As an exact science biology is still very young. Evolution is in its

infancy. Only in our generation has it become the nucleus of a growing

body of experimental research. It may be that when the history of the

evolutionary hypothesis is written two centuries hence, Bateson’s

_Materials for the Study of Variation_ will assume a more prominent

place than _The Origin of Species_. It may be that the name of Thomas

Hunt Morgan will be mentioned in its pages more often than that of

Charles Darwin. We are too near the footlights to view the matter

in its correct historical perspective. It is at least permissible

to entertain such a possibility. Ancestor worship has no place in

the ritual of science. If any display of sentiment is appropriate in

scientific discussion, it might be said that the only fit way in which

to honour the memory of a Darwin and a Newton is to press forward in

exploring the fields which their labours have fertilized.

Without entering into technicalities I shall make the attempt in this

essay to contrast the use of the term Natural Selection in Morgan’s

writings with the Darwinian doctrine in its original form. My aim will

be neither to justify in the one case nor exculpate in the other, but

to discover whether a difference exists, wherein the difference lies,

and how the difference has arisen. In contrasting the views held by

two men of science it is of the utmost importance to lay emphasis on

the type of data which they have respectively studied most. Morgan is

an experimental geneticist. Darwin was pre-eminently a geographical

naturalist. Morgan’s most brilliant contributions to the advance of

science have been focused on the study of those conditions which

are significant to the origin and transmission of new hereditable

properties in animals. Before the publication of _The Origin of

Species_ Darwin’s scientific labours had concentrated more especially

on amassing a wealth of information about the way in which species are

distributed in different parts of the world. In his long itineraries,

it is not difficult to surmise what aspect of the species problem was

constantly uppermost in Darwin’s thought. I think it is necessary to

appreciate this bias in any attempt to understand the way in which the

Selection hypothesis developed. Though Darwin spoke of the Origin of

Species, he was interested primarily in why some species happen to be

found in one place and other species in different places. Darwin had

two distinct problems in view when he set out to write _The Origin of

Species_. In the course of writing it he sometimes lost sight of the

distinction between them. One was how different types of animals have

come to persist in different parts of the world. The other was how

an evolutionary process could take place at all. That the struggle

for existence is the key to the former is highly plausible. No facts

are known which contradict such a view. It is not really an issue

with which the modern experimentalist concerns himself. Up to this

point there is no divergence between the Darwinian and the Mendelian

standpoint. But Darwin in very unequivocal language committed himself

to the view that in building up new specific forms the struggle for

existence makes use of all differences between parent and offspring

of “whatsoever” origin. He thus implicitly encouraged the view that

natural selection is a creative agency. Herein lies a fundamental

difference between the standpoint adopted by Morgan and the Darwinian

doctrine. Darwin really believed in the Origin of Species by natural

selection. Morgan believes in the Origin of Gaps by natural selection.

It is perfectly true that Darwin did not formulate this deduction so

explicitly or so prominently as did some of his followers. But it was

logically implicit in his earlier writings and very definitely set

forth in his later. It was in virtue of this aspect of the Natural

Selection hypothesis that evolution captured the support of Darwin’s

contemporaries. Till Darwin’s book appeared, biologists did not for

the most part believe that evolution could take place. Darwin’s

hypothesis demonstrated that evolution must take place in a world in

which organisms had to struggle for their existence. The experimental

data which Morgan employs as the basis for his conception of the

evolutionary process imply that the reasons which led the pre-Darwinian

biologist to think that evolution could not take place are unfounded.

They also imply that the reasons which Darwin advanced to show that

evolution _must_ take place are wrong.

It is easier to make this distinction clear at a later stage with the

aid of a concrete example than by stating general propositions. This

is because one result of experimental progress has been a change in

our use of the concept of “variation.” Darwin used the term variation

for any difference between parent and offspring. In affirming that the

struggle for existence makes use of all variations for building up

species differences, he logically implied one of two things. Either

all differences between parents and offspring are genetic in origin,

that is to say, referable to differences in the egg or sperm; or

alternatively bodily modifications which occur during the lifetime of

an individual influence the genetic structure of the offspring so as

to produce an analogous result. This principle, usually associated

with the name of Lamarck, was accepted by every one in Darwin’s time.

Darwin himself, while ridiculing Lamarck’s idea of the _modus operandi_

of evolution, accepted the inheritance of acquired characters. There

was therefore no need for him to make a distinction between the

two alternatives. Neither the one nor the other is in harmony with

the standpoint of a modern geneticist of Morgan’s school; but the

difference between the Darwinian standpoint and that of Morgan concerns

not only the question of fact but the deductions drawn from it.

The difference between either of these alternatives on the one hand and

the Mendelian standpoint on the other can be illustrated by reference

to one of Mendel’s original experiments on the hybridization of peas.

In crossing pure-bred peas of the variety characterized by a dwarf

shoot with the normal tall variety, Mendel obtained only tall types

on the first generation, and in the second generation derived from

crossing the latter _inter se_ one-quarter were dwarf and the remaining

three-quarters tall. Now the individuals of either the tall or the

dwarf class are not all alike. Any dwarf shoot grown under ordinary

conditions is distinctly smaller than a tall shoot, so that the two

classes are discontinuous and quite easily distinguishable; but when

the conditions are standardized as much as possible small differences

of light, moisture, soil-content, temperature or proximity exert their

influence, so that no two dwarf plants are of exactly the same size.

What is transmitted through the gametes is something which determines

the extent to which an individual is capable of growing under

appropriate conditions. This distinction greatly clarifies our thought

about the so-called inheritance of acquired characters.

A criticism of the Lamarckian doctrine is irrelevant at this juncture.

It is referred to in this connexion because it was only in the

eighties, after the Lamarckian view was challenged by Weismann, that

the full force of the logical implications of Darwin’s teaching was

felt. It is true that his followers were far more definite than the

author of _The Origin of Species_ in emphasizing the creative rôle of

selection. It is true that the discredit into which the Lamarckian

principle fell after the discovery of the nature of fertilization

led the Selectionist writers to exaggerate this aspect of Darwin’s

hypothesis. Nevertheless Darwin did express himself in unmistakable

language with regard to this issue. His followers, forced to be more

specific concerning the nature of differences between parents and

offspring, made the bold, and, it transpired, unwarranted assumption

that all those small differences between parent and offspring now

referred to as fluctuating variability are in the main genetic in

origin. The Selectionist doctrine thus assumed that hard outline which

produced its first vigorous reaction in Bateson’s _Materials for the

Study of Variation_ (1894), a work which laid down the main lines of

investigation which have been elucidated by the Mendelian renaissance.

To avoid vagueness concerning what Darwin actually did say I shall

quote once more from _The Origin of Species_:

“Any being, if it vary in any manner profitable to itself, under

the complex and sometimes varying conditions of life, will have a

better chance of surviving, and thus be naturally selected. From

the strong principle of inheritance, any selected variety will tend

to propagate its new and modified form.” (Introduction.)

“Each of the endless variations which we see in the plumage of

fowls must have had some efficient cause; and if the same cause

were to act uniformly during a long series of generations on many

individuals, all probably would be modified in the same manner.”

(Chap. 1.)

“A high degree of variability is obviously favourable as giving

the materials for selection to work upon, not that mere individual

differences are not amply sufficient, with extreme care, to allow

of the accumulation of a large amount of modification in almost any

desired direction.” (Chap. 1.)

“Over all these _causes_ of change, the accumulative action

of selection, whether applied methodically and quickly, or

unconsciously and slowly but more efficiently, seems to have been

the predominant power.” (Chap. 1.)

“Variations, _however slight, and from whatever cause_ proceeding,

if they be in any degree profitable to the individuals of a

species, in their infinitely complex relations to the individuals

of a species... will tend to the preservation of such individuals

and will generally be inherited by the offspring. The offspring

also will have a better chance of surviving, for of the many

individuals of a species which are periodically born, but a small

number can survive. _I have called this principle, by which each

slight variation if useful is preserved, by the term Natural

Selection._” (Chap. 3.) (Italics inserted.)

If, as Darwin believed, it were true, that variation occurs in every

generation, the evolutionary process would be a continuous one. To

Morgan the production of mutants is a discontinuous break in a

normal routine of stability. To Darwin variation and heredity were

co-extensive terms. The offspring are always on the whole like their

parents. That resemblance constitutes inheritance. On the other hand

they are never quite the same. The difference was what Darwin called

variation. To Morgan heredity and variation are not co-extensive terms.

The structure of the chromosomes is fundamentally stable. From time

to time there occur disturbances of this normally stable equilibrium.

New hereditable properties emerge into being in a quite discontinuous

fashion. There is no self-evident reason why a particular stock should

not remain indefinitely in a phase of stability. To the experimental

geneticist there thus exists no difficulty in interpreting the fact

that some animals have remained unchanged since the earliest rocks.

To the generation in which Darwin lived there seemed to be only one

logical outcome of the view that variation is a continuous process

involving all the individuals of every generation. This deduction

was never stated very explicitly by Darwin himself, though it was

definitely asserted by Wallace. There can be no doubt that this

deduction gave the Selection hypothesis such a strong appeal to

Darwin’s contemporaries, and contributed largely to the success of

the hypothesis of Natural Selection. Before Mendel, investigators

in hybridization had treated the individual as the unit for study.

From this arose the belief that hybrids are intermediate between the

parents. This belief in its turn gave rise to the notion that on

crossing a new type back to the parent stock there would be a dilution

of the new character, culminating after a number of generations in

swamping it out of existence altogether. Evolutionists of the Darwinian

period therefore introduced a variety of devices, such as geographical

isolation and, above all, the survival of the fittest, to counteract

the effect of this swamping and account for the persistence of new

types. To Darwin’s generation it seemed that without selection there

could be no evolution. The new type would always be swamped out in the

long run. In the struggle for existence the less viable variations

would tend to be eliminated, and since there would always be less of

them on that account, the swamping process would favour the gradual

moulding of the species in the direction of more favourable variation.

On this view the struggle for existence is the agency which makes

species change. Evolution becomes a necessity.

From Morgan’s standpoint evolution is only a necessity in so far as

it happens that mutants do from time to time appear. The struggle for

existence though eliminating the less viable types has no creative

rôle in the Darwinian sense. Mendelian analysis shows that though

the first generation of a cross between pure-bred parents may be

intermediate between the parental types, both parental types appear

in their original purity in the next generation, and will continue

to breed true to type, whenever they mate with other individuals

similarly constituted. The modern geneticist feels no necessity for

an _argumentum ad hominem_ to explain how evolution can occur in

spite of a supposed swamping process. To him the swamping process is

an illusion based on imperfect knowledge of the facts of hereditary

transmission. The importance of this difference in standpoint lies in

the fact that the idea of natural selection would never have assumed so

powerful an influence over biological thought, unless it had provided

the evolutionist with train of reasoning which seemed to prove that

evolution must be going on all the time.

This interpretation of the Darwinian standpoint is not a caricature

drawn by the pen of an adverse critic. An enthusiastic contemporary

exponent of Natural Selection, Mr. H. G. Wells, thus defines the

selection theory in his _Outline of History_:

“the young which a living thing produces... are like the parent

living thing. But they are _never exactly like it_ or like each

other.... Suppose, for example, there is some little furry

whitey-brown animal living in a bitterly cold land which is usually

under snow. Such individuals as have the thickest, whitest fur will

be least hurt by the cold, less seen by their enemies and less

conspicuous as they seek their prey. The fur of this species will

thicken and its whiteness increase _with every generation_, until

there is no advantage in carrying any more fur.” (Italics inserted.)

Having cited the above, it is somewhat surprising to note that in

replying to Mr. Belloc’s strictures, Mr. Wells makes the following

statement with reference to the Natural Selection theory:

“Among questions bearing upon it but not directly attacking it

has been the discussion of the individual difference.... What

rôle is played by what one might call normal relatively slight

differences and what by the sports. Can differences establish

themselves while outer necessity remains natural? Can variations

amounting to specific differences... be tolerated rather than

selected by Nature?... What happens to differences in cases of

hybridization?... None of these subsidiary questions affect the

stability of this main generalization of biology.”

In explaining the Natural Selection theory, as quoted above, Mr. Wells

himself states or implies every one of these “subsidiary” questions,

and answers them in his own way.

Let us now see how a modern geneticist would interpret the evolutionary

process by taking an analogous concrete example. He would argue

somewhat as follows. Supposing a single white mutant hare arises in a

grey parent stock, the behaviour of the chromosomes leads us to infer

that eventually other white hares, pure for the white gene or genes,

will reappear. These mated _inter se_ will breed true to type. On the

assumption (not conclusively proved) that it is advantageous for a hare

in temperate climates to be grey and in arctic regions to be white,

there will be more white hares in the long run in northern countries

and more grey ones in temperate countries. If there were no competitive

struggle at all, there would in the long run be grey and white hares in

northern and grey and white hares in temperate countries. There would

have been the same amount of evolution. The only difference that the

struggle for existence introduces is that the final picture presents

a more discontinuous aspect. This was not at all what Darwin meant by

Natural Selection. He would have said that a single mutant would be

swamped out of existence by intercrossing. He would have formulated the

problem in the following terms. Of all hares born to grey parents some

are lighter and others darker. In a region where it is advantageous,

the half that are lighter than the mean will have more chance of

surviving to maturity. In any given generation there will therefore be

more lighter than darker parents. The result of this will be that in

every generation the swamping process will always be on the side of

the lighter individuals. Darwin postulated that, if this process went

on long enough, a white hare would eventually be produced. Such a race

would only be produced in the region where natural selection favoured

its survival. On this view natural selection is the creative agency,

or at least a paramount creative agency in the evolutionary process.

Without the struggle for existence hares everywhere would remain grey.

In every generation the half that are lighter than their parents would

always be swamped by the half that are darker.

To Darwin and more especially to Darwin’s followers selection was the

agency which preserved not merely new individuals but new characters,

since characters would otherwise be diluted out of existence. For

Morgan the preservation of new characters ultimately resides in

Mendel’s law of segregation. It has its material basis in the behaviour

of the chromosomes. The contrast between the alternatives is at once

made clear when we consider what would happen in a universe so large

and so abundantly supplied with the necessities of life that no

struggle for existence intervenes. Given unlimited time in a Mendelian

universe in which natural selection did not operate, all the species

we know to-day would be present, and many more besides. Evolution

would have occurred; but the pageant of life would present to the

taxonomist a more continuous appearance, and the striking gaps which

we now see would be filled not by fossil relics but by living forms.

Except in so far as he was prepared to invoke the Lamarckian principle

to circumvent difficulties inherent in his own hypothesis, natural

selection was to Darwin the necessary condition not merely for gaps but

for any evolution to take place at all. In a Darwinian universe without

natural selection there would be no progressive differentiation of new

characters.

§2

When, out of deference to Darwin’s contribution to biological thought,

the experimentalist of Morgan’s school asserts his belief in Natural

Selection, he is in fact referring to something very different from

Darwin’s Natural Selection, indeed to a view of the process which

Darwin would have rejected emphatically. Of course it is admitted that

all scientific hypotheses become modified as new data accumulate; and

phrases imperceptibly change their meaning in the course of time.

But the natural selection of Morgan’s school is not a continuous

development from the original concept. Within two decades of the

publication of _The Origin of Species_ the selection hypothesis had

assumed a clarity of outline which had an influence on subsequent

developments in biological thought, persisting till the present day,

and not likely to disappear for some time. In 1881 Weismann challenged

the prevailing belief in the inheritance of acquired characters.

Thenceforth in the hands of the Selectionists environment became merely

an agency by which the hereditary materials are preserved or rejected.

As an aspect of the problem of development it faded into the background

of the picture. To question the almightiness of heredity became

equivalent to defending the Lamarckian principle, though the two issues

are logically independent.

Educated people frequently use the words environment and heredity in

a very different sense from that in which they are employed by the

biologist. Unless we are accustomed to the study of embryonic and

larval life, we are apt to think of an organism as a finished product.

The rôle of environment and of heredity as seen through the eyes of

a contemporary biologist can be made explicit by reference to recent

work on the metamorphosis of tadpoles. We know to-day that the thyroid

gland of all vertebrates contains a high percentage of iodine. Barger

and Harrington have now prepared in pure crystalline form an iodine

compound which has the same therapeutic properties as extracts of

the thyroid gland. A few years ago the discovery that frog tadpoles

will change very rapidly into adults if fed with thyroid gland, was

followed up by the development of a successful technique for removing

the rudiment of the thyroid gland in frog embryos. Thyroidless tadpoles

never undergo metamorphosis. They continue to grow as tadpoles when

the normal tadpole would change into a frog. The change into the adult

in the normal tadpole is initiated by the liberation of the thyroid

secretion into the circulation. It has also been shown that tadpoles

reared on an iodine-free diet in water containing no trace of iodine

remain permanently in the larval state. This clarifies what is meant by

an _environmental_ factor in development. In contradistinction to the

influence of environment the influence of inheritance in development

may be illustrated by reference to an American salamander, _Amblystoma

tigrinum_, which has a characteristic larval form. In the lakes around

Mexico city there is a local race of this species which never undergoes

metamorphosis in nature, reproducing in the larval form. It can be

made to develop into the land-dwelling adult in a few weeks, if fed

with thyroid gland in the laboratory. Addition of iodine salts to the

water in which it lives or to its food will not induce metamorphosis.

Its permanent fixation in the larval stage is due to the fact that it

_inherits_ from one generation to another a deficient thyroid gland,

which cannot make use of the iodine in its surroundings. Absence of

iodine in minute quantities from the water, a purely environmental

agency, or on the other hand a hereditary difference between two races

with respect to the efficiency of thyroid secretion, may either of

them be _independently_ instrumental in deciding whether a particular

individual shall attain sexual maturity in the form of an air-breathing

land-dwelling salamander, or an aquatic half-way house between a

salamander and a fish. A geological epoch, if you like to put it in

that way, is thus summed up in a mutant gene or in a trace of iodine.

In the attempt to understand the tenacity with which belief in the

Lamarckian view persisted in biological thought, it must be borne

in mind that embryology is the most recently developed branch of

anatomical science. Until the classical researches of von Baer and

Meckel were published in the first half of the nineteenth century, the

prevailing idea about development was the teleological doctrine that

an animal is from the very first complete in all its parts and only

needs growth to make its minute structure manifest to the eye. Caspar

Wolff in 1759 made observations on the hen’s egg, and was led to state

the “epigenetic” as opposed to the prevailing “evolutionary” view. He

sought to show that the hen’s egg is at the beginning without any gross

anatomical organization and that structural organization within the

egg is a gradual development. His work failed to attract attention.

Von Baer’s researches on the same subject were published synchronously

with the formulation of the Cell doctrine (1832). One might say that

until the middle of the nineteenth century, the current conception of

inheritance in biology was closely analogous to the legal notion. The

parent was supposed to hand on its anatomy to its offspring in the same

sense as the well-to-do hand on their belongings. With so erroneous

a conception of the nature of development prevailing, it is little

wonder that the idea of the inheritance of acquired characters seemed

a perfectly reasonable one. It is not surprising that the doctrine of

Lamarck should have been first challenged during the decade in which

the nature of fertilization and the process of maturation of the germ

cells were elucidated.

As stated by its author the Lamarckian principle implied that any

reaction of the organism to its environment is carried over to

subsequent generations. It was especially _adaptive_ reactions such

as the effect of use and disuse which Lamarck emphasized in his

evolutionary speculations. When the Lamarckian principle was first

challenged, prominent scientists like Cope were willing to assert such

fables as the story that a cock deprived of one eye transmitted eye

defects to all his offspring. When it was conclusively proved that

mutilations effected through several generations left no impress on

the hereditable characters of the stock, the Lamarckians fell back

on the gratuitous postulate that only “adaptive” changes could be

transmitted. The precise meaning of this adjective was never defined,

nor was any reason forthcoming to suggest the existence of a mechanism

that could discriminate between mutilations and bodily changes that are

“adaptive.” This is yet another example of the perils of introducing

teleological preoccupations into the construction of biological

hypotheses. If recent experimental research conserves any element

of truth in the Lamarckian idea, it has robbed it of any special

significance to the way in which adaptive structures originate.

Structural changes may arise in the course of development from two

conceivable sources. The chromosomes which represent the hereditary

materials may find themselves reacting to a different type of “internal

environment.” The majority of modifications in the normal course of

development undoubtedly come within this category. Modifications of

this type, including in all probability relative sizes of organs, all

mutilations and habits are clearly not hereditable. Belief in their

hereditability was only possible so long as biology was dominated

by teleology and the essential features of the reproductive cycle

were undiscovered. There is another possibility which was entirely

disregarded by Weismann in his Theory of the Germ Plasm. It is a

possibility that has no bearing on the problem of adaptation. If

environmental agencies can produce mutations by a structural change

in the chromosome itself, there is no reason why such structural

changes should be confined to the chromosomes of the germ cells. We

must therefore preserve an open mind with regard to the possibility

of encountering phenomena having a superficial similarity to what

is implied in Lamarck’s doctrine. The exposure of young larvæ of

the fruit-fly to X-rays has led to the production of individuals

which show bodily resemblances to forms which have arisen in the

ordinary course of events as mutants. The effect of X-rays may be

to change the environment in which the chromosomes operate. But

the recent investigations of Patterson indicate the likelihood

that the modification is due to the action of the X-rays on the

chromosome itself. We know that X-rays will produce mutant changes

in the chromosomes of the germ cells. If Patterson’s interpretation

is correct, it may well be found that X-rays can simultaneously

effect mutant changes in all the chromosomes of the body. If applied

sufficiently early in the course of development, radiation with

X-rays would then produce bodily changes of a transmissible nature.

This possibility resides in the fact that the agent is capable of

acting on all the cells of the body in the same way at the same time.

There is no inherent unlikelihood that temperature and the chemical

constituents of an animal’s food may simultaneously produce bodily

and germinal mutations. Strictly speaking this is not the same as the

traditional belief in the “inheritance of acquired characters.” The

Lamarckian principle completely disregards the distinction between

modifications which arise from a change in the internal environment of

the chromosomes and a physical change in the chromosomes themselves. It

takes no account of the possibility that the environmental agent can

act in the same way simultaneously on all the cells of the body.

There are still students of fossil forms who claim that the

traditional Lamarckian view is necessary to explain the historic

succession of animals by continuous generation. There seems to be no

satisfactory reason to justify the statement that evolution can only

be satisfactorily explained by assuming the inheritance of acquired

characters. If there were, it would not be an argument in favour of

the Lamarckian principle. It would be as an argument against the

evolution theory. It would imply that the truth of evolution depends on

assuming a mechanism whose existence is most unlikely. What is often

called the neo-Lamarckian standpoint, the view that acquired characters

only gradually become impressed on the hereditary constitution after

countless generations, transfers the issue from the plane of verifiable

experience to one of pure surmise, rendering further discussion

profitless. In such a matter as this when experiment is silent, the

student of fossils must also be silent.

The objection rests in fact on a misapprehension. The earlier phase of

experimental enquiry along the lines laid down by Mendel was confined

to the analysis of simple clear-cut hereditary differences which

present themselves in almost any environment in which the animal can

live. They were also largely concerned with differences that could be

resolved into the simplest arithmetical ratios, or as Morgan would say

with mutants that have arisen through a change at a single point on

one pair of chromosomes. It is only as technique has progressed that

it has been possible to analyse the more complex cases in which single

characteristics depend on numerous Mendelian factors, or where the

character differences are so variable that they can only be defined in

statistical terms. The palæontologist being occupied very largely with

size differences is sometimes disappointed, because such phenomena lie

outside the scope of the simpler problems, which were once thought to

define the scope of the Mendelian hypothesis. Recent progress which has

led to the recognition that Mendel’s principle of segregation underlies

the inheritance of size is therefore of no little significance to

evolutionary theory. As we come to recognize the dependence of

hereditary transmission on discrete particles which maintain their

entities uncontaminated through all the cell divisions of the body,

segregating in their entirety in the formation of the gametes, the

unlikelihood of the Lamarckian principle in its traditional form

becomes more and more evident.

If the Lamarckian principle in its traditional form was undoubtedly

based on a confusion of ideas and an ignorance of fact, the Theory

of the Germ Plasm put forward by Weismann shows how facts may be

distorted to fit in with preconceived ideas which are in themselves

logically flawless. The discredit into which the Lamarckian principle

fell, almost as soon as the elementary facts about the nature of

fertilization became known, led Darwin’s successors to assume that

all those differences between parent and offspring which Darwin had

referred to under the term variations are genetic in origin. The

assumption was gratuitous, as later experimental analysis has shown.

Without that assumption the Selection doctrine would have been

robbed of the immense importance it had already begun to assume. From

a complete misapprehension of the true rôle of the environment in

relation to inheritance, the biological pendulum swung in the opposite

direction to a complete disregard of the influence of the environment

in relation to development. It is from Weismann’s writings that we

can best appreciate the fundamental dissimilarity of Darwin’s Natural

Selection and Morgan’s views. For Weismann’s “germinal selection” is

the logical outcome of Darwin’s selectionism, once it had been purged

of the Lamarckian principle. It is a triumph of Hegelian reasoning

applied to biology. There is nothing wrong with it but its premises.

Weismann’s theory embodied an atomistic conception of heredity.

Unlike Mendel’s it had no connexion with experimental data. Weismann

identified his hereditary determinants with the substance of the

chromosomes. Unlike Morgan’s hypothesis, Weismann’s speculations were

based on incorrect observations about the way in which the chromosomes

behave. In the long run the influence of Weismann’s teaching has

probably been more sterilizing than the Lamarckian doctrine which he

challenged.

Weismann imagined that his atoms of heredity or “determinants” multiply

in the cell and in some rather abstract way compete with one another

for survival. Hence the hereditary constitution of the individual

is never quite the same in two successive generations. Heredity

and variation are thus co-extensive, as Darwin’s Natural Selection

postulates. Weismann also thought wrongly, it transpired, that the

reduction division of the germ cells takes place in such a way that

each cell receives half a maternal and half a paternal chromosome

of each pair and not, as we now know, a whole paternal or a whole

maternal element. Hence he argued that the formation of the germ cells

involves not, as Mendel proved by experiment, a segregation but a

closer intermingling of the germinal materials. From this the swamping

of new characters on crossing became an absolute necessity. To Weismann

selection alone could prevent this swamping. Selection must act in

every generation, because the mingling of the hereditary materials

becomes more intimate with every generation. Only under the influence

of continuous selection could any change be brought about. Without it

universal stagnation would exist. In short Selection was the creator

and the preserver of the benefits of variation. In all this Weismann,

with the support of Wallace, went much further than Darwin himself.

But the Selectionist doctrine in its main features was implicit in

the Origin of Species. The sociological exploits of biologists belong

especially to the period in which the Selection doctrine assumed this

doctrinaire aspect. Doctrinaire Selectionism has persisted in our own

generation in the writings of many eugenists.

§3

We set out in the first place to contrast the views of the modern

geneticist with the Selection hypothesis in its original form. The

main differences arise in connexion with two issues. One concerns

Darwin’s own view that evolution is a continuous process. Darwin

believed that selection operates on all the individuals of every

generation. This implies either that acquired characters are inherited

or alternatively that all differences between parent and offspring are

hereditary differences in the modern sense. The views to which modern

geneticists have been led by their experiments are diametrically

opposed to both conclusions. The other question concerns the creative

rôle of selection. This belief arose from ideas about hybridization

and artificial selection current among those biologists to whom Darwin

addressed his argument. Darwin himself did not stress the point; but

it was this corollary of his theory which accounts for the successful

appeal which Natural Selection made to Darwin’s contemporaries. They

were satisfied that, if a struggle for existence occurs, evolution must

be taking place. This was because all biologists before Mendel confused

the characters which do blend with the genes that do not. To the modern

geneticist this corollary has no significance, because experiment has

forced him to reject views about hybridization prevalent before the

publication of Mendel’s researches. To Morgan, as to Darwin, selection

through the survival of the fitter is essentially like artificial

selection. Morgan differs radically from Darwin in his understanding

of the way in which artificial selection itself operates. According

to Morgan selection has no creative significance. “Selection has not

produced anything new, but only more of certain kinds of individuals;

Evolution however means producing new things, not more of what already

exists.”

Thus from the standpoint of Morgan the status of evolution is more

satisfactory in the light of modern research. For there is no need to

advance any special device to explain why new types are not swamped

out of existence through the blending of characters on crossing. From

the point of view of the Darwinians, if they were still with us, the

outlook would be disconcerting. The modern geneticist no longer regards

evolution as an imperative consequence of the struggle for existence.

On the other hand the modern view presents no greater difficulty than

the former one in explaining the tendency towards greater adaptation.

It is free from the objection that it proves too much. New hereditary

types would persist even if there were no struggle for existence. Since

there is one, the chance that a given mutant will reach the age at

which it can produce offspring will be greater if the mutant character

has “survival value.” At present there are insufficient experimental

data to make profitable the discussion of the amount of advantage

necessary to ensure survival. At the same time it is of interest to

record that the application of Mendelian method furnishes materials

for a precise statement of what selection can achieve and the rate at

which it works, when the extent of differential fertility or mortality

in a population is known. The mathematical theory of selection has been

made the subject of some illuminating researches by J. B. S. Haldane

and by Fisher. Haldane’s calculations have led him to conclusions very

different from the dialectical deductions which some eugenists have

drawn from the recent decline of the European birth rate.[7]

VIII. THE SURVIVAL OF THE EUGENIST

“I am that ancient hunter of the plains,

That raked the shaggy flitches of the bison:

Pass, world: I am the dreamer that remains,

The Man, clear-cut against the last horizon.”

Roy Campbell, _Flaming Terrapin_

Concerning Vesalius one of his biographers has said: “in dissecting

monkeys he became convinced that the many discrepancies between the

Galenic teaching and his own observations on the human body were due

to the circumstance that Galen had derived most of his knowledge from

dissecting monkeys, and had not thought it necessary to mention the

fact.” Perhaps the biographer of a future Vesalius who succeeds in

laying the foundations of social anatomy will record that “in studying

the writings of the Eugenists he became strengthened in the conclusion

that they were discussing the habits of fruit flies rather than human

beings, but had not thought it necessary to mention the fact.”

I have called this essay _The Survival of the Eugenist_; but I wish

to make it clear that I entertain no lack of sympathy for _Eugenics_

as defined in general terms by Galton, the Galen of social biology. I

have chosen this title to lay emphasis on the part which eugenists have

played in perpetuating a certain attitude towards human society. This

attitude starts from an examination of those characteristics which man

shares with all other animals, but neglects the equally important task

of defining those characteristics which distinguish man from all other

animals. The weakness of all mechanistic systems hitherto proposed

lies in their refusal to recognize the existence of anything which does

not yet come within the province of scientific method. A mechanistic

philosopher can legitimately entertain the hope that the study of

human society will become an ethically neutral science, and that the

methods of biology will fertilize sociological enquiry, as the methods

of physics and chemistry have fertilized biological investigation. He

is not entitled to pretend that biology can at present provide a key

to the interpretation of human history. I am well aware that there are

eugenists who would repudiate any such pretensions. At the same time

the general tendency of eugenic propaganda has been to exaggerate, and

grossly exaggerate, the applicability of genetic principles to the

analysis of human society. This tendency is a legacy of the period in

which Eugenic ideas had their origin.

Whatever disadvantages the Christian cosmogony imposed upon the study

of human society, it possessed the merit of emphasizing that the proper

study of mankind is man. The immediate influence of the evolutionary

controversy was a reversion to the Galenic practice in social anatomy.

There is nothing surprising in this reaction. To Huxley and Spencer the

important fact was that Man is a brute. It was necessary for them to

emphasize man’s genetic similarity to other animals in opposition to

the traditional view which placed man in a special category apart from

other natural objects. How strongly the need to emphasize Man’s new

status was felt can be inferred by a well-known dictum in _Man’s Place

in Nature_. “Whatever systems of organs be studied,” wrote Huxley, “the

comparison of their modification in the ape series leads to one and the

same result--that the structural differences which separate man from

the gorilla and the chimpanzee are not so great as those which separate

the gorilla from the lower apes.” In his dispute with Owen, Huxley went

much further than any modern anatomist would be prepared to follow him.

If like Cuvier he had based his objections on the structure of the

human foot instead of the hippocampus major, Owen might have made a

stronger case. His opponents were too busy disposing of man’s Cartesian

spirit to devote much attention to his Cuvierian sole.

The evolution of Thomas Henry Huxley, of Herbert Spencer and of Francis

Galton was a precocious baby. Its parents and relatives entertained

high hopes of its future career. In that tradition it has been nursed

by their loyal disciples who have encouraged it to discourse upon

sociology before it has learned to read and write. Huxley, Spencer and

Galton were fundamentally right in recognizing that any theory of the

development of human society implies certain biological assumptions.

Their anticipations of immediate progress in the biological treatment

of human society was inevitably coloured by the issues which made the

first claim on their attention. Those issues are no longer topical.

The experimental biologist of to-day cannot approach the structure of

human society from quite the same angle. The pioneers of evolution

were goaded by theological opposition to adopt an attitude which is

easy to condone but unnecessary to emulate. To justify their right

to speculate, they found it necessary to convince the non-scientific

public that their speculations were correct. To do so they were driven

to minimize the gap between man and the apes and make the best of

any evidence pointing to the missing link which popular imagination

demanded.

The missing link provided the occasion for one of the first

sociological exploits of anatomical science. There is an account of the

incident given in Dr. Haddon’s _History of Anthropology_. Three years

after _The Origin of Species_ was published Dr. James Hunt, President

of the Anthropological Society, read his paper on “The Negro’s Place in

Nature.” In it he maintained that “the analogies are far more numerous

between the ape and the negro than between the ape and the European.”

In 1866 he recorded a further contribution to the detection of the

missing link by asserting that “there is as good reason for classifying

the negro as a distinct species from the European as there is for

making the ass a distinct species from the zebra.” In this discussion

Huxley gave the exponents of the missing link a half-hearted support

tempered somewhat by his humane and sceptical disposition. An obituary

notice of Dr. Hunt in a New York paper announced in 1870 the “Death of

the Best Man in England.” Sixty years after the publication of Hunt’s

first communication, a leading American anthropologist, Professor

Kroeber, summed up the present state of knowledge in the following

terms:

“The only way in which a decision could be arrived at along this

line of consideration would be to count all features to see whether

the Negro or the Caucasian was the most unape-like in the plurality

of cases. It is possible that in such a reckoning the Caucasian

would emerge with a lead. But it is even more clear that which ever

way the majority fell, it would be a well-divided count.”

Speculation upon the ancestry of man has continued with unabated

vigour to the present time. Huxley’s generation had one good excuse

for confusing the process of social and organic evolution. It cannot

be pleaded by our own. Modern men were known to be associated with

the later palæolithic cultures. The Mousterian artefacts had been

associated with the Neanderthal type. There was much to encourage

the hope that further research would reveal a close parallelism

between the physical differentiation of specific or racial types

and successive stages of cultural development. It now appears that

Mousterian artefacts were also fashioned by types who, as Sir Arthur

Keith puts it, “would excite no comment, if dressed in modern

garb in any assemblage of modern Europeans.” Our own species has

served a long apprenticeship in a much earlier phase of cultural

development than that which was at one time attributed specifically

to the Neanderthalers. The data presented in Sir Arthur Keith’s

book _The Antiquity of Man_ show that it is not easy to press blood

relationships out of stone implements. There are already signs of a

reaction against the extravagant claims which have been put forward

by some physical anthropologists. The most recent hypothesis of the

origin of civilization completely breaks with the earlier tradition to

harp on the racial aspect of the problem. Professor Elliott Smith is

distinguished both as a physical and cultural anthropologist, and it is

therefore noteworthy that his theory emphasizes the characteristics of

man’s physical environment as the significant factors in the appearance

of the first civilized communities of the Nilotic region.

Under Weismann’s influence environment as an aspect of the problem of

development assumed a nebulous outline. For a generation biologists

were hypnotized by the discredit of the Lamarckian teaching. Eventually

the progress of experimental embryology and cell anatomy relegated

Weismann’s theory of germinal selection to the same limbo as the

Lamarckian hypothesis. In Weismann’s hands the Selection doctrine

had assumed a particularly rigid form. Evolution was necessarily a

continuous process. All differences between parents and offspring were

genetic. Heredity and variation were coextensive processes. From this

it followed that a continuous evolutionary process had accompanied

the development of social institutions. It was a natural step to

confuse the two. The conviction that eugenic legislation is a matter

of overwhelming urgency arose as a direct outcome of that step. That

the same confusion still dominates eugenic propaganda is illustrated

by a statement made by Mr. Lidbetter, a prominent eugenist, in his

paper at the World Population Congress of 1927, “It is a platitude,”

Mr. Lidbetter stated, “in these days to speak of natural selection as

the essential agent in human progress.” It may be a platitude. It is

not a truism. It is simply a misuse of terms. Social development is

the communication of social tradition and social accomplishment from

one generation to another, with the addition of new ingredients in

each. Organic evolution is brought about by the transmission through

the gametes of new hereditable properties. The mechanism of one is

education. The mechanism of the other is sexual reproduction. It is

possible that they react upon one another, but the extent to which they

do so cannot be ascertained by _a priori_ reasoning. The experimental

study of genetic variation has made it abundantly clear that evolution

is not a continuous process. At present we do not know the precise

conditions relevant to the production of mutant types; consequently

it is unjustifiable to make any general assumptions about genetic

variation in human societies without recourse to direct experimental

inquiry.

That is the task which now lies before the social biologist. Its

successful accomplishment will not be facilitated by under-estimating

the difficulties inherent in the problem. The study of human

inheritance is beset by innumerable obstacles. Man is a slow-breeding

animal of low fertility. His chromosomes are numerous. The geneticist

cannot control his matings. In spite of these drawbacks some insight

into the nature of hereditary transmission within the human species

can be gained by formulating the results of random mating on certain

hypothetical assumptions. Familial studies of colour blindness,

brachydactyly and the blood groups provide clear illustrations of

Mendelian phenomena. So long as family pedigrees are employed to

demonstrate the inheritance of physical characteristics, it is not

difficult to recognize the nature of the environmental influences

with which the hereditary materials react, and to make allowance for

them. The geneticist is on familiar ground. The constituents of man’s

physical environment have been classified by the physicist, the chemist

and the bacteriologist. Their effects upon the physical characteristics

of an organism form the subject matter of physiology. It is possible to

speak of the action of sunlight and humidity, oxygen pressure and diet,

infectious and contagious germs, iodine and calcium salts with some

measure of confidence. All these things are features of man’s physical

environment or of the physical environment of any other animal. The

methods for investigating their influence are well tried. The concept

of a uniform physical environment is tangible. It can be explained to a

pragmatist or a presbyterian, a behaviourist or a bimetallist.

It is another thing to speak about a uniform social environment.

The factors which determine man’s social behaviour are obscure and

elusive. Even to-day any dogmatism on the relative importance of

heredity and environment assumes an almost frivolous aspect when the

attitude of the experimental biologist is brought to bear on the

evidence. Analogies from the animal kingdom have been pressed into

the service of those who emphasize the rôle of either the one or

the other. Kropotkin’s _Mutual Aid_ was the _reductio ad absurdum_

of that attitude to social problems. Kropotkin was neither more nor

less scientific than the exponents of nature red in tooth and claw.

Both were irrelevant. The same irrelevance has been evident whenever

biologists have attempted to rationalize their political sentiments.

The anti-feminist appeals to the fighting and protective male. The

feminist can retort by invoking the worm Bonellia of which the male

lives as a parasite in the generative passages of the female. The

eugenist pictures the human poultry farm nicely mapped out in pens,

each surrounded by its own partition of wire-netting with a few holes

here and there. Maybe the Rhode Island Reds have scratched their way

into the proper preserve of the Partridge Cochins. Sooner or later the

cosmic poultryman, aided by wise statesmen, will put them back where

they belong. His opponents can reply that class differences exist in

insect communities. The difference between a white ant queen and a

termite worker is more striking than the difference between royalty and

factory girls; and it is a difference determined by diet. Encouraging

illustrations in support of any social doctrine can be brought forward

by those who prefer analogy to analysis.

It might be hoped that the study of human history would assist, but the

record of history is ambiguous. A striking instance of this ambiguity

is to be found in Professor Carr Saunders’ book on the Population

Problem. In the course of a temperate and on the whole well-balanced

discussion of the racial factor in history, Carr Saunders remarks that

the

“Nordic peoples are mostly Protestant and the Mediterranean peoples

mostly Catholic and Greek. The fact,” he continues, “that during

the Reformation a choice was set before most European nations as to

what religion should be adopted--the issue hanging in the balance

for some time in many places--seems to indicate that the conditions

were more or less equalized and the adoption of the Protestant

religion by the Nordic type was influenced by certain innate

characters attaching to that type.”

Even if we make a very generous allowance for the genetic homogeneity

of the Nordic and Mediterranean populations in mediæval times, an

entirely different interpretation of the same facts is equally

plausible. At the time when Christianity received official recognition

the countries to which Carr Saunders refers as predominantly Nordic lay

on the fringe of Roman Imperial domination or completely outside it.

The process of christianizing the Nordic geographical region was still

in its infancy when the Holy Roman Empire embarked on its ephemeral and

inglorious career. It was hardly complete, when controversy within the

Western Church began to assume sinister proportions. With the exception

of the Saxons the conversion of the Germanic peoples, including the

Frisians, took place in the early part of the eighth century. The

official conversion of Saxony occurred about A.D. 800. Christianity

was accepted by the ruling powers of Denmark towards the end of the

tenth century and by those of Norway and Sweden at the beginning of

the eleventh century. The conversion of East Prussia, Latvia and

Pomerania occurred during the twelfth century, and the conversion of

Lithuania did not occur until the middle of the fourteenth century. In

those countries which Christianity penetrated last of all the conflict

between the ruling houses and the temporal claims of the Papacy was

generally most acute. Where reformers could seek protection in the

clemency of monarchs at loggerheads with the Pope, they spread their

doctrines successfully. Where there only existed a religious movement,

it was speedily extinguished. The Reformed doctrines spread in those

countries where Christianity had been more recently introduced, and

where the political sovereignty of the Pope and the economic power

of the Church as a landowner were least firmly entrenched and least

agreeable to the secular authorities. Catholicism had taken root in

the ancient civilization of the Mediterranean region, when the Nordic

peoples were outside the pale. If it is true that the Nordic peoples

gravitated to Protestantism, it is equally true that they happened

to inhabit the geographical region most remote from Rome. There is

no reason to suppose that their choice of locality was determined by

any characters peculiar to their type or relevant to the progress of

theological discovery.

In seeking to make allowance for the significant factors of man’s

social environment there is no body of accredited information to which

the geneticist can turn. There are as many schools of psychology

as there are schools of philosophy. The introspective psychologist

approaches social behaviour from a purely teleological standpoint,

interpreting the means in relation to the end it fulfils. The

behaviourist adopts a mechanistic attitude, seeking to interpret the

end as predestined by the means. One speaks of a directing intelligence

and instinctive action. The other speaks of intelligent behaviour and

unconditioned response. Between the two schools there is a great gulf

fixed. It is that which separates the philosophy of Plato from the

teaching of Democritus. It is not merely a difference of perspective

or of minor issues. Such differences exist in an exact science. The

psychologists disagree about the very nature of inquiry into the basis

of social behaviour; and there is no immediate prospect that they will

come to terms. Meanwhile the eugenist finds himself impaled on the

horns of a dilemma. The methods of animal genetics are mechanistic;

but the behaviourist is suspicious of the genetical standpoint; while

the introspective psychologist fails to define the characteristics of

social behaviour in a form suitable for genetic analysis.

When Binet and Terman published their psychological tests, it seemed

that there was a brighter prospect for the objective study of mental

inheritance. Of late the psychologists themselves have begun to adopt a

less confident attitude. Recently the Stanford school of workers have

conceded a conservative allowance of 20 per cent. for the influence of

home environment on the intelligence quotient. We have no grounds for

believing that the ingenious system of home ratings adopted by Miss

Burks (1927) in this investigation include all the significant factors.

Consequently this figure represents a minimum. The Chicago school

have investigated the intelligence quotients of foster children, and

adopt an even more sceptical attitude to the value of the I.Q. as a

measure of genetic endowment. Tallman has investigated the intelligence

quotients of sixty pairs of identical twins. It was found that the mean

difference between pairs of brothers and sisters of different ages on

the one hand and pairs of non-identical twins on the other was larger

than the difference between pairs of non-identical twins and pairs of

identical twins. Accepting the most conservative allowance, it may

be stated with some confidence that the contribution of environment

to the intelligence quotient is at least as large as the recorded

differences between racial and occupational groups subject to different

environmental influences.

For two generations eugenists have been writing about mental

inheritance. As far as I am aware Professor MacDougall alone has

pointed out that the attempt to formulate a concept of mental

inheritance raises a very formidable issue which challenges the

foundations of current biological philosophy. He himself faces the

difficulty by returning to the Lamarckian fold. Lamarck’s position

was at least consistent. He conceived heredity in mental terms. His

theory was teleological throughout. Galton was not consistent, and

his disciples have been less so. Since Weismann’s time the study of

heredity has become more and more explicitly materialistic. To the

modern geneticist heredity is one aspect of the physical process

involved in the production of a new unit of living matter. His

hypotheses are conceived in physical units. The gene has space-time

dimensions. Mental inheritance is a meaningless collocation of words,

unless it is possible to bring the concept of mentality within the

mechanistic framework. That is what the behaviourist school in

psychology has undertaken to do. The future of social biology depends

on the success which attends their efforts.

Fifty years have passed since Francis Galton published _Hereditary

Genius and An Enquiry into Human Faculty_. Since then there have been

notable changes in the attitude which scientists have adopted both

towards heredity and human faculty. The work of Mendel, Bateson and

Morgan has enormously enriched our knowledge of hereditary transmission

in animals. The work of Loeb, Sherrington and Pavlov has opened up new

horizons in the study of animal behaviour. The biological analysis

of social behaviour presupposes that both methods can be brought

to bear upon it. It may be premature to adopt a confident attitude

to the prospects, but it is legitimate to state that there is no

likelihood of solving the problem which Galton propounded so long as

eugenists continue to regard it as the exclusive prerogative of the

evolutionist. The enthusiasms engendered first by the reception of

Darwin’s hypothesis and subsequently by the spectacular advances which

have resulted from Mendel’s discovery, encouraged the eugenist to adopt

an extremist attitude. New and no less noteworthy developments in the

physiology of the nervous system have encouraged the behaviourist to go

as far as possible in the opposite direction.

It is not difficult to understand how this has happened. In Galton’s

time the analysis of animal conduct had not progressed beyond the

recognition of those simple units of behaviour which Pavlov calls

“unconditioned” reflexes. The scratch reflex evoked on stimulating

the lumbosacral region in the spinal dog is an example of this type.

Given the same external situation, it can be elicited in any member of

the canine species. There are therefore two principal factors which

determine the scratch reflex. One is the immediate stimulus. The other

is the _inherited_ structure of the nervous system. Simple reflexes

of this kind play very little part in man’s social behaviour; but

modern physiology recognizes a more complex type, which Pavlov calls

the “conditioned” reflex. The study of these promises to meet some of

the requirements of a biological analysis of man’s social behaviour.

The conditioned reflex is not characteristic of all the members of a

species subjected to the same immediate situation. It depends upon

the time relations of other stimuli which have previously acted upon

the organism. Within certain limits it is possible both to predict

the outcome, when the time relations of previous stimuli are defined,

and to account for a totally different pattern of behaviour in two

individuals who inherit the same neuromuscular organization. It was

natural that Galton’s generation should harp on the hereditary basis of

social conduct. They were beginning to understand a type of behaviour

in which the genetic factor is the significant variable, and to apply

their knowledge to the interpretation of “instinct” in animals. It is

not surprising that the behaviourists should adopt the opposite point

of view. They are beginning to understand a type of behaviour in which

the genetic factor is less important, and to apply the new methods to

the study of Man himself.

Even if the behaviourist reaction goes too far in neglecting the

genetic aspect of social behaviour, it will have performed one

considerable service to social biology. Biology and sociology coincide

in the attempt to distinguish what characteristics of human society

are related to those characteristics which man shares with all other

animals, and what characteristics of human society are related to

characteristics which man shares with no other animals. The geneticist

is only concerned with the former, since the material basis of

inheritance in man and other animals is substantially the same. It is

the physiologist who is brought into contact with the characteristics

which distinguish man from other animals. Man inherits an immensely

developed forebrain; and this circumstance frees him from many of

the restrictions which heredity imposes upon the brute creation. The

forebrain is the structural basis of conditioned behaviour; and what

distinguishes man pre-eminently from all other animals is the extent

to which his behaviour is conditioned by previous experience. A truly

biological analysis of human society must build on the recognition that

man is the most teachable of animals. This is a profound truth which

the eugenist has neglected. The behaviourist has reopened the door

which the eugenist closed. The selectionists succeeded in presenting

evolution in a form acceptable to their contemporaries. Man was dragged

down from his celestial eminence. His place among the brutes became an

accepted commonplace of the naturalistic outlook. Sentence had been

passed upon him. Henceforth he must live within the prison of his

own genetic limitations. Before the portals of his primeval dungeon

Heredity stood with a flaming sword. In his new surroundings Man could

still demand a retrial, because selectionism was the product of his

own forebrain. That trial is still in process. Science has not yet

promulgated its final verdict. Galton conducts the prosecution. Watson

cross-examines for the defence. Man is released on bail, pending the

result of his appeal.

In English law there is a wholesome provision which forbids the public

discussion of evidence until the case is closed. In science there is

no penalty for contempt of court. It is a pity that there is not. The

discussion of the genetical foundations of racial and occupational

classes in human society calls for discipline, for restraint and for

detachment. Nothing could make the exercise of these virtues more

difficult than to force the issue into the political arena in the

present state of knowledge. This is precisely what the eugenist has

done. The result is that social biology is encumbered with a vocabulary

of terms which have no place in an ethically neutral science; and a

growing literature of inquiries repeats all the shortcomings which

animal genetics has outgrown. Of these shortcomings anecdotalism is

the least. All biologists recognize the disastrous consequences of

constructing evolutionary hypotheses on the testimony of the stock

breeder and the pigeon fancier. Only an undue haste to establish

conclusions which can be made the basis of legislation has arrested the

development of social biology in its anecdotage.

Quotations from well-known contributions by eugenic writers will

exempt me from the charge of overstating the danger to which I

allude, when I speak of the anecdotal method. Few would deny the

desirability of shedding further light on the contribution of heredity

to feeblemindedness. It is the concern of the social biologist to do

so. Goddard’s familial studies on this problem have been extensively

quoted by eugenic writers. In his investigation several hundred

individuals in the Vineland training-school for mental defectives were

classified by the Binet test as morons. Goddard conducted inquiries

into the family histories of these individuals, and records them

in his book. He concludes that a certain type of feeblemindedness

is determined by a single Mendelian factor. This conclusion is

logically untenable apart from the evidence, because his criterion

of feeblemindedness was a segment arbitrarily cut off from a normal

distribution curve; but the method which he employs rather than the

conclusions he infers is the issue to which I would direct attention.

Mendel initiated a new epoch in genetics by clearly defining the nature

of the character which he studied. That practice is the keystone of

the science which has developed from his pioneer labours. The Binet

test may be legitimately employed as a means of providing an objective

definition of feeblemindedness; but since the Binet test is a recent

innovation, it is obvious that Goddard could not employ it to identify

feeblemindedness in the parents and grandparents of his cases at the

time of writing. The method he adopted is stated in the following

passage (_Feeblemindedness_, p. 20):

“The ease with which it is sometimes possible to get satisfactory

evidence on the fifth generation is illustrated in the Kallikak

family. The field worker accosts an old farmer--‘Do you remember

an old man Martin Kallikak (Jr.) who lived on the mountain edge

yonder?’ ‘Do I? Well I guess. Nobody’d forget him. Simple, not

quite right here (tapping his head), but inoffensive and kind. All

the family was that. Old Moll, simple as she was, would do anything

for a neighbour. She finally died, burned to death in a chimney

corner. She had come in drunk and sat down there. Whether she fell

over in a fit or her clothes caught fire nobody knows. She was

burned to a crisp when they found her. That was the worst of them,

they would drink. Poverty was their best friend in this respect,

or they would have been drunk all the time. Old Martin could never

stop as long as he had a drop. Many’s the time he’d rolled off of

Billy Parson’s porch. Billy always had a barrel of cider handy.

He’d just chuckle to see Martin drink and drink until finally he’d

lose his balance and over he’d go.’”

At the conclusion of this recital Goddard asks, “Is there any doubt

that Martin was feebleminded?”

It may at least be said for Goddard’s work that it contains some

presumptive indications that genetic factors play a significant part

in determining certain kinds of feeblemindedness. It is doubtful

whether any plausible conclusions can be drawn from the dreary history

of the Jukes. In his monograph on the Jukes in 1915, Estabrook only

ventures to proffer one definite statement concerning hereditary

transmission in the Jukes family. It is that “there is an hereditary

factor in licentiousness.” I have searched through his memoir for a

single indication of the way in which he defines licentiousness and its

allelomorphic opposite chastity. Out of a large number of monotonously

similar family case histories I shall quote the only one which contains

any suggestion of the meaning he attaches to the latter. This (Case G)

is as follows:

“A cousin mating of chaste individuals was followed in the first

generation by no licentiousness. In the second generation from the

cousin mating no licentiousness appears, although the father of

one of the children of this generation had cohabited previous to

marriage. Their one daughter was chaste, but she has one daughter

brought up in a good home free from bad influences, who was very

erotic but is at present chaste. The third child of this cousin

mating of chaste people, Addie, married a man who had acquired

syphilus and had one son an inefficient syphilitic who died of

tuberculosis. Addie died of syphilis at 20. The fourth child Alta

V 78 who was always chaste, married but had no children. Horace

the only other child of Alfred who reached maturity was reputed

chaste but was intemperate: he married a chaste woman and had nine

children, all of whom are chaste.”

Before we take the risk of wrecking the machinery of social biology

by exceeding the speed limit of rational inquiry, it is desirable

to ascertain the reasons for such haste. Dr. Estabrook has recorded

his own reasons in quantitative terms. “Dugdale estimated a loss to

society of $1,250,000 by the Jukes family from 1800 to 1875. The loss

to society caused by mental deficiency, crime, prostitution, syphilis

and pauperism of these 2,800 people is now estimated at $2,093,685. If

the drink bill is added, this total becomes $2,516,685.” The reason

for this addition will be more apparent to a prohibitionist than to a

brewer. Mr. Chesterton might retort by asking whether there are no idle

young clubmen in New York whose annual upkeep is equivalent to the loss

entailed by the Jukes during the last century and a half. Deplorable

as the history of the Jukes may be, its consequences to civilization

may be less disastrous than half an hour’s conversation between a

manufacturer of armaments and a newspaper proprietor. In such matters

private values influence our opinions more than those issues which can

be discussed in the public forum of science. Estabrook’s arithmetic

does not convince me that we should exchange the experimental and

sceptical temper of scientific inquiry for the facile slogans of the

parliamentary candidate.

The eugenic movement was founded to encourage “the study of agencies

under social control that may improve or impair the racial qualities

of future generations either physically or mentally.” That aim might

be taken as a statement of the scope of social biology, when due

allowance is made for the full requirements of a scientific inquiry

into the nature of “mental inheritance.” There are a few prominent

eugenists who have adhered to this praiseworthy and modest programme.

Professor Carr Saunders who has been prominently associated with

the eugenic movement in England has consistently expressed himself

with discrimination and restraint on the complex issues which the

genetic structure of human society involves. If I am disinclined

to follow him in the alarmist attitude which he adopts towards the

differential fertility which has accompanied the recent decline of the

European birth-rate, I entirely agree with him in recognizing that the

differential fertility of occupational groups is a matter for careful

and comprehensive investigation. To make any satisfactory predictions

about the outcome of the present decline it is necessary to ascertain

what factors have contributed to the reduction of the birth-rate, what

genetic differences distinguish different occupational groups, and how

such differences are transmitted. The impressive array of evidence

which Beveridge, Stevenson and Carr Saunders have presented strongly

suggests that the spread of contraceptive practice has been the main

factor in the decline of the birth-rate. The German and Swedish data of

Grotjahn and Edin point to the conclusion that contraceptive practice

is spreading to all sections of society. If this is so the problem

of differential fertility is solving itself. Of genetic differences

which distinguish occupational groups we have no definite information.

Even if we had, it would be necessary to know how such differences

are transmitted before prophesying disaster. Haldane’s mathematical

analysis of the effect of selection shows that a selective process

must be continued for a very long period in order to produce an

appreciable effect on the distribution of a character which depends on

the co-operation of several recessive genes. An attitude of calvinistic

gloom towards the future of human society is not a necessary

consequence of the biological study of human society.

In discussing the influence of eugenic propaganda in this essay I

have been primarily concerned with the dangers of speculating upon

questions whose philosophical importance is less apparent than their

practical interest. I trust that I have made it abundantly clear that

I am in no sense hostile to eugenics as defined above. Were I to

indulge in the luxury of stating a purely personal opinion about the

genetics of human society, it would be somewhat as follows. It is

probable that extremes of intellectual accomplishment or defect are

significantly determined by genetic variation. It is highly unlikely

that extreme types of defective are reproducing disproportionately. It

is also doubtful whether genius has ever been biologically fertile.

Between the two extremes there is probably a neutral zone in which

somatic variability plays a larger part than genetic differences in

determining social behaviour. At present it is impossible to assess

with precision the mean genotypic endowment of different social

groups, whether occupational or racial. Even if it were, the precise

significance of the mean would be problematical. I think it highly

unlikely that such mean differences as may exist provide any basis for

establishing new social barriers or reinforcing old ones, still less

for curtailing opportunities of education and the exercise of political

responsibility. On the other hand it is not unlikely that there does

exist a section of genetic types on the borderline of extreme defect

not segregated from the rest of the community and more fertile than

others of the same social grade. With Mr. Chesterton I am inclined to

doubt whether they represent a larger proportion in one social class

than in any other. Unlike Mr. Chesterton I see no reason why society

should not deal with this issue as a genetic problem, when it is

clearly proved to be a genetic problem. Indeed I think it arguable that

it would be wiser not to take any risk of encouraging the feebleminded

to breed. At present I see no way of stopping them.

There can be no disagreement concerning the desirability of exploring

every avenue in human genetics. This cannot be done without enlarging

the scope of the official census with the support of a sympathetic

government. Hitherto Eugenic propaganda has been dominated by an

explicit social bias which, in England, can only serve to render the

Eugenic standpoint unpalatable to a section of the community which for

good or ill seems to be assuming the rôle of a governing class. The

greatest obstacle to the spread of a sane eugenic point of view is the

eugenists themselves. By recklessly antagonizing the leaders of thought

among the working classes the protagonists of eugenics have done their

best to make eugenics a matter of party politics, with results which

can only delay the acceptance of a national minimum of parenthood.

These last remarks I repeat are a statement of purely personal opinion.

Biologists share the human frailty which prompts all of us to entertain

beliefs fortified by insufficient evidence; but there is no reason why

the biologist should fail to make it clear, when he is speaking as a

professional biologist and when he is speaking as a private citizen.

From a purely scientific standpoint the problem of human inheritance

can only be regarded as a virgin field in which the prospects of an

early and abundant harvest are by no means bright. I believe that the

eugenists have performed a useful task in emphasizing the need for a

biological analysis of human society. The furtherance of that task will

not be promoted by propaganda which overstates the achievements of

the present, while underestimating the difficulties which lie ahead.

Evolutionary inquiry was brought to an end in ancient Greece, when

philosophy became the handmaiden of politics. Further progress was

checked when philosophy became the bondservant of theology. Eugenics

like Greek philosophy derived its first impulse from natural science.

It soon entered into alliance with the politician. It is fast finding

its most stalwart supporters among the clergy. It can only realize

the aims of its founder by bringing the science of genetics into

closer relationship with other methods of studying human biology and

annulling the marriage of biological inquiry with political propaganda.

As a private citizen the biologist is entitled to his own opinions

concerning the merits of sterilizing the unfit, just as he is entitled

to his own opinions on the Single tax or the advantages of capital

punishment. Such opinions usually belong to his private world. In

his public capacity, as a biologist, he is primarily concerned with

sterilizing the instruments of research before undertaking surgical

operations upon the body politic.