general tired feehng and headache, these being followed by nausea, vomit-
ing and sharp gastro-intestinal pains. These early symptoms were followed
later by pains in the eyes and a marked swelling of the lower eyelids; at the
same time marked swellings were noted in the muscles of the lower por-
tion of the abdomen and in the flexor muscles of the limbs. The symptoms
mentioned, especially the early symptoms, were, in the opinion of the at-
tending physician, suggestive of food poisoning, and it was suspected that
the venison which was one of the constituents of the sausage might have

1 The account of this outbreak is based on information supplied by the attending
physician.

320 READINGS IN BIOLOGICAL SCIENCE

been tainted. As the patients failed to improve, but grew instead increas-
ingly worse and developed fever, the state epidemiologist, who was notified
of this outbreak, visited the premises, and obtained samples of water and
samples of blood and stools from the infected persons. The samples were
submitted to the state health laboratory for bacteriological examination;
the results were negative. The youngest member of the family in the
meanwhile became severely ill and was placed in a hospital, where the usual
laboratory examinations were made, including a microscopic examination
of the spinal fluid, a spinal puncture having been resorted to because menin-
gitis was suspected. One microscopic field showed a single trichina larva,
and this at once led to a suspicion that the patient, as well as the other mem-
bers of the family, was suffering from trichinosis. Samples of the pork
sausage still available on the farm were sent immediately to the laboratory
of the Montana Livestock Sanitary Board, and a telegraphic report from
that laboratory to the hospital contained the information that the sausage
was heavily infested with trichinae. The hospitalized patient succumbed
to the infection about three weeks after eating the infested sausage. In the
meanwhile other persons outside of X's immediate family became ill and
on the date of the last report 38 persons, as already noted, were ill and suf-
fering from trichinosis.

The symptoms shown by the affected persons were due to the progress
in the growth, development and migration of the trichinae in the bodies
of their victims. The early gastro-intestinal irritation and pain were the
result of the growth and development of the worms in the intestine, and
the swellings and pain in the muscles were caused by the penetration into
this tissue of the new-born trichinae, which wandered from the intestine
in the lymph and blood stream until they reached the muscles. The symp-
toms which were suggestive of meningitis were due, at least in part, to the
penetration of the wandering worms into the central nervous system.

One of X's daughters ate some of the sausage well cooked and escaped
infection, while several members of her family who ate the sausage only
half-cooked became ill. A neighbor of one of the beneficiaries of X's
generosity is said to have stolen a number of sausages and his family of
five, including himself, became stricken with trichinosis.

A sample of the sausage that brought about this epidemic was forwarded
to the Bureau of Animal Industry and was found in our laboratory to con-
tain approximately 2,800 trichina larvae per ounce. A piece of muscle from
one of eleven hogs purchased from X by the Montana Livestock Sanitary
Board and later slaughtered was examined in our laboratory and found to
contain an average of about 168,000 trichinae per ounce.

This outbreak has been described in detail because it illustrates the point
that human beings acquire trichinosis from eating raw or slightly cooked
pork, shows the principal symptoms of trichinosis, and that this disease
may terminate in death. The data given afford conclusive proof that the

HEALTH AND DISEASE 32 1

suffering of those stricken as well as the untimely death of the youngest
member of the family could have been avoided, if the sausage in question
had been cooked, as shown by the experience of one of X's daughters, who
apparently did not share her family's fondness for semi-raw pork. The case
history of the boy who succumbed to trichinosis illustrates that this disease
may be confused with other febrile diseases, such as food poisoning and
meningitis. Trichinosis is commonly confused with typhoid fever and oc-
casionally with undulant fever.

Another outbreak which occurred late in October of last year involved
forty-four persons in one of the New England states. Fortunately all these
cases were moderate or mild. The infection was traced to a meal of under-
cooked pork loin of which all the persons who later became ill partook.
The diagnosis in these cases was established on the basis of clinical
symptoms.

Still another outbreak occurred late in the summer in Rochester, New
York, and came about as follows: A social organization of that city held a
picnic which was attended by about 200 members. The food served was
of the customary picnic variety, including pork sausage, which was cooked
hurriedly and avidly consumed by the picnickers, following several hours
of exercise in the open. The resultant casualties were as follows: Stricken
with trichinosis, 85; succumbed to the disease, i. Aside from the fatal case,
only a few individuals developed sufficiently severe symptoms to warrant
hospitalization; most of those stricken escaped with rather mild symptoms
and were treated in their homes. An article regarding this outbreak, pub-
lished in the bulletin of the Health Bureau of Rochester, New York, con-
tains the following significant statement: "All this suffering could have
been so easily prevented, if only the pork had been thoroughly cooked."

The total number of cases involved in the three outbreaks is 167, with
two deaths. In addition to these cases, there occurred during the year a
number of more or less isolated cases in various parts of the country which
probably will bring the total number of reported cases of the year up to
about 250.

In the absence of an economically practical method of inspection of
pork to detect infected carcasses and in the absence of a practical system
of rendering fresh pork and ordinary varieties of cured pork safe for con-
sumption before the meat is released for sale, the consumer should protect
himself by cooking all pork thoroughly, unless he has definite assurance
that a particular processed pork product intended to be eaten without cook-
ing was prepared with this in mind in a meat-packing establishment operat-
ing under federal inspection or competent state or local inspection. When-
ever any doubt exists as to whether a particular product may be eaten
without cooking, it should be cooked thoroughly.

Under federal meat inspection, all products containing pork muscle
tissue that are to be sold as cooked products are heated or cooked under

322 READINGS IN BIOLOGICAL SCIENCE

the scrutiny of inspectors, according to methods which are known to in-
sure a sufficiently high temperature to destroy in all parts of the meat the
vitahty of any trichinae that may be present. For all products which are
not cooked or heated to a sufficiently high temperature, but which are
nevertheless intended to be eaten by the consumer without cooking, various
alternative methods of preparation are prescribed, such as prolonged freez-
ing at low temperatures, or curing, smoking and drying in accordance with
methods that are known to insure the destruction of life in all trichinae
present. As already stated, for fresh pork and ordinary varieties of cured
pork, there is no inspection or required treatment for reasons already given.
Some persons, upon discovering that between i and 2 per cent, of hogs
in this country contain trichinae, and that these parasites are dangerous to
human health, conclude that all pork, no matter how prepared, is dan-
gerous. Such a conclusion is unsound and unwarranted. There is no danger
whatsoever of acquiring trichinosis or any other parasitic disease from thor-
oughly cooked pork. Cooking of pork is a health safeguard and is com-
parable to the pasteurization of milk, the chlorination of drinking water
and similar hygienic measures that have been adopted the world over to
protect human health. If one concludes that there is something wrong with
pork because it must be cooked to make it safe, to be consistent such a per-
son would also have to conclude that there must be something wrong
with milk because it is commonly pasteurized. As is well known to hy-
gienists, cooking is the greatest health safeguard; the facts presented in this
paper confirm this generalization.

>>><<<■

DEGENERATIVE DISEASE *
KARL B. MICKEY

It is difficult to realize that less than three generations of human life have
passed since Pasteur discovered the bacterial causation of disease. That
knowledge so profoundly influences our attitude toward the world we live
in, that we tend unconsciously to think of it as having always been a part
of the intellectual equipment of civilized peoples.

Of course, the scientific approach to human disease antedated Pasteur.
Hippocrates, in Greece in the fifth century before Christ; Galen in Italy
in the second century of the Christian era; Harvey, in seventeenth century
England — these are but three of the most illustrious of those who, within
historical times, attempted by exact observation and reasoning to dispel
the demonism and crude ignorance which pervaded the practice of medi-
cine. However, it was not until the young French scientist, from his study

* Reprinted from Health Froiii the Grotmd Up by Karl B. Mickey with the per-
mission of the International Harvester Company, 1946.

HEALTH AND DISEASE 323

of the fermentative diseases of wine and beer, evolved his concept of animal
diseases the result of invasion of the tissues by microscopic organisms, that
scientific medicine acquired a solid foundation upon which to build.

Upon Pasteur's concept Koch quickly founded the science of bac-
teriology. Lister, from the same concept, developed antiseptic methods
which phenomenally reduced the hazards of surgery and made possible
the dramatic progress of that branch of the healing art. Sanitation, public
hygiene, immunology, preventive medicine, and the other modern methods
which have all but robbed communicable diseases of their terrors followed
one upon another, almost without pause. Today's developments of the sulfa
drugs and penicillin are milestones on the road originally opened up by
Pasteur.

The new ability to cope with infectious diseases, viewed in the light of
the cheerful Victorian ideas of progressive evolution and human perfecti-
bility, at first was hailed as presaging a wonderful new world of supermen
living in unalloyed happiness and health.

The dream has failed to materialize. True enough, the great plagues of
smallpox and typhus no longer decimate the populations of entire coun-
tries; the incidence of such infections as diphtheria and scarlet fever is in-
significant compared to that of little more than a generation ago; even
venereal diseases are under control; ^ virtually every infectious illness ex-
cept the common cold is on the decline. Nevertheless, the sum total of
human disease has increased and continues to increase.

Another kind of disease — degenerative disease — increasingly exercises
a selective effect against civilized men. These are the disorders character-
ized by deterioration of the body tissues in which disease-producing agents
such as bacteria play no part or at most a secondarj'^ part — diseases such as
dental caries and periodontal diseases, rickets, osteomalacia and other
diseases of the skeleton, arthritis, nephritis, arterial sclerosis, heart ailments,
etc. And the medical profession, by reason of its success in reducing infant
mortality and in keeping the chronically disabled alive and its comparative
helplessness in preventing these diseases of degeneration, stands accused
by men respected in its own ranks of unwittingly helping to defeat natural
selection and hastening evolutionary degeneration.

Evolutionary degeneration! The very words come as a surprise and a
shock to modern man. For in no other time has the average man been so
pleased with himself as in the present era. Quite a few things have happened
in the past 150 years to give him a fine opinion of himself. For one thing,
he has achieved a considerable measure of political freedom and is accus-
tomed (in the United States) to hearing himself and his fellows referred to as
the "sovereign people" — as kings. By reason of the inventiveness, thrift, and

1 "Dr. Thomas Parran, surgeon general of the United States, said recently in an
Office of War Information report that there is every reason to predict that syphilis
and gonorrhea will be eliminated as a major public health problem in five years." —
Chicago Daily News, March 13, 1945.

324 READINGS IN BIOLOGICAL SCIENCE

daring of the more exceptional of his fellows he has received more for less
work than the average man ever received before. During normal times of
peace he has been better housed, better clothed, and better fed (quantita-
tively) than ever before. Moreover, he had been told by the popular philoso-
phers of the nineteenth century that his evolution was a triumphal, one-
way procession ever onward and upward toward perfection. This earlier
optimism may have been somewhat dampened by periodic economic crises
and two world wars, but now to be told that human evolution is a reversible
process and that, as an organism, he may be deteriorating instead of im-
proving— well, it comes as a shock!

Dr. Thomas Parran, Jr., surgeon general of the United States Public
Health Service, reported a few years ago that one of every 20 gainfully
employed persons in this country is prevented by illness from attending
to his customary duties each day of the year, and every man, woman, and
child, on the average, is incapacitated by illness 10 days of each year. The
oldsters average 35 days sick in bed each year.

A two-year study of the nation's health by a United States Senate Sub-
committee on Wartime Health and Education has revealed that of more
than 14 million men examined for the draft, only two million were up to
standard. About one of every six citizens of the United States, the subcom-
mittee reported has a chronic disease or physical impairment.^ A later re-
port states that approximately 12 per cent, of all those examined by the
armed services were found mentally unfit for military duty.^

As to the incidence of the chronic, constitutional type of disease, an
analysis by the Selective Service System of reports of physical examina-
tion of registrants for military service from 21 selected states is deeply
revealing. During the period November, 1940, through September, 1941,
approximately 3 million registrants in these states were examined at the
local boards. These registrants were, of course, between the age limits
within which men presumably are at the physical prime of their lives. And
yet, the combined rejection rate at the local boards and the induction sta-
tions was 52.8 per cent. The following paragraph from the report sets forth
the incidence of defects causing rejection:

Tooth defects were the leading cause of rejection, accounting for 16.5 per
cent, of all rejections at local boards and induction stations. Other causes of
rejection, and the percentages they constitute of all rejections, are: eye defects,
1 1.7 per cent; mental and nervous defects, 10.4 per cent; cardiovascular defects,
1 0.0 per cent; musculoskeletal defects, 8.9 per cent; hernia, 5.9 per cent; venereal
diseases, 5.9 per cent; ear, nose and throat defects, 5.5 per cent; tuberculosis and
other lung diseases, 3.8 per cent; educational deficiency, 3.8 per cent; defects of
the feet, 3.0 per cent; underweight, 2.9 per cent; other causes, 11.7 per cent.*

2 Time Magazine, January 15, 1945.

^ Ibid., October 15, 1945.

* Causes of Rejection and Incidence of Defects, Local Board Examinations of Selec-
tive Service Registrants in Peacetime, Medical Statistics Bulletin No, 2, Selective Service
System, August i, 1943, P- '•

HEALTH AND DISEASE 325

To those who have studied the phenomenon of physical degeneration it
will be no surprise that tooth defects head the list of causes of rejection.
Dental caries, together with degeneration of the jaw bone and disease of
the periodontal tissues, combine to form the most universal scourge of
modern civilization. Examination made in public schools throughout the
country reveal that from 85 to 100 per cent, of the children are afflicted
with dental decay.

From the evolutionary point of view, dental caries is a comparatively
modern disease with an affinity for civiHzed peoples. Dr. Weston A. Price,
whose extensive researches into the causes of this and related diseases have
attracted widespread attention, finds it to be practically nonexistent among
primitive peoples isolated from civilization. Price reports, further, that
even in the first generation after primitive races adopt the foods of white
civilization tooth decay appears, together with such evidences of evolu-
tionary degeneration as the narrowing of the face and the dental arches.^

Physical anthropologists, and particularly Dr. Earnest Albert Hooton,
of Harvard University, regard the condition of the teeth and dental arches
as of great evolutionary significance. Diseases of these structures may be
used as a measure of the physical degeneration of any race, for they are al-
most invariably accompanied by deterioration of other tissues. The nar-
rowing of the dental arch, depriving the teeth of normal room, causes
malocclusions which may result in gastric disorders. The narrowing of
the face may alter the shape and affect the capacity of the brain cavity.
These malformations usually are accompanied by a general diminution
and deterioration of bony tissues, notably the narrowing of the pelvis
which, in women, affects the reproductive function.

But how, the reader may protest, is this talk of evolutionary degenera-
tion to be reconciled with studies which show that Americans are growing
taller and heavier each generation? There is impressive evidence on both
sides of this case, and much of it cannot be reconciled. It is more a matter
of weighing the evidence in order to see on which side the preponderance
lies.

Several studies have shown Americans to be taller and heavier than Euro-
peans descended from the same stock. Other studies have shown second-
generation Japanese in California and off-spring of Europeans in Ameri-
can cities to be larger and better built than their parents. The most recent
study of this sort is that of the Metropolitan Life Insurance Company,
which shows that the average height of men beru'een the ages of 20 to 29
inclusive, examined at military induction centers in May, 1943, was 68.15
inches, or two-thirds of an inch greater than that of the same age group
among the first million men mobilized for war in 1917; that the proportion
of six-footers among men in their twenties is about one-third greater than
it was 25 years ago; and that the native women of the United States, in the

'^ Nutrition and Physical Degeneration, p. 18.

32(5 READINGS IN BIOLOGICAL SCIENCE

20 years following 1920, have caught up with and now exceed the birth
rate of foreign-born women, with an annual rate of 50.7 children per 1,000
women, as against 49.5 per 1,000.*

Hooton reports the results of a study of Harvard University under-
graduates which showed an increase in body size for three generations.''
The men in the third generation had increased in height nearly one and
one-half inches over their grandfathers and more than 10 pounds in weight.
Generally speaking, the grandsons' measurements exceeded those of their
grandfathers by 2 per cent. The shoulder breadth of the grandsons was
greater than that of the grandfathers, but the depth and expansion of their
chests were less. While the bony structure of the grandsons was longer
than that of their grandfathers, it was more fragile. Though admitting that
their impressions had not been scientifically verified, Hooton stated that
he and other physical anthropologists believe the grandsons are constitu-
tionally weaker than their more compact grandfathers.

Carrel commented on the magnificent physiques of our college athletes,
but remarked that their longevity is no greater than that of their ancestors
and their resistance to fatigue and worry seems to be less. He said they
have more delicate nervous systems than their ancestors and break down
more easily.

It is a matter of common knowledge that average men of primitive races
isolated from civilization are capable, as a matter of routine, of sustained
physical efforts that seem prodigious to us. The men of the Hunzas, a tribe
of northern India, frequently travel 60 miles on foot in one stage, transact
business, and make the return trip immediately. The Austrahan Aborigines,
the polar Eskimos, and the many other peoples among whom Price made
his comparisons of primitive and modern diets and their effects, all were
endowed with a physical and nervous stamina far surpassing that of our
most rugged and highly trained athletes.

In weighing the evidence of increase in size, two additional considera-
tions should be kept in mind. One is that the more notable increases re-
ported have been among descendants of foreign-born whose ancestors
frequently were undernourished for generations. The other is that anthro-
pological opinion does not hold a mere increase in size alone as indication
of biological improvement; the rate of metabolism frequently fails to keep
pace with the increase in size, with the result that the larger organism may
be less efficient than the smaller organism as a converter of food into
energy.

Regardless of differences of opinion as to its evolutionary significance,
leaders of the rnedical profession and alUed branches of scholarship regard
degenerative disease as civilization's major health problem. Even making
the most generous allowance for the advances in the art of diagnosis, which

^ Time Magazine, December 25, 1944.
"^ Twilight of Man, pp. i-ji-ij^.

HEALTH AND DISEASE 327

reveals many disorders that formerly went undetected, degenerative disease
is on the increase. It respects neither economic status nor age. Though its
incidence is greater among the old, its destructive effects progress more
quickly among the young.

Its burden upon society is incalculable. Medical practice, by lowering
infant mortahty and by prolonging the lives of the physically inadequate
whom pathogenic agents otherwise would weed out, some authorities
charge, places an increasing weight on the shoulders of the physically fit.
In addition, chronic physical disorder must inevitably be accompanied by
chronic mental and moral disorder: where physical stamina is lacking the
will lacks power; and the process of digestion, is profoundly influenced
by the state of general health. Carrel, Hooton, and Price — to mention only
three men already named in these pages — agree in attributing much of the
adult insanity and criminality which fills our institutions, and much juve-
nile delinquency, to the mental and moral consequences of diseases of
physical degeneration.

The next question, logically, is — What causes diseases of degeneration?
Many answers have been given — most of them tentatively. In the case of
some of these diseases — particularly cancer — no honest man would attempt
an answer on the basis of the knowledge at hand. In the case of cardio-
vascular disorders, for example, many answers have been given — the stress
and strain of modern life, infections, increased indulgence in smoking,
metabohc disturbances, dietary deficiencies. Diseases such as scurvy and
pellagra have definitely been traced to vitamin deficiencies. Rickets has
been unmistakably traced to calcium deficiency or disorder of the calcium
metabolism due to endocrine disturbances or deficiency of vitamin D, or
all three. Although clinical medicine has made great advances in recog-
nizing and classifying the symptoms of degenerative diseases, and has
achieved some success in alleviating their discomforts and in prolonging
the lives of their victims, therapeutic measures necessarily remain empirical
— processes of trial and error — because of the almost incredible complexity
of the disorders.

Take — for one further example of the difficulties which the subject im-
poses upon medical science — arthritis, a common malady whose incidence
is increasing. Frequently, it has been attributed to infection, and many a
tooth has been extracted and many a tonsil removed in efforts to cure it.
But why should a focal infection cause arthritis in one man and the same
focal infection not cause it in another?

This complexity undoubtedly is due in large part to the fact that the
dearth of knowledge obscures many simple relationships. It is the usual
experience in scientific inquiry that, as knowledge increases, relationships
that at first were baffling in their complexity become progressively more
clear and can often be reduced to relatively simple laws. However that
may be, medical science stands today, with reference to these clironic, con-

328 READINGS IN BIOLOGICAL SCIENCE

stitutional diseases, almost where it stood in the days preceding Pasteur
with reference to infectious, communicable diseases. There exists an in-
sufficient body of exact, scientific knowledge upon which to base an ef-
fective program of preventive medicine.

There are, however, certain important differences between the situation
today and that of seventy years ago. Quackery and spiritism will always
exist in some quarters, human nature being what it is; some persons will al-
ways carry a buckeye as a sovereign cure for "rheumatiz"; but, in general,
superstition has been replaced by rationalism. Techniques of investigation
and experimentation are vastly improved.

Some investigators think they have found the key to the problem of de-
generative disease, and that the key is nutritional deficiency.

The trail has been blazed by such groups as the Medical and Panel Com-
mittee of the County of Cheshire in England, and by such men as Dr.
Robert McCarrison in India and Dr. Price in the United States. The Com-
mittee embodied the results of 25 years of study in a remarkable document
entitled "A Medical Testament," which attributed the alarming increase
in illness in Cheshire County to "a life-time of wrong nutrition." ^ Dr. Mc-
Carrison fed rats the same diets as eaten by peoples in various parts of India
and in each case produced in the animals a state of health corresponding
to that of the people. Dr. Price carried on his researches among a large
number of primitive people in many parts of the world; he compared those
living in isolation with their blood brothers exposed to white civilization,
as to tooth decay and skeletal deterioration; analyzed and compared their
respective diets in the laboratory.

It will be apparent to the reader that, on the surface, the problem of
nutritional deficiency presents a paradox. In the past century and a half the
peoples of North America and Western Europe have had more to eat than
any peoples in any time or place known to history, and yet it is within that
period that the physical degeneration now attributed by some authorities
to malnourishment has been on the increase. Prior to the year 1800, when
hunger was the daily companion of the average man, degenerative disease
is believed to have been rare.

A number of factors doubtless enter into this. One is that the rigors of
life and the ravages of infectious diseases formerly killed off the weaker
individuals before they had a chance to acquire degenerative diseases. But
a factor most pertinent to this discussion is that quantity does not con-
stitute the only food problem or even the most grave food problem. It is
the quahtative, not the quantitative, deficiencies in diet that cause dental
caries, rickets, osteomalacia, and other degenerative diseases. A man may
be positively satiated with bulk and still be malnourished for lack of those
food elements essential to the building and maintenance of the structural
integrity of his body and to the development and repair of its tissues.

* Quoted from An Agricultural Testament, by Sir Albert Howard.

HEALTH AND DISEASE 329

In fact, the recent researches of such men as Price and Sir Albert How-
ard, as well as the studies of some physical anthropologists, tend strongly
to the conclusion that man frequently has been least well-nourished where
and when his food supply has been most ample. The peoples who live at
the lowest economic level — primitive hunters and fishermen — show the
fewest evidences of constitutional disease and the physical features of evo-
lutionary degeneration, except when they come into contact with civiliza-
tion. Pastoral peoples, too, on the next highest level, show relative free-
dom from dental decay and other degenerative conditions.

Food is so scarce with these primitive hunters and shepherds that they
eat all that is available; nothing goes to waste. They cannot aflrord, like
peoples on a higher economic and cultural plane, to eat only the muscles
of an animal and scorn the viscera, the internal organs. And as the viscera
are especially rich in the minerals and vitamins required by health, the
savage is likely to be healthier than men on higher cultural planes.

It is when man moves upward to an artificial existence, when he do-
mesticates plants and practices agriculture, that physical degeneration be-
gins to set in — dental caries, diseases of the gums, skeletal weakness,
arthritis, and other kinds of chronic constitutional ailments, frequency
of acute infections, and other diseases directly and indirectly referable
to dietary deficiency. And when life becomes urban and industrial, then
physical degeneration becomes appalling. Civilized man, with a plentiful
supply of food, is able to pick and choose. Lacking the instinct of the lower
animal, and the intuition and tribal lore of the primitive man, he all too fre-
quently chooses what isn't good for him.

A strict regard for the facts, however, demands the noting of an excep-
tion to the generalization developed in the preceding three paragraphs.
The health of some primitive peoples within the zone extending about 700
miles on either side of the equator, for example, is far from enviable. It is
within this zone that the habitual practice of cannibalism is largely con-
fined today.

In this region high temperatures, accelerating chemical reactions, and
torrential rains, exerting both chemical and physical action, carry the cal-
cium and other minerals essential to health down to levels where the plant
roots cannot reach them. There is everywhere a definite correlation be-
tween minerals and proteins, both because calcium stimulates the nitrify-
ing bacteria and because the nitrates, too, are easily soluble and are leached
away with the minerals. The result is grave lack of mineral and proteins
in the foods available to the natives of this zone.

Even where cannibalism is practiced as a magical ritual, its basis could
be the need of conserving proteins and minerals, for ritual observances
usually have their foundations, no matter how obscurely, in practical neces-
sity. Cannibalism in the lower animals is known to be due to mineral hunger.
Cannibalism is far from universal among savage peoples, which indicates

330 READINGS IN BIOLOGICAL SCIENCE

that it must arise from special necessity. Along the Guinea Coast south-
ward into the Congo and for some distance eastward in Africa, the eating
of human flesh is today the main part of the diet of some tribes and the
market in human flesh is just as commercial and free from ritual as the
cattle market in the United States. This market undoubtedly owes its
existence to the need of foods containing adequate amounts of minerals
and proteins.

The popular vitamin craze in the United States is evidence that the peo-
ple have awakened to the danger of nutritional deficiencies and are at-
tempting to correct them. The unfortunate fact is, however, most people
are not aware that vitamins, essential as they are to health, are merely activa-
tors. In the absence of the appropriate minerals, proteins, and other
nutrients taken by the plants from the soil, the vitamins have nothing to
activate. Moreover, some professional students of nutrition question
whether the synthetic vitamins and mineral salts purchased at the drug
store are not considerably less beneficial than vitamins and minerals taken
in the form of vegetable and animal foods.

According to Dr. Parran, more than 40 per cent, of the American people
did not consume enough milk and milk products, citrus fruits, green vege-
tables, and meats to maintain good health and vigor; their diets were partic-
ularly deficient in calcium and the vitamins A, B complex, and C.** Under
wartime food restrictions they ate of necessity more of the energy-
generating carbohydrates and less of the protective foods which maintain
the organism in good development and repair.

The author has seen no published reports on this subject, but during the
war physicians told him orally that the efltects of food rationing had ap-
peared in decreased resistance to illness, particularly in the case of grow-
ing boys and girls. "They look all right on the outside," said one busy
pediatrician of his patients, "but on the inside they haven't got what it
takes." This was in America, whose civilians as compared with those of
Europe had scarcely been touched by the war.

A tragic glimpse of how war ravaged the civilian populations of Europe
with diseases of degeneration was revealed in a report from Paris by A. J.
Liebling.^° Liebling stated upon the authority of Professor Pasteur Vallery-
Radot, a physician of the Academie Fran^aise, that 54 per cent, of the chil-
dren born in Paris during the German occupation had rickets. Due to de-
ficiency of calcium and phosphorus in the diet, the bones of adults broke
"with sickening ease," and French physicians reported cases of adults who
lost as much as four inches in height due to the effect of this deficiency
upon their vertebrae. Similar tragic conditions were found in Poland,
Yugoslavia, Italy, Greece, and elsewhere.

Despite the fact that the science of genetics holds acquired characteristics

® Nutrition and National Health, The Technology Review, June, 1940.
1° Letter from Paris, The New Yorker, November 4, 1944.

HEALTH AND DISEASE 33 I

not to be inheritable (there is some dissent from this tenet) a number of
highly competent investigators report much evidence that degenerative
characteristics resulting from nutritional deficiency are inheritable in the
first generation. This would seem plausible since our inheritance consists
of a complex set of chemicals called chromosomes, which we get from
our parents. Though nature "guards" the germ plasm more jealously than
any other tissue, it is difficult to understand why chemical deficiencies in
the diet, if sufficiently pronounced, would not cause corresponding de-
ficiencies in the chromosomes and their constituent genes.

Thus we have attempted to outhne the situation which has impelled the
surgeon general of the United States Public Health Service to declare that,
today, knowledge of nutrition opens up to medical progress a field com-
parable to that opened up less than three generations ago by Pasteur's dis-
covery of the bacterial causation of disease.^^

WALTER REED AND YELLOW FEVER *

GRACE T. HALLOCK AND C. E. TURNER

The struggle against yellow fever began more than 200 years ago. It ap-
proached its close when a master detective unmasked the chief villain that
carried the fever from one person to another. The detective was Walter
Reed, and he was helped by brave American soldiers who offered their
lives in the conquest of this disease.

THE HISTORY OF YELLOW FEVER

The earliest record of yellow fever says it occurred in Central America
in 1596. Then it was heard of in New England among the Indians, in 16 18.
It appeared in the Island of St. Lucia in 1664, where it killed 1,411 of a
population of 1,500 soldiers. In 1665, in the same place, 200 of 500 sailors
died of it. New York was visited by it for the first time in 1668; Boston in
1691, and Philadelphia in 1695. ^^ 208 years there were 95 invasions of
our territory by yellow fever. From 1793 on there were not less than
100,000 deaths from it. New Orleans, Philadelphia, Memphis, Charleston,
Norfolk, Galveston, New York, Baltimore, and many other cities suffered
a tremendous loss of life.

In the terrible epidemic of 1793 in Philadelphia, all the streets and roads
leading from the city were crowded with families flying to the country
for safety. So many doctors were sick or had died of yellow fever that "at
one time there were only three physicians who were able to visit patients,

11 Parran, Nutrition and National Health, The Tech?iology Review, June, 1940.
• Reprinted from Health Heroes, Walter Reed by permission of the Metropolitan
Life Insurance Company. Copyright 1926.

332 READINGS IN BIOLOGICAL SCIENCE

and at this time there were probably not less than 6,000 persons ill with
the fever." Dr. Rush, then a physician in Philadelphia, relates that a cheer-
ful countenance was scarcely to be seen in the city for six weeks. Once in
entering the house of a poor man, he met a child of 2 years who smiled in
his face, and he says, "I was strangely affected by this sight. Few persons
were met in the streets except those who were in quest of a physician, a
nurse, or the men who buried the dead. The hearse alone kept up the re-
membrance of the noise of carriages or carts in the street."

For more than 200 years, learned men searched for the clues that would
tell them how to prevent the crime of yellow fever which was repeated
year after year. The strange part of the story is that they found the clues
and described them many times, but they didn't have sufficient knowledge
to trace the villain. It lived in the community undisturbed and went its
criminal way unchecked, until the master detective, using the very same
clues that puzzled everyone else, came along and pointed it out.

The first thing Major Reed and his associates decided to do when they
reached Cuba was to sift the evidence that seemed to point to an insect-
carrier of the disease. Insects, like flies and mosquitoes, had already been
convicted of carrying certain other diseases. Walter Reed himself had
proved that flies spread typhoid fever; and an English army surgeon. Dr.
Ross, had discovered that the parasite of malaria gets into the blood of a
human being through the bite of an A?wpheles mosquito and in no other
way. Another species of mosquito had been suspected of carrying yellow
fever. There were many clues that pointed to it as the guilty party.

THE FIRST CLUE

In almost all the old accounts of yellow fever epidemics, mosquitoes
were mentioned as being very troublesome. Dr. O'Halloran, describing an
outbreak of the disease in Barcelona, Spain, in 182 1, wrote: "It is worthy
of remark that during the month (July) the flies and mosquitoes were in-
finitely multiplied." Dr. Drysdale, a Baltimore physician, writing of an
epidemic, said: "Locusts were not more numerous in the reign of Pharaoh
than mosquitoes through the last few months; yet these insects were very
rare only a few years past, when a far greater portion of Baltimore was a
marsh." Thus it appears that the suspect was at the scene of the crime.

THE SECOND CLUE

Epidemics always started in the low wet regions or near the docks. All
epidemics in Baltimore broke out at Locust Point, a low-lying section al-
most surrounded by water, or about the docks and wharves.

The report of the epidemic in Mobile, Ala., in 18 19 says the first cases
were among the people employed on the wharves. "A number of car-
penters and sailors employed about the wharf and who were much on board
the schooner Sally which was filled with stagnant water, and about the

HEALTH AND DISEASE 333

Steam sawmill, where there was a pond of like offensive water, were taken
with violent fevers." Dr. Rush in describing the outbreak of the 1793 epi-
demic in Philadelphia says: "Upon inquiry, it appears that the first per-
sons who died with this fever . . . had been previously exposed to the
atmosphere of the wharf." As the mosquito breeds in still water, here was
another clue pointing to it as a carrier of yellow fever.

THE THIRD CLUE

In the high and dry parts of a city the disease was not contagious. In
many epidemics people from low-lying sections fled to the higher part of
the city or to the country districts. Although many of these people came
down with yellow fever after they had left their homes, the disease did
not spread to other people in the new neighborhood.

This clue pointed to the thought that yellow fever must be carried in
some way other than directly from one person to another. This was the
conckision arrived at by a great many intelligent observers, but the only
explanation they could give was that the disease must be present in the
air of certain districts and not in others.

THE FOURTH CLUE

Another clue strengthened the idea that the disease was air-borne. Some
people noticed that the fever spread in the direction of the prevailing wind.
Whenever the wind blew strongly in a certain direction, yellow fever
broke out in its path. When the air was still, the infection was content to
pay its calls in the houses of an already infected neighborhood. As the
mosquito is a great lover of home, and never travels far unless it gets a free
ride on the wind, or on a ship, this clue explains why yellow fever spread
so quickly in narrow streets, and broke out at a distance from the wet low-
lying districts of a city only when the villain of the drama was carried there
by wind.

THE FIFTH CLUE

Yellow fever flourished when the weather was hot but was stamped out
by frost. A4osquitoes, also, are active in hot weather and disappear after
a frost. Here was another important clue, but it didn't mean anything ex-
cept that "heat was a very common exciting cause of the disorder," until
suspicion was thrown on the mosquito. It is easy to explain facts that seem
mysterious as soon as the villain of a detective story is uncovered. Then
it seems strange that the important clues, which pointed to the guilty person
as clearly as a signboard points out a road, could have been misunderstood.

Anyone who has studied the life history of the mosquito can see how
the spread of yellow fever tallies with the mosquito's habits. But it is one
thing to suspect a villain, and another thing to prove the suspicion to be
true. Someone had already suspected that the mosquito carries yellow

334 READINGS IN BIOLOGICAL SCIENCE

fever, but had been unable to prove it. This person was Dr. Carlos J. Finlay,
of Havana, who had advanced the mosquito theory in 1881.

Walter Reed and his associates decided to investigate this theory not only
because they had observed that the mosquito's habits tally with the spread
of the disease, but also because of one peculiar fact about the infection of
houses. This fact was the length of time that it takes to change a nonin-
fected house to an infected.

SIXTH CLUE

A picture story of what happens when a case of yellow fever breaks out
in a house is given on the following page.

In this picture it is shown that A's house was not infected with yellow
fever for 1 5 days after A came down with the fever, because people could
go there and not take it. But after the 1 5 days were up, everyone who went
there took the disease in from one to six days.

What were the germs doing, and where were they, before they finally
infected the house? Walter Reed suspected they were being entertained in
the stomach of a mosquito, and stayed there until they were capable of pass-
ing on the disease through the mosquito's bite.

As it was then believed that yellow fever could not be given to animals,
the only way of investigating it was to experiment on human beings. This
meant a tremendous responsibility for the members of the Board. They
agreed they must experiment on themselves as well as on the men who
volunteered for inoculation. Think of the high courage of the men who
took this great responsibility, and the gallantry of the American soldiers
who accepted the risk of suffering, or even death. These men were heroes
in the greatest war of all, the war against disease.

THE FIRST EXPERIMENTS

The first experiments were made in August 1900. Eleven persons were
subjected to the bite of mosquitoes of the species Aedes aegypti (for-
merly called Stegojnyia fasciata) after these mosquitoes had already
bitten patients with well-marked cases of yellow fever. Of these 1 1 per-
sons, two developed the disease. One of the positive cases was that of Dr.
James Carroll, a member of the Board. Both cases recovered. In one of these
cases it was proved that the infection could have been received in no other
way than by the bite of the mosquito. A third case developed later, ac-
cidentally.

On September 13, 1900, Dr. Jesse W. Lazear, while visiting a yellow
fever hospital, was bitten. He dehberately allowed the mosquito, which
had settled on the back of his hand, to remain until it had satisfied its hunger.
Five days after the bite he came down with yellow fever of which he died,
a true martyr to science. From these three positive cases Walter Reed and

'^:m^

:■:.!■ ^*«-*

Q) On July 1 this ship arrived from
Havana, where there was an ep-
idemic of yellow /ever. There
were no cases on board how-
ever, so the ship was
allowed to dock. . / if

This is MrA's house

(D Mr. A helped unload the boat
^^ from Havana In/iVe daus he
liad yellow /ever.

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out taking" the fever but on
the fifteenth day she came
do vn Wi th ib . jf 'fYiSl

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the first Veek,
ofAls illness and
uet he did not
cake the ^er. y

V

,-►•

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went to As house
on the first day •
thatMrs.Ahadtiie;
uelloW feVer In /
flireedaysflrsL /
E had it.

As house on the second

^ day of the fever anddidnt

% take it. But he came bad

V on the eighteenth day

and in three days haa

yellow fever.

; ©This is Mr.D. He Visit-
V ed As house on the
\ twentieth day after A
V came down with the
•fever. InfiVedaus
D had it.

Mrs: F Went to As house
twenty -five days after
A came down. In two
days Wr5. F haduelloW
fever.

336 READINGS IN BIOLOGICAL SCIENCE

his associates came to the conclusion that the mosquito serves as the inter-
mediate host for the parasite of yellow fever.

To prove this definitely, it was necessary to carry on experiments in
such a way as to make it impossible for the men experimented on to get
yellow fever accidentally.

THE EXPERIMENTS AT CAMP LAZEAR

Major Reed and his associates took a piece of ground about 6 miles from
Havana and built a camp there, which they named Camp Lazear after their
dead comrade. The camp site was well drained, and freely exposed to sun-
light and winds. In this camp were quartered men who had never had
yellow fever and who were therefore called nonimmunes. These men were
American soldiers who bravely volunteered for the experiment, and Span-
ish immigrants who gave their services for pay.

If a person is going to have yellow fever, he develops it within six days
after exposure. Therefore, if the men were kept in quarantine for two
weeks without developing the disease, this fact would show they had not
become infected before they entered camp. Things were now so arranged
that if a mosquito was allow^ed to bite a man and the man afterward de-
veloped yellow fever the Board would know the disease was due to the bite
and to nothing else.

KISSINGERANDMORAN -^

When it became known in the American troops in Cuba that soldiers
were wanted for yellow fever experiments, John R. Kissinger and another
young man from Ohio, John J. Moran, volunteered. Major Reed talked
the matter over with them, explaining the risk of suffering and even of
death. They held to their purpose. Major Reed told them they would be
rewarded with a sum of money. They both refused any compensation.
Then Reed touched his hat and said, "Gentlemen, I salute you." Kissinger
volunteered, to use his own words, "Solely in the interest of humanity
and the cause of science." Major Reed's comment on this young man was:
"In my opinion this exhibition of moral courage has never been surpassed
in the annals of the army of the United States."

Kissinger was bitten on December 5, 1900, by mosquitoes which had
bitten yellow fever patients from 15 to 20 days before. Four days later he
had a well-marked case of yellow fever, from which he recovered. In all,
13 men at Camp Lazear were infected by means of the bites of contami-
nated mosquitoes, and the disease developed in 10. Fortunately, they re-
covered. No one else in the camp of 30 or 40 men became ill.

THE MOSQUITO PROVED GUILTY

As a result of these experiments it was found that yellow fever could
be carried from one person to another by the bite of a female Aedes aegypti

HEALTH AND DISEASE 337

mosquito that had bitten a yellow fever patient in the first three days of
his illness, and had then been kept for at least 1 2 days before it was allowed
to bite a human being who had never had yellow fever. If that plan were
followed, the person bitten would generally come down with the disease
within six days. It now became clear as to why it took so long for a case
of yellow fever to infect a house. Mosquitoes had to bite the patient during
the first three days of his illness, then 12 days had to go by before they
could pass on the disease by biting another person. But after that interval
of 12 days they were a menace to everyone who entered the immediate
neighborhood.

ANOTHER SUSPECT

In a detective story not only must the villain be proved guilty but all
other suspects must be proved innocent. Almost everyone at that time
thought yellow fever was carried by fomites — that is, by excretions of
yellow fever patients in the articles of clothing, bedding, or other mate-
rials that had been contaminated by contact with people who had the
disease. That belief resulted in the destruction of a great deal of valuable
property supposed to be infected, and worked a real hardship on merchants
trading in infected ports.

FOMITES PROVED INNOCENT

Walter Reed and his associates now set to work to prove that fomites
do not carry the disease. For this purpose a small frame house consisting
of one room 14 by 20 feet in size was erected at Camp Lazear. It was tightly
built, and the doors and windows were so placed as to admit as little sun-
light and air as possible. A coal-oil stove kept the temperature at 90 degrees
during the day, and the atmosphere was provided with moisture. The room
was thus kept like the hold of a ship in the tropics — warm, dark, and moist.

The building was now ready for the experiment. Three large boxes filled
with sheets, pillow slips, blankets, etc., contaminated by contact with cases
of yellow fever, were placed inside; and on November 30, 1900, Dr. R. P.
Cooke, acting Assistant Surgeon, United States Army, and two privates of
the Hospital Corps, all nonimmune young Americans, entered the build-
ing. They unpacked the boxes, giving each article a thorough shaking in
order to fill the air with the specific agent of yellow fever if it was con-
tained in these fomites. They then made the beds with the soiled bed cloth-
ing and slept in them. Various contaminated articles were hung about the
bed in which Dr. Cooke slept. For 20 nights this room was occupied by
these nonimmunes. They packed up the soiled articles every morning and
unpacked them at night, but not one of the men developed yellow fever.

From December 21, 1900, to January 10, 1901, the room was again oc-
cupied by two nonimmune young Americans. These men slept every night
in the soiled garments and on the bedding used by yellow fever patients

338 READINGS IN BIOLOGICAL SCIENCE

throughout their entire attacks. They also remained perfectly well. The
experiment was repeated a third time with the same results. This experi-
ment explained why people had been able to wash the bedding and cloth-
ing of yellow fever patients without taking the disease. It absolutely cleared
the fomites of suspicion.

HOW A HOUSE IS INFECTED WITH YELLOW FEVER

Since it was proved that a house could not be infected with the yellow
fever by fomites, the question now arose: "How does a house become in-
fected?" To answer that question with certainty, a second building was
erected similar to the first, except that it was well ventilated. It was screened
so that mosquitoes could not get in or out. The room was then divided
by a wire netting that extended from top to bottom and allowed the air to
pass freely from one side to the other. Therefore, if there were any germs
or "miasms" floating in the air that could cause yellow fever they would
be found on both sides of the screen. To show that the building was un-
infected, four men slept in it for two weeks, two on each side of the netting.
They remained perfectly well. "Now," said Major Reed, "I am going to
infect one side of this room with yellow fever and not the other side." He
took out the two men from one side and set free there 15 Aedes mosquitoes
that had previously bitten yellow fever patients. John J. Moran then en-
tered the mosquito-infested space for a short time on three successive days.
Four days after his first visit John Moran came down with a well-developed
case of yellow fever, from which he recovered. During each of his visits
two other nonimmunes remained in the building on the other side of the
wire netting, and they slept there for 18 nights. They remained in perfect
health. Therefore Reed concluded that as the air on both sides of the wire
screen partitions was exactly the same, it must have been the presence of
contaminated mosquitoes that infected the side in which Moran contracted
yellow fever, and the absence of mosquitoes that made the other side per-
fectly healthful.

HOW AN INFECTED HOUSE IS DISINFECTED

Walter Reed then said: "Now that I have shown you a house infected
with yellow fever, I will demonstrate how it can be disinfected and ren-
dered safe." He caught the mosquitoes and put them back in their jars.
Then he said that the building was disinfected. The two men returned to
the side that had been infected and they and the two on the other side con-
tinued to live there in perfect health.

PASSING SENTENCE ON THE VILLAIN

The experiments of Camp Lazear proved beyond the shadow of doubt
that the Aedes aegypti mosquito is a carrier of yellow fever. Apparently

HEALTH AND DISEASE 339

no grounds remained for doubting that one of the greatest detective stories
of all times had been brought to a successful close. Sentence was passed
on the A'edes aegypti mosquito in these words of Walter Reed: "The spread
of yellow fever can be most effectually controlled by measures directed
to the destruction of mosquitoes and the protection of the sick against
these insects."

EXECUTING THE SENTENCE IN HAVANA

W. C. Gorgas, then a Major in the medical corps, United States Army
and Chief Sanitary Officer of Havana, set the example for vigorous and
energetic measures against the mosquito.

The female mosquito lays her eggs in still water. About 36 hours later
these eggs hatch into larvae, also called "wigglers" or "wiggle-tails." The
wiggler moves about actively, feeds much of the time, and breathes air
which it secures by thrusting its breathing tube up through the surface of
the water. After six or seven days it changes into a pupa or "tumbler." In
this stage it is an air-breather but it does not feed, and after 36 hours or
more it is again changed and comes forth as the perfect winged insect.

When the campaign started in February 1901, all houses and yards in
Havana were examined and all tin cans, empty bottles, and similar trash,
which were generally found filled with rain water and full of yellow fever
mosquito wigglers, were carted off. Openings in cisterns were covered
with mosquito netting. The Health Department fitted covers over rain-
water barrels, and a wooden spigot was placed in the lower part of the
barrel so that water could be drawn off without lifting the cover. As the
Aeds aegypti mosquito lives and breeds almost entirely in or near houses,
these measures were very effective.

When a yellow fever case was reported, employees of the Health De-
partment went to the house and screened it so that no mosquitoes could get
out or in. Then they fumigated the house to kill the mosquitoes inside.

As a result of this general mosquito hunt yellow fever decreased rapidly,
and since September 1901 not a single case has developed in the city. That
historic month was the first in which Havana had been free of yellow fever
in 150 years. Later, Gorgas repeated this performance in the Canal Zone,
with the result that the United States was able to build the Panama Canal.
Since then the example of General Gorgas has been followed wherever
the A'edes aegypti had a hiding place.

The mosquitoes that frequent the United States and Canada now prob-
ably belong to the harmless tribes of that innumerable race. But it is well
to remember that all mosquitoes are a great pest, and that the Anopheles
mosquito is still spreading malaria. For the sake of comfort and of health
everyone should make war on them just as General Gorgas did.

340 READINGS IN BIOLOGICAL SCIENCE

THE DEATH OF WALTER REED

The master detective in this story, Major Walter Reed, died of acute
appendicitis on November 23, 1902, in Washington. It is good to know
that before he died he saw the great city of Havana delivered from her
ancient foe, and the way made clear for the saving of his own beloved
country from a great plague.

THE SEQUEL TO THE TALE

The heroism of Walter Reed's little band of scientists and volunteers has
run like a golden thread through all the later work done in connection with
this disease. The search for the real cause of yellow fever continued even
after its chief carrier had been discovered. Fortunately, certain kinds of
monkeys were found to be susceptible to yellow fever, so it became un-
necessary to use human beings as subjects for experiment. However, the
search for the virus proved to be so dangerous that valuable lives were
lost until 193 1, when a yellow fever vaccine was perfected.

Campaigns against the Aedes aegypti mosquito were so successful in
eliminating yellow fever from the centers where it had once been a major
cause of death that the manner of its spread came to be regarded as "one
of the best examples of a closed argument" in the entire history of medi-
cine. However, experiments in West Africa have proved that yellow fever
can be transmitted by mosquitoes other than Aedes aegypti, and within
the past few years the disease has been discovered in rural and jungle areas
in South America where no Aedes aegypti mosquitoes can be found.

The knowledge that yellow fever is caused by a filterable virus and can
be vaccinated against, together with the proof that in certain localities it
is spread by carriers other than the Aedes aegypti, is being used by workers
today in their efforts to realize that noble vision which came to Walter
Reed just before the clock struck midnight on New Year's Eve in 1900
— the complete conquest of yellow fever in the 20th century.

MENTAL DISEASE A CHALLENGE *

WINFRED OVERHOLSER

Mental disorder is a subject which merits the attention of every intelli-
gent citizen, for it constitutes to-day one of the largest and most pressing
social problems. It is important from the medical, public health, social and
economic points of view. Very nearly one half of the hospital beds of the
entire country are devoted to the care of mental diseases. At the beginning

* Reprinted by permission of the Scientific Monthly, American Association for the
Advancement of Science. Copyright 1938.

HEALTH AND DISEASE 34 1

of the year 1936 there were, in the United States, 469,100 patients in mental
hospitals or on visit to hospitals, and during the year following that date
150,208 others were admitted. Thus, during that year (1936) well over
600,000 people were at some time or other patients in a mental hospital —
in other words, one out of about every 150 adults of the general population!

The investment in mental hospitals in this country is approximately one-
half billion dollars, and the annual cost of the maintenance of these institu-
tions is about one hundred million. The wreckage of human lives, with
the accompanying loss in productivity to the community, and the untold
heartaches caused to the families of mental patients, can not be fully esti-
mated or expressed in monetary terms. One need only mention, too, the
bearing of mental disorder upon dependency and delinquency. There cer-
tainly are relationships here which are difficult to evaluate but which are
none the less real. To bring the matter somewhat more closely home to
the reader, it may be pointed out that it has been estimated from the statistics
of the New York mental hospitals that the probabilities are that of all per-
sons in New York, at least fifteen years of age or over, one out of every
twenty will at some time during his fife be a patient in a mental hospital.^

In spite of the vital importance of the topic of mental disorder, there is
probably no subject on which more misconceptions of facts are prevalent
among the public and even among many educated people. When it is borne
in mind that for countless centuries, from the time of Christ or earlier down
through the Middle Ages, mental derangement was interpreted as due to
demoniac possession, presumably as a punishment for sin, it is perhaps not
strange that relics of the medieval attitude still hold over in the form of a
disguised fear or hatred or contempt of the mental patient. Many persons
even to-day are inclined to look upon the existence of mental disorder in
relatives as a "stigma," as something to be kept secret, even though intel-
lectually they may recognize that it is simply another manifestation of
disease, and no more cause for shame than the occurrence of, let us say,
pneumonia. The lot of the mentally ill person has never been a happy one,
but for too long a time in man's history and, indeed, even to-day that lot
has been and still is being made more unhappy by man's inhumanity to
man.

Institutions for the care of the mentally ill are relatively new things.
During the Middle Ages and the early Renaissance these unfortunates were
driven out of communities to perish miserably or were executed as witches.
The Bethlehem Hospital in London was founded probably in the thirteenth
century and has had a continuous history since that time, but for centuries
after its opening stood alone as an "asylum" for these unfortunates. Paren-
thetically, it may be noted that the word "bedlam" is a corruption of
Bethlehem, the name of this hospital. One can well imagine the reasons why

1 A convenient synopsis of the statistics and their interpretation is to be found in the
recent volume of Landis and Page entitled Modern Society and Mental Disease.

342 READINGS IN BIOLOGICAL SCIENCE

when it is realized that only the "furiously mad" were confined in institu-
tions, that little or nothing was done for them even in the line of elementary
hygiene, and that these places were scenes of the worst types of filth and
confusion.

The first public mental hospital in this country, at Williamsburg, Vir-
ginia, was founded in 1773, but it was not until the middle of the nineteenth
century that the practice of building public mental hospitals became gen-
eral, thanks to the activities of Dorothea L. Dix. The purpose of these in-
stitutions, which were then known as asylums, was primarily to care for
the "furiously mad," as they were denominated. The more quiet patients
were often cared for in jails or in almshouses, a situation which is not un-
known in some parts of this country even to-day. It may be pointed out
and emphasized that mental disorder was early looked upon as being of
public interest only in connection with the disturbance of the peace or
with "pauperism"; it was a subject to be dealt with by the police or by the
poor authorities, not as a medical problem. Historically, these facts are
probably connected to some extent with an attitude not entirely unknown,
that mental disease impresses some sort of "stigma" upon the person who
suffers from it and upon his family. Indeed, even to-day in many parts of
the country the mental hospitals are under the control of departments of
public welfare; that is, under organizations which are designed primarily
to deal with the dependent, rather than raised to the dignity of recognition
as medical institutions. The development of the medical attitude toward
mental disorder, the attitude that we are dealing with disease and which
is amenable to treatment, is relatively recent. It is this evolution which has
brought about the change of name from "asylum" to "hospital," with all
that that name implies.

In the early days in this country admission to mental hospitals was not
especially difficult, although those who were able to pay for care avoided,
so far as possible, being sent to the public institution. The "asylum" was
designed, as we have said before, primarily for "paupers" and for those
who had been considered dangerous to the public peace. In the beginning
hospital admission was a simple matter, but in the '50's the "railroading
myth" seems to have become established. As a result of the fear that per-
sons would be improperly sent to mental hospitals and there detained for
the purpose of permitting others to obtain control of their property, the
admission to mental hospitals was in a good many states made decidedly
difiicult, and some went so far as to require a trial by jury on a charge of
lunacy before the patient could be admitted to the hospital. Such a barbaric
and antiquated procedure was abolished by statute in the District of Co-
lumbia only as recently indeed as 1938, and is still retained in at least one
state. There are many people to-day who believe seriously, in spite of the
overcrowding and the constant pressure by hospital administrators to dis-
miss patients from hospitals, that patients are actually sent to such institu-

HEALTH AND DISEASE 343

tions improperly. Any one who has had experience in the administration
of mental hospitals knows that this is a most untrue accusation, yet laws
still exist which make it difficult for patients to enter mental hospitals, al-
though admission to any other kind of hospital is very simple. When ad-
mission is made difficult, and particularly when a jury trial (which often
appears to the patient and to the public both to be in the nature of criminal
proceedings) is necessary, admission to a mental hospital is delayed and
often the best chance of cure of the patient is lost. The existence of the
popular notion of "railroading" has done much to delay the early admis-
sion of patients and thereby to deprive the mental hospitals of one of their
proper functions. Again it should be pointed out that in some localities it is
permitted to use the jail for temporary care of mental patients until such
time, sometim.es several weeks or months, as the mental hospital finds room
for the patient. Such proceeding is, of course, seriously out of line with
sound practice and is grossly unfair to the mentally afflicted patient.

Some of the feeling that mental disorder is something apart from general
medicine, that it is something which labors under a stigma, is perhaps due
to the way in which psychiatry has been presented and in which in the past
mental hospitals have been operated. There was a time when the asylum
with its forbidding wall made no effort to overcome in the community the
attitude of suspicion which was directed toward it by those ignorant of
its activities. The "asylum doctors" were looked down upon by the physi-
cians in the locality and an atmosphere of hocus-pocus and of something
mysterious tended to keep people away from the institution, both physi-
cally and mentally. In medical schools the student was given the impression
that mental disorder was something not akin in any way to the rest of
medicine; the lectures were the most sketchy and sometimes not even ac-
companied by a visit to the mental hospital, with the result that physicians
have in the past not been in a position to assist in breaking down the public
distrust. To-day we find psychiatry integrated with the rest of medicine
in medical training. We find medical students spending much of their time
in mental hospitals, working at close quarters with the patients and coming
to realize that psychiatry is something which touches every other field of
medicine. They realize, too, from what they see in the institutions that
they are not the places of horror and misery which some even to-day seem
to consider them. Further, many general hospitals are establishing psychia-
tric wards — a decidedly salutary step in bringing psychiatry and general
medicine into closer union.

Another misconception has been that once a patient was admitted to a
mental hospital all hope was lost, and there are many who think that the
inscription described by Dante over the gates of the Inferno is written, even
though invisibly, over the entrance of mental hospitals. Such is, of course,
far from the case. Mental disorder does not warrant the attitude of hope-
lessness which the public ascribes to it, even though certain types of mental

344 READINGS IN BIOLOGICAL SCIENCE

disorder have not so favorable a prognosis as have others, and although in
general mental disorders tend to take somewhat longer for their cure than
do the disorders which take patients to general hospitals. Most readers will
probably be astonished to learn that during the year 1933 for every one
hundred patients admitted there were forty-six discharged, of which
number thirty-nine were considered recovered or improved. Of those dis-
charged 22 per cent, had been hospitalized for two months or less, 55 per
cent, for less than six months, 74 per cent, for less than one year, and 87 per
cent, for less than two years. Furthermore, it has been found that at the end
of ten years over one half of the patients discharged are living in the com-
munity, a small proportion of them, to be sure, having had in the interval
one or more readmissions to mental hospitals.

It should be understood that mental disease is not a unitary thing; there
are many different types, some of which occur early in Hfe, some in middle
age and some in advanced years. The discharge rate and the prospects for
these various types are not all alike by any means. This is true likewise of
the symptomatology. The average citizen probably thinks of the mentally
disordered person in the terms of a "raving maniac," one who is disturbed,
noisy, disheveled, annoying others, possibly even making homicidal at-
tacks, and so on. As a matter of fact, patients of this type constitute per-
haps not over 5 per cent, of the population of a mental hospital. Some pa-
tients are depressed, some are confused, some are apathetic, many show
relatively little disorder of conduct. Some of this difficulty is perhaps due
to the legalistic notion that a person is either sane or insane, and to the
rather fixed definitions most of them entirely out of line with psychiatric
thought, which the law gives for that legal term "insanity." Mental disorder
represents a failure of the individual to adjust to his environment, but such
adjustment depends on many things: it depends upon his heredity and
the constitution with which he was born, on his training, on the function-
ing of his ductless glands, on the situation with which he is confronted,
his education, his native endowment and many other factors. In some in-
stances we have degenerative processes due to old age, in others we have
brain disease due to infection or intoxication, and it is quite obvious that
with so many varying factors the types of reaction and the manner in
which adjustment fails will vary. Mental disorder is not necessarily accom-
panied by disease of the brain, although brain damage often produces men-
tal symptoms. It is rather a failure of adjustment of the entire personality.
"Mind" is not a unit, but rather an abstraction which symbolizes the sum
total of the reactions of the individual at the social level.

A few words may be in order concerning some of the broader general
types of mental disorder which find their way into hospitals. One of the
important groups is that due to degenerative processes, that is, hardening
of the arteries of the brain (cerebral arteriosclerosis) and senility. By the
very nature of the disorder, the outlook is poor. Together these types make

HEALTH AND DISEASE 345

up about 1 8 per cent, of the admissions to mental hospitals. As for the future
a factor which can not be overlooked is the changing composition of the
age groups in the population. Human life is lengthening, the birth rate is
falling, immigration has almost ceased. Furthermore the incidence of mental
disease increases steadily as age advances; the rates of mental disorder for
the respective age groups of the population are somewhat more than four
times at age 80 what they were at age 20. Whereas in 1900 only 4 per cent,
of the population was over 65, at present 6 per cent, is over 65, and it is
estimated that by 1980 somewhere between 14 and 16 per cent, of the popu-
lation will be over 6^.- In other words, there is every reason to beheve that
the number of patients in mental hospitals suffering from cerepsychoses
will probably increase rather materially as time goes on. It is difficult to see
how very much can be done about this.

There is another group due to the infections, of which general paresis
is a conspicuous example. This disorder is one of the late results of syphilitic
infection, and until about twenty years ago was considered to be a rather
promptly fatal disorder once it had reached the stage of calling for hospital
care. During the world war considerable impetus was given to the cam-
paign against syphilis, and the campaign has been carried on since, having
been given more recently a very strong reenforcement through the splen-
did efforts of Surgeon General Thomas Parran and the symposium organ-
ized and presented by the American Association for the Advancement of
Science. Already the effects of the twenty-year-old campaigns are being
realized in a fall in the admission rate of general paresis; it is confidently
to be expected that as time goes on the rate will fall still further. Further-
more, since very striking advances have been made in the treatment of
this disease through the fever therapy devised by Wagner-Jauregg, the
prospects of this group, which now constitutes about 9 per cent, of first
admissions, are good.*

As an example of another group of mental disorders we may mention
that due to intoxications; the alcoholic psychoses are a type. Although a
drop in admissions for this type of disorder began about 19 14, apparently
as the result of the campaign against the excessive use of alcohol, and al-
though there was a sudden drop in 1920 when prohibition went into effect,
there has been a rather gradual rise since 1920, with the result that we are
approaching the pre-war levels in the admissions of alcohohc psychoses,
now about 5 per cent. The educational program against alcohol was badly
disrupted by prohibition, and it will take a number of years to make this
effective again. Ultimately some drop in the rate of alcoholic psychoses
is perhaps to be expected. Mental disorders due to other drugs, such as
opium, cocaine and marihuana, are relatively negligible. Admissions due

2 "Problems of a Changing Population," National Resources Committee, p. 25.
Washington, 1938.

* Drug therapy with penicillin is a promising new approach. — Ed.

34<5 READINGS IN BIOLOGICAL SCIENCE

to head injuries are rather infrequent; although mental disorders sometimes
ensue following head injury, they are generally not sufficiently disturbing
to call for commitment to mental hospitals.

There are some types of mental disorder which have no uniform and
clearly demonstrable organic bases. They are, perhaps, constitutional in
predisposition and environmental as far as precipitating factors are con-
cerned. With the group of depressions, which account for about 12 per
cent, of first admissions, some progress has been made with "shock therapy"
in recent months. These depressions are rather inclined to spontaneous re-
covery and usually do not call for a long hospital residence, except for
that relatively small group which occurs during the involutional period
and in which the duration is somewhat longer and the prognosis somewhat
less favorable. Another large group and very important one is that of
dementia praecox, or, as it is frequently termed, schizophrenia. On account
of the relatively early age at which this tends to develop and the rather
long course which it is inclined to run, nearly one half of the population
of any mental hospital is found to be suffering from this disorder, although
the first admission rate is only about 20 per cent. Much research work is
being carried on in the field of schizophrenia, and a little progress has been
made recently through the so-called "shock" treatment. Many baffling
problems are still presented, however, and the future is not entirely clear.
It is felt by those experienced in this field that much depends upon preven-
tive activities, which will be touched upon later.

The question is often asked whether mental disorder is increasing. The
warning should be given that the only reliable statistics are those of hos-
pitaHzed mental patients. We have very inadequate means of knowing how
many cases of mental disorder there are in the community. Consequently,
if a state provides inadequate facilities and makes it extremely difficult to
enter a hospital, it may boast of a low mental hospital rate. If, on the other,
hand, it is progressive, as New York State is, providing ample facilities,
a large proportion of those in need of care will receive it. The discrepancy
among the several states in the rate (per 100,000 general population) of
the patients hospitalized is enormous, the figures for New York and Ala-
bama being respectively 464.5 and 163.5. ^^ ^^^Y t>e said very briefly that
there appears to be a slight general rise in the admissions to mental hospitals,
and a slight increase, rather steady, in the population of these hospitals. It
is questionable whether at the present time, at least, the prospect is alarm-
ing. The figures which have been given for the trend in the senile and
arteriosclerotic groups, however, certainly seem to indicate heavier future
demands for mental hospital facilities.

Much used to be said about the influence of heredity in mental disorder.
That there is such a thing as heredit)^ can not be denied, but it is not looked
upon to-day as one of those inescapable things to which one may as well
surrender without a struggle. The growth of the mental hygiene movement

HEALTH AND DISEASE 347

has laid stress upon the importance of attempting by proper training,
guidance and environment to overcome native handicaps, and much can
be done in that Hne. As for environment, it is quite hkely that the con-
stantly increasing pace of hfe has no particularly beneficial effect upon
the mental hygiene of the public; on the other hand, it can not be proved
to be the principal factor in any increase in mental disorder. The old myth
about farmers' wives, who were generally reputed to be particularly sus-
ceptible to mental disorder, has long since been exploded, and it has been
found that the rates for hospitalization are in general slightly higher in
urban than in rural communities. This, however, may be due in large
measure to the fact that peculiarities of conduct are much less well tolerated
in closely settled areas than they are in rural districts, with an increasing
likelihood of commitment.

The modern mental hospital is as far different from the old asylum as
could well be imagined. It is a general hospital thoroughly well equipped,
surgically and medically, to deal with any physical disorder which may
arise among its patients. It is equipped in addition with occupational
therapy, with hydrotherapy and other speciaUzed forms of treatment de-
signed to remedy the disordered mental attitude of the individual. Padded
cells have not existed for many years, and seclusion and restraint have long
since been virtually abandoned, having been found to have a deleterious
effect on patients. As much freedom as possible is given to patients, and
the atmosphere of the hospital is one as nearly approaching normal com-
munity life as can well be secured in an institution. There are various types
of entertainment and social activities, all designed for the purpose of help-
ing the patient to readjust himself to mingling with his fellows in a normal
way. Recently considerable attention has been given, partly for economic
reasons, to the possibility of caring for the mentally ill in families after the
more acute problems have been dealt with in the hospital. The system of
family care, which was first introduced into Massachusetts in 1885, has at
last been adopted by several other states.

It should not be thought, however, that all mental hospitals are the ideal
places that have been described. Unfortunately some states have been de-
cidedly backward in their care of the mentally ill, have been niggardly in
the appropriations voted, and have allowed partisan spoils politics to inter-
fere with efficiency and with the securing of adequately trained and in-
terested personnel. It is to be hoped that the new interest in public health
now being fostered by the Federal Government will bring about improve-
ment in those states in which it is needed. A4ental hospitals, in addition to
their intramural activities, are engaging constantly more and more in com-
munity activities, particularly with relation to child guidance and adult
mental hygiene cHnics. These activities are extremely important from the
preventive point of view, being designed in the case of children to over-
come habit difficulties, and in the case of adults to prevent mental break-

348 READINGS IN BIOLOGICAL SCIENCE

downs in those who appear to be showing symptoms of incipient difficulty.
Mental hospitals, or at least the more progressive ones, are centers of re-
search and of teaching — a trend which is rapidly developing.

Even the most vigorous opponents of "state medicine" have always ad-
mitted that the care of the mentally ill is a proper function of government.
As the public becomes more acutely aware of the true importance of mental
disease in the community and the needs of hospitals administering to this
group, we may look to see the standards raised and greater efficiency
brought about in the humane care and treatment of the mentally disordered.

->■»<<<■

MENTAL DISEASES *
BERNARDJAFFE

"Everywhere, skin deep below our boasted science, we are brought up
short by mystery impalpable, and by adamantine gates of transcendental
forces and incomprehensible laws." This was Charles Kingsley's reaction
to the panorama of the onward march of science, an advance which seemed
only to demolish every obstacle in its path. He was thinking of man's ef-
forts to banish not only all the multitudinous sicknesses of the body but also
the countless tortures of the mind. Millions of souls with their minds in
ruins — one out of every twenty-two destined for mental hospitals — is the
dark picture which still confronts science as its outstanding challenge to
redeem mankind from illness.

Throughout the ages four furies pursued those frames from which the
mind had gone awry. Superstition, nourished on a demonological concep-
tion of insanity, burned, harassed, and beat those frames to exorcise the
devils playing havoc with their thoughts and behaviors. Skulls were
trepanned to allow egress of demons, bats, snakes, crows, vultures, and other
animals housed within the sacred precincts of what would otherwise have
been rational men. And when the devil was too firmly intrenched and
would not leave, thousands of unfortunates, as late as the beginning of the
eighteenth century, were burned amidst heinous cries of "witch."

Brutality, under the cloak of necessity, tortured these "wild beasts" by
methods worse than those of the Inquisition, strapped them into choking
straight) ackets, shackled them to tranquilizing chairs, crucified them on the
bed saddle — a steel cross strapped to the bed — and pinned them down in
restraining sheets of canvas. To frighten the insane into submission when
they became difficult to manage they were placed in wells where the water
rose slowly until it reached their mouths, ice-cold water was poured down
their sleeves to the aching armpits, or they were whirled on rapidly rotating

* Reprinted from Outposts of Science by permission of Simon and Schuster, Inc.
Copyright 1935, by Bernard Jaffe.

HEALTH AND DISEASE 349

wheels until they lost consciousness. Keepers restrained their wards with
threats of death, and often beat them into insensibility. The same treatment
was meted out to the poor and the rich. Wallowing in their own excrement,
they fell victim to every passing epidemic.

Before 1850 most of the insane in the United States were housed in
prisons or almhouses. Poormasters boasted of how cheaply they could keep
their wards alive. Similar conditions prevailed in Europe. When William
A. White, a director of St. Elizabeth's Hospital in Washington, one of the
largest and most advanced of such institutions in the world today, visited
Europe twenty-five years ago he saw: "One ward occupied by some forty
men, every one of them stark naked and strapped to his bed. There was only
one bed that was not occupied by a patient, and that was occupied by a
giant of an attendant who was asleep. He jumped up as I came in and
walked through the ward with me, and I remember those naked men curs-
ing and spitting at us as we went by." To this day some insane asylums,
even in civilized countries, reek with primitive ideas and methods. But
most of the old lunatic asylums are now things of the past, gone with the
rack and other instruments of torture, London's Bedlam, open until 1777,
and the Lunatics' Tower of Vienna, closed in 1853, where caged insane
were exhibited to sightseers who paid for admission, have been banished
forever. Lunatic asylums have been changed to hospitals in more than
name.

Many things have been listed as causes for insanity. In one form of
mental disease, there seemed to be some strong indications of connection
with a bacterial infection. Ten per cent, of all new admissions to insane
asylums were general paretics. Their Wassermann blood tests were often
positive and their spinal fluid was always positive. Their histories showed
venereal infection of some ten or more years' standing. Syphilis and paresis
seemed linked. Often they had fared well socially for more than twenty
years after infection, until suddenly a strange change came over them.
Their memory began to fail, they became contrary, irritable, suspicious,
and sufi"ered from illusions. Frequently, hke Ivan the Terrible of Russia
who was undoubtedly a paretic, they were drawn to acts of violence. The
deterioration of the mind was progressive. Half of the victims died within
a year after reaching the hospital; few survived as long as five years after
commitment.

A diagnosis of paresis was a verdict of a sure and ugly death. There were
few exceptions and no method of treatment. Syphilis was shown to be the
sine qua non of paresis. But no one knew just how the connection existed.
Salvarsan, the magical chemical weapon which Ehrlich had forged in his
laboratory, brought healing to some syphilitics, but never to paretics. These
were doomed. Some talked about sexual excesses, sunstroke, religious ex-
citement, and the stress of life. Emil Kraepelin taught the equation. Syphilis
plus Alcohol equals Paresis, but nothing had really been proved. Then

350 READINGS IN BIOLOGICAL SCIENCE

with the discovery by Schaudinn of the pale spirochete bacterium which
showed its spiral form in every syphilitic, began the search for this organism
in the brains of paretics. Perhaps it was this microscopic invader which was
sending its host to a paretic death. And while thousands of paretics died of
emaciation, with bed sores exuding daily pints of pus from the back of
their heads to their heels, only one persistent man searched unrelentingly
for the spirochete in paretics.

Hideyo Noguchi, who knew more about spirochetes than anyone else
alive, had carefully examined one night a lot of two hundred slides of
paretic brain material stained for spirochetes. In the early morning he
had detected what he thought were spiral organisms in seven slides. He
would not trust his eyes and rushed to the home of Simon Flexner for con-
firmation. This discovery proved a landmark in the study of paresis. The
organism responsible for syphilis sometimes reached the brain and, lodging
there, changed its victim into a paretic.

These facts accounted for a phenomenon that a Viennese physician,
JuHus Wagner-Jauregg, noticed while treating soldiers during the Italian
campaign of the first World War. Syphilitics, after getting over an attack
of malaria, showed a milder form of the "social disease." Paretics, on recov-
ering from some infectious disease, had long been known occasionally to
improve considerably. Wagner-Jauregg reasoned that the spirochete,
which could not endure high temperatures, might have been killed off by
fever, thus reducing the virulence of the disease. Perhaps this was the ex-
planation of the occasional cure of feverish paretics from whose chest
laudable pus had been forced. The infection which produced the pus
brought on the fever.

Wagner-Jauregg was almost sixty at the time. He had seen an army of
paretics die in asylums. He was going to test out a hunch. Surely there was
nothing to lose. Into the veins of two men crazed by the spirochete of
syphilis, he injected two cubic centimeters of the blood of a shell-shocked
malarial patient. Then he waited for the fever to burn out those bacteria.
It was frankly a dangerous experiment. His patients might succumb to
malaria. The fever rose and almost burned out their lives. But they re-
covered from the malarial attack, their memories returned, they became
less irritable, and with frequent doses of salvarsan the symptoms of paresis
never reappeared. The fever attack on paresis has become a standard prac-
tice in mental hospitals.

Research men have been driven into other channels of investigation. The
most recent attempt to explain and treat mental disorders from the view-
point of abnormal physiology is with the data and tools of glandular in-
vestigations. As far back as 1881 Kraepelin had fought insanity by intro-
ducing extracts of every possible gland of thyroid, testes, ovaries, and so
on, but unfortunately without effect. When later, however, cretins, hopeless
humans disabled in both body and mind, responded miraculously to treat-

HEALTH AND DISEASE 35 I

ment with the iodine compound thyroxin produced in the thyroid gland,
and this glandular therapy had actually succeeded in salvaging those who
for centuries had been considered lost souls, visions of a new day for all
the mentally disabled loomed on a blurred horizon.

"The diseases of the mind," said Cicero, "are more numerous than those
of the body." The ancients recognized this, yet for convenience divided
all mental ailments into two classes. The individual was either melancholic
or manic. In mania, said Aurelius, the head was disordered; in melancholia,
the stomach. This classification, in more or less modified form, lasted until
the nineteenth century. Then many began to make careful studies of the
mentally sick, watching their histories, listening to the language of lunacy,
and daily recognizing new groups of symptoms. Descriptive psychiatry
became the dominant form of investigation in this field, and reached its
highest peak about fifty years ago in the work of Emil Kraepelin, a pioneer
in experimental psychology of which Wundt, his teacher was the father.
From a mass of classic case histories he drew a new classification of the
insanities, which included as its two most important groups the manic-
depressive and the dementia praecox. The latter is now commonly termed
schizophrenia.

Manic-depressive insanity is a psychosis of adults. It begins with nervous-
ness, restlessness, and emotional irritability, and ends in such morbid states
that incarceration becomes necessary. The afflicted often become suicidal
or homicidal. Schizophrenia, the most frequent form of insanity, usually
begins at puberty or even earlier. The child becomes queer, shy, dreary,
seclusive, different, and a cleavage of the mind develops insidiously. An
internal break in the harmony of the personality occurs; the individual be-
comes, in fact, a split personality. The adult grows even more sensitive
and suspicious and less capable of making concessions. The outer world
is gradually renounced, and the victim drifts into a realm of fantasy, de-
lusion, and hallucination.

Various forms of schizophrenia have been classified. The catatonic va-
riety finds the victim plunged in a deep despondency followed by sudden
irrational excitement. He may refuse to talk (mutism), and to comply
with any request (negativism). He may adopt and maintain certain fixed
and peculiar positions such as keeping one arm outstretched for hours at a
time. These periods of depression and excitation vary both in length and
in suddenness of change. The paranoiac is recognized by fixed and systema-
tized delusions. The patient appears perfectly normal except on certain
topics. Reason seems preserved but sidetracked, as in this typical case: A
childless Russian woman is being tortured every night in her sleep by oper-
ations removing children from her body, and she believes that her husband
cooperates to get children for scientific experimentation. Otherwise she is
apparently quite normal.

Dismissing both the extravagant belief of Watson that "we do not inherit

352 READINGS IN BIOLOGICAL SCIENCE

our character, temperament, and special abilities; they are forced upon u§
by our parents," and the pronunciamento of E. A. Wiggam that the en-
vironment plays no part, and that we can never escape the effects of hered-
ity, science is drawing closer to the conviction that with the mental diseases
as with such physical characteristics as sex and stature, T, H. A4organ's
opinion is the most trustworthy, Morgan says: "The gene acts as a differen-
tial turning the balance in a given direction affecting certain characters
more conspicuously than others. Let us not forget that the environment
may also act as a differential, intensifying or diminishing as the case may
be the action of the genes."

Neurotics are both born and made, and it is wise not to be alarmed at
the implications of genetics. If mental abnormality is due to a single gene,
the defective genes of the child inherited from both parents may be so
arranged in the chromosome threads that they do not lie side by side, and
the child will not inherit this defect. Said Ray Lyman Wilbur, "Human
beings do not deal with our defectives, our insane, in the same way as do
animals. No doubt foolish dogs are born, but unless they happen to get
into the hands of foolish ladies, they soon succumb." Nazi Germany in
1934, in the name of race purity, issued a decree ordering the sterilization
of its 200,000 feeble-minded, 60,000 epileptics, 50,000 schizophrenics,
20,000 manic-depressives, and another 47,000 defectives including "heredi-
tary" alcoholics and the hereditary deaf, decisions to be made by Heredi-
tary Hygiene Courts. More than fifty-six thousand sterilization operations
were performed there within one year of the issuance of the decree.

Eugenic sterilization laws are on the statute books of twenty-seven states
in our own country but they are seldom enforced. New York passed such
a law in 19 12, but it was declared unconstitutional. Oklahoma sterilizes
the hereditarily insane as well as its three-time convicts. California, home
of the over-zealous Human Betterment Foundation which would sterilize
fifteen million Americans, accounts for two-thirds of all the eugenic sterili-
zation in the United States. During the last thirty years, more than four
thousand insane and two thousand feeble-minded persons were sterilized
by this state. It uses the painless technique of tying the ducts from the
testes or ovaries without modifying the internal secretions of the gonads
or otherwise interfering with the sex life of the individual. Such individuals,
however, can no longer become fathers or mothers.

The other camp numbers a large army of men and women who oppose
sterilization on the ground that science knows too little about mental
diseases. Who can say, they insist, what will be incurable tomorrow? They
point to Mozart, Pascal, Mohammed, Schiller, Paganini, as great men who
were epileptic. They single out Kepler, both of whose parents were men-
tally diseased, and they tell us that Francis Bacon's mother was insane. And
some are willing to pay the price of mental disease for the world's geniuses.
Convinced that the partition between sanity and insanity is indeed a thin

HEALTH AND DISEASE 353

one, and that very often genius and insanity are not so far apart, they would
not sacrifice one single genius for relief from the burden of tens of thou-
sands of mentally diseased pei"sons.

The natural history of the mind is as yet only imperfectly known. The
study of the mental diseases has been left far behind in the onward march
of science, and today Mever says, "We are very much in the beginning
with the outstanding problems still to be solved in this field." And in such
a complicated world Adolf Meyer believed with Voltaire, "It is part of
a man to have preferences but no exclusions," especially when this mortal
is exploring in the devil's own domain.

>>><<<■

THE SIGNIFICANCE OF PLANT DISEASE
IN AGRICULTURE *

K. STARR CHESTER

Waist deep in a sea of ripening wheat stand two men, and they mark a
turning point in American Agriculture. The man in overalls dejectedly
pulls a few stalks from the soil. The stems are cracked and dried, stained
with red and black streaks. He breaks off a head of grain and rubs it be-
tween his palms, and as he blows the chaff gently away there remain in his
palm a few pitifully shrivelled kernels. Many of the stalks have broken
over and fallen beneath the reach of binder or combine. The field that just
a few days ago gave promise of forty bushels to the acre, today will hardly
yield the expense of harvesting. Perhaps it would be better to cut it for hay,
or plow it under to give way to a summer crop of fodder.

This is the grim side of black stem rust, the scourge of wheat farmers in
every land. The scene, which took place in 1935 or '37 or '39, is a classic
scene, which had its prototypes four thousand years ago in the grain fields
of the ancient Hebrews.

What will this mean to the man in overalls? Perhaps another postpone-
ment of the children's chance for education; perhaps failure to meet the
payments on the nearly paid-up farm; perhaps this year will mark the be-
ginning of the long, sad back-trek from combine to binder, from tractor
to mules, from a square mile of rich, flat bottom land to a quarter section
of eroded hillside, — on from wheat which takes machinery, to cotton or
corn, which you can raise if you have a mule and a family, on to working
for the insurance company or the W.P.A.

That's the dark side. But what about the other man beside the man in
overalls? He is the county agricultural agent. He's saying something to
this effect: "You don't need to put up with this loss another year. The men

* Reprinted from The Nature and Prevention of Flant Diseases by K. Starr Chester,
by permission of The Blakiston Company, Philadelphia. Copyright 1942.

354 READINGS IN BIOLOGICAL SCIENCE

at the Experiment Stations have been working to breed varieties of wheat
that are resistant to the stem-rust fungus. They have been able to combine
rust resistance with the other quahties we need in wheat, — high yields,
drought- and cold-resistance, and good milling and baking qualities. Jim
Beard, out west of town, has been growing one of these varieties, and it's
making thirt)^-seven bushels to the acre this year. You can get some of
that wheat for seeding, and be ready for rust another year."

Because disasters like this occur today and often mean the difference
between success and failure in agriculture and because many such disasters
can be averted by timely intervention of simple preventive measures, some
acquaintance with the science of plant pathology is indispensable to agri-
cultural workers.

You are studying a comparatively new science, that of plant disease. It is
only a few decades since plant pathology came into being. Some of the
pioneer plant pathologists, founders of the science in America, are still
vigorously carrying on their warfare against plant disease, setting a stimu-
lating example to their army of young followers. But plant diseases them-
selves, and their prevention by empirical or intuitive recipes, are by no
means limited to problems of today. Long before the appearance of civilized
man, the agents of disease were leaving petrified thumbprints in the fossils
that tell us of the leaf spot diseases and other ailments of prehistoric vege-
tation. Among the earliest written records of man, the unmistakable com-
plaints of blights, mildews, and plagues show us clearly that plant disease
has shadowed the agricultural path of man since he first scratched the soil
with a pointed stick and planted seed. The Old Testament tells us of plant
diseases visited upon man in punishment of his transgressions. Three hun-
dred years before Christ, Theophrastus, the Father of Botany, was well
famihar with plant diseases of his time, and in his writings we can recognize
many of our plant troubles of today, scorch, rot, scab, and rust. So formida-
ble were the cereal rusts in those early days that the Romans evolved a pair
of rust Gods, Rubigus and Rubigo, whom they annually honored as a
means of rust prevention.

As ancient times gave way to the intellectual darkness of the Middle
Ages, these early sparks of understanding of plant disease were all but
extinguished by the superstition and avoidance of reason that over-
shadowed that period. Plant diseases continued to take their toll from the
European peasant and landowner, but we learn httle of them save that
from time to time great epiphytotics * occurred, attended by disaster,
famine, and migrations, and historical documents of the early days tell us
of entreaties to The Diety to ward off the evil blights, of tragic suffering
and death from the "holy fire" which we now attribute to the eating of
ergot-diseased grain, of the suffering and famine in Ireland when disease

• The name given to a destructive outbreak of plant disease; comparable to epidemics
of human disease or epizootics of animal diseases.

HEALTH AND DISEASE 355

destroyed the potato crop in 1 845 and drove many of the Irish people to
America, and of the powdery mildew which wiped out the wine industry
of Madeira and forced the population of that little island back to their
ancient occupations of sugar-cane growing and cochineal gathering.

The story of the Irish potato blight is the story of a microscopic fungus
which wrought havoc in Europe equalled by few of Europe's many wars.

It is believed that the potato was first brought to Europe by Sir Francis
Drake from the Andean hinterland of South America, where it had long
been revered, emblematic of fertility, and even been the inspiration of
mutilation and human sacrifice. Thanks to the efforts of Sir Walter Raleigh
and many other enthusiasts, the potato soon won its rightful place as a lead-
ing source of carbohydrate food throughout all of Europe, from the Medi-
terranean to northernmost Scandinavia, and in northeastern North Amer-
ica as well. In its migration from South America the potato had left
behind its most serious agents of disease; for two hundred years or more it
enjoyed comparative freedom from disease. But in the early half of the
nineteenth century, disturbing reports of potato failures began to appear.
In ever-increasing intensity, a plague of potato fields was laying waste the
crops of individual farmers, and of whole communities.

In 1 845 the crisis was reached. With unbelievable fury the potato blight
devastated millions of acres in Europe, the United States, and Canada. So
sudden was the catastrophe and so complete that in only a few days fields
with every promise of abundant harvest were transformed into blackened
wastes of vegetation overlying foul and putrifying masses of rotten tubers.
And this was not a local problem, nor limited to a few fields, — everywhere
where potatoes were grown the tragedy was repeated, bringing in its wake
privation, then starvation or the fever that inevitably follows malnutrition.
In Ireland alone, a quarter of a million people fell victim to the famine, and
many others migrated to America and became the basis of the Irish-
American population of the United States.

Like most tragic experiences of mankind, the potato blight was not with-
out some benefit. In the nineteenth century science was rapidly throwing
off its stupor of the Middle Ages: the chains of superstition that so long
had bound and suppressed creative thought were rusting away. The intel-
lectual genuises Louis Pasteur and Robert Koch were performing the first
crucial experiments that were to open up the vast field of modern research
on contagious disease. Charles Darwin was revolutionizing biology and
philosophy with his keen deductions on organic evolution. Von Liebig was
laying the foundations of modern agricultural chemistry. The stage was
set for the first fundamental discoveries on the nature and control of plant
disease, and the catastrophe of the potato blight forced the attention of
master minds to the solution of this and related problems in plant pathology.
Out of the labor pains of Europe, racked by the potato blight, was born
modern plant pathology, the science of plant disease. The brilliant young

356 READINGS IN BIOLOGICAL SCIENCE

German, Anton de Bary, stared at the dying potato leaves through his
primitive microscope, saw the green leaf cells in the clutches of the sinuous,
pallid fibers of the fungus, and its myriads of wind-driven spores, proved
that the fungus was the cause, the sole cause of the blight, and paved the
way for Alillardet a few years later to give humanity an effective weapon
against any future recurrence of the blight, Bordeaux mixture.

The story of Bordeaux mixture itself is worth the telling. According
to the tale, a farmer in Medoc, France, had a vineyard that bordered the
highway. Passers-by are alike the world over, and to the despair of the
farmer, the wayfarers could not resist the luscious bunches of ripening
grapes, just over the fence. In a moment of inspiration, the farmer decided
to take steps. He went to the barn, and his eye falHng on a sack of lime,
he made a milky broth to splash on the vines. As the mixture didn't look
repulsive enough, he threw in a shovelful of bluestone. This accomplished,
he spattered it over the vines, posted a "Poison" sign and awaited results.
History does not tell us whether the wayfarers were deterred by the
farmer's ingenuity, but it does recall that Dr. Millardet came past the vine-
yard, noted that the sprayed grapes alone had escaped the destructive
mildew disease, learned of the spray so accidentally appHed, tested its ef-
ficiency against fungus diseases of the vine, and gave us the completely ef-
fective protection against future outbreaks of both vine and potato blights
which we now know as Bordeaux mixture.

Man has a tendency to learn things the hard way. It took another epiphy-
totic which has practically exterminated one of our finest forest trees, the
American chestnut, to establish the science of plant pathology in America.
The chestnut blight fungus was a foreigner that sneaked into America from
Asia. Starting its deadly work about 1904, it spread swiftly, destroying
every tree in its path. Today there hardly remains a chestnut tree in the
great forests of the East which were once dominated by this tree. This
disaster taught us what might be expected from unwelcome foreign pests;
it was largely responsible for the establishment of the National Plant
Quarantine Act in 191 2.

Today new and potent enemies of our cultivated plants are coming to
the attention of growers and scientists. The Dutch elm disease for a while
threatened to exterminate the American elm, as it had done in many parts
of Europe. In the royal gardens at Versailles were long avenues of stately
elms that were mature trees in the hey-day of the pre-revolution French
court. Only a few years after the Dutch elm disease appeared, the avenues
were Kned with dead and dying trees, nearly all sacrificed to the elm disease
fungus. Thanks to our lesson from the chestnut blight and to energetic
eradication of diseased elms in America, the elm disease has been brought
under control, but any relaxation of these efforts could still release the
disease in all its destructiveness.

Few of the main groups of crop plants are free from occasional but

HEALTH AND DISEASE ^57

disastrous attacks of disease. Among the fruits may be mentioned fire blight
which caused "one of the greatest industries of the San Joaquin valley
to vanish like a dream" when 500,000 pear trees were killed by the disease
within a few years. In the rich fruit section of New York State a new virus
disease of peaches has broken out in epiphytotic form, promising to be
even more destructive than any of the other twelve or more virus diseases
of this tree. In the tropics banana plantations cannot be permanent. In-
variably they become infested with the "Panama disease" after a few years.

Among vegetables, the ravages of the potato blight are seconded by
those of watermelon wilt, at first welcomed as nature's way to maintain
price levels by restricting production, but soon wiping out the melon
industry in important sections of Florida, Iowa, and California.

And in field crops the story is the same. Flax has always been a pioneer
crop, moving on to virgin areas and leaving behind a trail of "flax-sick"
soil, infested with the flax wilt fungus, soil upon which susceptible flax can-
not again be grown for many years. Texas root rot has rendered great
areas of the Southwest unsuitable for culture of cotton, alfalfa, and many
other crops. The disease causes a loss in Texas of 300,000 bales of cotton
a year, and in addition, attacks more than 2,000 other species of plants,
aggregating a total loss from this disease, in the seven states affected, which
reached $150,000,000 in 1947. And finally, no account of epiphytotics in
field crops can omit mention of the cereal rusts. Stem rust is always with
us, and now and then, when the weather is suitable, it rages northward
from the Great Plains to Canada leaving in its wake millions of acres of
wasted grain. These epiphytotics are coming more and more frequently.
There have been three in the past five years. That of 1935 destroyed a
quarter of the national wheat crop, a total of 160,000,000 bushels, and in
North Dakota and Minnesota 60 per cent, of the wheat crop was sacrificed
to stem rust.

This is the spectacular side of plant disease, the great epiphytotics that
are so often followed by privation, suffering, loss of homes and farms, even
famine, migration, or abandonment of farming.

How many farmers realize that a small percentage of loss in the field
represents a much larger loss, perhaps all, of the profit. To be specific, take
the case of a farmer with a quarter-section in wheat, and assume that under
disease-free conditions his average yield is a conservative 25 bushels to the
acre, or a total of 4,000 bushels. The harvest return is divided into two
elements, part, usually most of it, must be paid out to cover all the costs of
production of that crop, the remainder is the farmer's profit, and may be
applied to maintaining and improving his standard of living and of farming.
Under normal circumstances the 4,000 bushels would be used somewhat
after this fashion: use of the land, 40 per cent; seed, 3 per cent; labor, 12 per
cent; machinery and maintenance, 20 per cent; insurance, 5 per cent; leav-
ing a profit of 20 per cent, based on disease-free conditions. The loss from

358 READINGS IN BIOLOGICAL SCIENCE

diseases in the American wheat crop for the period 1919 to 1937 averaged
slightly more than 10 per cent, per year. Let us assume that our potential
4,000 bushel wheat crop was subjected to disease to this extent, and that
10 per cent, or 400 bushels were lost through disease. All of the costs of
production are unchanged; it still cost 3,200 bushels to produce the 3,600
bushel yield. The bills could not be paid with the diseased grain or that
which failed to materialize. Ten per cent, disease in the field did not strike
the farmer as an unusual or serious loss; yet, the 10 per cent, field loss cost
him one-half of his profit.

We hear much today of the misfortunes of the American farmer as com-
pared with the greater security and prosperity of the American Business
man. We blame this difference on many factors, but is not a part of the
explanation in the differences in methods between the two? To the business
man a loss of one per cent, in his industry through waste is a vital loss, one
to be corrected. The story is that Mr. Rockefeller, in an inspection of one
of his factories, noticed a machine dripping solder on oil cans. He asked
and found that the superintendent had never tested the exact amount of
solder needed. Mr. Rockefeller counted and found that the machine was
applying 39 drops of solder per can. An experiment was devised on the
spot; it was discovered that 38 drops would suffice. In a year's time the
concern had been saved $10,000 worth of solder and time through this
slight economy. No business a fraction as wasteful as the average farm
could survive without subsidy in the face of its competition. When the
American farmer learns to regard his farming as the business man regards
his business, we venture to predict that the need for farm relief and crop
subsidy will be materially decreased.

When watermelon wilt first appeared in Florida melon plantings a few
growers reported the new disease that was killing the vines, and the Experi-
ment Station undertook to find means of checking the disease. The attitude
of some of the growers in the early 1920's savors strongly of 1940 agri-
cultural philosophy. They said: "If this disease is eradicated, there will be
a surplus of watermelons; the price will be lowered, and our profits will
lessen. We do not approve of efforts to prevent wilt." But wilt is not a
disease that can be trifled with. A few years after its introduction, affected
land became useless for melons; losses of 90 per cent, of the crop were not
uncommon. The industry must move on to new land, expensive to clear.
The abandoned land went back into scrub-oak, since it was not suitable
for other crops.

And now a new thought crystallized in the growers' minds. A profitable
industry was seriously threatened. They carried their problem to the Flor-
ida Legislature, and in 1929 funds were appropriated for a study of wilt.
At the Experiment Station a watermelon wilt project was initiated, and by
1936 Dr. Walker of that Station announced that the "Leesburg," a new
and desirable wilt-resistant melon, was available to the growers.

HEALTH AND DISEASE 359

At this point we meet the challenge of modern agricultural philosophy.
Is our farm prosperity dependent upon reducing production? And is tolera-
tion of disease losses an intelligent way of reducing over-production? As
to the first question, opinions may justifiably differ. To those, who like
Joseph, look forward to the seven lean years, any interference with pro-
duction may ultimately work hardship. And the others, the sponsors of
reduced production, insist at the same time on uniform production, the
"ever-normal granary." So long as plant disease is out of hand, we have no
control of production; the ever-normal granary is the shuttlecock of fungus
and weather

Cotton diseases are causing a loss of one-fifth of the crop annually. Pre-
vention of these diseases, many of which can be controlled, does not need
to mean a 20 per cent, increase in American cotton production. Might it not
better mean a 20 per cent, reduction in the labor of planting, chopping,
and picking, some release of children and women from this grinding
drudgery, a release of 20 per cent, of depleted cotton land for a program
of soil restoration. Whichever philosophy we accept the moral is the same;
the prevention of waste from plant disease does not mean suffering from
overproduction; it means on the contrary an opportunity for improving
the lot of the farmer by aiding to buffer him against the shock of sudden
and unpredictable crop losses, and by giving him some measure of allevia-
tion of the economic and social burden under which he labors.

This, then, is the challenge of American agriculture to the American
scientist: "You can see our problem; we are calling on you to help us,"
a challenge blended of thousands of pleas to the Federal and State Experi-
ment Stations.

And how are the scientists meeting this challenge? One of the newest
branches of science, plant pathology, already has enlisted a thousand or
more specialists. In Washington, at the state colleges, in private institu-
tions and plant industries these men are devoting their lives to a crusade
against plant disease. Much has been accomplished; against many destruc-
tive diseases highly effective chemicals of prevention have been found;
sprays for fruit and vegetable crops, simple and inexpensive chemical dust
treatments for ridding seeds of the germs of disease, tear gas for sterilizing
soil, benzol vapor for protecting tobacco seedhngs from mildew, fermenta-
tion acids for sterilizing tomato seeds, and a host of others. Better, because
they are simpler, are the measures of disease control which depend only
upon slight changes in the ways of cultivating plants; changing the date
of planting to favor the plant and inhibit its parasites, rotation of crops
to starve the parasites out of the soil, farm sanitation to destroy the breed-
ing and hiding places of plant pests, to mention only a few of these. Best of
all are the scores of new varieties of plants, joint contribution of the plant
breeder and the plant pathologist, varieties that are innately resistant to the
attack of parasites and at the same time desirable commercial types. There

360 READINGS IN BIOLOGICAL SCIENCE

are, for example, the wilt-resistant Bison flax, A4arglobe tomatoes, Stone-
ville and Rowden cottons, Stone Mountain and Hawkesbury watermelons,
and Ladak alfalfa. New rust-resistant small grains are coming to the fore
and enormous acreages have already been planted to some of these, such
as Thatcher wheat and Red Rustproof oats. One of the most outstanding
of these recent accomplishments is the development of the Wisconsin
Refugee bean which is at once immune from mosaic and rust, tolerant of
two bacterial bean diseases, and resistant to two of the three races of the
anthracnose fungus.

The story of this winning fight against plant disease is a gripping story
of onward marching in the face of many obstacles. There have been failures,
and much remains to be accomplished. Many plant diseases still resist ef-
forts at their control. With others, we have methods for prevention but
they are costly, difficult, or disagreeable. But as the American farmer moves
on into the task implied by the economic stress of today, he will have in
the background the hundreds of scientists, quietly working with him, pro-
viding him with the knowledge he needs to lighten his own economic load
and permit him to produce the raw products that America needs, amply,
efficiently, and economically.

POLLEN AND HAY FEVER *
MARGATE KIENAST

Your allergy is your personal hard luck. If you have one it is because
you are abnormally sensitive to food, pollen, hair, or other substances that
you inhale or eat. Whatever it may be that causes this kick-back is an aller-
gen. Allergies are various, strange and surprising. Medically the field is
broad, requiring volumes for complete discussion. However, the majority
of people who are allergic are poisoned by a simple vegetable substance
that to most is absolutely harmless. This is pollen. In the summer season
hundreds of thousands of people in the United States are following a hand-
kerchief around. They have hay fever. Ninety percent, of our hay fever is
caused by ragweed pollen.

Some of the measures you can take in your defense program against
this nuisance are medical. If the problem were strictly a medical one, there
would be no point in telling about it here. But hay fever is not caused by
lack of mineral in the bones, by jumpy nerve endings in your nose, by
cruising germs in your bloodstream — or by imagination. A useless weed,
in full bloom, broadcasting a simple vegetable substance, is responsible for
all this discomfort.

• Reprinted from Nature Magazine with the permission of the American Nature
Association. Copyright 1942,

HEALTH AND DISEASE 36 1

Ragweed is an unsightly, troublesome plant, good for just one thing — to
make an outstanding contribution to the population's stuffy nose. In some
eastern sections it is the giant ragweed that is the main offender^ in other
parts of the country it is the short ragweed.

Its generic name is Aiiibrosia. Linnaeus chose for it this label of the
immortality-giving food of the Gods. John Burroughs regarded the high-
sounding name in another light. He said: "It must be the food of the Gods,
if anything, for as far as I have observed nothing terrestrial eats it — not even
billy goats."

It is an easy jump from billy goats to the vacant lots and dumping places
of our big cities. Right in these vacant lots, beside apartment houses, behind
bill boards, along railways, in factory districts, in detached residential de-
velopments, there are large areas of neglected weed-grown land. Dense
growths of ragweed, sometimes ten feet high, are found along the banks
of canals and rivers.

In a survey made in Chicago, there were pieces of empty land adding up
to 20 thousand acres, all supporting a luxuriant growth of ragweed. It was
calculated by scientists, who set pollen catchers — plates covered with
sticky substances — in outlying residential districts and on top of Chicago's
tallest skyscraper, that hundreds of tons of ragweed pollen were liberated
each year within the city limits. In mid-city you are as open to attack as
if you had gone into the highways and hedges to look for it.

Allergists are a cautious lot. Some maintain that if a whole state were
cleared of ragweed plants, not more than seventy-five percent, of the at-
mospheric pollen would be reduced. Replacements would drift in on the
wind from nearby states. But the most pessimistic analyst of the situation
will admit that the sufferer is surely better off if the pollen-shedding weeds
growing within a few hundred feet of his residence are eliminated.

Cutting down exposure is a gigantic task. It has, at times, claimed the
attention of whole cities. Ordinances have been passed, and brigades of
interested people have carried out intensive cutting and pulling campaigns.
But cities and citizens alike usually have worked at it for a while — then
rested on their implements and said "Well, what's the use — the stuff just
keeps on coming back!"

Hay fever is new among recognized diseases, but we find mention of
discomfort due to contact with plants in medical writing for the past 400
years. We cannot back up our suspicions as to the antiquity of hay fever
with museum specimens gleaned from a buried city, an Indian mound or an
Aztec temple. People do not die from eczema, hives or hay fever, even to-
day. Hives leave no trace on a mummy. Asthma — the allergic kind — is
closely related to hay fever, and Aretaeus, a Roman, first recognized asthma
as a disease about a. d. 500.

Thomas Phaer, who died in 1560, wrote of "Nesying out of Measure."
He said: "It is good to stoppe it, to avoyde a further inconvenience." He

362 READINGS IN BIOLOGICAL SCIENCE

suggested that the victim should "eniplayster the forhead and temples with
mylke, oyle of roses, and vynegre a lytle."

Possibly the earliest reference to what we call hay fever was the descrip-
tion by Botallus of Batavia in 1586. He wrote of people in whom the smell
of roses produced sneezing, headache, running at the nose and weeping.
Cardinal Caraffa, in the 17th Century, placed guards at his gates to un-
burden visitors of any roses. Helmont, in 1607, described an asthmatic case
in which symptoms occurred only in the summer time. This was the first
reference to "seasonal occurrence." All these were just personal notes on
the fact that odor of roses brought on odd attacks. There were never any
suggestions on what to do about it.

In 18 19, John Bostock, an English physician, placed hay fever in the list
of clinical diseases by accurately describing his own case. Evidently the
disease was quite well known in England by that time and was already
popularly called "hay fever." The British developed their hay fever then,
as now, from exposure to grasses. Ragweed is not native to England.

Then came Charles Blackley — also an English doctor. He was an honest
observer, and besides, he had hay fever. In 1859 Blackley collided with
dried grass blossoms that one of his children had placed in a vase in the
parlor. He got hay fever — and out of season, too.

Blackley thought: "In most diseases known to medicine something is
out of kilter in the makeup of the patient when sickness strikes. Yes, and
when it does, something comes in from outside and starts the actual trouble.
Now what could there be about that grass that could make hay fever
happen to me?" He went back to the dry grass bouquet and examined it. He
had his clue. He got hay fever.

Here was a starting point — a scientific one, dooming Dr. Blackley to
years of discomfort, for he doubled as his own guinea pig. He could not
go about applying plant and pollen mixtures to the eyes, nose and throat
membranes of his patients. They came to be cured, not tormented. He
had to use his own trigger-mechanism to test the pollens. He studied pollens
of a hundred or more different plants and grasses. He learned what they
did to him. Hay fever symptoms, if left to Nature and the patient, began
when pollen of the grain started to increase in the air. They were at their
worst when pollen concentration was at its height. He made of himself a
human pollen meter. He had figured out a queer little process to test out
pollens that were poison to him. He rubbed moistened pollen extract into
himself to produce those welts that rose and itched and burned on his arms
and legs. He knew which kinds made him "react," but he still needed to
learn how many kinds of pollen caused hay fever. Then, too he wanted to
know how much of it was floating around. He suspected that there was
a whole world of plants busily at work pouring out pollen. Blackley did
not want to know why people got hay fever — he just wanted to know hoiv.

To his patients it seemed as if there was no practical use for what he was

HEALTH AND DISEASE 363

doing. What could you expect of a doctor who spent his time smearing
vaseline on glass plates and leaving them around, collecting them and count-
ing pollen grains. He would not try to treat folks. He did not want to cure
himself, because then he could not continue his studies. He admitted he
did not expect to cure hay fever. He just told his patients sick with hay
fever to go to some place where there was no pollen — if they could find
such a place.

There was one famous concentration camp for hay fever "reactionaries"
that has gone down in history and literature. By 1 860 a few bright people
had accidentally discovered places where they were free from hay fever.
About 1874 a group of men foregathered in Bethlehem, New Hampshire,
and formed the United States Hay Fever Association. The reports, pro-
ceedings, and the collected papers of this society read like a cross between
Bernarr A4acfadden advocating a new breathing exercise and a staff meet-
ing of the New Yorker magazine. Witticisms were set off like fireworks.
The circle encompassed Dr. Morrill Wyman, Reverend Henry Ward
Beecher, Hon. Daniel Webster and Dr. Elias Marsh. Beecher said one of
the meetings was the most interesting he ever attended "for no one had
said anything that someone else did not contradict."

The humanitarian objectives of the society reached out into all Eternity.
They agreed in writing to "carry on work to relieve all sufferers from
hay fever, wherever found, during their natural life, and afterward, if
permitted."

In 1886 somebody in the club put up $100 as an award for the most out-
standing piece of research. A "best essay" contest was held for the pollen
pot of gold. Dr. Bishop of Chicago sent in a well-written httle item, con-
tending that hay fever was a functional nervous disorder (imagination,
to you:). The Association did not subscribe to his theory, but they had
to admit he turned in the best-written essay, so he got the research award.
This is a clear example of just how far research usually gets when left to
groups of jolly laymen.

Hay fever clubs began to form all over the nation. It may be whispered
that most of them were closely allied with local chambers of commerce.
If you were going to run a health resort what could be better than one for
hay fever? Crafty innkeepers, deep in the woods or at the shore, soon found
that Mister Average Hay Fever Victim was so glad to be free of his dis-
comfort that he was pleased with everything. But the very ease of the con-
duct of the business began to defeat commercial resorts. As patients
thronged to favored spots, it became necessary to clear more land for
kitchen gardens, for tennis courts, for boat houses and canoe clubs, for
outhouses and stables. And with clearance of the land up popped the Devil
— Ragweed. In a short season or two suspicious sneezes began to vex the
guests. Commerce had again overshot its mark.

Of course, as we have intimated, ragweed is not the only source of the

364 READINGS IN BIOLOGICAL SCIENCE

nose-tickling pollen. But ragweed is the most important. We can pin this
statement down with a dollar sign, because commercial drug houses make
up their autumn "treatment kits" with ragweed.

The pollen trapping idea of Dr. Blackley was a smart one. Today, pollen
catchers furnish advance notice of what is in the air. They measure the
amount of trouble on the way and identify the agent causing it. There is a
battery of pollen spotters, employed by specialists in allergy — some of
them in cooperation with the U.S. Weather Bureau. They learn which
weeds are coming into pollen-shedding season. They report that weeds
have their preference as to soil, rainfall, and climate, and chart the geo-
graphical distribution and trends of the various kinds. Today we have de-
tailed hay fever maps for each type of pollinosis. Spotters reach high up into
the air. Even in Blackley's time, he used tandem kites to make exposures
of his greased plates. The highest exposure was at 1500 feet. Fifty years
later airplanes were used to make pollen concentration studies. Today there
is an elaborate network of aids to allergists throughout the United States.

Ragweed is high in the index of our national pollen count, but so are
grasses. Grasses are so much a matter of everyday life that most people
do not think of them as a possible source of trouble. Trees are possible
sources of trouble. Male and female trees may be miles apart. Nature has
made it imperative that enormous amounts of pollen be shed to make sure
air borne messages may reach the lady.

But it is never the grass, or the tree, or the flower that makes the trouble.
It is that ole debbil pollen riding the wind and reaping a whirlwind of
sneezes.

Pollen granules are formed in the male organs of plants. Their function
is to fertilize the seed. Not a single fertile seed can form in any one of our
flowering plants unless a grain of pollen has carried the spark of life to the
undeveloped seed.*

It is the drab, uncolored plant, which the allergic person has probably
passed by unnoticed, that produces unbelievable amounts of light, dry
pollen. The bee snubs it, too. Ragweed has to depend upon the wind to
deliver its pollen, and the wind carries it high and scatters it far and wide.

When you consider the hit or miss method of sending pollen grains in
the air for fertilizing eggs, the reason for the high rate of overproduction
is apparent. Even in an ordinary ragweed patch, enough pollen has to be
poured out to hit a mark the size of a needle point twenty blocks away.
Nature's office of production management runs her air force on a scale
that puts humans to shame. There are no bottlenecks.

A single well-developed short ragweed plant has been watched and
found to produce one million 7Jiillion polleti grains. Under observation, a
giant ragweed produced about eight billion pollen grains in five hours.

* The pollen grains contain the male sex cells or sperms which fertilize the egg in
the young seed, — EcJ.

HEALTH AND DISEASE 365

Pollen grains vary enough in size, shape and general conformation, so
that — in a general way — the plants they come from may be identified by
inspection of the granules under the microscope of the pollen specialist.

Pollen is a spore and can live for a long time, and under adverse cir-
cumstances. A pollen grain is said to be "alive" only so long as it is capable
of fertilizing an egg cell. It may live from a few hours to several months.
However, alive or dead, botanically, dry hay fever pollens retain their
power to produce allergic responses for years. Some have been potent for
twenty years.

Some pollens have wings — stationary wings like an air glider. Pine pollen
has them and is carried many miles on them. They are microscopic wings
and not to be confused with winged seeds. Grass pollens are smooth-
walled and spherical and may have indentations on the surface. They look
like a golf ball under the microscope, or like a smooth, round ball of clay
into which a child has pressed his fingers.

Pollens of the ragweed tribe, Ambrosiaceae in part, include ragweeds,
false ragweeds, marsh elder, sunflower, aster, daisy and goldenrod. All have
rough and spiny surfaces under the microscope, looking like cockleburs.

Ragweeds shed their pollen best on days when the sun shines. Rainfall
washes the pollen out of the air. You have probably noticed that hay fever
victims always welcome damp, cloudy days. A heavy wind, of course,
stirs more pollen into the air and carries it farther. A wind storm is often
followed by an "epidemic" of hay fever.

Weed crops respond to good growing weather just as noticeably as do
cultivated crops. The amount of sun and rain during the growing season
may determine whether we have an abundant ragweed pollen crop.

Nature, in her distribution plan, adjusts herself to many situations. In
the North where the warm season is shorter she hurries to scatter her pollen
earlier and continues later in order to pass around enough to reach and
satisfy her waiting clients. In the South, where spring comes earlier, one
would think the pollen season would be advanced by just that much. But
here pollination starts late and lasts but a short time.

Among doctors, allergy has become as much a specialty as is ear, nose
and throat work. A large part of the time of the allergist of today is spent
in running down the substance that causes that explosive response in his
patient. Everything from the pillow you sleep on, the t^^ in your pancake,
to the bears in the zoo, may have to be investigated before your doctor can
attempt to protect you from future attacks. The scratch tests he gives you
stem from the same idea that Dr. Blackley gave the world through his
personal martyrdom.

Ragweed can be ousted by cutting the plant. First, just before the flowers
form, and, again, before the flowers develop on the low-growing branches
that sprout out again after the first cutting. Watch the weed pile if you
cut ragweeds. If you do not whack the tops oflF before flower buds form,

366 READINGS IN BIOLOGICAL SCIENCE

pollen will go right ahead and ripen on the severed plant. All cut plants
should be burned. Stubble lands should be plowed shallow before the
weed forms flowers. If a field is seeded to grass, the autumn growth of rag-
weed should be cut over with a high-set mowing machine before plants
bloom.

Short ragweed may mature and shed pollen at the height of an inch and
a half. Do not judge the enemy by the size of the general. Roots are shallow
and live only one season, in any case. Spread is through seeds, and they are
almost everywhere. As soon as a bit of land is robbed of its forest trees or
native grasses, ragweed springs up. Ragweed followed the plow that broke
the plains.

Why not get rid of it? It can be cut, pulled, burned and the whole
nuisance disposed of within a few short years. Ragweed is one of the most
conveniently accessible pests in the world. You do not have to invade a for-
est, dive under water, or look through a microscope to find it. You just take
the walk around the block. It will not hit back at you if you catch it young.
The root system is shallow so the whole plant will come up readily to your
hand. It exudes no nasty smelling protective juices or oils to stain your
clothing; it does not bite or sting or blister.

Can you live with your allergy? If it is caused by ragweed, why should
you?

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XIV

Economic Biology

THE economic side of biology is important because it deals with figures
on the importance of the oyster industry in dollars and cents, with
the amount of money spent to control weeds, insects, and coyotes, with
the value of the cotton crop and with hundreds of other equally-important
topics. Much credit should accrue to those men and women who take time
out to make up and show us our biological balance sheet. These cost sheets
and inventories show us how we stand with regard to many industries and
businesses dealing with zoological and botanical materials. They show the
degree of prosperity or decadence and they show, in some instances,
whether we are winning or losing our economic battles.

It is difficult, however, to interest most people in dry facts and figures.
The layman scarcely shudders when told that insect control and damage
costs one billion dollars and that weed control and damage costs us three
billion dollars yearly. If a wage earner were handed a bill each year for
about thirty dollars for each member of his family for insect and weed
control, the basic problem would come closer to home. We pay most of
this bill in increased food, clothing, and lumber costs mainly and so natu-
rally the impact is not felt directly.

Economic biology and conservation are tied together. The former may
tell us that the forests are being cut three times as fast as they are being re-
placed. Conservation scientists, who work in both fields of course, will
then attempt to insure that an adequate lumber supply will be planted and
in time. Other measures such as increased fire control, more careful lum-
bering, prevention of waste and the development of substitutes will be
looked into.

A strong America can remain strong only as long as her natural re-
sources are protected from exploitation. Biologists are vitally interested in
the forests, in soil erosion, in good grassland and in any subject which af-
fects plant and animal fife. In 1947 prolonged rains prevented early plant-
ing in many areas of the country and in addition caused such a rise in the
main rivers that the levees broke and hundreds of thousands of acres were
flooded. A few days after this happened, the experts were able to predict
just what this would mean to our winter food supply and what it would
mean in the way of increased food costs. Water, soil and organisms are

367

368 READINGS IN BIOLOGICAL SCIENCE

all tied together in a circle of mutual dependence and should one factor
get out of balance, someone will have to pay for it.

MAN AND NATURE *

R . T . YOUNG

An ardent French entomologist in Medford, Mass., was one day eagerly
inspecting some caterpillars which he had reared from eggs brought by him
from Europe, when some of them, growing tired of his society, made their
escape and went on their way rejoicing. This was in 1869. From 1890- 1900
Massachusetts spent about $1,000,000 to fight the gypsy moth. At this time
the pest being partly under control the efforts were relaxed, with the in-
evitable increase of the pest, and its further spread over a large part of New
England and into Canada.

In 1850 caterpillars were devouring the trees of the eastern United States.
But in England there was a merry, if not melodious little sparrow, who was
supposed to enjoy nothing so much as a meal of luscious juicy caterpillars,
and so what was more natural than to bring sparrows from the old world
to enjoy the rich feasts of caterpillars provided by the new? Today he has
spread over all of the United States and much of Canada, and is emulating
the example of his fellow countrymen by driving before him many of the
native inhabitants and inheriting their patrimony.

Inhabiting the wheat fields of the greater part of the United States is a
little fly known as the Hessian fly, about an eighth of an inch long, which
lays its eggs on the leaves of the wheat, and whose larvae as they hatch crawl
down the stem, burrow into it, and kill the plant. This fly is supposed to
have come to America as an unintentional ally of King George with his
Hessian soldiers; hence its name. Another immigrant which came to us in
Revolutionary days was the brown rat.

This rat first crossed the Russian frontier of Asia in 1727 in such numbers
that it soon overran Europe, whence it came to America. With the rat came
its parasite, the deadly Trichina, while more recently the yet more deadly
bacillus of the bubonic plague has become established in California, brought
in by rats from oriental ports. What a pity we cannot return to Europe with
our compliments all of the undesirables, four-legged, as well as two-legged
and winged ones as well!

To kill a hawk is, in the minds of most of us, a laudable act for are not all
hawks "hen hawks," the inveterate enemies of the poultry men? So at least
thought the farmers in the Humboldt valley in Nevada, which in 1907 was
visited by a plague of mice, which ate up everything in sight, gnawing the
bark from fruit trees, burrowing in the alfalfa fields and destroying the

* From Biology in America by R. T. Young, copyright 1922 by Chapman and
Grimes, Boston.

I

ECONOMIC BIOLOGY 369

potatoes and other crops. At the height of the plague, it was estimated that
there were from 8,000 to 12,000 mice per acre, while the total loss to the
valley was estimated at $300,000. The abundance of mice in the Humboldt
valley attracted hawks in large numbers. But failing to recognize in the
hawks their best ally in their war against the mice, the ignorant residents
seized their guns and proceeded to slay their best friends.

So too thought the legislature of Pennsylvania when they passed the no-
torious "scalp act," providing for a bounty of fifty cents for every hawk and
owl killed within the state, as a result of which half-baked legislation more
than 100,000 valuable birds were killed, at an expense of nearly $100,000 to
the state for bounties and notary fees, and an estimated loss of more than
$4,000,000 from the increase of harmful rodents resulting from the destruc-
tion of their enemies, the hawks and owls. And yet all this in the short space
of a year and a half.

Hawks and owls have the habit of throwing up the undigested portions
of their food in the form of pellets containing the hair, bones, feathers, etc.,
of their prey. For many years a pair of barn owls were wont to nest in the
tower of the Smithsonian Institute in Washington. An examination of two
hundred pellets found beneath their nesting site revealed 454 skulls, of which
412 were those of mice, 20 of rats, 20 of shrews, one of a mole, while only
one was that of a bird (sparrow).

An examination of 562 stomachs of the red-tailed hawk showed remains
of poultry or game birds in 54, other birds in 51, mice in 278, other mammals
in 131, insects in 47, miscellany in 59, and nothing in 89.

The habitue of field and forest, who seeks his favorite haunts after the
first snow fall of the winter, is likely to encounter companies of little birds,
who, in spite of winter and its snow, are busily engaged in reaping a bounti-
ful harvest of the weeds. Flitting from stem to stem, they pick out the seeds
from their shells, while others follow in their wake to pick up the gleanings
from the snow. The late Dr. Judd of the Biological Survey, in his studies
of the food habits of sparrows, examined a piece of ground eighteen inches
square in a patch of smartweeds where several species of sparrows had been
feeding. On this patch he counted 1,130 half seeds and only 2 whole seeds.
During the ensuing season no smartweed grew where the sparrows had
caused this extensive destruction. It has been estimated that in Iowa alone a
single species, the tree sparrow, destroys in one year 875 tons of weed seed,
and that in the United States as a whole the different species of native spar-
rows, numbering more than one hundred, save $35,000,000 for the farmers
every year.

Many a wild creature is the farmers' inveterate enemy and does untold
damage to his cattle or his crops. As an indication of the losses due to preda-
tory animals it may be stated that the chairman of the State Live Stock Board
of Utah estimates an annual loss in that region amounting to 500,000 sheep
and 4,000,000 pounds of wool. The president of the New Mexico College

37© READINGS IN BIOLOGICAL SCIENCE

of Agriculture, as a result of a survey in that state, estimates an annual loss
of 34,000 head of cattle and 165,000 sheep. A single wolf killed in southern
New Mexico was reported to have killed in the preceding six months 150
head of cattle valued at not less than $5,000.

Through the watchful activity of the Biological Survey bureau it is proba-
ble that many another catastrophe similar to the introduction of the Eng-
lish sparrow, gypsy moth, and Hessian fly has been averted. Some years
ago the mongoose applied for admission and a few individuals did indeed
gain an entrance. The mongoose preys on mice and rats, but unfortunately
attacks poultry and wild birds as well. It has been introduced into Jamaica
where it has proven a nuisance through its depredations. By the passage of
a law placing the importation of foreign animals under the Secretary of
Agriculture, the bureau has been able to prevent its establishment in the
United States.

Monstrous as is the tax which we pay to our four-footed foes, it is small
in comparison with the tribute levied by our winged enemies. Estimates
of so uncertain a sum as the loss caused by insects are bound to vary, but
even accepting the minimum figure of $1,000,000,000 annually, the amount
is surely ample.

In the eighties the orange and lemon groves of California were threat-
ened with ruin by an innocent-looking but destructive scale insect. Soon
the Bureau of Entomology had experts on the ground learning all they
could about the vicious stranger. They learned that the scale insects were
natives of Australia, whence they had been imported into California on
young orange trees in 1868. Now it occurred to them that in the native
home of the scale might perchance be found some natural enemy, which
if introduced into California might drive out, or at least hold in check the
terrible scale. And so one of them journeyed to Australia and there he
found the ladybird beetle which preyed upon the scale. And this he brought
back with him to California, where it throve; and making war upon the
scale it has ever since held it in check.

In Hawaii the ravages of the sugar-cane weevil, which bores its destruc-
tive way into the sugar canes, have been materially reduced by the intro-
duction of a parasitic fly from British New Guinea.

Scab mites, which in years past levied a heavy toll upon the cattle grower,
have been nearly exterminated; the foot and mouth disease, which in 19 14
was epidemic in twenty-two states, and was seriously threatening the live-
stock industry of the country, was stamped out after a hard fight; hog
cholera, ever a serious drain upon the hog industry, is gradually being
brought under control by the use of a serum and other measures, and an
active campaign is now under way for the suppression of tuberculosis in
hogs and cattle, a disease not alone serious to the animal industry, but,
when present in dairy cattle, a very probable menace to human life.

The duties of the members of the Office of Foreign Seed and Plant In-

ECONOMIC BIOLOGY 37 I

troduction of the Bureau of Plant Industry are manifold but one of them
is to go into "the uttermost parts of the earth" and bring back to us its
treasures. From the Asian steppes to the jungles of the tropics its explorers
have gone, and from the fertile isles of Japan to the deserts of Arabia, in
their search for the useful and the beautiful, to enrich our fields and adorn
our dwellings.

We are accustomed to think of the bamboo in terms of wicker work or
fishing rods, but how many of us realize that the young bamboo shoots,
which grow at the rate of a foot a day, are succulent and may be eaten hke
asparagus tips. How often do we think of the bamboo as serving such varied
uses as pulp for paper, masts for vessels, pipes for water and timber for
buildings? There is no plant in the world which is put to so many uses as
the bamboo, and in the regions where it grows it is apparently the most
indispensable of all plants. Strange as it may seem, the bamboo is not a tree
in the ordinary sense of the word, but a grass. Several species of bamboo
have been introduced into California, while in Florida and other southern
states are bamboo groves planted by the bureau.

The tung oil tree of the orient, from the seeds of which is obtained one
of the best drying oils known, has been introduced into California and the
Gulf States, where it appears to be thriving; while the pistache tree is doing
nicely in California.

The date palm, that wonderful tree of the oasis in the scorching deserts
of Arabia and Africa, is now domesticated in Arizona and Southern Cali-
fornia and has taken kindly to its new home. With some trees bearing more
than 100 pounds of dates an average profit of $100 to $150 per acre is a fair
estimate.

Many are our natural resources unused as yet, while many another fast
disappearing can be restored in part at least to its former abundance, not
only by negative measures of conservation, but by the active ones of propa-
gation as well.

In the days of the pioneer the United States was teeming with game. To-
day the flocks of wild pigeons, the herds of buffalo, elk and antelope are
but memories of the past. Of the wild pigeon not one wild bird remains
today to bear testimony to their departed glory. To save others from a
like fate the Biological Survey in cooperation with our National Park
Service and the Audubon Society has established havens of refuge through-
out the country, where the remaining herds of large game are safe from
the depredations of man, and others where our wild fowl may breed in
safety and replenish their fast thinning ranks.

The rapid diminution of our fur-bearing hosts, with the consequent
rise in the price of furs, has led to experiments in breeding these animals
for market. That enormous profits are possible in successful fox farming is
shown by the value of the best animals for breeding, as high as $25,000
having been paid for a single pair of silver foxes for this purpose. Not alone

372 READINGS IN BIOLOGICAL SCIENCE

foxes, but fisher, marten, mink, skunk and other animals have been culti-
vated for their furs.

The "king" salmon occurs on both coasts of the pacific from California
and China north to Bering Straits. During the winter the fish sojourn in
the sea, but in early spring they slowly gather in the rivers and begin the
long and arduous journey to their breeding grounds, which in the Yukon
may be over 2,000 miles from the sea. In the ascent of the rivers they per-
form prodigious feats, ascending falls 10-15 ^^^^ ^^ height. Arrived on the
spawning grounds in autumn the male excavates a little hollow in the gravel
of the stream bed, where the female deposits her eggs, upon which the
male sheds the "milt" or sperms, after which they cover them with gravel;
and then the function of reproduction performed, which is the crowning
act in the life of animal or plant, they float downstream to die.

The average number of eggs laid by a female is four thousand. If one-
half of these developed into females and reached maturity in four years,
and if their progeny in turn were all to reach maturity, one-half being
females, this rate of increase remaining constant from generation to genera-
tion, there would result in 32 years 256,000,000,000,000,000,000,000,000
salmon weighing 2,816,000,000,000,000,000,000,000 tons or 468 times the
mass of the earth. (Such an increase does not occur of course because of
the many natural enemies of the salmon including man.)

Sealing privileges have long been a bone of bitter contention between
American, Russians, Canadians, and more recently the Japanese. The
Pribilof Islands, the principal sealing grounds, originally belonged to Russia.
With the sale of Alaska to the United States in 1867 these rights passed to
our government. It is an interesting commentary on the foresight of the
opponents of the Alaska purchase proposition, that from 1 870-1 890 our
government received in leases, royalties, and duties on furs made up in
London, but most of which came originally from Alaska, some |i 3,000,000,
or nearly double the price paid for the entire territory.

>>><<<■

WONDER PLANTS OF COMMERCE AND INDUSTRY ^
A . HYATT VERRILL

One of the most wonderful features of plants is the important part they
play in our commerce and industries, as well as in our daily lives.

This article, for example, would not be possible were it not for plants.
Even if the paper upon which it is printed had been made from old rags
it would still be a plant product, for the rags used would have been cotton
or linen cloth made from plant fibers. The same plants have supplied the

* From Wonder Plants and Plant Wonders by A. Hyatt Verrill, D. Appleton-
Century Co. Copyright 1939.

ECONOMIC BIOLOGY 3^3

thread with which the leaves have been stitched together. The ink used
in printing was made of carbon which came from burning wood, and the
glue and paste used in making the cardboard covers and attaching the bind-
ing to the leaves were probably manufactured from gums or juices of
plants, perhaps even from the stalks of maize. And even if the adhesives
were wholly or partly animal glue, they would not have been possible
without plants which provided food for the features whose hoofs, horns,
and hides supplied the glue.

Until one gives serious thought to the matter and looks about at the
innumerable things upon which we depend, one does not realize the extent
to which we employ plants to supply both the necessities and luxuries of
life. It is not even necessary to trace back various substances and materials
to their original plant sources, or to argue that by doing so all animal life is
dependent upon plants. So let us confine ourselves to materials obtained
directly from plants.

Among the most important and valuable plants of commerce and indus-
try are those which supply us with fibers. Moreover, there is a vast number
of these fiber-producing plants, some of which are very familiar to every
one and serve us everywhere every day. Others are strange to most per-
sons, even though their fibers are commonly used, while others are seldom
used except by the natives of the lands where they occur. Yet some of these
little known fiber-plants are superior to many of our own and deserve to
be much more widely used than they are.

Probably the most famihar of all plant fibers is linen which is made
from the leaf and stem fibers of the flax plant, and cotton from the seed-
coverings of the cotton plant. Next in importance in our everyday life
are hemp, iManilla, jute, and sisal. An entire volume might be written about
these alone, and a very romantic and interesting story it would be, for
these four fibers come from widely separated parts of the world and are
grown and gathered by strange races amid strange surroundings.

Hemp is obtained from the heinp pla?it which is a native of India and its
vicinit}^ Manila or Manila hemp, which is the source of the best cordage
and ropes, especially for use on shipboard, is obtained from a very diff'er-
ent plant, a variety of the banajia which is a native of the Philippines and the
East Indies. Jute is another Oriental fiber derived from an East Indian an-
nual plant with tall stalks and yellow flowers. Although one of the most
important and valuable of fibers it is not very strong and hence is not suita-
ble for high-grade cordage. But it is fine, silky, easily woven and serves a
multitude of purposes. Great quantities are used in making gunny sacks or
burlap bags. Immense amounts in the form of "tow" are employed for
caulking the seams of vessels, for making coarse and cheap papers, for fiber
carpets, rugs, seat-covers, curtains, draperies, and "art" fabrics, while the
finer grades are used in place of hair on wigs for actors.

Sisal comes mainly from Mexico, Central and South America, the West

374 READINGS IN BIOLOGICAL SCIENCE

Indies, Hawaii, and South Africa. This well-known fiber is obtained from
the leaves of the henneqii'm, a species of agave or "century plant" which is a
native of Mexico and Yucatan. Although the hennequin had been culti-
vated and the sisal fiber had been used by the Indians for countless cen-
turies, yet it was not until comparatively recently that it came into general
use by the white races. It is a rather coarse fiber, harsh and somewhat brittle,
and much inferior to hemp or Manila for cordage, especially when wet.
But some one discovered that it was the best of all fibers for bindertwine
used for tying sheaves of grain, and instantly sisal became one of the world's
most important and valuable fibers. Where only a few of the stiff-leaved
hennequin plants had been cultivated by the native farmers, vast planta-
tions sprang into existence. The crop increased from a few hundred to tens
of thousands of tons of sisal yearly. Railways were built to transport the
countless bales of fiber from the inland plantations to the seacoast. Tiny
towns that had been forgotten by the world became transformed to busy
important seaports. Where only an occasional sailing vessel or coasting
steamer had been moored beside ramshackle wharves, scores of great wall-
sided iron freight steamships lay alongside concrete and steel docks. Plant-
ers who had found it hard to make both ends meet became millionaires,
stupendous sums were invested in planting more and more land with henne-
quin and in erecting mills and factories for manufacturing sisal twine and
other products, and from Yucatan the hennequin industry spread to
Hawaii, the West Indies, South America, Egypt and the Orient. Probably
no other plant of industry and commerce has had such a meteoric career
or has risen so rapidly in importance and value as the hennequin or sisal.

In the Philippines and the East Indies the natives weave beautiful fine
silky cloth from the fibers of pineapple leaves, which is also used to some
extent in our textile mills, while in other Oriental countries mulberry fiber
is an important product. The well-known raffia fiber used in art work and
for making baskets and hand-bags, is the fibrous bark of a palm-tree, while
another pahn-tree supplies the strong, pliable material used in weaving the
famous Panama hats.

Even more important in some ways than are the fiber plants used for
cordage and textiles, are those which make it possible for us to publish
books, print newspapers, or write letters. Without paper we would be sadly
handicapped indeed. Imagine what a task it would be to write a novel such
as Anthony Adverse on clay tablets or to compile a dictionary by inscrib-
ing the letters on stone. And think of the size of the hbrary that would be
needed to house thousands upon thousands of clay or stone or even metal
volumes. For that matter, try to visualize the occupants of a crowded sub-
way train all carrying morning papers of baked clay or made of metal
sheets. And how could our post-offices ever hope to handle millions of
letters written on bricks?

No one really knows what race was the first to make that epochal dis-

ECONOMIC BIOLOGY 375

cover)'', for paper of some sort or another was used by several races in
widely separated parts of the world in very remote times. The ancient
Egyptians used excellent paper made from the papyrus plant and from the
lotus. The Chinese, thousands of years ago, used paper made of rice straiv,
and in the New World the Aztecs and Alayas had been using splendid
parchmentlike paper made from the agave or maguey plants for untold cen-
turies before the arrival of the Spaniards.

Today a vast number of plants are employed in making paper. Bamboo,
banana leaves, palm fibers, seaweeds, cotton, hemp, jute, Manila, reeds, mul-
berry, bidrushes, straiv and countless other fiber-plants are ground to pulp
and passed between massive rollers to come forth as sheets of paper. But
by far the greatest quantity of paper is made from forest trees. Spruce,
poplar, fir, cedar, and many other woods may be used for paper-making,
but the best of all "pulp" trees, especially for the cheap newspaper stock,
are the spruces. Whole forests have been leveled to supply our people with
their daily papers, and few persons have any conception of the almost in-
credible quantities of pulp wood that are consumed in this way.

Merely to supply the paper for a single edition of one of the big New
York newspapers necessitates the complete annihilation of eighty acres of
forest. Multiply that by the number of similar papers of the metropolis,
and multiply the result by 365 and we will get some vague idea of the al-
most inconceivable numbers of trees which are annually felled and con-
verted into paper-pulp. I say "vague" idea, for big as they are, the papers
published in New York City are only a very small fraction of the total
number of papers published daily throughout our country. More than
14,000,000 cords of wood are required to supply the paper needs of the
United States annually. The United States and Canadian newspapers print
annually enough paper to encircle the world with a belt fifty miles wide. If
this paper was in the form of the standard roll with a width of 73 inches, it
M'ould be 13,000,000 miles in length. Moreover, vast quantities of trees are
used in making cardboard, various composition substitutes for lumber and
for crates, boxes, and other purposes, while whole forests are felled to
supply the tens of thousands of cords of wood needed to manufacture
matchsticks.

Mineral and chemical dyes have taken the place of many plant-dyes, yet
there are certain dye-plants which are still in demand, and which have
never yet been replaced by artificial substitutes.

Although the use of indigo has decreased until very little of the once
important dye-plant is cultivated, yet no one has ever discovered an arti-
ficial indigo that can equal that of the plant for color and fadeless quality.
Fustic from the big forest trees of South and Central America is still used
in enormous quantities, for it is the best and most durable of khaki dyes.
When we use butter or eat chili con carne as well as other foods, we
swallow a dye made from the seed-coverings of a tropical American tree.

376 READINGS IN BIOLOGICAL SCIENCE

This is the anotto or achiote, and as the orange-red dye or pigment is harm-
less and even contains a certain amount of nutriment, it is perfectly adapted
to coloring foods. In its raw state it is a vivid red and is used by the Indians
for painting their faces and bodies, but when diluted it imparts a deep
yellow color. Its principal use is for coloring butter, hence it has become
generally known under the trade name of "butter color."

Formerly our own native trees supplied many world-famous dyes. But-
ternut-brown was widely used and became famous as the color of the uni-
forms of the Confederate soldiers during our Civil War. But to-day it has
no real commercial value, and the same is true of our yellow or quercitron
oak which furnishes a wonderful yellow dye. At one time hundreds of
tons of the chipped oak bark were exported to Europe, but to-day its use
as a dye has been almost forgotten.

Even when plants have supplied us with wood for our houses and furni-
ture and fabrics for our garments, our carpets, our draperies and the up-
holstery on our chairs and couches, and other plants have yielded the
stains, dyes, and pigments with which to color them, we still need oils, var-
nish, and wax with which to finish the woodwork. And when it comes
to these important and essential substances we are compelled to rely on
plants to supply them. There is no substitute for linseed-oil except other
vegetable oils. No one has been able to manufacture a synthetic varnish
to compare with those made from copal, coiiri, or other plant gums and
saps. Turpentine and resin from pine trees still hold their own against all
competitors made from petroleum or other chemicals, while tung oil is
the basis of all our finest quick-drying lacquers, enamels, and varnishes.

It is the same with the various kinds of vegetable wax. Who wouldn't
prefer a bayberry wax candle made from the aromatic berries of the sea-
side bay berry bush to a paraffin or tallow candle? What would scientists
do without oil of cloves for use in microscopy and Canada balsam from
the fir trees for mounting their sHdes and cementing the lenses of their
instruments? Palm-oil and palm-wax have never given way to synthetic
products of the laboratory. And finally there is the oil from the castor-
bean plant. No doubt many a youngster wishes the broad-leafed tropical
plant had never been discovered, but the thick white oil from the plants'
mottled seeds has many other uses besides that of medicine and possesses
properties unlike those of any other oil. It never thickens, no matter how
cold it may be; it never becomes thin even under the terrific heat of high-
speed motors when used as a lubricant, in which respect it exceeds all other
oils, and it is practically non-inflammable. But it has one important use
which few persons suspect, for it is castor oil that makes sticky fly-paper
remain sticky and prevents the combination of resin and gum from dry-
ing up.

To the ladies there are many plants which are of tremendous importance,

ECONOMIC BIOLOGY 377

for they supply the feminine population of the world with scents and per-
fumes, hair tonics and washes, face powders and toilet soaps, creams and
other aids to beauty — even with their lip-sticks and eyebrow pencils, and
mascara. Quite aside from the innumerable flowers used in manufacturing
perfumery there are many other plants vital to the industry. The leaves
of the West Indian bay-tree supply bay-oil from which bay-rum is made.

On one occasion when I was visiting a tribe of primitive Indians in the
South American jungles, the women and girls gathered about my camp-fire
chatting and sniffing the air as Sam, my black camp-boy, prepared my
dinner. Presently, having peeled and sliced an onion, he tossed aside the
waste. Instantly there was a wild scramble among the brown-skinned belles
followed by squeals of delight as the lucky ones smeared the fragments
of odorous bulbs over their faces and naked bodies. That gave me an idea.
I was short of trade goods, especially beads and knives, and had been
unable to secure many of the ornaments and other ethnologic specimens I
desired for my collections. But the women's fondness for onion perfume
solved the problem, and for the next thirty minutes or so I did a rushing
business doling out sections of onions in exchange for weapons and imple-
ments, musical instruments and feather work, bead aprons and jaguar teeth
necklaces. But our stock of the bulbs was soon exhausted and there were
still many objects I wished to acquire, while many of the Indians were still
minus a supply of the perfume they so greatly desired.

"Can't you dig up any more onions, Sam?" I asked while the Indians
stood about laden with possessions they wished to trade. "Perhaps some
got into the potato bag by accident."

The Negro dumped out the contents of bags and boxes and searched
diligently. "No, sir. Chief," he replied at last. "Ah 'spec' they complete
finish. But Ah come 'pon httle garlic, Chief, an' they sure do smell a-plenty."

The little bulbs certainly did "smell a-plenty" and how those Indians
did clamor for them! To them the odor of garlic compared to that of
onions was as delightful and desirable as attar of roses compared to the
cheapest rose-water would be to any white woman. They were willing
and anxious to exchange anything or everything they owned for a mere
fragment of garlic, and had I possessed a few pounds of the bulbs I could
easily have purchased the entire village with all it contained — including
the entire feminine population — had I so desired. Taking all things into
consideration, perhaps it was just as well that our supply of garlic was so
very limited.

378 READINGS IN BIOLOGICAL SCIENCE

THE VANDALS *
ANGELO PATRI

It was Sunday evening and the cars were filled with returning holiday
makers. Every seat held its quota of weary, sleep-beset children, and from
their relaxed hands drooped thousands of dead and dying wild flowers.
When the car stopped at their corner their guardians pulled them up and
dragged them out and the flowers strewed the passageway.

One sleepy towhead clutched a little tin pail, and as she was dragged
along the pail caught somehow and overturned. A foot kicked it along
and its contents were scattered about. I looked at them and saw that the
child had gathered a score or more of white violet plants. Now they lay
smashed beyond recognition on the floor of a dirty trolley car.

I knew the spot where those violets had grown. There is a little dark
brown wood pool in which tall trees stand, each rising from a throne of
velvet green moss. Out of the moss grow the tiny white violets and the
"wind lily of the valley." It is a fair^^ place, a place that catches one's breath
by its exquisite solemn beauty. And the child had tried to gather the beauty
and carry it home in the little pail.

Why didn't the grown person with her tell her that she could never do
that? Why didn't she tell her that the beauty was a thing of sky and sun-
shine and color and fragrance and water and wood and could be carried
away only in her heart?

Why didn't she tell her that she was carrying death to something that
the Creator had instilled with life that it might make glad the spaces of
a spirit? Didn't the mother know? I'm afraid she didn't, because she left a
bundle of dosrwood in the seat behind her!

People with gardens, gardeners who cherish beautiful grounds in great
estates, park superintendents who fight to preserve a little of the beauty
of the earth that its people may see and know it, cry out against the van-
dalism of the children.

Better cry out against the vandalism of their elders, who teach them that
flowers are to be gathered regardless. The children only follow their par-
ents' example.

There are some people who cannot bear to see anything lovely without
longing to possess it. Flowers cannot defend themselves and fall victims
to the greed of possession. Women who could not bear to kill a noxious
fly will slaughter a bank of wild flowers and go carelessly on their way.

There must be a sad spiritual lack about such people, and the saddest
part of it is their passing it along to the children.

Teach the children to look at the beauty of the flowers and keep their
hands off. Show them the difl'erence between the beautiful little flower

• Reprinted by special permission of Angelo Patri.

ECONOMIC BIOLOGY 379

growing in its mossy bed and the dead and dreary thing they hold in their
hands. Teach them to love and preserve the beaut\' that gladdens their eyes
and rests their souls in the fields and woods about them.

■>>><<<•

THE CONSERVATION OF WILDLIFE *

SETH GORDON

WILDLIFE AND THE PIONEERS

When the first white settlers reached our shores, the Indian was the only
human inhabitant, and wildlife abounded ever^^where. The "balance of
nature" still prevailed, because the Indians took only what they needed
for food, shelter and clothing. No waste characterized their use of game,
and traffic in the creatures of the wild was unknown. The original colonists,
coming from lands where the enjoyment of the chase was restricted to the
ruling classes, found here a hunter's paradise. Wildlife, like the forest, was
considered inexhaustible and free to all for the taking. Furthermore, game
was all important as a source of food, and clothing. It soon became an
article of commerce, and that was the beginning of the end for many
species.

The fur traders Mere the real trail blazers. The settlers followed in
their wake. The earlv history of both the United States and Canada was
influenced more by our wildlife resources, and the battles which were
fought over them, than by desire to possess the land. The mistreatment
of two young pioneer French fur traders who penetrated the Great Lakes
region in 1658 is credited with having been largely responsible for Canada
becoming an English instead of a French possession.

With the opening of the west, and the development of agriculture, the
extermination of the buffalo became inevitable. Its valuable coat alone
did not bring about its destruction. In some regions, the United States
Army aided in its extermination in order to more easily whip the roving
bands of Indians into submission by removing their main source of food.
The advancement of agriculture, and the wasting of our forests, did more
to destroy our wildlife than did the firearms of the pioneer settlers or the
sportsmen. This is especially true of our waterfowl, today a pitiful rem-
nant of the former millions which s\\armed the sky in migration.

THE MARKET HUNTER

Commercial exploitation of wildlife resources was by no means con-
fined to fur-bearing animals. The last of our former myriads of passenger

• Reprinted from American Conservation in Picture and Story, compiled and edited
by Ovid Butler, copyright 1935 by The American Forestr)' Association.

380 READINGS IN BIOLOGICAL SCIENCE

pigeons died in the Cincinnati zoo September i, 19 14, a race exterminated
by trapping and other methods of the market hunter. Many men living
today witnessed the wholesale slaughter and carload shipments of these
magnificent birds to satiate the demands of city markets. William B.
Mershon in "The Passenger Pigeon" estimates that in the last great nesting
in Michigan from three to five million birds were slaughtered. Hunting as
a business accounted for millions upon millions of birds and animals an-
nually between 1840 and 19 10. Dr. William T. Hornaday, in one of his
books, cites a professional market hunter who admitted having killed more
than 139,628 game birds and mammals.

The buffalo, passenger pigeon, antelope, elk, deer and many other species
were persecuted and destroyed by the carload, not only to fill the demands
of city markets, but also to feed the many railroad construction crews and
other outposts of the advancing frontier in its sweep westward. Song and
non-game birds were killed by the millions for their plumage, demanded
by the millinery trade. Market hunting was unquestionably one of the most
devastating factors in the decimation of our wildlife. The wonder of it
all is that any birds, mammals or other valuable fur-bearers are left today.

GAME LAWS

In the beginning there were no game laws. Wildlife was so abundant
that restrictions were not deemed necessary. But gradually the need for
protective legislation became evident, and the statutes on the subject now
fill many volumes. The first game law recorded called for a closed season
on deer in Massachusetts in 1694. In 1739, the first game wardens in Amer-
ica were appointed in the Bay state as "deer wardens." Delaware prohibited
Sunday hunting in 1750. By the time of the revolution, most of the colonies
had a few game laws.

The first Federal law, passed in 1776, decreed a closed season on deer
in all the colonies except Georgia. Alassachusetts in 18 18 prohibited the
killing of robins in the spring of the year. New York in 1 864 was the first
state to adopt a hunting Ucense law, and Iowa in 1878 the first state to fix
a bag hmit on game of any species. About 1885 the American Ornithologist
Union, organized in 1883, became active in promoting the protection of
North American non-game birds, preparing a model law for states to adopt.
Both New York and Pennsylvania adopted the law within five years and
by the close of the century more than a dozen states had written it into their
statutes.

These meagre beginnings have been, especially since the opening of
the twentieth century, elaborated and extended in an effort to prevent the
destruction of game by legislation. Today the game codes of the states
are a veritable maze of inhibitions. But recognizing that legislation alone
will not bring back the vanished legions of Colonial days, the federal gov-
ernment and many states have in recent years extended their wildlife

ECONOMIC BIOLOGY 381

restoration policies to include not only careful regulation of the annual
kill but the development of practical management methods on farm lands,
the reservation of portions of the hereditary ranges of wildlife for its per-
manent use, and its definite inclusion in all land utilization plans involving
drainage, the impounding of water, or the withdrawal of lands from agri-
culture.

Advancing civilization, drainage, agriculture, destruction of the forests,
pollution of waters, have progressively taken heavy toll of our wildlife.
Breeding grounds have been destroyed by promotion schemes which were
economically and biologically unsound. Just as the range of the bison
was needed for domestic cattle, so the vast prairies of the North Central
states were needed for wheat and corn, cows and pigs. Millions of acres
of wildlife habitat were needlessly destroyed, with no benefit to agriculture.
Approximately 75,000,000 acres were drained in the United States alone.
Added to these encroachments upon wildlife habitats, intensive farming
practices, the elimination of the hedgerows and stake and rider fences of
yesteryear, removed much desirable breeding and feeding cover for game
and other wildlife.

WILDLIFE ADMINISTRATION

Wildlife conservation through enforcement of game laws and propa-
gation of game stock is now an established policy in every state; but wild-
life management is a comparatively recent conception of public administra-
tive responsibility. It is commonly accepted that wild birds and mammals
are under state control, excepting birds of migratory habits and wildlife
in the national parks, which by specific acts of Congress have been made
wards of the federal government. The great bulk of the nation's wildlife
resources are therefore in the custody of the states. The first state game
commissions were established in California and New Hampshire in 1878.
State game administration today varies greatly, but the majority of the
states nov/ operate under the supervision of non-salaried commissions as
the policy-making body, with state organizations charged with enforcing
the game laws, propagation and planting of game, administration of state
refuges and promotion of wildlife research.

The Biological Survey of the United States Department of Agriculture
began in 1885. As the principal federal agency concerned with wildhfe,
the survey deals scientifically with the resource in all its aspects. These
include the relationship of wildlife to agriculture and forestry, and the
interrelationships existing between various forms and species, the study of
diseases and food habits and the control of injurious forms.

MIGRATORY BIRDS

The ducks and geese of North America have decreased with appalling
rapidity. Destruction of nesting and breeding areas by reclamation, drain-

382 READINGS IN BIOLOGICAL SCIENCE

age, and intensive grazing combined with recent droughts and market and
sport hunting have reduced migratory waterfowl to a critical point.

Early conservationists foresaw that protection of migratory waterfowl
could not be successfully accomplished by the states. The ducks and geese
knew no state lines. The Migratory Bird Treaty Act of 19 18 provided
special protection for birds migrating between the United States and
Canada.

In 1929 Congress supplemented this legislation by passing an act authoriz-
ing the purchase of inviolate refuges for migratory waterfowl but each
year thereafter it consistently failed to provide the funds authorized. Dis-
couraged, conservationists in 1934 secured the passage by congress of "The
Duck Stamp Law" placing a license charge of $1 on all hunters of migra-
tory birds, the revenue to be used in the purchase of breeding grounds.

Continuation of the program contemplates the acquisition and restora-
tion of about 3,000,000 acres of land as sanctuaries for waterfowl and other
forms of wildlife. A considerable portion of the total area will be within
the region formerly used by the migrants as nesting grounds, but other
refuges will be established along the principal flyways to the gulf. The
work will have considerable effect in the stabilizing of water levels and
the reduction of soil damage by flood and erosion.

FINISHING THE MAMMALS *

ROSALIE EDGE

KILLING WHOLESALE

Man the Destroyer

Ages ago, the reptile group dominated the animal world — on the earth,
in the air, and in the sea. Yet this dominance came to an end; and the great
reptiles were eliminated in a way we can never fully understand. They
were succeeded as "lords of creation" by the mammals, once almost as wide-
spread and dominant as the reptiles, and now clearly being exterminated —
but in a way we can understand, for it is we ourselves who are causing their
extermination.

Scientists state that the fur trade is definitely bringing to a close the Age
of Mammals. If the fur trade alone is so pow^erful a menace, then the end
must indeed be near, for the fur trade is only one of several mighty forces
that are visibly combining to annihilate mammalkind. Occupation by man
of more and more of the environment available for mammals is contribut-

* Reprinted from Finishing the Marmnals by Rosalie Edge with the permission of
the Emergency Conservation Committee, 1936.

ECONOMIC BIOLOGY 383

ing heavily to their extermination. Hunting has reduced big game species
everywhere so greatly that they exist only as wards of government. Bounty
payments slay their thousands, and "control" campaigns their millions,
while "vermin" destruction has in view the absolute elimination of preda-
tors; and, carried on without cessation, in some places its object is almost
achieved.

Trappers and hunters should be interested to conduct their activities so
as to ensure a continued supply of the animals on which they depend for
livelihood, or for "sport"; but ignorance, selfishness and greed among pro-
fessional trappers and "sportsmen" prevent positive steps toward this end.
The false propaganda of "sportsmen" against harmless creatures is insti-
gated largely by the gun and ammunition manufacturers, and is abetted
by the state game commissions. Hunters now pursue small animals that
men a generation ago would have scorned to call "game"; and are wiping
out many of the small creatures of the woods and fields.

"Vermin" control provides no incentive for the perpetuation of species;
its proponents would hail with great satisfaction the death of the last preda-
tor on earth; and "vermin" control is the most inexcusable of all the inimi-
cal factors now pushing our small animals into oblivion.

KILLING FOR PROFIT

The Fur Trade and the Steel-Trap

The fur business has been pursued so recklessly that the fur-bearers of
every civilized country have been almost completely wiped out. The
trapper has gone where he could most easily get the greatest money return;
until quite recently, he has trapped with little regard to season; and he has
relentlessly tracked down the scarce survivors of high-class fur-bearing
animals, regardless of sentiment, reason, or law.

Professor H. Fairfield Osborn, late President of the American Museum
of Natural History, said: "Nothing in the history of creation has paralleled
the ravages of the fur trade." The United States kills more fur-bearing ani-
mals than any other country in the world; Russia comes second. Though
furs are, or were, one of our richest natural resources, no accurate figures
can be given of the number of animals killed annually. Only a few states
require reports from trappers; and it must be remembered that licensed
trappers are not the only ones who trap; the Biological Survey says that
"the large majority of trappers are farm boys and farmers"; trapping in its
most cruel forms is a pastime of every rural section.

The Department of Agriculture estimates that sixty million animals are
killed yearly in the United States, or two animals every second. This De-
partment values the fur production of the United States at sixty million
dollars yearly. And in addition to the animals on which these figures are
based, are those other trapped creatures that are killed and discarded be-

384 READINGS IN BIOLOGICAL SCIENCE

cause their pelts are not prime, or because in the days and nights of torture
in the steel-trap they have so torn themselves as to be worthless for the
market. Probably for every marketable pelt, two other animals are killed
and left to rot.

America was first explored by fur traders; their wilderness trails are
now our great highways; their far-flung outposts have grown to be our
great cities; the romance of their names is written on the map of almost
every state. The profit on furs from Louisiana and New France helped
to build Versailles. Beaver skins were currency; and these riches fostered
the heartless display of the French Court. But the extravagance of the fur
trade of those days, when the wealth of the wilderness was barely tapped,
was as nothing to the killing of fur-bearers that goes on today. Stand at
the door of any fashionable church any Sunday in winter (or even in sum-
mer), and count, if you can, the skins of dead animals that come forth into
the sunshine, often two hundred or more in one garment, on the backs of
the worshippers. When we consider the fur trade, we marvel at the short-
sightedness of business men who have so looted their resources. In the
United States and Canada few valuable fur-bearers remain. The trade seeks
its pelts further and further to the northward; and, unless restrained, its
trappers will one day take the last fox that vainly tries to conceal its white-
ness against the snow on the polar ice.

Besides being wasteful, steel-trapping is attended by torturing cruelties.
It is universally recognized that the steel-trap, chief implement of the fur
hunter, causes intense and long-drawn-out suffering to its intended victims,
and is besides a menace to small domestic animals. Dogs often get into steel-
traps, and lose a foot, or leg; a case is on record of a dog remaining in a trap
fifty-five days; in which time hunger, thirst, starvation and torture reduced
its weight from sixty-five to fifteen pounds. Put the trapper in a bear trap
and leave him there a week, and he will have a greater appreciation of what
he is doing. To leave traps uninspected, certainly longer than twenty-
four hours, should be an offense subject to severe punishment. The man
who will set a trap and leave it unvisited for a long period, or worse, even
forget about it entirely, is too irresponsible to be allowed to trap at all. .

The fur trade and its allies, the manufacturers of steel-traps, cannot plead
ignorance of the situation. By the trappers' and furriers' own admission,
the American fur crop is only about 50 per cent, of what it was some twenty
years ago — and everyone knows it had vastly decreased even then. The
Department of Agriculture has warned us that even "the remnants of our
rich fur resources are fast dwindling," a report of the Bureau of Biological
Survey states: "The annual turnover in the retail fur trade has shrunk from
$5,000,000 in 1929 to $1,500,000 the past year.* " Take the muskrat, for
instance. It was once so plentiful, and is so prolific that the supply was
thought to be inexhaustible. The muskrat is Louisiana's chief fur resource,

• 1935.— Ed.

ECONOMIC BIOLOGY 385

and Louisiana has made research to determine how best to foster the musk-
rat, her most valuable asset; yet the catch of muskrats in Louisiana fell from
six million in 1930 to two million in 1935; and the catch for 1936, is said
to be 40 per cent, or 50 per cent, less than that for last year.

The American Trappers' Association has a program embodying certain
desirable principles such as the elimination of unnecessary cruelty in trap-
ping. It opposes the use of poison baits, and unfair methods of capture, such
as smoking, den-digging and tree-cutting; it advocates protective laws;
and urges the protection and improvement of environment. This program
is, however, but a single "voice crying in the wilderness"; the trapping of
fur animals is carried on by so many individuals scattered in remote dis-
tricts that propaganda can reach only a limited number; and any form of
compulsion reaches only a very few. The tone of the voice, moreover, lacks
sincerity, threatening as it does any "fanaticism," such as the prohibition
of the steel-trap, which might be detrimental to the interests of the trappers
and traders.

Exploitation by the fur trade, together with hunting for "sport" and
"vermin control," has either extirpated, or dangerously reduced in numbers,
all the more valuable species of mammals indigenous to the eastern United
States. The sea-mink and the fisher have been practically exterminated in
this territory; the marten has been brought to a state of great rarity; and
otters and wildcats of two species persist only in small numbers and very
locally.

The beaver, at one time practically exterminated in our eastern states,
has responded to a determined effort to protect it, mainly by the reintro-
duction of colonies; so that there has resulted an encouraging increase of
beavers in some states. This shows that the public cmi he induced to recog-
fiize the plight of the fur-bearers, and can be persuaded to do somethiyig
effective to remedy the situation. Strict regulations should protect such
animals as skunks, rabbits, raccoons and opossums; beavers and foxes should
be given closed seasons that shall last over a period of years, until the animals
shov,' encouraging increase. Mink, marten, wolverines, fishers and otters
should be given complete protection ^ for an indefinite period. The rare
fur-bearers can be preserved, if preserved at all, only by absolute protec-
tion requiring that, regardless of value, trappers stay their hands, and deal-
ers forego tempting profits.

Propagation of fur animals is a logical and legitimate means of meeting
the demand for furs, but unless a system is devised of confining the mar-
keting of rare furs to those actually produced in captivity, and of excluding
a boot-legged wild supply, fur farming will not prevent the extermination

1 "The fur of the marten sells for high prices and always commands a good market.
The American Marten is close kin to the famous Russian Sable." — H. E. Anthony:
Field Book of North American Mammals.

In January, 1936, New York State passed a law closing the season on "otter, fisher,
marten {sic) or sable."

386 READINGS IN BIOLOGICAL SCIENCE

in the wild of any species on which there is a considerable premium. The
only real hope for the preservation of the rare fur animals is the end of
the practice of wearing their pelts. Giving up the wearing of the feathers
of wild birds was all that prevented the extermination of many species
by the millinery trade; and giving up the wearing of valuable furs is all that
will save the rare animals.

To conmiercialize any ivild creature is the surest way to bring about its
extermination.

KILLING FOR FUN

^^Sportf'^ ''SportS7ne7j" and "Sportsmanship'^

Among the smaller mammals, the chief prey of the hunter includes the
squirrel, rabbit, opossum, raccoon and fox. The hunting of each of these
animals is characterized by abuses and cruelties that would not be permitted
if man were really civilized, or as the dictionary quaintly puts it, "reclaimed
from the savage state."

It is customary in some regions to seek the winter nests of squirrels after
the leaves are off the trees, (an easy matter requiring no exertion or acu-
men), and then to blast the nests with the myriad-pellet discharge of a shot-
gun. The nest is a large target that cannot well be missed, and its occupants
are victims that have no chance of escape. Sport? Perhaps so, in the estima-
tion of hopelessly deficient morons. For appraisal, however, contrast this
method with that of the old time rifleman. He secured the squirrel needed
for an occasional stew with the aid of a muzzle-loading rifle; he never
thought of shooting-up a squirrel nest, and he prided himself upon a skill
that avoided mutilation of the animal. He stunned or killed it by placing
the single bullet on which success depended in the bark close to the squirrel,
a practice so widely followed as to call for the addition to the vernacular
of the phrase "barking squirrels."

Nor is importation a solution of the problem of game maintenance. Im-
portation is proof that regulation of hunting activities either has failed,
or has not even been attempted. Where hunting is not regulated, importa-
tion can at best be only a stop-gap. The importation of rabbits is a serious
indication of the depletion that must surely be overtaking other species
that have a much smaller reproductive capacity. Nor will there always be
"sucker states" that will permit their stocks to be commercialized out of
existence. Years ago, certain states allowed the wholesale trapping and sale
of Bobwhites. Try now to find such a state; there is none, though in 1935
Mexico foolishly permitted us to import 23,358 Bobwhites which were sent
to twelve states. Soon, the importation from state to state of rabbits will
also have to be abandoned.

The use of dogs in the pursuit of the raccoon (and of the opossum) is

ECONOMIC BIOLOGY 387

universal, and the term ^cooii dog is everywhere understood. In the crisp
autumn nights, 'coon hunting with its hghts and flares, its rough and tumble
chase, its shouting of men and baying of hounds, takes its devotees for a
time to another world. It has a strong appeal for some men, otherwise
civilized, and entitled to be ranked among the better classes.

Among those who cannot plead the need of food but who hunt just for
the fun of killing, 'coon hunting is attended by grave abuses. Carried on
at night, and followed wherever the chase may lead, the permission of land-
owners is rarely obtained, if a 'coon or 'possum is "holed up," a tree will
be cut into; and, if "treed," the tree often is felled. This destruction is an
aggravation of trespass, and is something the perpetrators would bitterly
resent if done on their own property. Caustic criticism has justly been
passed on those who will cut down a tree (not their own) worth ten dollars,
or more, in order to get a two-bit 'possum.

From a humane point of view, the practices of 'coon hunting are a sad
throw-back to a barbarous age. The treed victim is either shaken out, or
dropped by felling of the tree, into a pack of eager, yapping dogs, where
it is literally torn to pieces while yet alive. We pretend to regard with
scorn the barbarities of the arena as conducted under the Roman Empire,
but many of the things we countenance today are just as bad; and this rend-
ing of raccoons by dogs, in order to provide amusement is a deplorable
example of barbarism.

The finish by rending is characteristic also of fox hunting, where the
animal is so mangled by the dogs that only the very hairy tail, or brush,
which is of no interest to the bloodthirsty hounds, remains for a trophy.
Fox hunting is participated in by both women and men, and is often an
important social event.

KILLING WITHOUT WARRANT

Fropagcmda versus Facts

The gun and ammunition manufacturers and the trades that cater to
"sport" have organized a shameless campaign of propaganda against wild
creatures. The "sportsmen" have shot the wildfowl and the upland birds
so wilfully and so recklessly that game bird shooting is near its end. Years
ago the industries realized that new targets must be found, if the sale of
sporting goods was to be maintained.

Propaganda was first directed against the birds of prey, the eagles, hawks
and owls; in consequence, they too are fast disappearing; and the relentless
cruelty of false propaganda is now being directed against the little animals
of the fields and woods, hitherto rightfully regarded as the friends of man.
Publicity is distributed through the medium of the rod-and-gun columns
of every city and county newspaper, and the magazines of the out-of-

388 READINGS IN BIOLOGICAL SCIENCE

doors which, while purporting to glorify nature, never forget the sources
from which come their advertisements.-

The Game and Fish Departments of various states also stimulate hatred
toward many wild creatures. This is done in order to curry favor with the
sportsmen and trappers, for the money paid for licenses supports the game
departments. Nature lovers are taunted with the fact that they contribute
no state or federal funds for wild life protection; but officials generally
turn an ear of stone to any proposal that would admit the general public,
and especially the women, to a share in wild life protection.

The shooter of upland birds is the relentless foe of the small animals of
field and woodland. Any bird or animal that might under any circum-
stances take a game bird, or the egg of a game bird, comes under the ban
of extermination by "sportsmen." The ignorance betrayed by the propa-
ganda of "sportsmen" and game-officials is profound. Ignorance may be
understood, though not excused, in game-officials; they are political ap-
pointees, and in many instances have had no training in biology. The honest
ignorance of an honest official can be enlightened; and many game-officials
are now numbered among the more intelligent conservationists. But what
hope is there of enlightening the "sportsmen," often college graduates, who
cannot grasp the fact that game and predators lived side by side on this
continent in untold abundance until the coming of man; that game has
disappeared not because of bird and animal predators, but because of the
unbridled predaciousness of men, of "sportsmen" — of themselves.

The emotions of the farmer are played upon with skill. Rodents and
insects are the enemies of the farmer — every child knows that; but the
farmer is persuaded to kill the very animals that would destroy for him the
pests that.^ost him the greatest loss. First the skunk must be killed, and the
farmer is told that the skunk habitually steals the eggs of poultry. He may
do this — but rarely. There are "rogues" among all creatures; an egg-stealing
skunk may easily be caught in a box-trap, and destroyed. Why kill every
skunk? A dog may be found killing sheep, but a farmer would not be
justified in killing every dog. Skunks eat mice, and the skunk that is seen
about the poultry yard may be mousing. Large insects, crickets, beetles
and grasshoppers, serious pests of the farm, are the chief food of the skunk.
"Sportsmen" accuse the skunk of eating the eggs of game birds. At the
season when game birds are nesting, insects are plentiful, and the skunk
rarely seeks other food; often game birds are known to nest close to the
den of a skunk without being molested. The University of Michigan exam-
ined the stomachs of 1700 skunks, and found not a trace of a game bird

2 One notable exception is Nature Magazine. It does not accept advertisements of
merchandise destructive to wild life, and its editorial policy courageously demands the
protection of wild creatures.

feCONOMiC BIOLOGY 389

Foxes are accused of preying on game birds. The U.S. Biological Survey
made a special investigation of the food habits of foxes; it reports that foxes
take few game birds. In Michigan on a certain 800 acre game preserve,
stocked mainly with pheasants, an investigation was made of the food habits
of the fur-bearers occupying the same territory. It was found that the
bulk of the food of foxes was meadow mice and rabbits. In only six out
of sixty-eight fox droppings were the remains of pheasants found with
certainty.

Among the interesting and comparatively harmless mammals that are
being shot and poisoned from our forests, the American Porcupine stands
out as notable in many respects. It is found only in North America, and
mainly in those sections where coniferous trees are common. The wilder-
ness dweller regarded the porcupine as a friend, for it assured food to an
unarmed person who by any accident of fate might become lost in the
wilderness.

But when, about twenty years ago, the craze for the destruction of preda-
tors and rodents broke out, the porcupine could not long rely on what
little pity or tolerance could be demanded by an animal so poorly de-
fended, and which was known to carry barbed quills, and to bite trees. It is
noteworthy, however, that, although experiments in the control of por-
cupines by poison were instituted by the Biological Survey in 1922, the
animal did not attain headline importance until three years later, when
both the Biological Survey and the Forest Service seemed to awake to the
value of the porcupine as material for "control" propaganda. Within the
next few years, porcupines were declared to be increasing rapidly; and
soon were alleged to be a forest danger, sometimes greater than that caused
by fire, and also to be an enemy of several farm crops.

By this time, a salt and strychnine combination had been perfected that,
unless its use is curbed, threatens to "control" not only the porcupine, but
mammals of many other species so unfortunate as to share the habitat of
the porcupine, and to possess a liking for salt. In a certain cooperative
project in northern Pennsylvania, it was charged by competent local or-
ganizations that squirrels, rabbits and deer were killed by the salt-strychnine
baits put out for porcupines.

The Woodchuck, the eastern representative of the Marmot, lives fa-
miliarly in the meadows and pastures of the farm. It eats hay, clover and
other vegetation, taking a small toll of which no farmer complains. Its
habit is to sit motionless at, or nearby, the entrance of its burrow until
closely approached. A little boy with a .22 rifle may employ some skill
when engaged in a "careful and close stalk." But how degrading it is for a
grown man with a high-powered rifle to stand at a distance of 100 to 200
yards, and shoot this harmless, motionless creature.

390 READINGS IN BIOLOGICAL SCIENCfi

KILLING FOR GRAFT

Bounties

The belief is held that putting a price on the head of any species is a
certain way to reduce its numbers — and with rare species it certainly works
out that way. Often, however, frauds connected with bounty laws pre-
vent the accomplishment of the purposes of the legislation. Among the
more flagrant frauds is the manufacture of "scalps"; where the require-
ments do not strictly define the part of the animal to be presented for
bounty payment, many "scalps" may be made from a single animal. An-
other common way of "beating" bounty laws is to import "scalps," per-
haps from another State; and what is in eff'ect the same thing, is the paying
of a bounty on a migratory species. The supposed benefit, were there any,
to be derived from the killing of the creature, would accrue to some state
other than the one paying the bounty. For instance, it is altogether proba-
ble that crows killed for bounty in northern winter roosts are mostly nest-
ing inhabitants of Canada; a state paying a bounty on such crows, would
benefit (if there were any benefit) another nation.

Notwithstanding these objections to bounty laws, in 1935 twenty-eight
states still retained these archaic and harmful provisions. For common
species, the usual result of bounty laws, because of defects in their adminis-
tration, is the continued payment year after year of about the same number
of bounties, showing that the procedure is upon a cropping basis, and no
reduction in numbers is being accomplished. Where rare species are con-
cerned, the bounty is higher, the incentive to profit by it is much greater,
and the effect of the law is toward elimination of rare animals.

When species already have difficulty in maintaining themselves, bounties
are a finishing stroke. States usually deny that their object is the extermina-
tion of any creature, but nevertheless bounties are actually exterminating
numerous species. So, from the state's point of view, if their denial is sin-
cere, why are bounties paid? Our forefathers trapped an occasional weasel
that molested poultry, or shot an occasional fox for the same offense. They
did not think of rushing to authorities for aid, or having "control" subsi-
dized by the state. No, these refinements were left for their more politically
minded, and truly, even if unconsciously, communistic descendants.

As graft, bounties are nothing to brag about; they are, moreover, ecologi-
cally unwise and economically unsound; they are without warrant when
they concern animals with pelts of high value, the incentive for the de-
struction of which is already so great as to threaten the existence of the
species.

Bounty payments are entirely indefensible; by their means unique and
interesting species are, here and now, being exterminated, being banished
forever from the land of the living.

ECONOMIC BIOLOGY

"vermin" control

391

Trapping, hunting, bounty-grabbing and "vermin" control are the most
important of man's activities that are directly destructive of our small
mammal population; and the most destructive of these is "vermin" control.
This has not always been so; "vermin" control is a recently imported in-
novation, and was at first confined to a relatively few hunting estates and
game farms. These institutions have now increased in number, and have
intensified their destruction of "vermin"; prize contests in "vermin" kill-
ing, the result of propaganda, and stimulated by ammunition manufactur-
ers, have increased all over the country. So-called, but one cannot imagine
why — "conservation" departments are encouraging state-wide "vermin"
campaigns that are destroying small animals and other wild creatures liter-
ally by the hundreds of thousands; while the control campaigns of the
Biological Survey wipe out animals by the millions.

It must first be said with all possible emphasis that there is no justifica-
tion for state-wide killijig of a?iimals as ^'vermin.'' "Vermin" is a game-
keeper's name for the natural enemies of game; game species are a very small
minority of the wild life population of any State; and hunters in most places
constitute but a minority of the human population. For gunners to assume
that suppression of any and all creatures that they imagine inimical to their
"sport" (a minority indulgence based on a minor element of wildlife) must
be carried on over the state in general, is sheer arrogance that should be
sharply curbed. Their payment of nominal fees to state game departments
gives them no right to go roughshod over public interests. Game is a
product of the land, and an asset of the landowner; its production is not
paid for by license fees going into the state treasury; and its taking with-
out compensation is imposition. If its production were really paid for,
gunners would find that their license fees would purchase very little. Not
only game, but all that the wild life hunters recklessly slaughter as "ver-
min" is a product of the soil, and the landowner's interest in it is paramount.
It is his right not only to insist that all protective legislation be obeyed, but
also, by invoking trespass laws, to prevent any and all killing of wild life
on his property.

"Man's inhumanity to man" aroused the inspired scorn of a great poet,
but what could he say that would properly castigate man's inhumanity
to the small and defenseless creatures of the wild? Every state of the Union
has exterminated some of the forms of wild life inhabiting it when white
men took possession, and every state right now is pushing other species
into the abyss of extinction. Much of the destruction is being accomplished
or instigated by minorities of the population, by cliques, seeking only their
own advantage, or sadistic pleasure. The immolation of wild hfe on the
altars of fashion, sport, industry, and politics is accomplished by incon-
ceivable cruelty. An intelligent people will not permit the wanton waste

392 READINGS IN BIOLOGICAL SCIENCE

of their valuable resources; a humane people will not wittingly tolerate
such savagery. May the American people rouse before it is too late; may
they demonstrate that the public is both intelligent and humane; may they
irresistibly assert their interest in our wild life, and end forever the ex-
travagant, the unwarranted, the cruel and unpardonable persecution by
hunters and trappers, "sportsmen" and "vermin" killers, of useful, and for
the most part harmless wild creatures.

■>>■><<<■•

THE ITINERANT EEL *
PAUL BULLA

Off the North American continent, southeast of Bermuda and northeast
of Puerto Rico, lies a tract of slowly swirling water known to mariners
as the Sargasso Sea. Here according to song and story the Gulf Stream
is born, and here far below the weed-choked surface is the breeding and
spawning grounds of our own fresh-water eel.

Here these strange fish have their rendezvous. In this sea within a sea
they are born, and here, after years spent in far places, they return to repro-
duce themselves and die, for no spent eels have ever been seen, and adult
eels have never been known to run upstream.

Of all the fish known to mankind, few have a more remarkable life his-
tory, and none have puzzled scientists for so long a time as have these snake-
like denizens of the rivers and lakes of Europe and America. Down through
the ages they have been a food delicacy in the European and Mediter-
ranean countries, but centuries passed before their migratory habits and
method of propagation were explained. Each autumn uncounted numbers
of these slimy creatures moved downstream to the sea, where many were
caught in the nets of fishermen awaiting their migration. But great numbers
avoided this fate and disappeared never to return.

In the spring and summer of each succeeding year, tiny eel-hke creatures
appeared from somewhere in the vast ocean spaces and swarmed along the
coast of Europe and through the Straits of Gibraltar into the Mediter-
ranean. Later they entered the fresh-water streams and rivers that ran
down to the sea, penetrating to the interior where they grew to maturity.
Confusion further confounded the minds of scientists and simple fisherfolk
alike by the fact that eggs of unborn eels were never found in the bodies
of adults and males of the species were never seen.

Many strange theories were advanced in explanation of how they were
produced, ranging from spontaneous generation to the transformation of
horsehairs into little eels. Aristotle, in the fourth century b. c, held that

* Reprinted by permission of Natural History Magazine and the author. Copyright
1942,

ECONOMIC BIOLOGY 393

eels were born from earthworms, which were, in turn, produced from
mud or damp soil. The early Greeks, failing to find spawn or male repro-
ductive glands within the eels, named Jupiter as the father, as all children
of doubtful parentage were ascribed by them to this god.

Pliny the Elder, great Roman naturalist and author, declared with con-
viction that eels had neither masculine or feminine sex. In accounting for
their multiplication he concluded that they rubbed themselves against
rocks, and the pieces scraped from their bodies came to life as little eels.
He dismissed the subject as a matter for further controversy with the la-
conic statement that "they have no other mode of procreation." With the
acceptance of such beliefs it is small wonder that centuries elapsed before
such theories were dispelled and such superstitions overcome.

It was not until 1777 that the ovary of the eel was first recognized by
Carlo Mundini, a professor of anatomy at the University of Bologna, thus
definitely establishing a female sex. Ninety-five years later Reinhold
Hornbaum-Hornschuch announced the discovery of a male individual, and
the enigma that had endured for over 2000 years was on its way to being
solved.

But while these discoveries partly answered the riddle of their existence,
where they came from and how they were produced still remained a
mystery. It was left to a German named Johann Jakob Kaup in 1846, to
find in the sea a small ribbon-like fish with a tiny head. Curious as to its
species, he took it home and placed it in a bottle of alcohol. After labeling
it Leptocephalus brevirostris, a name which exceeded the length of the
specimen itself, he left it there to be forgotten.

Half a century passed before the subject emerged from the obscurity
into which it had been relegated. On a day in 1896 two Italians, Gracci
and Calandrucci, found one of Kaup's little fish in the Mediterranean, but
one much larger and more fully developed. This they identified as the
leptocephalus or larva of the edible eel that inhabited the streams of the
European continent. With that beginning the stage was set for a Danish
scientist named Johannes Schmidt.

As Director for the Danish Commission for the Exploration of the Sea,
Schmidt sailed in 1906, on the first of many subsequent expeditions, to lo-
cate the breeding and spawning grounds of this specter of the deep. For
fifteen years he towed nets up and down the Atlantic, taking specimens
of leptocephali from the English Channel to Chesapeake Bay, and from
Greenland to Puerto Rico. Over this vast area he collected and correlated
sizes of eel larvae, carefully noting the latitude and longitude in which they
were obtained.

He reasoned that the larvae were growing as they moved from the place
in which they were spawned toward the coast and their fresh-water homes.
It followed, therefore, that the smaller the larvae found in any part of the
ocean, the nearer such specimen must be to the place where it was born.

394 READINGS IN BIOLOGICAL SCIENCE

After years of tireless effort he was able, through this method, to fix the
breeding and spawning grounds of the European eel {Anguilla vulgaris)
and the American species {Anguilla rostrata) within the latitudes 20-30 de-
grees north and longitudes 60-78 degrees west. He further established the
fact that the European beds overlapped those of the American species.

But this discovery uncovered but one phase in the life cycle of the eel.
During the period of growth in the waters of their home continent, both
males and females are a uniform green to yellowish-brown above, shad-
ing to a pale dirty white beneath, and are called "yellow eels." When the
migratory instinct asserts itself at the breeding stage, which is in the autumn
when they are between the ages of seven and fifteen years, the sides of
their bodies take on a metallic sheen and their backs become a deep black.
This is their breeding dress, and they are then known as "silver eels."

Upon assuming this dress certain other marked changes take place in
the females. Their snouts become sharp, the eyes larger, and the pectoral
fins, just back of the gill slits, more pointed than usual. Although they have
been voracious eaters all of their lives they cease feeding at this time, and,
leaving the lakes and rivers in which they have lived, move downstream
to the sea. But while these visible changes have been taking place, it is not
until after they have reached salt water that the ovaries mature. In fact
no perfectly ripe female eel and only one ripe male has ever been seen.
Upon arriving in the bays and estuaries of their home shores they are joined
by the mature males that have been living there, and together they start
the journey back to their birthplace over 2500 miles distant.

It is not known how far below the surface they swim, but somewhere
beyond the continental shelf they pass from the range of observation.
Neither is it known how long it takes them to reach their destination, but
it has been estimated that the eel requires about six months to make the
crossing, swimming at the rate of one-half mile an hour. As the migration
from the European continent begins in early autumn, and spawning starts
in early spring at the breeding grounds, this estimate of the period of time
seems to be justified.

Upon arrival at the breeding grounds, the European species find that
they must share it with their American cousins whose beds overlap their
own, but extend westward from it. From Labrador southward to Panama
and the West Indies, the "silver eels" from America have journeyed to
the rendezvous in from one to two months after reaching salt water. Hun-
dreds of fathoms below the seaweed-clogged surface of this tropical sea
the eggs of both species are spawned; the females producing from 5-20
million tiny eggs, transparent and almost colorless.

Spawning begins in late winter or early spring, and a week or so after
fertilization the eggs are hatched and larvae of both species begin hfe with
a length of about one-fourth inch. Ribbon-like in shape and so transparent
that newsprint can be read through their bodies, they float for a time from

ECONOMIC BIOLOGY 395

600 to 900 feet below the surface. Later they rise into the upper layers of
water and slowly move northward. Reaching the latitude of Bermuda, a
separation occurs. The larvae of the European species move eastward on
the long journey back to their native shores, while their tiny American
relatives turn toward the coast line of America.

During their first summer of life the European larvae are found in the
western Atlantic. By the second summer they have reached the central
Atlantic, and by the third they have arrived off the coastal banks of Eu-
rope. During their two and one-half years in the ocean, they have attained
a length of from two to three and one-half inches, but still retain their flat,
leaf-like larval form. They are now faced with a new way of life and must
be prepared to meet it. In the course of the autumn and winter a meta-
morphosis takes place. They cease feeding, lose their larval teeth, shrink
in depth and length, and become elvers or little eels. While they are shaped
like their parents in miniature, they are still transparent, and so are known
as "glass eels."

Our American eel has a shorter larval history. Here again the timing is
perfect, for it reaches its home shores and the elver stage of existence in
about one year.

After the transformation from larva to elver, the females of both species
ascend the fresh-water streams of their native land to live their lives in the
interior until the moment when the migratory instinct drives them back
to the sea. In these journeys upstream they use pipe lines and sewers and
clamber over falls and surmount dams to reach their destination. The males
however, remain in the brackish waters of lagoons and estuaries, where
they grow to maturity, and await the downstream migration of the fe-
males.

As eels have been found in ponds having no outlets or inlets, it is be-
lieved they will travel overland to reach these oases, choosing nights when
the grass is damp for the journey. As there is no evidence to establish this
presumption, their presence in these isolated waters is still something of a
mystery. They are also at home in high as well as low altitudes, having
been found in Swiss lakes 3000 feet above sea level.

All eels in the headwaters of large streams are found to be females. As
a rule they lie buried by day in the muddy bottoms where there is still-
water, and venture to feed abroad at night. Being scavengers and omniv-
orous, they will eat almost any available food, either living or dead. They
have even been known to eat their own kind.

Female eels average from two to three and one-half feet in length, but
have been known to reach four feet and weigh as much as sixteen and one-
half pounds. A4ales average around fourteen to eighteen inches in length,
but never grow larger than two feet. The vertebrae of these fish mark the
only difference between the American and European species; the former
have an average of 107 segments, while the latter averages 1 14.

39<5 READINGS IN BIOLOGICAL SCIENCE

Differing from their salt-water cousins, the lower jaw of both species
projects beyond the upper, while the large mouth gapes back to a point
even with or somewhat behind the eyes. On the side of the neck are gill
slits with upper corners on a line with the center of the base of the pectoral
fins. A single fin, soft and without spines, extends along the back, around
the tip of the tail, and forward on the underside of the body. There is
no separation into dorsal, caudal or anal parts. After the third or fourth
year of life, eels develop small scales that are imbedded in the skin. These
are covered with a coating of slimy mucous, which has given rise to the
simile, "as slippery as an eel."

Perhaps the most intriguing part of the life cycle of this unusual fish
is that neither European nor American elvers have ever been known to
appear off the shores of any country but their own. This fact immediately
presents two puzzling questions that challenge the imagination.

1. What causes the immature larvae of the European species to move
eastward from the spawning grounds, while its American cousin works
toward the west side of the Atlantic?

2. How does it happen that the timing is perfect for both species to
reach the elver stage within a few months after arriving off the coast of
their home continent?

These may be answered in part by the difference in their individual larval
histories.

While the European larva requires from two and one-half to three years
to reach the elver stage of development after life begins, the larval stage
of the American species is terminated in about one year. This time element
not only acts to keep the two species distinct, but makes it practically im-
possible for either to survive in waters other than their own after meta-
morphosis takes place.

Should the larvae of the European eels move westward they would reach
the American coast line still in an undeveloped larval stage; while the
American species traveling eastward would reach the elver stage some-
where in the western Atlantic when the time arrived for them to seek
fresh-water retreats.

A geographic cause for their distribution is advanced by Doctor Schmidt
who points out that the center of production for the American eel lies
farther west and south than the center of the European beds. These, to-
gether with the movement of the ocean currents as an aid to the journey
in the early stages of larval development, must be considered as causes
directing the two species to its own side of the ocean.

While much has been learned of the habits of these sluggish, sedentary
fish, since the turn of the century, much remains unexplained.

With a singleness of purpose and an unerring instinct that has confused
scientists, untold thousands have deserted their home waters each autumn
to seek adventure in a tropic sea and to keep their rendezvous with death.

ECONOMIC BIOLOGY 397

Weak and Immature, their progeny is cast adrift far from its native land
and, unguided, these feeble swimmers travel a road over which they have
never journeyed, to reach their home continent.
Truly, the eel is one of the greatest of marine mysteries.

■>>><<<■

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XV

Biological Philosophy

IT has been correctly said — "there is a direct relationship between the
content of the human mind and world events." The way in which men
think determines largely whether we shall have war or peace, whether
we shall have progress or poverty. A course in biological science should
do more than teach biological principles; it should teach scientific logic,
the habits of suspended judgment and tolerance, and the fallacies of com-
mon superstitions. It is becoming clearer, I hope, that there is a fine correla-
tion between the above mentioned qualities and statesmanship. Not that
we believe the best statesmen are necessarily the scientists but the qualities
of common sense and forbearance and the belief in the oneness of human
knowledge that characterize the true scientist are essential for good leader-
ship. How often do we see our chosen leaders preach race hatreds and
intolerance, how often do they promulgate laws for the good of minorities
at the expense of the masses, how often do they twist facts to suit their
purpose?

Biological science can and should deal with the philosophical aspects
of nature. Is truth static or subject to change? How did man evolve — and
where and when? Is man changing now and if so is he improving physi-
cally or degenerating? Does science teach moral values and does it attempt
to take the place of religion? These are questions which the scientist should
be best able to discuss if not answer satisfactorily because they are in the
realm of science, A broad background is necessary to see all the implications
in these problems. Science has often been accused of assembling the data
and then allowing unqualified people to interpret it. They have also been
accused of being indifferent to the uses to which their discoveries were
put. Both of these accusations have a good deal of merit. It is heartening
to see some of the leading scientists of the country raising their voices in
an effort to interpret and direct the products of their toil.

398

BIOLOGICAL PHILOSOPHY 399

THE LIVING MACHINE *
R : T . YOUNG

Is there one law for the living and another for the dead, or is the universe
a unit in its workings and all matter governed by universal law? The former
is the contention of the "vitalist," the latter of the "mechanist." What is
life? Is it some inscrutable process, controlled by a "vital principle" operat-
ing outside the realm of physics and of chemistry? Or is it merely a special
expression of the forces which control inorganic matter. Our only answer
to these questions is that we do not know. Neither the substance nor the
energy of life has ever been analyzed, and the only way in which we can
identify life is by its manifestations. What are these manifestations, and
what light if any do they throw upon the ultimate nature of life itself?

Firstly, what is the stuff of which living things are made? An analysis
of living substances or protoplasm is exceedingly difficult if not impossible.
In order to analyze it, it must be killed, and the readiness with which the
protoplasm breaks down into innumerable simpler substances leads us to
suspect that after protoplasm is killed it is protoplasm no longer, so that
we are analyzing not protoplasm at all, but something else. Our analyses
are sufficient to show us however that protoplasm contains the same ele-
ments of which inorganic matter is composed, united into a marvellously
complex whole. The manifold varieties of life which we know lead us to
believe in as great a variety of protoplasm which determines this variability
in living things. In spite of its variability however all protoplasm alike
contains protein consisting of carbon, hydrogen, nitrogen, oxvgen and
sulphur, without which it cannot exist. Protein however is found outside
of protoplasm in egg albumin for example and in the various albumins and
globulins of the blood. These substances while protoplasmic products are
not protoplasm itself; hence we see that in its composition (in some partic-
ulars at least) living matter does not differ fundamentally from non-living.

One of the most characteristic features of hfe is its power of waste and
repair and growth. It is folly to attempt, as some have done, to compare
these processes in their entirety with any process in the non-living world.
There is nothing with which it can be compared. And yet if we analyze
them into their component processes, we find that they are composed of a
series of chemical and physical reactions, many of which at least can be
exactly reproduced in the laboratory.

In the warm spring days when the remnants of last year's crop of po-
tatoes in the cellar start to sprout, and those which are served upon your
table have an unpleasant sweetish taste, you are the victim of a ferment (or
enzyme) known as diastase, of wide-spread if not universal distribution

• From Biology in America by R. T. Young, copyright 1922 by Chapman and
Grimes, Boston.

400 READINGS IN BIOLOGICAL SCIENCE

among plants, which changes starch, the stored-up food of the plant, into
one of the sugars. When the maple sugar sap is flowing in the spring we
know that a similar reaction has been taking place within the tree, and all
the beauty of the young spring's growth depends upon it. A similar reaction
takes place in our own mouth, under the influence of an animal ferment
known as ptyalin, and present in the saliva of many mammals. But a similar
result can also be obtained in the test tube of the chemist by boiling starch
in dilute acid.

In the exchange of materials between the cell and its environment, its
(the cells) membrane "determines" what substances shall enter and leave
the cell. Thus an uninjured beet may be placed in water without losing
any of its color. But cut the beet and its color readily diff^uses outward.
So in the absorption by roots of substances from the soil and by the walls
of the intestine from the digested food stuffs, the cell membrane exercises
what is known as "selective absorption," taking some and rejecting others.
In the passage of substances between mother and child, through the walls
of the placenta, the cells of the latter exercise a selective function, allowing
food materials and oxygen to pass from mother to child, and waste mate-
rials to pass in the reverse direction. This selective activity of living mem-
branes is strikingly shown by experiments on barley fruits, which are not
killed by sulphuric acid because it cannot penetrate them, but are destroyed
by bichloride of mercury, which readily enters.

In the burning coal of the furnace and in the forest's decaying logs, one
of the final products of combustion or decay is carbon dioxide. So too
when we exhale the carbon dioxide from our lungs we are casting off one
of the end products in the combustion or oxidation of our foods and our
tissues.

Throughout the entire process of metabolism, of growth, repair, decay,
of body of animal and plant is a physico-chemical laboratory in which are
taking place the processes of the non-living world.

Another characteristic feature of living things is their power of move-
ment. This is not evident at first sight in all organisms, notably plants. In
fact, one of the criteria formerly presented as distinguishing plants from
animals was the fixity of the former as compared with the motility of the
latter. This distinction we now know to be false however, for even in the
apparently non-motile plants there is circulation of cell sap, and move-
ments of leaves and roots in response to stimuli; while among animals, the
attached forms such as sponges, sea anemones, barnacles, etc., either lack
locomotive power or possess it in very slight degree.

All living things then are motile to greater or less degree. But is this qual-
ity lacking in the non-living world? Place a diluted drop of ink under the
microscope and it becomes a microcosm of violent activity. Wind and
water are ever active. The earth is flying through space at the rate of i8^
miles a second and the universe is a realm of external motion. Light and

BIOLOGICAL PHILOSOPHY 4OI

sound are expressions of movement, and the electronic theory of matter
postulates that matter itself is a cosmos of ceaseless energy. But the vitalist
tells us that living matter possesses "spontaneity," which is lacking in the
non-living world. The living thing moves of its own "volition," the non-
living only under the influence of forces external to itself. But what evi-
dence have we of "volition" on the part of an Amoeba or a bacterium,
while the energy of the living machine is as truly the result of oxidation
of fuel as is that of the steam turbine or the automobile. Any distinction
then on the basis of motion alone between the world of the living and the
non-living is a fallacy.

Adaptation is one of the characteristic features of life. The bird and bat
are adapted for flight, the fish for swimming, the monkey for climbing:
one need not enumerate, for one cannot name a single living thing which
is not adapted to the conditions of its existence: otherwise it would not
exist.

But are living things alone adapted to their environment? Does not the
river adapt itself to its channel, the lake to its basin, and the gas to the form
and size of its container? Ice exists in winter because it is adapted to the
cold and disappears in summer because it is not adapted to the heat. Adapta-
tion indeed is merely an expression of action and reaction, of cause and
effect. The fact of adaptation in the inorganic world remains however
and when the riddles of life have been solved it is not unlikely that the
process of adaptation of living things can be resolved into simple physico-
mechanical terms, just as surely as can the adjustment of the river to its
channel or the snow drift to the wind.

Yet another manifestation of life is its irritability or power of response
to stimuli. Examples of this are so common that it is merely trite to repeat
them. But is this phenomenon limited to life alone? Does not lifeless matter
also respond to stimuli, or changes in its environment? Examples of such
changes must occur to the mind of everyone — changes in volume or in
state, whether solid, liquid or gaseous, in response to changes in tempera-
ture or pressure, are among the most famihar instances of these responses.
If a metal is heated, its electrical conductivity is decreased, sound travels
faster the higher the temperature, while atmospheric conditions will mate-
rially affect the messages of the radio. While the responses of living things
and changes in their environment are infinitely more complex and indirect
than those of the non-living, yet the same principle holds true for both.

Yet one great characteristic of life remains, namely, reproduction. The
development of a human being with his myriad cells, more varied in form
than the manifold parts of the most complicated machine, ranging in size
from the tiny corpuscles of the blood, less than one four-thousandth of an
inch in size, to the motor nerve cells of the spinal cord, which may reach
a length of over three feet; and including the intricate structures of the
brain by which are performed all the wonderfully complex»functions of the

402 READINGS IN BIOLOGICAL SCIENCE

human body, including the as yet inscrutable processes of thought; all these
coming from an apparently simple cell a little more than one-hundredth
of an inch in size, is a wonder beside which the magic of an Aladdin or the
miracles of holy writ fade into ghostly paleness. The enthusiast in the ranks
of the mechanist has attempted to remove even this most distinctive feature
of living things, by showing that non-living matter may in a sense repro-
duce itself, as new crystals form in an evaporating salt solution. However
feeble such a comparison may be, it is nevertheless true that all phases of
reproduction are all intimately associated with physico-chemical changes
taking place in these cells.

What of the mechanism whereby this wonderful machine of life utilizes
its fuel? Herein lies one of the fundamental differences between the living
and the non-living machine. Whereas the latter uses its fuel solely in the
conversion of potential energy into heat and work, the former, in addi-
tion to these two functions, also converts some of its fuel into its own sub-
stance to take the place of worn-out parts, and to build new parts and en-
large those already formed in development and growth.

Turning from the world of animals to that of plants, we find in the latter
a parallel to all of the metabolic processes of the former. The average per-
son is accustomed to think of a plant in terms of the green thing which he
finds in garden, field or forest. But when we go a-hunting mushrooms, or
poke aside the rotting remains of a fallen tree, we discover other plants
which live a different sort of life from that of the tree or shrub or herb.
And should we delve yet further into Nature's recesses, and penetrate that
hidden world to which the microscope gives entrance, we should discover
creatures concerning whom no one can say whether they are plant or ani-
mal. Some of these uncertain forms are claimed by both botanist and
zoologist as belonging to their own special field of study, for in some re-
spects they are distinctly animal, in others plant in nature.

Perhaps the most fundamental difference between the higher plants and
animals is in their metabolism. While the latter are spenders, the former
are hoarders of energy, taking raw materials, carbon dioxide from the air
and water from the soil, and from these constructing by the energy of the
sun, acting through the green chlorophyll of leaf and stem, their own
food stuffs; thereby converting the radiant energy of sunlight into the
chemical energy of sugar and of starch. From the soil and the air the plant
obtains its nitrogen and from the soil the other inorganic substances which
are used to build its protoplasm, and combining these with the sugar it
builds up its protoplasm. Someday, perchance, the chemist, imitating na-
ture will learn to make our starch and sugar for us, and bid defiance to the
"man with the hoe."

But while most plants differ widely in their metabolism, fundamentally
their ways of life are alike. Both must have food, from the combustion of
which their energy is derived, and from which their wastage is replaced and

filOLOGICAL PHILOSOPHY 40^

growth material obtained. And this food must be rendered soluble and
dialyzable that it may pass through membranes which surround each cell,
i. e. must be digested. While in the higher animal there is a place where
digestion and absorption occur (the digestive tract) and the digestive
enzymes are formed by special glands (liver, pancreas, etc.), in the plant
there is no such specialized tract or glands for the function of digestion
and absorption. There are however certain specialized tubes of cells in the
root, stem and leaf which taken together form "conducting paths" for the
water, with its dissolved salts ascending from the soil, and the sugar de-
scending from the leaves to root and stem, there to be stored as starch.

From the leafy surface of humblest herb and mightiest tree, transpiration
takes place, or the loss of water absorbed by the roots from the soil. The
pressure lifting the water from the soil to the leaf may be as great in some
cases as that which would be exerted on the earth's surface by an atmosphere
six to eight times the thickness of the present one, a pressure sufficient to
support a column of water between two and three hundred feet high.

Various attempts have been made to explain the rise of sap in plants but
as yet with no great success. The evaporation from the leaves and absorp-
tion of water by cells are not adequate to explain the phenomenon. (Lately
the cohesion of water molecules and capillarity occurring in the micro-
scopic stem tubes appear to offer a more reasonable explanation.)

But can physics and chemistry explain the as yet unknown processes of
nervous action; the bewildering complexity of the instinct of bee or bird
or beast, or the yet more amazing intricacies of human thought? To an-
swer this question, as indeed to solve any of the problems of living matter
aright, it is essential that we turn to the lowest rather than to the highest
organism, to those which present to us in their simplest terms, all the funda-
mental processes of the living thing. If the extended processes or pseudo-
podia of an Amoeba, one of the simplest types of living things, be touched
with a finely drawn out thread of glass, the processes are retracted and
the direction of movement of the animal is altered thereby. If on the other
hand the Amoeba comes in contact with some object, which serves as food,
it reacts positively toward it, thrusting out its processes and engulfing the
object. Furthermore Amoeba can pursue its food, so that to the observer
it seems as if this tiny bit of protoplasm, so small that the largest specimens
appear to the naked eye as mere specks of white, were endowed with a
sort of primitive intelligence.

Injurious chemicals cause Amoeba to withdraw from them. Similarly, if
the water on one side of the Amoeba be warmed, the animal will contract
on that side, and thrusting forth its pseudopodia on the other side, move
in the opposite direction. If a weak electric current be passed through the
water containing Amoeba, its behavior is similar to that under a heat stimu-
lus. The side toward the positive pole contracts, while from the opposite
side pseudopodia are extended and the animal moves toward the negative

404 READINGS IN BIOLOGICAL SCIENCE

pole. When starved, Amoeba becomes more active than usual, while after
a heavy meal it becomes sluggish.

One must not however be too sure of the simplicity of an Amoeba. While
to the eye of the microscopist it appears as an "almost structureless mass of
jelly," nevertheless the complexity of the molecules composing this jelly
is such as to defy analysis by the most skillful chemist. And even were it
possible to obtain an exact analysis of the Amoeba molecules, the number
of atoms composing the latter is so great as to render possible several million
combinations of these atoms, each in a different way and each possibly re-
sponsible for every new response which it makes to its surroundings.

The ability of higher plants to respond to stimuli is a matter of common
knowledge. We place a plant in our window and soon leaves and stem are
bending toward the light. The compass plant is a devoted 'worshiper' of
the sun. In the dawn it turns its opening flowers eastward to greet the rising
sun, while at eventide they face the west attendant upon its setting. The
mold Filohohis grows upon horse manure. When its spores ripen they are
thrown by the plant with considerable force, surrounded by the spore
cases, in the direction of the light. If a little fresh horse manure be placed
in a box with a small window, the filaments of the mold turn toward the
window, and as the spores ripen they are thrown in their cases against the
window to which they adhere. A tree is felled by a land-slide or a tornado
and some of its roots are left embedded in the ground. Soon the young
flexible branches turn and grow upward opposite to the direction of grav-
ity. Roots, on the contrary, when placed in a horizontal position, or in-
verted so as to point upward, will soon respond to the pull of gravity and
grow downward. A seedling is suspended with its rootlets immersed in a
stream of water, and soon they bend and grow against the current of the
stream. Touch the leaves of the Mimosa or sensitive plant and almost im-
mediately the paired lobes of the leaflets fold together and the leaf it-
self droops slightly, soon however resuming its original position if undis-
turbed.

Can these responses of the unicellular animals and plants be explained
on a physico-chemical basis? This the leader of the mechanist school in
America, Jacques Loeb, endeavors to do with his "forced movement" or
"tropism theory." According to this theory every organism is in a state
of physiological equilibrium or balance with respect to a median plane
of symmetry, until it is subjected on one side or the other to a stimulus,
such as heat, light, electricity, etc.; which stimulus induces certain physico-
chemical changes, differing in degree on either side of the body, this dif-
ference forcing the organism to respond unequally on the two sides, and
then perform a "forced movement" or a "tropism" (turning). The stem of
a plant turns toward the light, or bends upward, because of a difference
in the amount of chemical substances * on the two sides, and "this causes

• These are now known as plant auxins, hormone-like substances. — Ed.

BIOLOGICAL PHILOSOPHY 405

a difference in the velocity of chemical reaction between (the two sides)."
The organism has no control over its behavior.

But what proof have we that such chemical changes as Loeb assumes do
occur in the organism? If we suspend a stem of a plant in a horizontal posi-
tion, it soon bends downward, taking the form of a U. This bending is not
due to sagging of the stem as a rope sags, but rather to unequal growth of
the two sides, which can be proven by marking equal distances on upper
and lower sides by Hnes of India ink and later measuring the amount of
growth occurring between the marks. If the amount of bending in such a
stem with leaves attached be compared with that in a stem lacking leaves,
it will be found to be much jjreater in the former due to the greater amount
of growth material available, and similarly there is greater bending in a stem
furnished with a complete leaf than in one with a leaf which has been
partly cut away. "What has been demonstrated in this case explains prob-
ably also why the apex of many plants when put into a horizontal position
grow upward, and why certain roots under similar conditions grow down-
ward. It disposes also in all probability of the suggestion that the apex
of a positively geotropic root has 'brain functions.' It is chemical mass ac-
tion and not 'brain functions' which are needed to produce the changes
in growth underlying geotropic curvature."

The purely mechanical response of an animal to stimuli is beautifully il-
lustrated by the behavior of the caterpillar of the butterfly (Porthesia
chrysorrhoea). This butterfly lays its eggs upon a shrub, on which the
larvae hatch in the fall and on which they hibernate, as a rule, not far from
the ground. They leave the nest in the spring when the first leaves have
begun to form on the shrub. After leaving the nest they crawl directly up-
ward on the shrub where they find the leaves on which they feed. If the
caterpillars should move down the shrub they would starve. What gives the
caterpillar this never-failing certainty which saves its life? It is merely posi-
tive heliotropism and the light reflected from the sky guides the animals up-
ward. If we put these caterpillars into closed test tubes which lie with their
horizontal axes at right angles to the window they will all migrate to the
window end where they will stay and starve, even if we put their favorite
leaves into the test tubes close behind them. These larvae are in this condi-
tion slaves of the light.

The light which saved its life by making it creep upward where it finds
its food would cause it to starve could the animal not free itself from the
bondage of positive heliotropism. It can be shown that a caterpillar after
having been fed loses its positive heliotropism almost completely and per-
manently. If we submit fed and unfed caterpillars of the same nest to the
same source of light in two diiferent test tubes the unfed will creep to the
light and stay there until they die, while those that have eaten will pay
little or no attention to the light. It can be shown with a reasonable degree
of probability however that even here what we call "instinct" may be

406 READINGS IN BIOLOGICAL SCIENCE

purely a response to physical and chemical stimuli, modified by certain
substances secreted by the body and known as "hormones" from the Greek
verb honmo, to excite. What are these substances, how are they formed and
what role do they play in animal physiology?

The recognition of the value of certain organs in curing disease goes
back to the days of Hippocrates, the "father of medicine," and since his
time many such remedies have been proposed. Thus the liver of the pigeon
or the wolf were used in cases of diseases of the liver, the rabbit's brain
was given for tremors and the lung of the fox for difficulty in breathing.
The testicles of the donkey or stag were recommended by Pliny for the
renovation of the debauchee. It is now known that one kind of diabetes,
which is marked by the presence of sugar in the urine, is not a kidney dis-
order, but is due to improper action of the pancreas, as a result of which
a specific secretion, passed by the latter into the blood stream and function-
ing in sugar metabolism, is absent or reduced in amount.

Imperfect development of the thyroid gland leads to the condition known
as cretinism. Feeding the extract of the thyroid gland of the sheep, or the
gland itself, either raw or cooked, result in great increase in growth and
development of both mind and body in such cases. Attached to the lower,
central part of the brain is a small gland, the pituitary body, which some
enthusiastic theorists have fancied to be the seat of the soul. If this gland
is partly removed from a young puppy it ceases to grow except for the
accumulation of fat. It keeps its puppy hair and milk teeth, while the de-
velopment of the genital organs and of the intelligence is much retarded.

One of the most striking examples of the role of hormones or internal
secretions is the action of the sex glands in controlling both body form and
mental activity. The physical and mental changes occurring in both boys
and girls at the time of puberty are too well known to require even passing
mention here, while the dependence on the proper functioning of the sex
glands of the secondary sexual characters, such as the horns of the deer,
the comb and feathering of the cock, the size of the stallion, is equally
f amihar to everyone. Horses and cattle are castrated to render them docile
and serviceable as draft animals, and the cock is castrated in order that
he may take on more flesh and become a welcome member of our dinner
parties.

Of all the features characteristic of living matter, none is more so than
reproduction. Attempts have, it is true, been made to compare the growth
of many crystals of salt in a concentrating solution with this miracle of
life, but such attempts sound like a mere play upon words. There is noth-
ing in the inorganic world in any way comparable to this wonderful
phenomenon. Here then, if anywhere in the world of life, we should find
evidence of some force higher than the physical forces, did any such exist.
But what do we find? The method of reproduction (bi-sexual or partheno-
genetic) can be altered by external means; furthermore in Hydra it can

BIOLOGICAL PHILOSOPHY 407

similarly be changed from asexual (budding) to sexual. In some plants
likewise the kind of reproduction can be determined by external factors.
The attraction between the sex cells is in some cases, though apparently
not in all, a chemical one. If a capillary glass tube containing a weak solu-
tion of malic acid be placed in water containing the sperms of ferns and
mosses, the latter are attracted by the acid, and will enter the tube in great
numbers. It is a well-known fact that it is very difficult to cross different
species of animals, this difference indeed being made the basis for a physio-
logical definition of species, those animals which breed together and pro-
duce fertile offspring being grouped as one species; and those which do
not interbreed, or do not at least produce fertile offspring being classed as
distinct. In lower animals union of egg and sperm of different species may
be prevented by physical differences such as size, or chemical differences
may prevent the development of an egg into which by chance a foreign
sperm has entered. Occasional instances of crossing and the production
of fertile offspring are known, in crosses of hares and rabbits, various
species of fish, etc. Loeb has succeeded in cross-fertilizing the sea urchin's
egg with the sperm of several species of starfish and one of the brittle stars,
by simply adding a little sodium hydroxide or carbonate to the water con-
taining the eggs.

Far distant though we be from a solution of the "riddle of life" our only
present hope of ultimate success is to proceed from the known to the un-
known, working on the hypothesis that nature is a unity and not a duality,
and that the same fundamental laws control organic and inorganic worlds
alike.

TELEOLOGICAL ARGUMENTS *
ARCHIE J. BAHM

Arguments for the view that the world has a purpose are many and
devious and based often upon curious and dubious premises. In the fol-
lowing, some of the more typical arguments have been selected, stated,
and "refuted" — refutations consisting of criticisms typically raised against
the arguments. Insofar as the case for the view is refuted, the case against
the view is not thereby established. This case must be established on its
own account. Arguments for the view that the world has no purpose, and
criticisms of these arguments, have not been included here. As to the valid-
ity either of the arguments or of the criticisms, the reader will judge for
himself.

Design. Familiar to all is the argument that "the world has a pattern and

* Reprinted by permission of the Scientific Monthly, American Association for the
Advancement of Science. Copyright 1944.

408 READINGS IN BIOLOGICAL SCIENCE

therefore must have a purpose." Different terms are used to express what
is meant by "pattern," such as "design," "structure," "order." Usually the
argument is stated so as to involve a purposer. For example, beginning with
the assumption that the world has a design, the argument deduces that
"there can be no design without a designer and that if a designer produced
a design he must have done so for a purpose. Thus, if the world has a de-
sign, it must have a purpose."

Critics attack the argument in several ways. They say that the assump-
tion that "the world has a design" is unwarranted. For there is also obvious
disorder and lack of design which cannot be ignored in claiming that the
world as a whole has a purpose, and it is possible that only our part of the
■world is orderly and the rest of the world which we do not know is chaotic
and disorderly, and design may be merely apparent or a product of the
processes of perception in human beings who are uniquely purposive and
yet persist anthropomorphically in interpreting all other things as pur-
posive.

Secondly, critics contend that the assumption that "there can be no de-
sign without a designer" is false. At least some designs are accidental. For
example ink drops folded in paper sometimes appear strikingly symmetrical.
If some patterns are produced unpurposively, then it is at least possible that
such patterns as the world as a whole may have have been produced un-
purposively. Also, perhaps teleologists have been deceived by ambiguities
of the term "design." Sometimes "design" means "intention" or "purpose,"
as when one asks, "What did you design to do?" Here of course, "design"
involves "purpose." But "design" also means pattern apart from purpose,
as exemplified by patterns produced accidentally. Thus deduction of "in-
tended pattern" from mere "pattern" is unwarranted.

Thirdly, critics point out that even if the world has a design and a de-
signer it still would not follow that "if a designer produced a design, he
must have done so for a purpose." For he too might have produced the
world accidentally, or he might be designing the world as a consequence
of some mechanical necessity rather than as a result of purpose. Finally,
even though the world was designed for a purpose in the past, there is the
possibility that it now no longer has the purpose that it once had, because
it may have lost its purpose, or it may have fulfilled its purpose. If so, pat-
terns produced by previous purposiveness may remain without the patterns
remaining purposeful.

Such criticisms seem not to down those who would argue from design.
When attacked, they reply not so much by refuting these criticisms as by
reiterating their argument in a more plausible form. The three following
arguments, from analogy, from complexity, and from evolution are really
variations of, or extensions of, the argument from design.

Analogy. "Even as a watch requires a watch-maker, a building an archi-
tect, an airplane a designer, a vessel a potter, so the world-machine requires

BIOLOGICAL PHILOSOPHY 409

a master-watchmaker, a master-architect, a master-designer, a master-
potter. The number of obvious cases is so large that surely the argument
from this analogy is warranted. Even though it cannot be deduced that
the world has a purpose, still it seems highly probable."

Critics usually grant that there is some evidence from the analogy and
admit that strictly speaking, the conclusion does have some degree of prob-
ability. But the degree is not high. For, while illustrations may be multiplied
tiresomely, they nevertheless are selected examples and represent limita-
tions of man's anthropomorphic perspective. Believers tend to see what
they look for and the evidence presented represents, even though inno-
cently, a "stacking of the cards." One might if he tried find even more
illustrations wherein no analogous purposiveness of parts of the world
were overwhelming, still it would not follow that the world as a whole
is purposive. The argument from purposiveness of parts of the world to
purposiveness of the whole world involves what logicians call the "fallacy
of composition." The fallacy in the argument, "This is a bunch of large
apples, therefore this is a large bunch of apples," and the fallacy in the
argument, "This world is made up of purposive beings, therefore this world
is purposively made up," is the same.

Coinplexity . "Even though some patterns might occur accidentally, man
is too complex and intricate to have just happened. Man's chemical, physi-
cal, biological, physiological, psychological, economic, political, ethical,
aesthetic, and religious interrelations all fit together in multitudes of deli-
cate adjustments. Literary and artistic productions, governments and in-
dustries, moral codes and religious hierarchies do not just happen. Such
amazing intricateness presupposes purposiveness."

Critics respond in four ways. First complexity is relative. To anything
that is relatively complex, something more simple would seem relatively
simple. And to anything that is relatively simple, something more complex
would seem relatively complex. The world is more complex than the minds
which try to comprehend it, so the complexity of the world seems rela-
tively complex to comparatively simple human minds. Relatively simple
minds may be easily amazed. Such amazement at complexity is hardly proof
of purposiveness in complexity. Secondly, the possibility that the world
is one of pure chance, is made up of an infinite number of elements, and
has endured or will endure for an infinite time suggests the possibility that
the number and complexity of possible combinations is infinite. If, then, in-
finite complexity may occur from pure chance, complexity hardly pre-
supposes purposiveness. Similarly, if the world is mechanically determined,
complexity of result merely presupposes complexity of cause, rather than
purposiveness. Critics contend that those who appeal to amazing complex-
ity as proof of purpose merely reveal their ignorance of the complexity
of mechanical causation. Finally, if complexity presupposes purpose surely
it presupposes complexity of purpose. It seems questionable whether any

410 READINGS IN BIOLOGICAL SCIENCE

purpose or purposer could be complex enough to take into consideration
all of the complexities that actually occur. How could such successive series
of so many simultaneous complexities be integrated into a single purpose?
One might as easily argue that the world is too complex to have been pur-
posed as to argue that complexity presupposes purpose. Furthermore, if
the purpose is at least as complex as its purposed product, what purpose
could there be in duplicating the complexity?

Evolution. Although the idea of biological evolution was once ardently
opposed by those who believed it inconsistent with the idea of world pur-
posiveness, it is now appealed to as one of the strongest evidences of world
purposiveness. "Evolution seems directed toward certain ends. Mere com-
plexity may not presuppose purposiveness, but complexity that is going
somewhere does. Evidence of direction is plentiful. Each sta^e of the re-
productive cycle seems to serve the next stage. Each species that developed
seems to have served as a basis for the development of later species. The
history of biological development toward, and to, purposive man surely
must have been for a purpose." Some biologists even appeal to world pur-
posiveness for proof of the previous existence of what some call "missino-
links." These had to be in order to fulfill the purpose obvious in biological
evolution. "Furthermore," some say, "this is a world in which the fit sur-
vive, and since evolution has been rather consistently toward those beings
which are more purposive surely the superior success in survival of the
more purposive beings argues for world purposiveness."

Critics accustomed to defending biological evolution in non-teleological
terms may be somewhat taken aback by this appeal of teleologists to evolu-
tion. However, upon recovery, they contend that biological evolution has
been, and for the most part still is explained without appealing to world
purpose. Thus the idea of purpose is not necessarily to evolution. That
evolution has direction may be admitted, but that direction always implies
purpose may be refuted by pointing out that anything that goes anywhere
goes in some direction. The wind blows first in one direction and then in
another; but this is no evidence of change in purpose or of purposiveness
of any sort. Furthermore, if evolution of species serves a purpose, why have
some species developed only to become extinct? Some have developed not
merely to lay the foundation for higher species in the line of development
of man, but for other lines of development which eventually cease. Do some
purposes end? Is it a part of the world purpose that some purposes end?
Is such purpose as the world as a whole is supposed to have also endable?

Critics point out further that multitudes of simple species continue to
exist to survive, as well as complex and more purposive species. Thus, ap-
parently, development in purposiveness is not essential to survival. Likewise,
even if it be granted more purposive beings survive better than less pur-
posive beings, still it would not follow that such superior success in sur-
vival is for a purpose. Survival of purpose does not imply survival for a

BIOLOGICAL PHILOSOPHY 41 I

purpose. Finally, the argument illustrates human conceitedness rather than
objective fact. The purpose of evolution, as thus interpreted, is to develop
man, and man is the end, the,completion, the perfection of the process. We
accept the teleological interpretation of evolution because it glorifies man
as a superior product which required so many difficult aeons of prepara-
tion. Even those who add that the purpose of the evolution of man is to
serve God do so in the interest of human conceit by saying, or implying,
that man is the chief object of God's attention, and the trouble God went
to in planning such a complicated evolution demonstrates the greatness of
God's consideration for man. But, if man could discount his own conceit,
he would see that the argument for world purposiveness from evolution
would have little basis.

Value. "Even though the previous arguments from design, analogy,
complexity, and evolution fail to prove that the world has a purpose, one
other additional argument does. Value or goodness exists. Many types of
value or goodness exist. For example, the value of life, of hope, of love, of
companionship, of beauty, of faith, of honor, of loyalty have been mechani-
cally caused. Literature, music, art, drama, painting, pageantry, and poetry,
are more than machine-made or circumstantial products. The ecstasy of
love, the subhmity of symphonic music, the peace of worship, the exalta-
tion of success, the inspiration of faith in the future — all of these are values
which could not just have happened. Life is too worth-while just to have
occurred."

Critics may hedge and hesitate to explain value in non-purposive terms,
but usually they hold that even though it is not necessary, yet it is possible
to do so. Value consists in pleasant feeling and pleasant feehng is produced
in bodies by proper stimulation or, according to at least one psychologist,
when synaptic resistance to nervous impulses is decreasing. Such reduc-
tion of resistance is explainable completely by chemical and physical in-
terpretation. Value exists in the world because those chemical combinations
organized into living being that produced pleasure survived better than
non-plcasure-producing hving beings. Synaptic and glandular conditions
may cause objects to appear magnificent, grandiloquent, ecstatic, but such
illusions merely happen to have been useful for survival rather than to be
true ideas about the real world. Values exist, but exist as illusions, albeit
happy and pleasurable illusions. Illusions of value may beget illusions of
purposiveness, but unless these illusions also are enjoyable there is no point
in being deceived by them.

Critics call attention also to the existence of evil. Values might serve a
purpose, but what good is evil? The horror, fear, hatred, anguish, pain,
ugliness, nausea, and sufiFering of life and death are a part of the total pic-
ture. There is too much evil in the world for anyone to have planned it
that way. The existence of evil is at least as much proof that the world
has no purpose as in the existence of good proof that the world has a pur-

412 READINGS IN BIOLOGICAL SCIENCE

pose. If teleologists assert that evil is mixed with the good to make it all
better, critics reply that neither the observable suffering nor the coming
promise of eternal punishment warrant such optimism. If one has to choose
between believing that the world has no purpose and believing that the
world has a predominately evil purpose, surely the former would be more
desirable.

Progress. "Progress is possible. And progress means development toward
something better or more good, toward some goal or end, toward some
purpose. If there were no purpose, there could be no progress. But there
is progress, therefore there must be purpose."

Critics may admit that progress is possible. But so is regress. Life can
get better, and life can get worse. "The best laid schemes of mice and men
gang aft agley and leave us nought but grief and pain for promised joy."
Who can tell whether our present optimism about a more glorious future
is justified? In the end all values may be destroyed. In the end there may
be an end to both good will and evil. Those who continue to be in torment
and anguish say, "Let it come quickly." "Ashes to ashes and dust to dust,"
and between the two a period of pleasure and pain which while we have
it we should enjoy and hope happily, but when it is ended ends all for us.
Purpose there may be, but progress and regress do not prove it.

Cause. "The world was created. If the world has not been created for a
purpose, it would not have been created. For to be created or to be caused
means to be caused for some reason. If there were no reason for a thing
coming into being, it could not come into being. 'Reason for being' is just
another name for 'cause.' But 'reason for being' also means 'purpose.' There-
fore, to be caused means to be purposed."

Objection may be raised that the assumption that the world was created
is highly dubious. For, it is possible that the world always existed, that it
had no beginning, that it has been eternally. Or, if it did not exist eternally
then whatever caused it to exist either existed eternally or was caused by
something which existed eternally, and so on. Thus, either the premise, "the
world was created," is false, and thus the conclusion does not follow, or the
difficulties which one seeks to avoid by postulating creation are simply
pushed back to that which did the creating. If the latter be granted, that
is, that the world was created, then was that which created the world itself
created? If not, then it had no creator and thus no reason for being. Thus
there would be an uncaused and unpurposed creator of the world. But if
so, the creator of the world must, by the same argument, have been created
for a purpose; and the creator of this creator either must have been created
for a purpose or have existed eternally unpurposed. Thus purpose must
have arisen somehow without purpose. And even if there were an endless
series of creative purposes, one might still ask, "Was the series as a whole
purposed?"

Definition of "cause" as meaning the same as "reason for being" begs a

BIOLOGICAL PHILOSOPHY 413

question which critics will not admit. Causes are "necessary and sufficient
conditions," not "reasons." "Reason for being" is a loose popular expression
developed in a background which was saturated with human purposiveness.
Neither looseness and ambiguousness of popular usage nor question-
begging presupposition of purposiveness can be admitted as proof of world
purposiveness. "To be caused" does not mean "to be purposed."

Authority. Except for appeal to design, probably the most common argu-
ment is appeal to authority. Especially those who have tried to argue, and
seem to themselves to fail, appeal to authority, which sometimes seems
to be above argument. Authorities of many kinds are appealed to — eminent
men, the Bible, the Church, Jesus, God. This type of argument may be
illustrated by the appeal to the authority of God. "God, through revela-
tion, has said that the world has a purpose, and what God says is so."

Critics are expected to cringe before this appeal to the authority of God
himself, yet in fact they seldom do. They rebut as follows: Is there a God?
One first has to prove that God exists before he can claim that God is an
authority. One of the commonest arguments for the existence of God is
the argument from world purposiveness: "The world has a purpose, there-
fore the world must have a purposer, namely, God." However, such an
argument presupposes that the world has a purpose, whereas the present
argument for world purposiveness presupposes the existence of God. Using
both of these arguments would be to commit the fallacy of "reasoning in a
circle." Thus, unless one can find some other proofs of God's existence or
can get his critic to grant it, he will be unable to prove his case. But even
granting that God exists, it does not follow that the world has a purpose,
because God might have created the world accidentally, or have created
the world as a result of mechanical necessity, or have created the world
in the past for a purpose which he has now forgotten. Furthermore, still
granting that God exists, does it follow that God is an authority? God
might exist without being a person, or without being actively interested
in the world (as Deists claim), or without being interested in acting au-
thoritatively. However, granting both God's existence and authoritative-
ness, did God ever say that the world has a purpose? All alleged reports
of God's speaking to persons in such a way that one might infer that the
world has a purpose are dubious. Someone has questioned every one of
them. Furthermore, all those who appeal, not to the writings of historical
revelators, but to their own experience in communion with God and of
his revelation directly to them that the w^orld does have a purpose have
been accused of self-hypnosis and self-deception. Also, evidence may be
presented for God's nonauthoritativeness. For example, there are contra-
dictions among contentions of different revelators and most revelators con-
tradict themselves sooner or later. Such contradictions prove that God was
not involved, because God is always consistent.

Self-co?itradictio?i by mechanists. "Those who claim that nothing has a

414 READINGS IN BIOLOGICAL SCIENCE

purpose do so for a purpose, and thereby contradict themselves. The very
la\\s of mechanics used as a basis for explaining the behavior of things non-
purposivelv were formulated by human minds for a purpose. Alechanists
would be the first to discard those mechanical laws which were not suited
to their purposes."

Mechanists reply that the claimed contradiction is only an apparent one,
not a real one. For mechanists explain purpose in nonpurposive, or mechani-
cal, terms. Purpose is a notion in a casually (non-purposively) determined
mind. Even if the mechanist seems to those who interpret things pur-
posively to be acting purposively, he claims that such purposes are mechani-
cally caused. Thus he involves no contradiction.

Proof by inechmiists. "Since every normal person seems to himself at
times to act for a purpose, everyone must admit that there are at least hu-
man purposes in the world. If, as mechanists claim, the world is uniform,
then if there is purpose in part of it, why not also in all of it? Furthermore,
since, for the mechanists, nothing can occur spontaneously but everything
must have a cause that is capable of causing it, purposes which do exist
must have been caused, and in order for them to have been caused
there must have existed in the world other prior purposes capable of causing
them. These prior purposes must have been caused by still earlier purposes,
either backward infinitely or by somx first or ultimate purpose. Thus
mechanism really presupposes world purposiveness."

Mechanists may grant that personal purposes constitute a part of the
world, but maintain that it does not follow that the whole world is made
up of personal purposes nor that the world as a w^hole has a purpose. "Uni-
formity of nature" does not mean that everything is alike, but only that
when a given set of causal conditions recurs there will result an exactly
similar set of efi^ects. Argument from parts to whole are unwarranted, as
can be seen from the example of a worm in a partly rotten apple. If he is
in the rotten part, it may seem all rotten. If he is in the good part, it may
seem all good. If he is on the border between the two, it may seem either
a good apple with a rotten part or a rotten apple with a good part. One
might just as easily argue for non-purposiveness of the whole world on
similar grounds, for everyone will admit also that some experiences seem
lacking in purpose.

Unprovability of jtiechanism. "Since human knowledge is limited and
since there is much about the universe that we can never know, mechanists
can never prove conclusively that the world has no purpose. For even if it
were provable that everything in the known universe is non-purposive,
it still would not follow that the rest of the universe which we do not know
is non-purposive. So long as complete mechanism is unprovable, it is
reasonable to suppose that teleology is true."

Mechanists reply with almost exactly the same argument. "Since human
knowledge is limited and there is a part of the world which we shall never

BIOLOGICAL PHILOSOPHY 4I5

know, even if it could be demonstrated that everything in the part of the
world which we do know is purposive, it still would not follow either that
the rest of the world is purposive or that the world as a whole has a pur-
pose."

Universal agreement. "People of all times and places have believed that
the world is purposive. Except for a few oddities, everyone believes that
the world has a purpose. Can such a great majority be in error?"

Normal rejoinder is that popular agreement is no safe proof of truth of
any belief. For thousands of years people agreed falsely that the earth is
flat. Likewise all people naturally believe that color exists in things inde-
pendently of persons who see it; yet scientists tell us that color as experi-
enced is not really out there, even though naturally we must continue to
act as if it were. Such illusion is convenient, useful, natural, and universal,
but not for those reasons true. Popular consensus is indicative not so much
of cosmic teleology as of anthropomorphic teleology. People believe that
the world is purposive, not because the world as a whole has a purpose,
but because people are purposive and tend to interpret other things as if
they were like people. This accounts for universal agreement about world
purposiveness at least as adequately as does the theory that the world as a
whole has a purpose. Furthermore, who knows what the popular consensus
is? No poll of opinion on this question has ever been taken. No one can say
with certainty that everyone does believe that the world has a purpose,
certainly not with regard to those of the past who can no longer be polled,
nor those of the future not yet pollable.

Fragviatism. Many pragmatists define truth thus: "Those beliefs which
work successfully, which are useful in adjusting ourselves to our environ-
ment or in solving our problems, are true. And those beliefs which work
most successfully are most true." Teleologists who accept this pragmatic
definition of truth say, "The belief that the world has a purpose works
successfully and therefore is true. Furthermore, people who have faith in
world purposiveness get along better and are happier than those who do
not. Thus, it works more successfully and thus is more true."

"But," say mechanists, "such success of teleologists is due to the fact
that they haven't yet tried to use their belief in areas where it won't work
so successfully. Everyone has some ideas which work well for a while or
in certain areas, but which have to be given up when used in wider areas
or over a longer period of time. Teleologists are simply less-experienced
than the mechanists." Using exactly the same definition of truth, some
mechanists seek to "turn the tables" by saying that the belief in mechanism
works better than the belief in teleology. Appeal is made to the comparative
adequacies of the teleological and mechanistic hypotheses in promoting
scientific progress. Mechanists claim that most science presupposes mecha-
nism and the progress of science stands as testimony of the superior success
of the mechanistic hypothesis. The history of scientific progress is a sue-

41 6 READINGS IN BIOLOGICAL SCIENCE

cession of stories in which belief in mysterious purposes was given up for
behef in the reign of natural law. Relative backwardness of the social and
political science is accounted for because they deal with areas in which
people are least willing to give up their illusions about cosmic teleology
and accept the more useful mechanistic hypothesis. If the pragmatic test
proves anything, they claim, it proves that mechanism is more true.

-s, -"^sy 4' rf*.

TO WHAT EXTENT IS A SCIENCE
OF MAN POSSIBLE? *

FREDERICK OSBORN

Knowledge of man has been growing slowly over thousands of years.
But a science of man is something new under the sun. For though science
is knowledge, it is a special kind of knowledge. It is obtained by scientific
methods, usually involving a collaboration between theory and experi-
ment. Most science is based on the quantitative analysis of measured phe-
nomena. It differs from other knowledge chiefly in its quality of being
demonstrable. An experiment to have scientific value must be one that can
be repeated. Scientific phenomena can be measured and recorded over
and over again or related by theory to other phenomena that can be re-
peated. New knowledge of this sort becomes generally accepted when
it has been checked over by a sufficient number of people. The older type
of knowledge which is derived from personal observations and the con-
clusions of authorities is harder to check up on, is more subject to personal
bias and the mental fashions prevailing at any given time. Scientific knowl-
edge, on the other hand, is cumulative in its effect and has a known predic-
tive value.

In a hundred thousand years, by his use of the old forms of knowledge,
man developed an environment suitable for a civilized life. He domesti-
cated animals, produced cereal crops, and through the great religions as-
pired at least to a noble concept of the dignity and character of life.

Then, in a few brief generations, the new forms of knowledge which
we call science brought to men a marvelous control of their environment
— railroad, telegraph, telephone, electric light, motor car, submarine, aero-
plane, radio, television, reduction of labor needed on the farm, canned and
frozen foods, cheap goods by mass production, sanitation, medicine and
public health. Almost over night the natural and physical sciences have
brought these changes.

* Reprinted by permission of the Scientific Monthly, American Association for the
Advancement of Science. Copyright 1939.

BIOLOGICAL PHILOSOPHY 417

The biological quality and the training of man has not undergone com-
parable changes. Except for medicine, we know so little about man that it
is still fair to ask, "Can we have a science of man?" And the question is,
somehow, troubling. Man's new power to control the environment has
not made him humble. He seeks new short cuts to happiness. The older
knowledge of man, heritage of ages of experience and suffering, he tends
to discount, because it is not based on the new scientific method, not capa-
ble of scientific proof. He is not likely to go back permanently to the old
knowledge. He is too impatient of its restraints, too admiring of the suc-
cess of the new type of thinking based on the scientific method. Yet with-
out more knowledge of himself, of his needs, his weaknesses and his pos-
sibilities, we may wonder whether man can safely handle the extraordinary
tools he has recently created. They may inflict irreparable injuries. If we
ask, "To what extent is a science of man possible?" perhaps we are really
asking to what e.xtent can we achieve a secure and permanent civilization?

It is hardly encouraging to compare the present state of the science of
man with the marvelous development of the natural sciences. But the
picture is a more hopeful one if we make allowance for the respective ages
of these two fields of science. Several generations of men have been trained
and taught in the physical sciences. But no one of the age of forty-five or
more to-day could have had any serious training at college in the sciences
that have to do with man. They were not available for teaching twenty-
five years ago, which is a pretty brief span of time, even in this hurried

age.

Scientific work in psychology was in its infancy at the turn of the cen-
tury. Mendelian genetics were rediscovered in 1901. At about the same
time anthropologists got out of their armchairs and began collecting or-
dered data in the field. By 19 10, text-books were beginning to make signifi-
cant use of new scientific materials in these fields. By 1920, courses in
scientific psychology, genetics, human biology and anthropology were
available in most of our universities. To-day these subjects are among the
most popular of any that are offered. But much that is taught about man
and society is not science. Not enough research has been done to supply
the basic material needed; and, still more important, there has been too little
time for critical analysis, interpretation and organization of the research
that has been already carried out. Notwithstanding this present handicap,
the sciences of man have already begun to influence our thinking in a way
which suggests the effect that they may have in the future when they are
more fully developed. A few examples will make this clear.

II

Psychology has made important contributions to present-day points of
view. There are some two thousand registered psychologists in the United
States to-day, where they were only a few scattered individuals in 1900.

41 8 READINGS IN BIOLOGICAL SCIENCE

The sum total of their research fills innumerable volumes. But much of this
research has been badly done, as would be expected in so new and difficult
afield.

There is still controversy among psychologists; part of this may be de-
scribed as a controversy between older schools of psychologists and those
trained during the last decade. Laymen who engage in controversy are
often found to be leveling their lances against concepts and methods that
have been completely discarded by critical contemporary psychologists.
Much of this controversy relates to the roles of heredity and environment
in the development of intelligence. Recent work goes far to clarify this dif-
ficult field. In the past few years, the so-called fixity of the I.Q. has been dis-
proved. We know now that a stimulating environment in the home, in pre-
school, in elementary school, in high school, in college and in later life tend
to raise the I.Q. of an individual, and to maintain it at a higher level. We
know that in a depressed environment intelligence fails of a normal growth.
On the other hand, there are important differences between individuals in
the extent to which they respond to the stimulus of the same environment.
Individual differences do not disappear when the environment is equalized
at a high level. In a stimulating environment, able individuals show a ca-
pacity for response which takes them further than ever out of the class
of those of average ability. Among Newman's 19 pairs of identical twins
reared apart, there were 1 1 pairs in which the two members of each pair
had had similar amounts of education. In each such case the twins differed
in I.Q. only about as much as the same individual would vary when tested
at different times, the average of differences being 4.4 points. Among four
of the pairs there was considerable difference in schooling between the
members of each pair; their I.Q.'s differed on the average by 10 points.
Among the four remaining pairs, educational differences between the mem-
bers of each pair were large, and in these four cases the twins differed by 19
points, on the average. In every case the twin with the more education had
the higher I.Q. But at the same time where one twin was dull for his poor
environment, the other was dull for his good environment, and where one
twin responded well to his poor environment, his mate responded well to
his good environment.

Twin Eleanore only got as far as the fifth grade, and attained an I.Q. of
only 66. Her sister Georgiana went through grade school, high school,
four years of music and three years of normal school. After all that educa-
tion, her I.Q. was only 78. It is hard to escape the conclusion that this pair
of identical twins were not endowed with the genetic factors necessary to
ordinary intelligence.

Twin Gladys, with only three years' elementary schooling as the total
of her education, had the creditable I.Q. of 92. Her sister Helen, with a
college degree, had an I.Q. of 116. Evidently the genetic endowment of
these girls was sufficient for the development of average intelligence.

BIOLOGICAL PHILOSOPHY 419

The findings on identical twins reared apart check pretty well with other
studies on the relative contributions of heredity and environment to indi-
vidual differences in intelligence in the general run of our population. Of
course, nineteen pairs collected by Newman and one by Muller is a number
woefully inadequate for statistical validity, but this inadequacy is typical
of the present state of the science of man.

I II

In the field of genetics, the marvelous advances of the past forty years
have been largely limited to the genetics of plants and animals. For some
reason, human genetics has been largely neglected in this country compared
to what has been done by Fisher, Haldane and Hogben, in England, and
by Verschuer and others in Germany. There is almost no knowledge of
genetic factors in normal variations in general qualities, such as intelli-
gence, character or susceptibility to disease. Important work has been done
on blood groups. A considerable number of infrequent abnormalities are
known to be due to genetic factors, and in some cases the mode of in-
heritance is known. Research work on genetic factors in feeble-mindedness
and in mental disease is almost all in the future. Nevertheless, there are
many signs of an aroused interest in the medical profession and a new
recognition of their responsibiUty for preventing the spread of serious
hereditary defects.

Ultimately, scientific knowledge in regard to the part played by genetic
factors in causing individual differences, and further research on the in-
heritance of different genetic factors, may make possible measures that
would tend to discourage the reproduction of inferior genetic strains and
encourage the reproduction of those above the average.

Thus, scientific knowledge of the relative parts played by heredity and
by environment in developing individual differences may become a valua-
ble tool for improving human qualities, first on the environmental side
through changes in education and ultimately through raising the average
hereditary level.

IV

Anthropology has made at least one important contribution to the
American point of view by showing the extent to which culture patterns
are fixed by the social environment with little regard to the type of people
involved. The whole concept of race has undergone a violent transforma-
tion in the past fifteen years. It is said that Hitler during the two years he
spent in jail before coming to power read widely in what were then sup-
posed to be scientific books dealing with race. They were not scientific in
our present definition of the term: they were the German analogies of
Madison Grant's "Decline of the Great Race," which was having a vogue
in this country at that time. Modern research of a more scientific sort denies

420 READINGS IN BIOLOGICAL SCIENCE

most of their conclusions. It is interesting to speculate on what would have
been Hitler's attitude toward race if he had had access to present scientific
knowledge.

These few and tentative conclusions are suggestive for the future, but
they do not indicate to what extent the science of man may be possible. It
is only very recently that we have really lifted age-long taboos against an
honest examination of ourselves. In the past ru^enty years more of a start
has been made than might reasonably have been expected under the cir-
cumstances. The prospect for the future seems hopeful. The extent to
which we can have a science of man would seem almost unlimited provided
three major conditions are met:

The first is plenty of time.

The second is the enrolment in this work of men of high abilities, with
adequate support.

The third is freedom of thought, freedom of inquiry and freedom of
criticism.

Research problems concerning man are, in many cases, no different in
kind from research problems concerning other forms of mammals on which
effective work has been done. But the problems of man are infinitely greater
in complexity and require more time in proportion as the space betM-een
human generation is longer than the space between the generations of the
smaller mammals. What Tryon learned about the genetics of maze-running
ability in rats might be duplicated in human beings with regard to genetic
factors in differences in general intelligence, but it would take 200 years
and a quite inconceivable control of human breeding to carry out such an
experiment. The difficulties of studying environmental influences are al-
most as great, but there is no reason to believe they can not be solved by
sufficiently persistent effort and by the development and application of
new methods.

There remains one important difference between the study of lower ani-
mals and the study of man, namely, that in the latter case man is studying
himself and thus finds it more difficult to exclude his personal and emo-
tional biases and reactions. It is for this reason, among others, that freedom
of criticism is as important as freedom of thought in the development of
the science of man. With all these difficulties taken into account, there is
still every reason to believe that the development of the science of man
will go forward rapidly from its present modest beginning.

VI

It is worth while to consider the different practical applications that may
result from the sciences of man. The first has to do with education. Present
methods of education are the product of a long evolution under the guid-

BIOLOGICAL PHILOSOPHY 42 I

ance of the old type of knowledge. On the whole, education to-day is un-
doubtedly better than the education available in the past. But we do not
know in any precise way what a modern education really does or the dif-
ferent effect it has on different types of people. Psychologists in great
number are working on new measures for determining individual capaci-
ties along different lines. Other psychologists are trying to determine the
effect of different educational environments on people of different capaci-
ties. We may be sure that there is no single environment that would be the
optimum environment for every one. Each individual will make his maxi-
mum development in the environment that will most stimulate the partic-
ular responses of which he is capable. The environment that would be
optimum for a dull person would be insufficient for the full development
of a superior person. In the studies on orphanage and pre-school children
being made by Stoddard of the University of Iowa, the brightest children
showed the least growth in the deprived environment of the orphanage.
The Pennsylvania Inquiry on school and college education by the Carnegie
Foundation indicates wide individual differences in ability to respond to
a college education. A considerable proportion of those going to college
go backwards rather than forward intellectually during their last four years
of schoohng. It is not too much to hope that work of this sort will de-
velop a science of education such that ultimately we shall be able to measure
the specific potentialities of each individual and provide an educational
environment which would be the optimum for each of his particular abili-
ties. Such a change in our educational system if universally applied would
probably raise the average I.Q. almost 20 points. Few people would remain
without some specific capacity which, properly developed, would make
them more valuable members of society in their own recognized specialty.

VII

To date, the most effective applications of a science of man have been
in medicine, nutrition and public health. The expectation of life at birth
is now double that prevailing a century and a half ago, and has been in-
creased from 49.2 years in 1900-1902 to 60.3 in 1929-193 1. Medicine has a
long start on psychology. It is not unreasonable to suppose that in another
fifty years we may have a science of man which can prescribe the optimum
environment not only for the maximum physical but also for the maximum
intellectual and personality development of each individual. The applica-
tion will not be easy. But when the knowledge is available, some way will
be found to apply it.

The science of human genetics will ultimately supply psychologists with
additional knowledge necessary for an understanding of different human
types. But the major applications of the science of human genetics will be
in the field of direct improvement of the genetic qualities of human stocks.
That is far in the future. What a few men did in twenty years, working

42 2 READINGS IN BIOLOGICAL SCIENCE

in Drosophila, it may take several hundred men a hundred years or more
to do working on man. Given sufficient time, and the development of new
tools of research which will surely take place, a fairly complete genetics
of man is possible. Whether its practical applications will be important, I
leave to you to decide. Does your experience in plant and animal genetics
lead you to think that the average man's socially valuable qualities in our
changing environment could be improved by creating conditions in which
superior strains have the larger families and in which the breeding of in-
ferior strains is effectively discouraged?

VIII

We have been considering only the sciences relating to individual dif-
ferences and individual development, and the contributions which these
sciences may make to the improvement of human beings. But the study of
man can not proceed independently of his environment and his activities,
which are the field of the so-called social sciences. Nor can the social
sciences proceed successfully without more knowledge of this strange
and complicated creature, man. The development of the science of man
should therefore, have another important effect in the contribution it will
make to the sciences which deal with the behavior of men in the mass and
their relations to each other.

All branches of sociology are at present handicapped by lack of knowl-
edge of the human material whose activities they are studying. The postu-
late of the economic man, impervious to all other emotions, does not add
to the reality of economics. Perhaps the new field of population study
provides the best example of the interdependence of studies of man and
studies of man's activities. Here the analysis and forecasting of total popu-
lation trends has been revolutionized since 1925 by the introduction of
procedures for taking changes in age and sex composition accurately into
account. It is safe to say that the error in population forecasts for the United
States for the next thirty years has been cut in half by the application of
these techniques, and equally important information about future age dis-
tribution has been added, which was wholly lacking before.

The study of the adjustment of the population to resources in difl^erent
parts of the nation, which had never been given serious attention before
1930, has been developed to the point where its results already have very
practical and far-reaching significance. The study of differential reproduc-
tion rates, which prior to 1930 had been based chiefly on such fragmen-
tary and inaccurate data as reports by college students about the numbers
of children in their fathers' families, has been extended and refined until
it is possible to describe the reproductive tendencies of most population
groups in the United States with considerable accuracy, and we are now
beginning to get accurate information on how these rates are changing in
different groups under different conditions.

BIOLOGICAL PHILOSOPHY 423

But these so-called group differentials in fertility relate only to occupa-
tional groups or to regional groups. We know that farmers have more chil-
dren than city people, but we do not know what genetic types are surviv-
ing in the greatest numbers. It is impossible to say at present on the basis
of any scientific evidence whether the human race is improving or whether
it is deteriorating. This important question, with all its practical implica-
tions, can be answered only when population study can employ measures
of innate human qualities, and for these it must wait on the development
of the sciences of man.

Thus, the science of man may not only make it possible to improve man
himself by supplying the proper environment for his development and,
ultimately, even by an improvement in his genetic potentialities, but may
give the social sciences sufficient precision to make them truly sciences
capable of predicting the end results of current political, social and eco-
nomic trends.

The sciences of man may in these ways make an invaluable contribution
to human welfare. They may also make an even greater contribution in
setting up new concepts of human possibilities, new ideals as to the pur-
pose of life.

->->■><<<

SCIENCE VERSUS LIFE *

A . J . CARL SON

When the hurricane strikes ships at sea, frail hulls founder, while the
crews of sturdier craft experience anxiety, if not panic, and are for a time
deflected from their course by the temporary violence of wind and waves.
But they ultimately make their goal, thanks to human courage, the com-
pass, and the fixed stars. Such hurricanes, man made, have struck human
society, and its institutions, from time to time throughout recorded his-
tory. We call them war. There is anxiety and fear, if not panic, on board.
When storm clouds cover the heavens men of little understanding question
the compass of science, fear that the stars of rectitude will guide no more,
and with scant hope drift with the violent wind. The compass of science
is not only questioned, but it is charged that this very compass has led us
into the hurricane, that science is in conflict with society. So I propose
to address myself to these questions: Is our age led or dominated by
science? Is science in conflict with the best interest of society? Is it science
and the scientific method that lead nations into war? Only last year a Brit-
ish scholar said: "In Europe today it is rather dangerous to ask questions,
it is much safer to discuss how a question should be asked." Today this
danger is by no means confined to Europe. But as I read the human record

• Reprinted by permission of the Sigma Xi Quarterly. Copyright 1941.

424 READINGS IN BIOLOGICAL SCIENCE

in mud, and rocks, and ancient ruins, on tablets of clay, in scratches on
stones, papyrus, and paper, I think I discern evidence of the ascent of man,
through asking all kinds of questions at all times, and seeking the answers
by the best methods of the age. If we do less, we admit that science and
civilization is a blind alley in human evolution.

Is ours the Age of Science? Or rather, in what sense is ours the Age of
Science? An eminent physicist said, in this very city (Philadelphia): "In
no previous time in human history has life and thinking been so greatly in-
fluenced by science as it is today." This is undoubtedly true, but does that
alone make ours the Age of Science? I think not. Those who, accusingly or
proudly, describe our times as the Age of Science usually cite as evidence
the modern aspect of man's inhumanity to man, or the numerous practical
applications of the discoveries in physics, chemistry, geology, biology,
and medicine during the last hundred years, such as the steam and gas en-
gine, the telegraph, the telephone, the airplane, the radio, modern surgery,
fair control of infectious disease, modern sanitation, and many other in-
ventions and measures that contribute to the convenience, the efficiency,
the health, the comfort, and the happiness of modern life. It is true that
science has, during the last hundred years, increased enormously our under-
standing of the nature of the world and the nature of man, and with that
greater understanding has come greater control of the forces that act in
man and in his environment. But fundamental discoveries in science are
the achievement of but a few people. The practical inventions based on
these discoveries are also the work of a few men, speaking relatively. And
the physical and chemical inventions are mostly gadgets that merely
modify our tempo and external mode of living. I contend, and I think I will
be able to prove to you, that the great mass of the people of our age, the
rank and file of men and women of our day, even in the most enlightened
countries, in their thinking and in their motivation are nearly as untouched
by the spirit of science and as innocent of the understanding of science as
was the "Peking A4an" of a million years ago. The modern man adjusts to an
environment greatly modified by the scientific efi"orts of the few. The
"Peking Man," we may assume, adjusted himself as best he could to na-
ture in the raw. A span of about a million years separates the two. And yet
the two are about equally innocent of science, in the sense of the spirit and
the method of science as part of their way of life. For science is more than
inventions, more than gadgets, however useful and important they be.
Science is even more than the discovery of and correlation of new facts,
new laws of nature. The greatest thing in science is the scientific method,
controlled and rechecked observations and experiments, objectively re-
corded with absolute honesty and without fear or favor. Science in this
sense has as yet scarcely touched the common man, or his leaders.

The character of human society in any age is determined by man's think-
ing, motivation, and behavior rather than by external gadgets. The er-

BIOLOGICAL PHILOSOPHY 425

roneous assumption that ours is the Age of Science, or the very limited
sense in which this is true, has led many people to charge to science some
of the follies and failures, some of the violence, the brutalities, the suffering,
the confusion throughout the world in recent years. Some of these people
tell us that "science has failed," that we should declare "a moratorium on
science." People who talk thus, who advise thus, cannot understand either
the spirit or the method of science. We cannot afford to declare a mora-
torium on honesty, on integrity, on objectivity, on experimentation, for
that would take us straight back to the jungle. The way of science is away
from the jungle, away from its violence and fears. If the way of science at
times, such as the present, seems obscure and even dangerous that is due to
too little, not too much, understanding of the nature of man and our uni-
verse, and to the further fact that we do not or are not permitted to follow
the light of reason based on facts.

If our age is "The Age of Science," our rulers, our legislators, our busi-
nessmen, our educators, our farmers, our factory workers should give
evidence of comprehending, using, and following the scientific method. In
a recent book the Dean of Canterbury writes: "Our social and economic
order is neither scientific nor Christian. When I read, as a headline in the
Observer that Poland's good harvest was a severe blov: to recovery, I re-
called the words of an American professor of agriculture after seeing ten
million acres of cotton ploughed under and five million pigs slaughtered:
'If this will bring national prosperity, then I have wasted my life.' The
thing is monstrous, an age when science is frustrated." In the broader field
of human relations, what do we see on the horizon? Conspicuous, certainly,
are: greed, force, faith, and war. These are certainly more conspicuous
than the ways of reason based on scientific understanding. In the last
analysis, ivar is murder and steali?ig ofi the part of somebody. War is the ex-
tension of the practices of the jungle into modern life. The technique of
modern warfare is modified by scientific discoveries, but the elements that
make for war are certainly not scientific. Hence the persistence of war can-
not be laid at the door of science. It is due rather to the failure of science
and conscience to as yet essentially modify human conduct. For we must
assume that sooner or later reason based on understanding will modify
human behavior. Even animals with no cerebrum can be conditioned.

The scientific method demands that we suspend judgment until we know
the facts. It demands honesty, integrity and industry in ascertaining the
facts. The scientific 7Jiethod and dishonesty are i?7C07npatible. But scientists
are but human beings, and they frequently make mistakes both in facts and
interpretations. Now, is our age conspicuous for honesty and integrity? Is
there less lying and deceit locally, nationally, internationally, today than
yesterday? The answer is all about us. Modern propaganda, and a good
deal in modern advertising, have the earmarks of lying as a fine art, rather
than the character of honesty, objectivity, truthfulness, and accuracy of

426 READINGS IN BIOLOGICAL SCIENCE

science. It is, biologically, evident that we shall have to live with greed for
some time to come. But the more serious question is: ca7i human society sur-
vive without individual, social, and national guile? If the answer is "No,"
we probably have here the most fundamental conflict between the scientific
method and society.

Science, in spirit and method, knows no political aspects or national
boundaries. Individuals of all races and nations have contributed to our
present understanding of the nature of man and of the world. There is no
Democratic logic. Republican mathematics, Nazi physics, Fascist chemis-
try, or Marxian biology. The spirit and the method of science cannot change
with capitalism or socialism. This appears to me axiomatic. But fanaticism
in society and governments can temporarily retard discovery and further
advance in the understanding and control of life and nature. And yet we
hear claims from the Germany of today of a special Teutonic or Nazi
physics, claims from Russia of something called A4arxian genetics, what-
ever that is. These stupidities characterize our age, but they are not the
characteristics of science.

If even our so-called educated fellow citizens were scientific their con-
duct would be more influenced by proven facts than by wishful thinking.
If there is anything that has been proved to the hilt in biology and medicine
during the last hundred years, it is the effectiveness of vaccination against
smallpox. There are no "ifs and ands" about it. It is one hundred percent,
effective and practically one hundred percent, safe. Of course, wherever
human hands, human agencies, are involved accidents will happen some-
times. Despite all these facts, men and women in this and other civilized
countries neglect and oppose vaccination against smallpox. We have large
groups of people organized into "anti-vaccination societies." And these
are not all ignorant people. Some are college graduates. If these people
walked in the way of science, they would accept and be guided by proven
facts.

The exact biologic relations of man to other animals are still, in part,
a matter of theory. Animal evolution is probably now going on, but so
slowly that we usually fail to discern it. But the essential identity of the
structure and function of tissues and organs in man and animals is not a
theory. It is a proven fact. The heart, the liver, the stomach, the lungs, the
blood, the eyes, the ears, and even the brain are made up of the same stuff
and subjected to much the same diseases, wear and tear and ageing in man
and animals. It is also true that practically ninety percent, of the under-
standing gained in the last hundred years of preserving health and con-
trolling disease has been secured through experiments on animals. And yet
people, even in civilized countries, oppose experiments on animals as futile
and cruel, as of no benefit to man. These people are not all ignorant. But
they surely are not scientific. They do not accept, they are not guided by,
proven facts. Their thinking and motivation have not been touched by

BIOLOGICAL PHILOSOPHY ^if

the spirit and the method of science. Moreover, the majority of people in
some of our states, through their legislatures, pass "anti-evolution" laws,
as if the course of events of the past could be altered by legislative dicta
of today.

It is still a common practice of man, so-called civilized man, to follow
post hoc reasoning; that is, because one event may sometimes follow an-
other, the two events are, therefore, necessarily causally related. Man-
kind as a whole, and even leaders in business, industry, and government, do
not yet thoroughly understand or follow the principle of control, the prin-
ciple of experiment. Post hoc reasoning is one of the commonest sins against
the scientific method, and we still see it occasionally in those who have
been trained in science; for example, modern physicians. As an example
of post hoc reasoning in medicine, I can cite the case of a physician who
had practiced medicine honestly, if not intelligently, in a far western state
for forty years. A number of years ago he told me in all seriousness that
he had discovered a specific remedy for influenza. I was naturally curious,
because influenza is one of the maladies which has so far largely defied
modern scientific control. On being asked what his remedy was, he re-
phed, "Good whiskey and plenty of it." The doctor was apparently per-
fectly sincere about it. When I asked him how many influenza patients
he had treated without whiskey and how many of these recovered, he
looked at me in surprise and said: "You understand, I have treated every
one of my influenza patients with whiskey during the last forty years, and
I have had a high percentage of recovery." This physician, though stupid,
was too honest and venerable to poke fun at. I was tempted to ask him
how many recoveries from influenza he thought he would have had if he
had ordered his patients to read Mary Baker Eddy's Science a?id Health at
an angle of 45 degrees, practice Coueism, or have their spines or toes twisted
according to the chiropractor's cult. Another example is that of another
honest physician in a southern state using a remedy whose virtue, if any,
was essentially twenty percent, alcohol, a so-called female tonic, a southern
counterpart of Lydia Pinkham's "u^ell-known vegetable compound. The
case was that of a young girl working twelve hours a day in a factory in a
southern city at low pay. She lived in a garret room, with poor food, and
poor sanitation. She had a high degree of anemia. The doctor wrote: "I
took this girl out of the factory, sent her to the country for three months
with relatives and gave her this female tonic. After three months she had
nearly recovered from her anemia, thanks to this tonic." It is not surpris-
ing that even physicians fall into this error of reasoning, because in the not
distant past medical education was only partly scientific.

To what extent or m ivhat sense is science i?i conflict with society? I
think there is much confusion, misunderstanding, and unwarranted general-
ization on this point. Not so many years ago the American Association for
the Advancement of Science declared, by resolution: "Science is wholly

42 9 READINGS IN BIOLOGICAL SCIENCE

independent of national boundaries, and races, and creeds and can flourish
only where there is peace and intellectual freedom." This position is clearly
in conflict with the cyclical psychosis exhibited by Hojjio sapiens, in mass,
throughout the ages. But whether there is a conflict of science with the
primary interest and ultimate well-being of society is at least an open ques-
tion. Only last year an outstanding physicist declared: "Science makes man
human." I presume our colleague meant that science tends, or should tend,
to make man more human. The possible conflict between science and so-
ciety in this statement obviously depends on our conception of what are
the desirable human qualities, or behaviors, today and tomorrow. If de-
ceit, violence, and war are essential for survival and progress there is a con-
flict between science and society, for deceit, violence, and war are the very
antithesis of the scientific method. Two years ago a colleague uttered the
following dictum: "Here on this continent where science has achieved its
greatest application, science is in conflict with society. Science and tech-
nology have gone so far that the present social structure is facing its deba-
cle. Nowhere else in the world today is science in such militant conflict
with the social structure under which science survives." The same author
also speaks of the "prostitution of science for war." We have here, clearly,
a confusion of science and the scientific method with the uses, largely by
a non-scientific society, of the understandings and the gadgets developed
by the methods and the applications of science, for satisfactions of the an-
cient use of the hand, the teeth, the rock, the stick, and the club in similar
drives by our primitive ancestors.

The services of science to society are, primarily, increased knowledge,
understanding, freedom, and power. That such increased knowledge, un-
derstanding, and control of the forces of nature are used, not by scientists,
but by society, with increasing effectiveness in the continuous and recur-
rent drives to satisfy greed, lust, hate, and vanity, will, in my judgment,
ultimately prove to be due, not to the inherent nature of the scientific
method or of knowledge per se, but to the failure of man, so far, to be ef-
fectively conditioned by science and the scientific method.

It is sometimes asserted that science is amoral if not immoral. The latter
may be true, if it is immoral to challenge and destroy taboos and traditions
based on ignorance and misunderstanding. But to call the impartial, in-
dustrious, and earnest search for new knowledge amoral or immoral con-
flicts with my conception of immorality. As I understand it, there is no
conflict between the scientific method and our sense of justice, though I
admit that the latter stems from a much broader base than science. Indi-
vidual scientists may at times, in their ivory towers, express distrust of so-
ciety or the common man, as disclosed by the following recent statement
from an eminent surgeon: "Whether the public interest (in medical re-
search) is something deeper than curiosity, and whether it can be relied
on as a potent factor for the common good have not been demonstrated.

BIOLOGICAL PHILOSOPHY 429

Indeed a study of the historical background of surgery invokes in the mind
of the medical scientist a distrust of the public." The doctor cites among
other examples, the Edict of Tours (1165) declaring surgery not respecta-
ble. But that Edict was not the work of the common man. It was a product
of the leaders of the Church.

On the other hand, the defeatists among us, noting the conspicuous,
though superficial, role of science in modern life, occasionally see in science
and the scientific method the very root of some of our modern ills. Thus
the leaders of a little college on our Atlantic seaboard have boldly under-
taken to rectify a Harvard University educational failure, by providing
"conditions for liberahzing and humanizing science." And this the college
hopes to achieve by the "strategy of taking specialists in the sciences and
re-educating them in the liberal arts." We are not told what to do for, or
do with, the people who were "educated in the liberal arts" before they be-
came specialists in science. Maybe these unfortunates are acephalic satraps
of Satan, or just dead and do not know it. I think among the "persons who
can produce fine things" are the men of science, and among "the fine
things" are new facts about man in health and in disease, new facts about
the universe, new facts about the nature of life and matter, new under-
standing and new powers of control of the forces of nature.

Many world events in recent years have made some assert that worth-
while human society cannot persist or prevail without the perennial su-
premacy of deceit and greed, violence and war. Others question whether
these very antitheses of the scientific method can persist side by side with
science and the necessary human qualities that go with the method of
science. Deceit, violence, and war have certainly been with us before the
dawn of history as a part of the "struggle for existence," while science and
the scientific method are of a much more recent vintage. It is also true that
the "struggle for existence" in smaller groups such as the family, the tribe,
or the nation ultimately curbed, at least in part, both deceit and greed,
violence and war. Can such curbing be achieved on a larger scale or is it
desirable that such curbing of man's past drives be achieved in the interest
of the future welfare and progress of man? So far as I can see there is only
one answer to this question, and that answer is given both by history and
by the primary interest of society. To refer again to the resolution of the
American Association for the Advancement of Science: "Science can flour-
ish only where there is peace and intellectual freedom." Are intellectual
freedom and peace the desiderata for man? If this is so, there is no funda-
mental conflict between science and society, as I view society of the future.

The evident failure of modern science measurably to influence human
drives and conduct, individually, nationally, internationally, are probably
to be sought in three factors: (i) the character of our prevailing educa-
tion. Our prevailing education, starting in the home and in the church,
in the grade school and the high school, and extending into the college is

43 O READINGS IN BIOLOGICAL SCIENCE

largely education by dictation. It is indoctrination rather than education
by understanding the why and wherefore through experimentation. This
applies to countries other than our own. There are those in our own coun-
try who insist all along the line on education by more and more dictation
and indoctrination. Merely the memory of and the ability to repeat a
heterogeneous number of facts, or even coordinated facts discovered by
science, is not education in the method of science. We can teach a parrot
to talk Latin and repeat a syllogism, but that Latin-speaking bird is still a
parrot.

(2) Considerable responsibility for the failure of science essentially to
modify human conduct must be laid to the scientists themselves. Many of
us are scientists only during our working hours, and fall into the common
errors of the average man when we step outside our own specific field.
Many of us have considerable fog in our brains and clay in our feet, and
this is discerned by leaders in other human endeavors, and by the man in
the street. Scientists frequently become dogmatic both inside and outside
of their own fields, and it may therefore legitimately be asked: if the very
high-priests of science thus fail to be influenced by the spirit and method
of science, what hope can there be for the rank and file?

(3) The third factor is the tremendous resistance of man to new ways
of thinking and new ways of life. During the past million years that man
has evolved under the influence of the non-scientific or raw environment,
he has developed emotions and habits and drives that are not easily, speed-
ily, or permanently modified by the environments and techniques de-
veloped by man himself through science. There is no use crying over this
situation. It is one of the recognized scientific facts, and we must accord-
ingly work toward the goal with longer vision and greater tolerance and
patience. Science as an educational and social force is but of yesterday.
Man has been exposed for ages to the fundamental ethics of the great re-
ligions, using the elements of fear, punishment, and perpetual reward as mo-
tives, something that science cannot do. And yet the effects of this exposure
seem neither significant nor lasting.

From all the evidence now available it seems clear that in the past greed,
guile, and violence had survival value for primitive man. Assuming that
these drives can be curbed on a national and international scale by the new
mores based on understanding, reason, and emerging justice, will the latter
have equal survival value in and for the kind of society we hope to build?
My answer is yes, with this proviso: I think we must apply new and dif-
ferent measures to reduce the number of the antisocial, the less fit. We have
enough information to make a beginning in that direction now, but preva-
lent mores prevent it. Unless reason based on understanding effectively
guides social evolution of tomorrow in the direction of elimination or re-
duction in the number of the less fit, those who cannot or will not strive
for the individual and the common good, I see no escape from the de-

BIOLOGICAL PHILOSOPHY 43 I

generation that seems to follow biological parasitism, except the ancient
law of tooth and claw.

Now, I shall try to say in one minute what I probably failed to make
clear in fifty. As I see it, ours is not an age of science. Man is still driven by
greed and confused by guile, rather than guided by reason and justice based
on our expanding knowledge. Science has greatly enlarged man's under-
standing, conquered many of his diseases, lengthened his life, multiplied
his joys, decreased his fears, and added much to his physical comforts and
powers. But man may use these and other achievements for a greater social
injury, instead of for a further social advance. Science is specifically human,
in that it stems from the innate curiosity of all men, and the conspicuously
plastic brains of the ablest, if not the noblest, of our fellows. If this be so, it
follows that the scientific method and its products cannot be, in any funda-
mental and permanent sense, in conflict with human nature, though our pres-
ent human society, product of a past dominated by greed, force, and fear,
may be, and is in conflict with the scientific method. Whether science and
the scientific method, whether understanding, honest}^ reason, and justice
can contrive survival values equal, if not superior to the blind forces of na-
ture which shaped man's past, is as yet in the laps of the gods. Still, we can-
not deny the possibility, and we will nurse the hope, that the hairy ape who
somehow lost his tail, grew a brain worth having, built speech and song out
of a hiss and a roar, and stepped out of the cave to explore and master the
universe, may some day conquer his own irrational and myopic behavior
towards his kin.

THE BIOLOGIST LOOKS AT MAN *

JULIAN S. HUXLEY

The Western world today is caught in an apparent dilemma between
two conflicting modes of thought. The one thinks in terms of absolutes —
the absoluteness of truth, beauty, justice, goodness, themselves all deriving
from an Absolute of absolutes, which is God. The natural world is com-
plemented by the supernatural, the body by the soul, the temporal by the
eternal. This view gives an essentially static world picture; the flux of
events is merely change, in which the only progress is a spiritual one, to-
ward the perfection of eternal values. Empiricism and the experimental
method are alien to it; the absolute of Revelation and the absolute of pure
Reason will between them answer all the questions that can be answered.
Man's place in the universe is the place of an eternal soul, created by God,
and working out its destiny in terms of eternal values.

• Reprinted from Living In a Revolution by Julian S. Huxley with the permission of
Harper and Brothers. Copyright 1942, by Julian S. Huxley.

432

READINGS IN BIOLOGICAL SCIENCE

The other is the scientific method. It subjects the conclusions of reason
to the arbitrament of hard fact to build an increasing body of tested knowl-
edge. It refuses to ask questions that cannot be answered, and rejects such
answers as cannot be provided except by Revelation. It discovers the re-
latedness of all things in the universe — of the motion of the moon to the
influence of earth and sun, of the nature of the organism to its environment,
of human civilization to the conditions under which it is made. The super-
natural is in part the region of the natural that has not yet been under-
stood, in part an invention of human fantasy, in part the unknowable. Body
and soul are not separate entities, but two aspects of one organization, and
Man is that portion of the universal world stuff that has evolved until it is
capable of rational and purposeful values. His place in the universe is to
continue that evolution and to realize those values.

These two ways of approaching and thinking about the universe are ir-
reconcilable— as irreconcilable as is magic with scientific agriculture, witch
doctoring with preventive medicine, or number mysticism with higher
mathematics. Because our thinking still contains elements from both, it and
we are confused.

To me, this mixing of two totally different kinds of thinking can only
lead to confusion. When men assert that the scientific approach is incom-
plete, it is because they have not been willing to follow it to its final con-
clusion, or because they are mistaking an early stage in its growth for full
development.

Science inevitably began by trying its hand on the simpler phenomena
of nature. Its first triumphs were in mechanics, including the spectacular
celestial mechanics of Newton. It next proceeded to simple physics, like
the gas laws or the decomposition of white light. Chemistry, even elemen-
tary chemistry, did not take real shape till a century later. The life sciences
developed later than those of lifeless matter, for the sufficing reason that
they deal with more complex phenomena. Physiology had to wait on
physics and chemistry before it could become scientific. The central fact
of biology, evolution, was not established until modern science had been
in existence for over two hundred years; the mysteries of heredity did not
become clear until well on in the present century. In the same way the
science of mind developed later than biological science.

Scientific method today has reached about as far in its understanding of
human mind as it had in the understanding of electricity by the time of
Galvan and Ampere. The Faradays and Clerk Maxwells of psychology are
still to come; new tools of investigation, we can be sure, are still to be dis-
covered before we can penetrate much further, just as the invention of the
telescope and calculus were necessary precursors of Newton's great gen-
eralizations in mechanics.

However, even with the progress that science has already made, it is pos-
sible to give a reasonably coherent world picture based on the scientific

BIOLOGICAL PHILOSOPHY 433

approach; and this contains elements of the greatest importance to our
philosophy and to our practical outlook. One is that the universe is not
dualistic but monistic; another is the incorporation of values within the
scientific picture, and a reconciliation of their absoluteness in principle
with their relativity in practice; a third is the real existence of progress in
evolution; a fourth is the complete and sole responsibility of man for achiev-
ing any further progress that may be made on this planet, and the falsity
of all his attempts to shift any of the burden of his responsibilities onto
the shoulders of outside powers; and a fifth is the establishment of the de-
veloped human personality as the highest product of the universe (or at
least the highest product of which we have any knowledge), with all the
implications of this fact for our social and political philosophy.

DARWIN IS VINDICATED

Let me take these points one by one, to show their interconnection. The
way of advance for truth is in general the same as the way of advance for
existing life: of two alternatives, one dies out, not because the other destroys
it directly, but because it is less fitted to survive. Even after Copernicus,
the doctrine that the sun goes round the earth could still be logically main-
tained. But it demanded enormous complexity of epicycle upon epicycle.
The rival theory that the earth goes round the sun was far simpler and more
satisfying; in the climate provided by developing civilization it survived,
the other simply died out of human thinking.

The monistic, unitary vaew of the universe will survive for the same kind
of reason. Our scientific knowledge now permits us to assert definitely that
there is no break in the continuity of phenomena. All matter, living or life-
less, is composed of the same units — all the millions of diff"erent lifeless sub-
stances, as well as of living species, are made of different combinations of
still more elementary particles (or "Wavicles"). In reproduction, there is
no moment at which life enters; there is continuity of life between the off-
spring and its parent or parents. The offspring is merely a detached portion
of the parental living svibstance. Nowhere in the transformation of micro-
scopic ovum to adult human being is there a break at which one can say
"here mind appears," or "there personality enters"; development is con-
tinuous.

It is the same with the vast process of organic evolution. Here too grad-
ualness and continuity reign; there is no moment at which we can say that
reptile ends or bird begins, no definite demarcation between man and not-
man, no sharp line at which we must or indeed could postulate the sudden
injection of thought or soul into evolving life. The ideas of evolution by
brusque mutations of large extent have disappeared: with the new knowl-
edge of the last twenty years the overwhelming consensus of biology has
returned to support Darwin's original view of the extreme gradualness of
all evolutionary change.

434 READINGS IN BIOLOGICAL SCIENCE

THE QUICK AND THE DEAD

What then becomes of the apparent dualism between matter and spirit?
Many philosophers persist in affirming that the only alternative is mate-
rialism, according to which mind is "a function of the body (matter), and
depends upon it completely." This is an easy thesis to demolish; and having
demolished it, they can conclude that the dualistic alternative is true. The
real alternative to dualism they have conveniently omitted to mention.

The only logical alternative to dualism is monism — that matter and mind
are two aspects of one reality, that there exists one world stuff, which re-
veals material or mental properties according to the point of view. Looked
at from the outside, the world stuff has nothing but material properties;
its operations appear as mind only to itself, from within.* The first objec-
tion to this, that we have experience of the minds of other people, disappears
when we remember that this experience is not direct, as is the experi-
ence of our own psychic processes, but indirect, deduced from other peo-
ple's behavior (including expression and verbal behavior), combined with
our knowledge of our own minds. The second objection, that a dead man
still has the same body as a live one, and therefore differs by the loss of a
living soul, is still more easily disposed of. A dead body is not the same
as a living body: the chemical conditions in it — for instance the presence
of enough oxygen for the functioning of the tissues — are different. If you
substitute oil for acid in the battery of your automobile, no current will
pass.

But if the world stuff is both matter and mind in one; if there is no break
in continuity between the thinking, feeling adult human being and the
inert ovum from which he developed; no break in continuity between man
and his remote pre-amoebic ancestor; no break in continuity between life
and not-life — why then mind or something of the same nature as mind
must exist throughout the entire universe. This is, I believe, the truth. We
may never be able to prove it, but it is the most economical hypothesis:
it fits the facts much more simply than does any dualistic theory, whether
a universal dualism or one that assumes that mind is suddenly introduced
into existing matter at a certain stage, and very much more simply than
one-sided idealism (in the metaphysical sense) or one-sided materialism.

THE SIGNIFICANT ELECTRIC EEL

The notion that there is something of the same nature as human mind
in lifeless matter at first sight appears incredible or ridiculous. Let us, how-
ever, illustrate its possibility by considering certain well-established bio-
logical facts concerning electricity. Apart from lightning, the only power-
ful electric phenomena known before the late eighteenth century were
the electric shocks produced by the electric eel, the electric ray, and one

* Mind is used here broadly, to denote all psychical activity and experience, con-
scious or subconscious, sensory, emotional, cognitive and conative. — Ed.

BIOLOGICAL PHILOSOPHY 435

or two other kinds of fish. The production of electricity by hfe might
justly have appeared as something rare and sporadic. However, as physi-
ology progressed, it was found that electric currents pass when a nerve
is stimulated, when a muscle contracts, when a gland secretes; in fact we
know that all vital activities, of whatever kind, from conscious thought
to the fertilization of the egg, are accompanied by some electrical activ-
ity.

In the electric eel, certain muscles have been modified so that though they
have lost their original function of contraction, their electric discharges
are accumulated as in a galvanic pile, and the total voltage and current are
quite respectable. Whereas in the great majority of cases the electrical
properties of living matter play no special part in the life of the animal, they
have become the specific function of the eel's electric organs: an accident
of nature has become biologically significant.

One may suggest that the same sort of thing has happened with mind. All
the activities of the world stuff are accompanied by mental as well as by
material happenings; in most cases, however, the mental happenings are
at such a low level of intensity that we cannot detect them; we may per-
haps call them "psychoid" happenings, to emphasize their difference in in-
tensity and quality from our own psychical or mental activities. In those
organs that we call brains, however, the psychoid activities are, in some
way, made to reinforce each other until, as is clearly the case in higher
animals, they reach a high level of intensity; and they are the dominant and
specific function of the brain of man.

In evolution, science has not merely revealed the bridge that provides
continuity between man and lifeless matter, but has also discovered what
is perhaps the most important single biological fact yet known — the fact of
evolutionary progress. A great deal of evolution is mere diversification.
New species constantly arise, adapted to slightly different conditions, or
produced by the biological accidents of isolation or hybridization. Through
this frill of diversity, however, there can be perceived a series of long-
range trends, whose course runs for millions or tens of millions of years.
The great majority of these trends are specializations. They fit the existing
type more closely to one mode of life, and in so doing cut it off from suc-
cess in others. In the evolution of higher mammals, for instance, one line
specialized as predators, and became the carnivores; another specialized in
chewing and digesting foliage and herbage, and usually in swift running,
to become the ungulates; a third in flying — the bats; a fourth in marine life
— the whales and porpoises; and so on. It is a universal rule that one-sided
specializations eventually come to a dead end. There is a point beyond
which natural selection cannot push them. When a specialization has
reached its biomechanical limit, it remains unchanged — unless new com-
petition causes it to become extinct. Thus most mammals have not evolved
in any important way for ten or twenty million years, birds not for twenty
or twenty-five million, ants not for thirty million.

43 6 READINGS IN BIOLOGICAL SCIENCE

EVOLUTION OF PERSONALITY

To assert that man is the highest product of evolution to date is a state-
ment of simple biological fact. There are, however, some other points con-
cerning man's position relative to evolutionary progress that are less
obvious. First is the curious fact that the human species is now the sole re-
pository of any possible future progress for life. When multicellular ani-
mals first appeared, they all had reached a new level of progress: later, some
cut themselves off from further advance by entering on blind alleys, such
as the fixed, vegetative existence of the polyps and corals or the headless-
ness and radial symmetry of the starfish and other echinoderms. The process
of restriction has now gone so far that all future progress hangs on human
germ plasm. It is a biological impossibility for any other line of life to
progress into a new dominant type — not the ant, the rat, nor the ape.

Second, with the evolution of man, the character of progress becomes
altered. With human consciousness, values and ideals appeared on earth
for the first time. The criteria of further progress must include the degree
to which those ideal values are satisfied. The quest for truth and knowl-
edge, virtue, beauty and aesthetic expression, and its satisfaction through
the channels of science and philosophy, mysticism and morality, literature
and the arts, becomes one of the modes or avenues of evolutionary progress.

It is also important to note that biological progress demands no special
agency. In other words, it does not require the intervention of a conscious
Divine purpose, nor the operation of some mysterious life force or ela7i
vital: like most other facts of evolution, it is the automatic result of the
blind forces of reproduction, variation, and differential survival. Newton's
great generahzation of gravitational attraction made it possible and indeed
necessary to dispense with the idea of God guiding the stars in their courses;
Darwin's equally great generalization of natural selection made it possible
and necessary to dispense with the idea of God guiding the evolutionary
courses of life. Finally the generalizations of modern psychology and com-
parative religion make it possible, and necessary, to dispense with the idea
of God guiding the evolutionary courses of the human species, through
inspiration or other form of supernatural direction.

REPRESSION IS NORMAL

A corollary of the facts of evolutionary progress is that man must not
attempt to put off any of his burden of responsibility onto the shoulders
of outside powers, whether these be conceived as magic or necessity, as
life force or as God. Man stands alone as the agent of his fate and the trustee
of progress for life. To accept his responsibility consciously is itself an im-
portant step toward more rapid progress. Here is a field where a philosophy
based on the scientific outlook is of the utmost practical importance.

But the problem that most perplexes our present age remains the ques-

BIOLOGICAL PHILOSOPHY 437

tlon of moral certitude. As Dean Sperry says, it is the loss of the "ethical
universals," with which Christianity has equipped Western civilization,
that creates the "grave moral perplexities" of the present. This is where
modern psychology enters the picture. For a justification of our moral code
we no longer have to have recourse to theological revelation, or to a meta-
physical Absolute; Freud in combination with Darwin suffice to give us
our philosophic vision. The great contribution of Freud was the discovery
of the unconscious mind. What matter if logicians assert that the phrase
is a contradiction in terms? It is now firmly established that through the
process known as repression, desires and ideas, emotions and purposes, can
be forced out of consciousness, or at least out of contact with the main or-
ganization of consciousness that we call the self or ego. They are then "in
the unconscious," but in the unconscious they continue operating just as if
they were ordinary processes of the mind, and they are still able to influence
the conscious life of the ego in the most varied ways.

Repression is the banishment from consciousness of desires and ideas that
produce otherwise intolerable conflict. It is a special form of what psy-
chologists and neurologists call inhibition. The repressed ideas are so in-
tolerable that consciousness \\'ill not even recognize their existence or
examine them rationally; yet they are so powerful that they distort con-
sciousness itself.

It has not, I think, been sufficiently recognized that repression is normal
in man. Man is the only organism whose mind is so constructed that con-
flict is inevitable. The young child is subjected to powerful conflicts even
before it can talk and reason, and long before it has adequate experience
to resolve a conflict rationally. Repression is thus an adaptation to conflict,
especially to early conflict; in its absence, the degree of assurance necessary
for action and adjustment would be impossible.

Undoubtedly the picture of human psychology given by psychoanalysts
and other modern dynamic theories is crude and incomplete, but equally
undoubtedly it is a first approximation to the truth.

Its importance for philosophy, and especially for ethics, is enormous,
for it enables us to understand how ethical and other values can be abso-
lute in principle while remaining obstinately relative in practice; and in
conjunction with our knowledge of evolution, it enables us to reconcile
absolutism and relativism by uniting them in the concept of right direction.

THE ETHICAL CONFLICT

When, however, we come to practice, we find ourselves plunged back
into the confusion of the relative. For instance what will be the right way
of treating Germany? The absolute principle of justice makes us feel the
demand that crime should be punished. But, applied to the Germans, does
this mean punishing Hitler, the Nazi leaders, all those directly guilty of
cruelty and injustice, or the whole German people? Furthermore, the ab-

438 READINGS IN BIOLOGICAL SCIENCE

solute principle of justice conflicts with the equally absolute principles of
mercy and love. And finally these absolute emotional principles come in
conflict with the frankly utilitarian principles like the greatest good of the
greatest number, whose application must be decided rationally and rela-
tively to circumstances. Clearly one course will prove to be more right
than another; but in deciding which to adopt, the so-called absolute ethical
and moral principles will only take us part way.

The same is true of the individual. As he grows up, he finds that his ap-
parently absolute ethical values constantly need the assistance of relativism,
in the shape of rational judgment in the light of experience, if they are to
be applicable to particular situations. It is wrong to lie; but we all know
circumstances where it is more wrong to tell the truth. It is wrong to take
life; but it needs rational judgment to decide whether this applies to war,
to certain cases of suicide and abortion, to euthanasia, to birth control.

In fact, one of the chief tasks before each individual is to make a rational
and relative adjustment of the apparent absolute of his primitive ethics,
derived from infantile repression, to the practical realities of life. To ac-
complish this, it may even be necessary that the original structure of re-
pressed and repressing forces be destroyed, whether by some violent emo-
tional or rehgious experience, or by the deliberate "mental operation" of
psychoanalysis or other form of psychotherapy.

The task before us, as ethical beings, now begins to take shape. It is to
preserve the force of ethical conviction that springs up naturally out of
infantile dependence and the need for inhibition and repression in early
life, but to see that it is applied, under the correctives of reason and experi-
ence, to provide the most efficient and the most desirable moral framework
for living. This will undoubtedly mean radical changes in the early up-
bringing of children, as well as in the methods of education and in accepted
religions and codes of ethics. For instance, sociologists are beginning to
realize that existing ethico-religious systems often contain a large element
of psychological compensation: they compensate for the miseries of this
world with the bliss of a world to come, they compensate for ignorance
of fact with certitude of feeling, they compensate for actual imperfec-
tions of ethical practice by setting up impossible ethical ideals. This is not
merely hypocrisy; it is a primitive method of self-defense against a hard
and difficult reality.

Again, it is becoming clear that harshness of punishment in early life
tends to the development of a morally vindictive superego: other methods
are required for the development of character where the aggressive and
sadistic impulses are kept subordinate. The most difficult lesson to learn is
that irrational and intolerant certitude is undesirable. We have seen how
this applies to truth: the lesson is difficult there also, but science has learned
it. It will be even more difficult to learn in ethics: but it must be learned
if we are to emerge from psychological barbarism. To cUng to certitude

BIOLOGICAL PHILOSOPHY 439

is to prolong an infantile reaction beyond the period when it is necessary.
To become truly adult, we must learn to bear the burden of incertitude.

MAN IS the' MEASURE OF PROGRESS

I would draw some such general and final conclusion as this. A scientifi-
cally based philosophy enables us in the first place to cease tormenting
ourselves with questions that ought not to be asked because they cannot be
answered — such as questions about a First Cause, or Creation, or Ultimate
Reality. Secondly, it encourages us to think in terms of right direction and
optimum speed in place of complete but static solutions. At the present
moment, for instance, it is much more essential to know that we are moving
with reasonable speed toward certain general types of supernational co-
operation than to nail some elaborate blueprint of international organiza-
tion to our masthead. Thirdly, it is capable of giving man a much truer pic-
ture of his nature and his place in the universe than any other philosophic
approach. Man is now the dominant biological type, and the developed
human individual the highest product of the cosmic process that we know.
That is a proud piece of knowledge. It is tempered by the reflection that
very few human individuals realize a fraction of their possibilities, and that
in a large proportion, passive or active evil predominates. But the knowledge
has important practical bearings. Once we realize that the development of
individuals is the ultimate yardstick by which to measure human progress,
we can see more clearly how to formulate our war aims.

The fact that we, all the human beings now in existence, are the exclusive
trustees for carrying any further the progress already achieved by life is a
responsibiHty which, if sobering, is also inspiring; as is the fact that we have
no longer either the intellectual or the moral right to shift any of this re-
sponsibility from our own shoulders to those of God or any other outside
power. Indeed, the problem that appears to be the most perplexing and dis-
tressing turns out, in the light of a thoroughgoing scientific approach, to
be full of encouragement. I mean the problem of ethical and other values.
We have been accustomed to think of these as a scaffolding for our morals,
conveniently run up for us by some outside agency. Now that this is no
longer possible, we feel bewildered, unable to conceive of any firm moral
construction in which we can abide. The truth, however, as shown by the
extension of scientific method into individual and social psychology, is
that we create our own values. Some we generate consciously; some sub-
consciously; and some only indirectly, through the structure of the societies
in which we live. Through a fuller comprehension of these mechanisms we
shall be able to guide and accelerate this process of value creation, which
is not only essential for our individual lives but basic to the achieving of
true evolutionary progress in the future.

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MEET THE AUTHORS

Below will be found a very short sketch of the interests and accomplishments
of the men and women who have contributed to this volume. It is unfortunate
that space does not permit a more extended treatment of each author. Most of
the people below are cited in Who's Who, American Men of Science and similar
books.

ArEY, dr. LESLIE B.

Robert Laughlin Rea Professor of Anatomy, Northwestern University. Au-
thority on the sense organs, sensory behavior, mammalian histology, and
embryology.

Aristotle
Called by many "The Founder of Natural History." Aristotle lived from 384
B. c. to 322 B. c. and was Plato's most famous pupil. His writings were volumi-
nous, authoritative for that period and his influence has lasted for many
centuries. He did pioneer work on the classification, structure and physiology
of organisms and ascertained many important facts of biology, a remarkable
achievement considering the general ignorance of such matters in his day.

Bahm, dr. archie j.

Associate Professor, Department of Philosophy, University of Denver. Well-
known writer of articles on philosophy having written thirty articles, iovxy
book reviews, and several books.

Bulla, paul

Veteran newsman and writer.

Butler, dr. elmer g.

Professor and Head of the Zoology Department, Princeton University. Well-
known in the fields of comparative anatomy, embryology, and x-radiation.

Carlson, dr. anton j.
Emeritus Professor of Physiology, University of Chicago. One of the great
physiologists and teachers of our times, Dr. Carlson has received honors from
many institutions for his work in the nervous, alimentary, circulatory and
endocrine svstems.

Chester, dr. k. starr
Professor and Head of the Department of Botany and Plant Pathology, Okla-
homa A. and M. College. Dr. Chester is keenly interested in plant im-
munology, virus diseases, cotton and wheat diseases and research in general.

CONARD, dr. henry S.

Retired Head of the Biology Department at Grinnell College, Iowa. Dr. Con-
ard is a biologist of note. His studies in the Bryophytes and water lilies are re-
garded very highly by his colleagues.

CONKLIN, DR. EDWIN G.

Emeritus Professor of Zoology, Princeton University. Dr. Conklin has re-
ceived honorary Doctor's degree from many institutions and has held many
positions of trust in the scientific world. His interests lie especially in the
fields of embryology, cytology, heredity, and evolution.

440

MEET THE AUTHORS 44 1

Cutting, c. suydam

Member of many expeditions to central Asia, Tibet, Abyssinia and Burma for
the American Museum of Natural History and the Chicago Museum of Nat-
ural History.

Darwin, charles

Darwin's name is known to every school child, at least from the secondary
school level upwards. He was born in 1809 and died in 1882. Darwin is re-
nowned for his Theory of Natural Selection by means of which he attempts
to explain how evolution operates. It may be safely said that his work did more
to stimulate scientific endeavors along modern research lines than any pre-
ceding book. In addition to his work on Natural Selection, Charles Darwin
did notable works on animals and plants under domestication, the descent of
man, fertilization in the orchids, and earthworms, to mention the most im-
portant.

Edge, rosalie
Dynamic leader of the Emergency Conservation Committee.

FeNTON, dr. CARROLL LANE

Writer and humanizer of scientific knowledge, Dr. Fenton is also well-
regarded for his exact studies of various fossil groups especially the Brachio-
pods.

GarBEDIAN, H. GORDON

Journalist with the New York Times. Writer on science, Mr. Garbedian has
published five books on science and scientists.

Gordon, seth
Executive Director, Pennsylvania Game Commission.

GUYER, DR. MICHAEL F.

Professor of Zoology, University of Wisconsin. Dr. Guyer is an authority in
many fields such as cytology, experimental evolution, genetics and em-
bryology but lately he has turned his attention to the field of biological phi-
losophy, in which, incidentally, he is unexcelled.

Haggard, dr. howard w.
Director of the Laboratory of Applied Physiology, Yale University. Besides
having the ability to write lucidly for the public, Dr. Haggard has delved into,
with more than the ordinary amount of success, the fields of anesthetics, and
resuscitation from carbon monoxide poisoning.

HaLLOCK, GRACE T.

Director, Health and Welfare Publications Bureau, Metropolitan Life Insur-
ance Company.

HaMNER, DR. KARL C.

Director of the United States Plant, Soil and Nutrition Laboratory, Cornell
University.

Hippocrates
The most famous of the early Greek physicians, Hippocrates lived from 460-
377 B. c, although there is some uncertainty' about these exact dates. Some of
our present medical knowledge had its foundation in the work of Hippocrates
and his followers. They had a fairly good idea of the bones and muscles of
the body, the cavities of the heart and the general structure of the eye and the
ear. When one considers that dissections of the human body were not per-
formed after death and that chemistry and chemical experimentation on ani-
mals was almost unknown, one must be impressed with the amount of accurate
information that the early Greeks were able to acquire.

442 READINGS IN BIOLOGICAL SCIENCE

Holmes, dr. s. j.
Professor of Zoology, University of California. He has done much research in
the molluscs, in embryology, evolution and genetics and is well known for his
late work in the new field of eugenics. An eminent scholar.

HOWELLS, DR. W. W.

Department of Anthropology, University of Wisconsin. Dr. Howells
formerly held positions at Hunter College and the American Museum of
Natural History. He is working in the fields of racial history, and the anthro-
pology of populations.

Hunt, dr. willis r.
Lafayette College. He has done work on the rust fungi and the bacteria.

Huxley, julian

Grandson of Thomas Henry Huxley, champion of Darwin, and brother of
Aldous Huxley. Julian Huxley was Professor of Zoology at King's College,
London and Fullerian Professor of Physiology at the Royal Institution. It is
not well-known but he also taught at our own Rice Institute for four years.
He is active in the Zoological Society in London, Institute of Animal Behavior,
Eugenics Society and is associated with the Encyclopedia Britannica. He has
written or co-authored about twenty-eight books.

Huxley, thomas h.

Huxley was an English scientist who lived from 182 5- 1895. He is renowned
chiefly for his staunch support of Charles Darwin and his vigorous and skillful
defense of Darwin's views on evolution. However he did a vast amount of
original work in morphology and paleontology and therefore can be called a
scientist in his own right.

IlTIS, dr. HUGO

Profesor of Biology, Mary Washington College. Dr. litis was born in Briinn,
Czechoslovakia (sometimes spelled Brno) the place where Mendel did his
epochal work. Of course Brno was formerly in Austria. He has devoted his
life to a study of Mendel.

JaFFE, BERNARD

Head of the Department of Physical Science, James Madison High School,
Brooklyn, N.Y. Mr. Jaffe is the author of six textbooks in science and numerous
articles. He won the International Francis Bacon Gold Medal for his work
in humanizing knowledge. His books have been translated into several lan-
guages including Braille.

Johnson, dean victor e.

Dean of students in Biology and Medicine, University of Chicago. Dr. John-
son holds both the Ph.D. and M.D. degrees and is an authority on the circu-
latory system.

KiENAST, MARGATE

Author, editor, educational advisor, United States Forest Service.

KrOGMAN, dr. WILTON MARION

Anthropologist and Anatomist, University of Chicago. He is interested par-
ticularly in the comparison of growth in face and skull, racial differences in
human anatomy, and in child development.

Large, e. c.

Large is an English author and like several of his countrymen has succeeded
in bringing a deep subject into focus for the laymen.

MEET THE AUTHORS 443

LeEUWENHOEK, ANTONY VAN

A famous student of minute objects. Born in 1632, died 1723. Held numerous
jobs during which he carried on his scientific investigations with the aid of
lenses and simple microscopes- which he fashioned himself. Wrote over 400
letters describing his findings. Called the "Father of Protozoology and
Bacteriology" because he was the first to see living protozoans and bacteria
under a lens. Also the first actually to see blood circulating, noted the stripe
in voluntary muscles, structure of the crystalline lens and the morphology of
the sperm.

Lewis, dr. paul a.
Dr. Lewis was associated with the Rockefeller Institute. A martyr to science,
he died in Brazil while investigating the cause of yellow fever.

Linton, dr. ralph
Department of Anthropology, Columbia University. The fields of the
ethnology (study of races) of Polynesia and Madagascar claim much of his
attention.

MaTZKE, dr. EDWIN B.

Associate Professor of Botany, Columbia University. Dr. Matzke is working
on general problems of cell size and shape and has worked out some interest-
ing techniques here.

Mickey, karl b.
Late member of the Public Relations Department, International Harvester
Company.

MOHR, DR. OTTO L.

Professor of Medicine, Royal Frederick University, Oslo, Norway.

Morgan, dr. thomas hunt
Late professor at the California Institute of Technology. Dr. Morgan prob-
ably did more to further Mendelism than any other man. He has been
honored by at least eight Universities with honorary degrees for his work in
experimental embryology, heredity, sex, genes and the genetics of Drosophila.

Newman, dr. horatio h.

Emeritus Professor of Zoology, University of Chicago. Dr. Newman is known
chiefly for his textbooks and his work on twins but evolution and animal be-
havior are also his major studies.

OSBORN, brig, general FREDERICK

Chief of Special Service, War Department and Director of the Eugenics
Research Association. He is also Director of the Galton Society, a group
interested in the study of eugenics.

OVERHOLSER, DR. WINFRED

Superintendent of St. Elizabeth's Hospital, Washington, D.C. He has both
the M.D. and the Ph.D. degrees and has been associated with many state
hospitals and mental institutes. He is regarded as a leader in the fields of
psychiatry, hospital administration and gerontology (the study of old age.)

Patri, angelo
Teacher and principal in New York City public schools since 1898. Associated
with "Children's Activities."

Pearse, dr. a. s.
Zoology Department, Duke University. Dr. Pearse has been honored in many
places for his pioneer work in ecology.

444 READINGS IN BIOLOGICAL SCIENCE

PeATTIE, DONALD CULROSS

Botanist and author, one-time government scientist. Mr. Peattie has authored
or co-authored about twenty-five books which deal mostly with botany,
zoology, and nature in general.

Pliny
This is Pliny the Elder who lived in Italy from a. d. 23 to a. d. 79. Prior to his
scientific endeavors "he was commander of a cavalry squadron, a student of
law, Procurator of Spain, and holder of a naval commission. His scientific
curiosity caused his death for he approached too close to fuming Vesuvius
which was in eruption at the time. Pliny was mostly a collector and relater of
scientific information putting down fact and error with equal emphasis.

RaDL, professor EMANUEL

Professor of Natural History, University of Prague.

Rife, dr. david c.
Associate Professor of Zoology, Ohio State University. Dr. Rife, in addition
to writing a popular book on heredity, is doing work on the inheritance of
tuberculosis and intelligence in twins.

SCHEINFELD, AMRAM

Writer, New York City. Mr. Scheinfeld presents one of those rare and happy
combinations between fluid writing and accuracy. His two books on heredity
are widely read and one. You and Heredity has been translated into many
languages and was also a Book of the Month selection.

Schwartz, dr. benjamin
Principal Zoologist and Chief of the Zoological Division, Bureau Animal
Industry, U.S. Dept. Agriculture. He was born in Austria-Hungary but has
his Ph.D. from George Washington. He is an authority on parasitic worms
and the diseases caused by them.

Snyder, dr. laurence h.
Chairman of the Zoology Department, Ohio State University. His book on
heredity is one of the most popular and his researches on medical genetics,
blood groups, taste deficiency, and linkage in man are fundamental.

Theophrastus

Just as Plato's most famous pupil was Aristotle, so the latter's disciple was
Theophrastus who lived from 372 to 288 b. c. Theophrastus wrote on many
subjects but principally on plants and he has come to be known as "The
Father of Botany." Over two hundred and twenty-seven studies of plants
came from his pen. He knew over five hundred kinds of plants and was the
first to distinguish between flowering and flowerless plants, between angio-
sperms and gymnosperms, and, among other things, he recognized the true
nature of the fruit.

Turner, dr. c. e.
Professor of Public Health, Massachusetts Institute of Technology.

Vaughan, dr. warren

Late physician, Richmond, Virginia. Dr. Vaughan's practice leaned toward
allergy, immunology and influenza. He served on the editorial board of many
medical magazines.

VeRRILL, a. HYATT

Ethnologist, Archeologist. Mr. Verrill has traveled widely in his search for
ancient remains including the W. Indies, Central America, Bermuda, Domin-
ica Island, Santo Domingo, British Guiana, Panama, Peru, Chili, and Bolivia.

MEET THE AUTHORS 445

Ward, henshaw
Author of several popular science books.

Westgate, dr. lewis g.
Emeritus Professor of Geology, Ohio Wesleyan University. Dr. Westgate
has his Ph.D. from Harvard and was once associated with the United States
Geological Survey. He has done research on the Devonian flora and fauna of
Ohio.

Wilder, dr. russell m.

Mayo Clinic, Rochester, Minnesota. He has held important positions at Rush
Medical College and University of Chicago. His chief medical interests lie in
the fields of typhus fever, diabetes, metabolism, and nutrition.

Young, dr. robert t.

Scripps Institution of Oceanography, La Jolla, California. Dr. Young has held
numerous important positions in the biological field and is interested chiefly
in the development of certain parasitic worms, protective coloration, and the
biology of fishes.

»■>>»>>>>>>>>>>>>>>>>■>>■»><<<<<<<<<<<<■<■<<<■«<■<<<<<<<<

GOOD BROWSING

Biological Beginnings

NoRDENSKiOLD, ERIC, The History of Biology (New York, Tudor Publish-
ing Co., 1928).

One of the best of the histories of Biology.
Darwin, charles, The Origin of Species (London, edition i, 2, 5. 1859,
i860, 1872). Originally published in the United States by D. Appleton and
Company.

This book outlines Darwin's ideas on the method of evolution. It is quite

difficult reading but one should read bits of it from time to time.
Wallace, a. r., Darivinisvi; an exposition of the theory of Natural Selec-
tion with some of its applications (London, Macmillan Co., 1889).

Wallace arrived at much the same conclusions as did Darwin and at the

same time.
Galen, On the Natural Faculties (Cambridge, Mass., Harvard University
Press, Loeb Classical Library, English translation by Arthur John Brock,
1928).

Galen was one of the greatest of the early medical men and he is credited

with bringing Greek medicine to its peak.
Snyder, emily eveleth. Biology ifi the Making (New York, McGraw-Hill
Book Co., Inc., 1940).

This is one of the most interesting and readable accounts of biology.
LocY, wiLLLVM A., The Growth of Biology (New York, Henry Holt and
Co., 1925).

This treats of many of the important phases of biology in an interesting

way. The author's death prevented the publication of the second volume.

Life and the Cell

OsTERHouT, w. J. v., The Nature of Life (New York, Henry Holt and Co.
1924).

A small but good book covering the differences between the living and

the non-living.
ScHRODiNGER, ERWiN, What Is Life? (Cambridge, The University Press;
New York, The Macmillan Co., 1945).

This is a new book dealing with the physical aspects of the living cell but

life still remains a riddle.

The Structure and Function of Higher Plants

Ganong, WILLIAM F., The Living Plant (New York, Henry Holt and Co.

This is an old book but few write as interestingly about difficult subjects

as Dr. Ganong.
Swingle, d. b.. Plant Life (New York, D. Van Nostrand Co. Inc., 1942).

A textbook of botany but very easily read.
Wilson, ernest h.. The Romance of Our Trees (New York, Doubleday,
Page and Co., 1920).

The inside story of trees and man.

446

GOOD BROWSING 447

Nutrition

Macy, icie g. and Williams, harold h., Hidden Hunger (Lancaster, Penna.,
Jacques Cattell Press, 1945).
One of the most readable volumes dealing with food and nutrition.

Circulation

Wilder, -HARRIS hawthorne, The History of the Human Body, Rev. Ed.,

(New York, Henry Holt and Co., 1923).
This well-known book discusses the development of the circulatory sys-
tem among other things. Very advanced.

Nervous and Endocrine Control of the Body

RoMER, ALFRED SHERWOOD: Man and the Vertebrates (Chicago, Univ.
Chicago Press, 1941).

This has a good account of the nervous system as well as fascinating

pictures in other fields.
Dorse Y, george a.. Why We Behave Like Hwnan Beings (New York,
Harper and Brothers, 1925).

This is still one of the popular books in its field. While it covers a

tremendously wide field, it deals largely with human behavior.

Reproduction

Brambell, f. w. ROGERS, The Development of Sex in Vertebrates (New
York, The Macmillan Co., 1930).
Difficult reading for freshmen but full of worthwhile information.

Embryology

HuETTNER, ALFRED F., Fundamentals of Comparative Embryology of the
Vertebrates (New York, Macmillan Co., 1943).
The pictures of human embryos in this volume will be of interest to
students.

Heredity

Rife, david c, The Dice of Destiny (Columbus, Ohio, Long's College Book
Co., 1945).

A small but very readable and interesting book. Recommended highly

for elementary students.
Holmes, s. j., Human Genetics and its Social Import (New York,
McGraw-Hill Book Co., 1936).

This is one of Dr. Holmes' latest and best books and is of special interest

to those students of biology who are interested in man.

Eugenics

Holmes, s. j., The Eugenic Predicame?it (New York, Harcourt, Brace and

Co., 1933).
A fine treatise on the well-born and the ill-born.

Hunt, harrison r.. Some Biological Aspects of War (New York, Galton

Publishing Co., Monograph Series II, 1930).
Too seldom is the effect of war on the caliber of the human race under-
stood. A work for thoughtful students.

Evolution

Clark, Austin h., The New Evolution, Zoogenesis (Baltimore, Williams

and Wilkins Co., 1930).
Dr. Clark writes better than most scientists about this involved and con-
troversial subject of evolution.

448 READINGS IN BIOLOGICAL SCIENCE

Mason, Frances, Creation by Evolution (New York, The Macmillan Co.,
1928).

This is an interesting collection of essays on evolution by leading

biologists.
Ward, henshaw. Evolution for John Doe (Indianapolis, Bobbs-Merrill Co.,

1925).

A book for laymen written by a layman. Thoroughly enjoyable and

simple enough for students.

Ecology

Pearse, a. s.. Animal Ecology (New York, McGraw-Hill Book Co. Inc.,
2nd Ed., 1939).

The student will find lots of good browsing material here although it is

primarily a textbook.
King, eleanor and Pessels, wellmer, Working with Nature (New York,
Harper and Bros., 1939).

Contains discussions about animals and their lives.

Health and Disease

Pearl, Raymond, The Biology of Death (Philadelphia, J. B. Lippincott Co.,
1922).

A study of the causes and chances of death written by a great scientist.

For advanced readers.
Causey, david. Uninvited Guests (New York, Alfred A. Knopf, 1932).

A short, humorous account of animal parasites.
DiEHL, HAROLD s., Textbook of Healthful Living (New York, McGraw-
Hill Book Co., 1945).

A book hard to lay down once it is started.
De kruif, PAUL, Men Against Death (New York, Harcourt, Brace and Co.,

1933)-
A fascinating series of accounts of the conquest of disease, written by a

well-known and well-liked author.

Economic Biology

Fernald, m. l. and Kinsey, a. c. Edible Wild Plants of Eastern North
A7/ierica (Cornwall-on-Hudson, New York, Idlewild Press, 1943).

This book tells of the great stores of wild foods which may be safely

utihzed.
Hill, albert f.. Economic Botany (New York, McGraw-Hill Book Co.
Inc., 1937).

A reference book on useful plants.
Reese, albert m.. Outlines of Economic Zoology (Philadelphia, Blakiston
Company, 4th Ed., 1942).

Contains information about the dollar and cent value of animals to man.

Interspersed with interesting anecdotes.
Howard, l. o.. The Insect Menace (New York, D. Appleton-Century Co.
Inc., 193 1 ).

Dr. Howard is not only an authority but a pleasing writer as well. The

problem of the danger of insects to man is forcefully told.

Biological Philosophy

Wheeler, william morton. Foibles of Insects and Men (New York,
Alfred A. Knopf, 1928).
Most of this book is too involved for beginning students but attention is

GOOD BROWSING 449

called to the chapter entitled "The Termitodoxa, or Biology and Society"
for a highly hilarious comparison of termite and human society written
by the late and incomparable Professor Wheeler under the pen name of
"The King of the Termites."

General

Beebe, WILLIAM, The Book of Naturalists (New York, Alfred A. Knopf,
1944).

A fine anthology of natural history collected by one of our best-known

scientists.
Andrews, roy chapman, This A^iiaziyig Planet (New York, G. P. Putnam's
Sons, 1940).

A collection of short interesting stories about this earth and the life upon

it; very enjoyable.
DiTMARs, RAYMOND L., Thrills of a Naturalist's Quest (New York, The Mac-
millan Company, 1932).

Students cannot become acquainted too early with Ditmar's fascinating

tales of adventure.
Kahn, FRITZ, Man in Structure and Function, 2 vols. (New York, Alfred
A. Knopf, 1946).

A great work but a little advanced for freshmen. The pictures, however,

are unique and must be looked at.
Olmstead, CHARLES E., The Story of Living Plants (Chicago, University of
Knowledge, Inc., 1938).

This is botany for the laymen and it does a much better job of it than

most similar attempts.