JBS Haldane

Human Biology and Politics

Source: Being the Tenth Annual Norman Lockyer Lecture, Delivered on November 28th, 1934, AT 4-30 p.m., In the Hall of the Goldsmiths' Company, London;
Published: The British Science Guild, 193?;
Transcribed: for marxists.org in May, 2002.

Sir Norman Lockyer, whose name is commemorated by this lecture, was fortunate in certain respects. His work on the chemistry and physics of the sun, revolutionary as it was from the point of view of pure science, did not bring him into conflict with established interests either in religion or politics. This was, in a way, accidental. The scriptures might well have contained misleading passages concerning the composition of the sun, as they do about its motion. And had the persons with a vested interest in nineteenth century methods of illumination been sufficiently farsighted, they would have realised that a study of line spectra was likely to render obsolete all lighting methods based on the emission of a continuous spectrum, and have done their best to discourage this study.

The student of human biology can hardly hope for such immunity from worldly contacts. He may discover facts which go far to disprove the theories by which current politics, economics, hygiene, religion, and morality are supported. And he will not even have the satisfaction of whole-heartedly taking sides in a controversy. At one moment he may find himself attacking a religious dogma, at the next supporting the Pope against people who regard themselves as progressive. If he defends the medical profession against some of its opponents, he will be bound to admit that the Pharmacopeia embodies many practices which have absolutely no scientific foundation. In most human controversies truth resembles the Mexican god Yaotl, familiar to readers of Cabell's "The Silver Stallion." It is the enemy on both sides.

I shall naturally be dealing with aspects of human biology which are controversial to-day. It is worth remembering that a good deal which is common-sense in Britain to-day was once a novel and revolutionary hypothesis, and still is so in some primitive communities. It is said that certain peoples recognize no relation between sexual intercourse and the birth of children, but regard conception as solely due to the entry of a spirit into the mother. Others refuse to admit any causes of death except human agency, ascribing what we call natural death to sorcery. In each case we now accept the materialistic explanation without question. (Perhaps I should except "Christian Scientists" who attribute disease to error on the part of the diseased or malicious animal magnetism employed by others!). Nevertheless the fact that we rarely give children a perfectly straightforward account either of birth or death shows that very deep psychological resistances to clear thinking on either subject still exist in our society. Neither I nor my hearers can hope to avoid emotional prejudices when we take up these subjects.

These fundamental facts of human biology are as much part of the common stock of ideas on which we all act as are certain fundamental facts of chemistry or physics. For example, everyone knows that the rapid oxidation of cellulose is an autocatalytic process, in other words, that one, can light one piece of wood from another, a very fundamental and revolutionary discovery in its time. Other chemical and physical facts, not so generally known, are applied in industry, others again await application. What are the facts of human biology analogous to these two latter classes?

The most important group of data applied by specialists are those which constitute the medical sciences. Those which are not applied in medicine are, to a very large extent, not applied at all. Either they have no obvious application, or they form the basis of arts such as Eugenics, which, like inter-planetary navigation, are not yet practiced, at any rate in this country, even if their principles are partly understood.

Before I come to my main theme, I must crave your indulgence while I say a few words about the medical profession. The application of science to other branches of life has led to increase in organization. Some of these organizations are capitalistic like the railways or the great industrial combines, others socialistic like the Post Office or Woolwich Arsenal. But though we do not go to an individual artisan for our car or to an individual water-carrier for our water, we still go to an individual doctor for our healing. The largest organizations for medical and surgical treatment are the hospitals, which are neither capitalistic nor in this country socialistic, but survivals or imitations of mediaeval foundations. A few large clinics and nursing homes are run as business concerns.

The result is most unfortunate. The patient consults a doctor who is supposed to understand the whole gamut of human ailments, from broken bones to madness. If poor, he or she may ultimately be admitted to a hospital, but too often after a considerable delay. The middle class patient is treated in his own home or in a nursing home, where conditions are generally far worse than in a hospital. There are generally fewer specialists available, less adequate apparatus and laboratory facilities, and less constant attendance by nurses. Only the very rich secure as satisfactory treatment as the hospital patient. I speak from experience of both. I have been in a really good nursing home. I have also been in one where the conditions were inferior to those of the better hospitals in Mesopotamia in 1917.

The system is obviously unsatisfactory. Though I should prefer to see a state medical service, I am sure that the middle class patient would be very much better off with a capitalist type of medical organization than at present. He could go to an institution where he would find a team of competent specialists including a radiologist and a bacteriologist, and would very probably be able to avoid the very heavy occasional costs of illness by paying a fixed annual fee.

As medicine becomes more and more a matter of prevention as well as cure, the defects of the existing system show up more clearly. The preventive and prophylactic side of medicine is represented by the medical officers of health, the school medical officers, and a few voluntary institutions such as the Peckham health centre, which are models of what should be; but under a system of individual medical attendance adequate disease prevention is almost impossible, if only because it is far harder to detect latent disease in an apparently healthy person, than to determine the nature of a disease already existing.

If the existing knowledge of human biology and that which is likely to come into existence in the near future were adequately applied, there would, as we shall see, be an enormous demand for experts. It is a very serious question whether they should be members of the medical profession. Again it has been suggested that sufferers from certain incurable diseases should be killed, that persons with hereditary defects should be sterilized and that abortion should be permitted in certain cases where the mother's life is not in danger. If any of these practices are legalized I sincerely hope that they will not be entrusted to the medical profession. The relation of the physician to his patient should always be that of a healer, never of killer, and the whole psychology of that relation would be profoundly altered for the worse if this ever ceased to be the case. This fact was realized by the wise man or men who framed the Hippocratic Oath. If public opinion demands the application of medical technique to such ends as I have suggested, the profession will be well advised to surrender some of their rather jealous guardianship of this technique; rather than extend their functions unduly.

For the same reason I believe that it is desirable that the experts who in the future will be concerned, as I believe they will, with the enforcement of standards of diet, housing, reproduction, and so on, should not be medical men, though they will have to learn much of the science which is now taught only to the medical profession. The alternative would be an hypertrophy of the medical profession such as occurred in the middle ages when the church concerned itself not only with spiritual affairs but with government, education, and handicraft. Such an hypertrophy could only end in disaster. An expert on human biology need not be a doctor, and in many cases should not be, any more than every clerk should be in holy orders.

For as soon as human biology ceases to deal with the individual, it becomes inevitably mixed up with politics. In this lecture I propose to examine some of these repercussions. I shall deal chiefly with the questions connected with human reproduction, the questions of the quantity and quality of our future population. Here I have the advantage that the subject has already been treated by Dean Inge, who preceded me in this lecturership. It is always interesting to study the reactions of an intelligent outsider to scientific thought. But such an outsider is apt to label as scientific, ideas which have but a meagre claim to that title.

Let us begin with the question of numbers. Dean Inge believes that a happy and healthy England would be more sparsely populated than at present, by a population largely engaged in agriculture. This is only true if it is impossible to keep an industrial population healthy and happy. It will be time to conclude that this is impossible when the attempt has been made on scientific lines, and not till then. An urban population living in unplanned houses, and eating an unplanned diet, is bound to be less healthy than a rural population. An urban population which was adequately fed, and had opportunities for sport and country travel might be healthy enough. When I climb Snowdon, as I have done at least once, without meeting anyone else, I cannot resist the conclusion that our population is ill distributed rather than too large.

Whether I am right or not, it is certain that our population is going to diminish very greatly in the near future. This prediction is based on the statistical methods introduced by Dublin and Lotka in the United States, and by Kuczynski in Europe. Their work has recently been popularized by Charles in "The Twilight of Parenthood." If we have a table of deaths at different ages and children born by mothers of different ages, we can readily make the following calculation. If 1,000 girl babies are subject to these death rates and birth rates, how many daughters will they produce in the course of their lives? In England to-day this figure is about 750. The figure 0.75 is called the net reproduction rate. The population is still increasing because there are a large number of women of child-bearing age, but it will begin to fall within the next ten years. Wherever the net reproduction rate is less than 1, the population is bound to fall. In our own country at least no improvements in hygiene can possibly counteract the tendency. If we take 1,000 girl babies and suppose that none of them dies before the age of 50, while their fertility in each year is unchanged, we get a figure called the gross reproduction rate. This is, of course, higher than the net rate, but in England and Wales it fell below unity in 1927.

Similar figures are available for a number of other countries. The net rate is below unity throughout North-Western Europe, including France and Germany. It is near unity in central Europe, and rapidly dropping towards that figure in Italy and the Balkans. For example, the net reproduction rate in Bulgaria fell from 1.9 in 1903 to 1.3 in 1929, and is probably now very little above unity. In the United States it probably fell below unity in 1927. In the British self-governing dominions it is still slightly above unity, but approaching that figure. The position in the U.S.S.R. and Japan is entirely different. In 1926-7 the net reproduction rate of the former country was 1.7; that of Japan is also very high, though really adequate figures are lacking. It is of course probable that in both these, countries industrialization will ultimately lower fertility, but there are as yet no clear signs of this tendency.

The political consequences of these facts are interesting. Dean Inge disapproves strongly of Communism, and thinks that England should play an important part in combatting it. But he approves of a trend in population which is rapidly rendering England, and all other capitalist countries save Japan, less and less capable of effective action against the Soviet Union, should such action be desired by those who regard our civilization as superior to that of the Soviets.

Though I do not share all the Dean's views on international politics, I think that a great diminution of our population, while that of other countries is increasing, would intensify the present instability of the international equilibrium. If the population of Australia does not increase much more, while that of Japan does so, it will become increasingly difficult either morally or physically to resist the Japanese claim to immigrate into that continent. I think that it will be generally agreed that, even if a slight diminution in our population is desirable, the catastrophic fall which will occur if the fertility of Englishwomen is still further diminished, is undesirable. I shall consider later what steps should be taken to check this fall.

We next come to the question of quality of population, by which I mean innate quality. Dean Inge makes the surprising remark that "any progress which is not based on an intrinsic advance in human intelligence is very precarious." Of course all progress is precarious, but I have yet to come across any evidence whatsoever that there has been any advance in the intrinsic factors making for intelligence in Europeans during the last 50,000 years. We have no reason to suppose that a hundred babies gathered from Solutrean caves and transported by a time machine into the year 1934 would grow up, on the whole, stupider than the rest of us. Progress as far as I can see has been due to the substitution of one type of production by another, and in so far as the new social organization has been stable, the progress has been of a fairly permanent character. Progress and evolution are different processes with different time scales. We are surprised if we can detect evolutionary change in a section of the geological record covering as little as 20,000 years. But the whole of human progress since the old stone age is comprised in less than this period. It is no doubt desirable that man should evolve in certain directions, but such evolution is a quite different thing from social progress. It may be that there is a limit to the social progress possible without further evolution, but before such a conclusion is proved a good many experiments will have to be made; and the statement that the limit of progress has now been reached need not be taken seriously except as an expression of conservatism in the speaker.

As regards innate human quality three ideals are held up. Certain relatively rare types should be eliminated, certain classes within a given community should be encouraged to perpetuate themselves while others should not. And certain races should be prevented from immigrating into given areas or expelled from them. Curiously enough eugenic organizations rarely include a demand for peace in their programmes, in spite of the fact that modern war leads to the destruction of the fittest members of both sides engaged in it.

Let us first consider the undesirable innate characters which we want to eliminate. Many of them are due to the substitution of one gene for another. That is to say they are inherited in accordance with Mendel's laws. For example "lobster claw," a rare condition in which the hand and foot are reduced to a single pair of digits, is handed down by affected persons to about half their offspring, and never skips a generation. It is due to the substitution of an abnormal gene for one of the genes concerned in limb development. Affected persons have one normal and one abnormal gene of this pair, and hand down each to half their progeny. A gene like this which produces effects when heterozygous, i.e. associated with a normal allelomorph, is said to be dominant. If all affected persons were prevented from breeding, the condition would be wiped out in a generation, save for the very rare cases, probably less than one in a hundred million, where the abnormal gene arises anew by the process called mutation. In this case we should be sacrificing one normal child for each abnormal whose birth was prevented.

Some other dominant characters would not be so easily extinguished. Thus one cause of congenital mental defect is epiloia, or tuberous sclerosis. This is a dominant, but is rarely handed down for more than two generations, as it causes early death as well as mental defect. Unfortunately this adverse natural selection is balanced by mutation. Penrose showed that at least 20% of a series of cases arose in this way. So here sterilization would only reduce the incidence by about 80% even if every case were diagnosed, which is unlikely, and does not always cause mental defect. In only 22% of Penrose's cases had the disease been actually diagnosed in a parent, so probably sterilization would only give a reduction of this order.

Again Huntingdon's chorea is a dominant. This terrible disease begins with involuntary muscular movements, which are the first symptoms of a nervous disease culminating in madness and death. The average age of onset is about 35. By this age most people have already begotten the majority of their children. The sterilization of subjects of this disease under the recent German law, even if carried out very thoroughly, will therefore not abolish it within a measurable time, though it will slightly diminish its incidence. It could only be wiped out by preventing all children of affected persons from breeding, a sacrifice of 3 normal children for each abnormal.

Another group of diseases are sex-linked recessives such as haemophilia. This condition is due to a gene carried in the X chromosome, of which women possess two and men only one. A woman carrying one gene for haemophilia is normal but transmits the condition to half her sons. An affected male does not transmit it to his daughters, but it reappears in half their sons. However, it is so fatal that haemophilics rarely marry, and Bulloch and Fildes even doubted whether it was ever transmitted by a male, though I think the evidence for this is very strong. Haemophilics certainly should not beget children, though as they rarely do so, a prohibition would have little eugenic value. They could not be sterilized by operation, as this would often be fatal. X-rays might be used. The only measure which would appreciably diminish the frequency of haemophilia would be the prevention of further child-bearing by healthy women who have had a haemophilic son, and by the sisters of haemophilics. The sterilization of mothers would sacrifice three normal children for each abnormal, that of sisters seven normals for each abnormal. Such measures would perhaps be justifiable were the population increasing rapidly. I doubt if they would be so at present.

Finally we come to recessive abnormalities. These include many forms of blindness and deafness, and at least two forms of idiocy. The case of juvenile amaurotic idiocy is typical. This is due to the compresence in an idiot of two abnormal recessive genes, one contributed by each of two normal but heterozygous parents. When such parents marry, on the average one quarter of their children are affected. No case is recorded in Europe (though there is one in Japan) where an amaurotic idiot has lived long enough to have children. If two grandchildren of the same heterozygous carrier marry, the chance that both will be heterozygous is one sixteenth, whereas the chance that two unrelated persons will carry it is (in the population of Sweden) about one in 15,000. Hence it is not surprising that the condition is very much more frequent among the children of cousins than in the general population. Sjogren found that 15% of the Swedish cases were the children of first cousins, and a further 10% of other relatives. Similarly Usher found that 24 of 79 English cases of retinitis pigmentosia, a disease which causes about 4% of all blindness, were the offspring of first cousins, and 4 more of first cousins once removed.

It would be useless in such cases to sterilize the affected. Very often they do not breed, and when they do their children are generally normal. There is also no prospect of eliminating the recessive genes. Nearly 1% of Swedes are heterozygous for amaurotic idiocy, and probably most normal people carry some deleterious recessive gene.

At present only two eugenic measures are available. One is to discourage the marriage of cousins. The only body that does this is the Roman Catholic church, which is however hostile to other forms of eugenics. The other would be to allow or enforce the sterilization of one partner in a marriage which had produced a recessive at certain time, or to sanction or even compel the dissolution of such marriages.

Deaf mutes present a special problem. Deaf mutism may be congenital or due to infantile ear disease. Congenital deaf mutism is largely due to recessive genes, as appears from the fact that, in different populations, from 21% to 40% of congenital deaf mutes are the progency of consanguineous marriages. But deaf mutes very frequently marry. Were all deaf mutism due to a single recessive gene the progeny of two congenital deaf mutes would always resemble their parents. Actually several genes are concerned. So most marriages of congenital deaf mutes give normal children. Nevertheless Dahlberg finds that 29% of the children of two congenital deaf mutes are deaf mutes. I think there is a good case for sterilizing the husband in such a case, more especially as it is clear that normal children brought up by two mute parents must be considerably handicapped.

The scope of negative eugenics, as applied to physical defects, seems then to be severely limited. The possible methods include not only prevention of procreation by affected persons, but also by their relatives, besides the discouragement of inbreeding and the dissolution of certain marriages. Actually the prospects are far brighter than this. We know so little of human genetics that only such rough and ready methods are at present available. But if we possessed the same knowledge of human genetics as we do of the genetics of Drosophila or maize, we should be able to say, with very high probability, that such and such children of a sufferer from Huntingdon's chorea has received the gene for it, and should not marry; that some of the brothers of an amaurotic idiot carried the gene for that disease, and others did not. Possibly we could detect the gene for haemophilia in heterozygous women, and so on.

This sort of thing is possible in Drosophila because harmful genes, e.g., for short wings or defective eyes, are carried in the same chromosome with harmless ones such as those for slight abnormalities in bristles or wing veins, which are quite common in wild populations. Such genes are linked, that is to say are handed down together, and the harmless variations thus serve as indices of dangerous recessives.

Quite a number of human differences, for example those between members of the different blood groups, and between those who can and cannot taste phenyl-thio-urea, are due to very common gene substitutions. It would be perfectly practicable to discover a large number more of such genes. Indeed they were being discovered at a considerable rate by a German worker until political events put an end to his research. I should estimate the cost of an investigation which would give us a sufficient background of normal genes for linkage work at between L3,000 and L5,000 provided the right men were chosen for the work, and a number of families were available through co-operation with some hospital or authority.

Except with such aid I see little chance of investigating the problem of congenital defect. We already know that mental deficiency is due to very many causes, and naturally enough. There are some hundreds of causes of blindness; and the cerebral cortex is a more complicated organ than the eye, and therefore likely to work badly for a greater variety of reasons.

Of so-called congenital cases of defect some are due to injury at birth, some to infection, especially syphilitic. Here it is worth noting that chemists are only permitted to sell antiseptics for the prevention of that disease if no instructions as to their use are sold with them! This curious example of censorship doubtless accounts for some mental defect. Other types of defect, particularly "mongolism," are caused by prenatal environment rather than heredity. Of the truly innate types of mental defect some are due to dominant genes, as shown by their transmission to the offspring, some to recessive genes, as shown by the frequency of inbreeding among their parents. In most cases we have no definite information, and shall not until we can distinguish the different causes by clinical or genetical research. Quite recently Folling found, that 10 out of 430 defectives, and no normals, excreted phenyl-pyruvic acid. Here the mental defect was probably due to a metabolic error, and this latter very possibly to a recessive gene.

Now a proportion of mental defectives which different authors place between 5% and over 50%, are derived from defective parents. Thus if all defectives were prevented from breeding the number of defectives in the next generation would be reduced by a proportion which I do not personally think would exceed 20%. The dominant genes concerned would be abolished, but the recessives would remain. This result would be worth while, but would not abolish mental defect, and would be slight compared with other equally practicable results, such as the abolition of venereal diseases, which would also involve some restrictions on liberty.

There are several objections to the policy of wholesale sterilization which has been suggested. The operation is trivial for men, but for women it is about as serious as that for appendicitis, and there would inevitably be occasional fatalities. Any attempt to make this operation compulsory or even alternative to seclusion in an institution would be a violation of the principal of the sanctity of human life, which underlies so much of our legal practice. Except as a punishment for murder or treason the law does not permit that people should be killed, though it permits an operation risking their lives in order to eliminate a graver risk. If a government once violates this principle it is opening the door to very serious consequences. Our more intelligent politicians realize very well that if the government starts killing people, people will sooner or later start killing the government. Hence it is to be hoped that they will not legalize such operations as salpingectomy on imbecile women, even if it is done with her consent. The consent of a mental defective is not worth very much.

Another objection is that we have no adequate criterion of mental defect. The late Professor Trouton did not learn to read until the age of 12. If he had been an elementary school child he would have been sent to a special school for defectives. He was so far from being defective that at the age of 17 he discovered the law which bears his name.

Sterilization would not be carried out without class discrimination. Idiocy and imbecility are about equally common in all classes. Certified feeble-mindedness is commoner among the very poor. While genuine mental defect may be rarer, it is obvious that it is often not certified among the rich, although a glance at the press will convince anyone that they include a number of persons who satisfy the legal criterion of imbecility in that "they are incapable of managing themselves or their affairs."

It is worth pointing out that where mental deficients are sterilized this is done from economic as well as from biological motives. Judge Holden of Yakima, Washington, U.S.A. sentenced John Hill to a sentence of from 6 months to 15 years imprisonment for stealing hams, the sentence being suspended during his good behaviour. He also suggested that Hill should be vasectomized, to which he consented. What follows are the judge's own words:

"Hill, his wife, and five children, are all mentally subnormal, even for their situation in life. For many months the children have been half starved and half clothed ... The case was brought to the attention of the public authorities through the discovery of the theft of the hams, since which time he and his family are partly dependent on public charity, and without the addition of more children to the family, will undoubtedly continue to be more or less of a public charge; with more children the extent of demand on public charity will, be increased."

It did not occur to the judge either that there might be any connection between the starvation of children and their mental dullness, or that there was anything wrong with conditions under which a beet sugar labourer could not earn enough to support five children.

It may be necessary that the richest country in the world should sterilize its citizens as a measure of economy. But at least it is to be hoped that if Britain follows the example of Washington the suggestion will not be made that such action is taken in response to the demands of biologists. Biologists may legitimately demand that a proportion of mental defectives should be prevented from breeding. The demand that they should be sterilized comes from those who consider such a measure to be cheaper than segregation, and to whom this consideration is paramount. But there is I think a real case for legalizing the sterilization of those who desire it, if they carry a sufficiently harmful dominant gene, such as those for some forms of cataract, blue sclerotics with brittle bones, epiloia or lobster claw. Such a measure seems desirable as an addition to our liberties whose effects would be biologically advantageous.

Besides demanding sterilization and similar measures for defectives, many eugenists hold a doctrine which may be stated as follows: "Men and women born into one economic class are constantly passing into a richer one if they possess more innate intelligence than the average of their class, into a poorer one if they possess less. But the poor breed faster than the rich. Hence the innately stupid breed faster than the innately clever, and the mean innate ability of the population is falling. Before examining the proposed remedies for this situation I must consider whether the fundamental proposition is true:

At first sight it appears obvious, but there are two good reasons to doubt it. In the first place it is clearly flattering to the self-esteem of those who hold it, and therefore suspect. Secondly, if it were true, a system which allotted a number of wives to people who made money would clearly tend to produce a race of great ability, at least in commercial matters. Now this system has been tried, and what is more, tried with an adequate control. In Mohammedan countries during the last twelve centuries followers of the Prophet who have acquired wealth have practiced polygamy, while their poorer co-religionists have had one wife or none. On the other hand Christians and Jews in Mohammedan countries have been on the whole monogamous, even if the rich had some illegitimate children. Hence we should expect that Mohammedans would have acquired greater commercial ability than members of other religions, in fact that a Turk would generally beat a Jew or an Armenian in a commercial deal. This is not the case. Hence I do not regard it as certain that if in England the rich bred faster than the poor our race would acquire greater innate ability, even of that particular kind which leads to a rise in the economic scale.

I wish to suggest that the phrase "innate ability" is meaningless. We cannot say that in all environments A will prove abler than B by any particular test, save in exceptional cases, as when B is a microcephalic idiot. An analogy from agriculture will make my case clear. Put a Jersey cow and a South Africa scrub cow in an English meadow. The Jersey will give far more milk. Put them on the veldt, and the Jersey will give less milk. Indeed she will probably die. The Jersey has been selected, not for high milk yield in all environments, but for a yield which varies more than that of the primitive cow in response to environment.

A number of writers on eugenics have dealt with the so-called "social problem group," men and women who are petty criminals, unemployed even in times of prosperity, more fertile than the average, and on the whole endogamous. There is evidence that their behaviour is partly due to inherited dispositions, and it is assumed that they would be socially inadequate in other environments, as they are in the slums. I think this far from certain. They include some real defectives, but the rest, for all that anyone knows, may be like the Jersey cows, on the veldt, yielding little of value in their actual environment, but possibly capable of better things if they got out of it than men and women who are more contented with social conditions as they exist in the slums. It is only when people have failed in a favourable environment such as we may hope to see throughout Britain in the future that they can be regarded as probably unsuitable parents of future generations. Differences within a social class are far more likely to be heritable than differences between members of distinct classes.

I know that most writers on eugenics disagree with me, and I will briefly examine the consequences to be drawn from the theory that as regards human achievement the effects of nature and nurture are additive, even though they are not so as regards the yield of cattle or wheat.

If the well-to-do are innately abler than the poor it is desirable that they should breed quicker. They appear to breed more slowly for several reasons. They are more cautious, have greater knowledge of, and opportunity for, birth control, and carry more genes making for low fertility. This last characteristic is due to the fact that low fertility is inherited, and makes for economic success, as is obvious if we compare the possibilities either of saving money open to a man with two children, and a man with ten. In this country it has been specially stressed by R. A. Fisher. In view of our already inadequate birth rate no proposal tending to reduce the existing fertility of any classes not definitely defective can be seriously entertained. A new system of family allowances would have in Fisher's view three distinct advantages.

In the first place it would check the coming fall in our population. In the second it would act most sharply on the fertility of those who now limit their families on economic grounds, and are regarded by most eugenists as possessed of better innate endowments than those who breed more freely. And thirdly, by checking the social promotion of infertility as such, it would end the present sterilization of ability. For, according to Fisher's argument, infertility and ability equally lead to a social rise, and hence, as people generally marry within their own social class, genes making for ability and infertility are associated in the same families, and thus the genes making for ability tend to disappear.

There is, however, an argument for family allowances which appears to me very much more cogent. In the last twenty years we have, for the first time, arrived at definite criteria of a satisfactory diet for human beings. We know that a very great deal of our existing physical defects are due to qualitative as well as quantitative under-nourishment.

Qualitative under-nourishment is not confined to the poor, But it is certainly far commoner among the poor than the rich, And in a family with a sufficiently small income it is impossible to avoid it. There is surprisingly little controversy as to the minimum cost of an adequate diet for children under English urban conditions. The British Medical Association's Committee find that this rises with age from 2/8 to 5/5 per week. Professor Bowley' s standard including less milk, rises from 1/10 to 4/8.

It is at any rate clear that the 2/- per week allowed for the child of an unemployed man for all purposes is entirely inadequate, and that if this sum were raised to 5/- the unemployed with a family of four or five would receive a larger income than many employed men with similar families.

It is not for a biologist to suggest how this situation should be remedied. But if it is not remedied then the research of the last few years on dietetics has been largely useless, and there appears to be little point in continuing it. Clearly the action of the Government in lowering the price of milk to school children is an example of one possible method, which if properly carried out will tend to canalize the demand for foodstuffs into channels approved by biochemists. It is a compromise between allowances and rationing.

But though it is a great step forward it is very far from adequate. A definite standard of diet is available, and no biologist should be satisfied until it is reached. It is worth noting, by contrast, that no similar standards can be given as regards housing or clothing. A biologist may demand the abolition of slums, but he cannot say what constitutes a slum, while he can say what constitutes an inadequate diet. In the future scientific standards of housing may be attainable, but they are not as yet.

I have tried to show that three different arguments may be brought forward for some form of family endowment. In the first place an adequate diet is now as much part of preventive medicine as an adequate water supply. Secondly, our population is likely to decline rather rapidly unless the present economic incentives to family limitation are removed. Thirdly, such a measure would check the association of innate ability with infertility which is thought by many eugenists to exist. For the last two purposes family allowances would have to be roughly proportional to the family income. Fisher regards 12% per child as adequate; other authors would give a higher figure.

It is not for me to say whether adequate family endowment is compatible with our present economic system. There are good reasons to doubt it. If our rulers tell us that it is impossible under capitalism, then we had better try socialism. However, it can also be argued that an assured effective demand for a certain minimum would tend to stabilize capitalism, and that the existence of even our present biologically inadequate minimum in Britain has stabilized it.

Whichever of these alternatives is true, I am certain that as biologists begin to deal with human problems they will increasingly demand a minimum dietary for the whole population, and a system of family endowment which will counteract the existing trends in our population.

I have not had time to deal with the racial question. A good case can be made out for discouraging immigration of negroes into Europe, or of Europeans into tropical Africa, since in each case the immigrants are ill adapted. Unfortunately as the result of political factors there are far greater difficulties in migration between England and Denmark than between England and Nigeria. No such cases can be made as between the different genetical types (I hesitate to use the word "races") who have lived in Europe for many centuries.

There is, of course, a strong case against the admission of persons of whatever race who are physically or mentally below the average. On the other hand the opportunity has arisen, as the result of recent political disturbances in Europe; of admitting to British citizenship exiles of proved intellectual ability. Every eugenist should be prepared to recommend the admission to British citizenship of such exiles, provided that they attain a sufficiently high standard.

I fear that I have said little that is novel, nor have I offered any particular panacea. The application of the data of human biology to politics and ethics will probably be more complex than that of the data of physics to industry. It is very important, if the whole science is not to be discredited, that premature steps should not be made, and that biology should not be harnessed to the car of any political party. For the latter reason I have here suppressed many of my own views, for example the opinion that our existing society is biologically unstable, and have tried rather to stress those opinions which enjoy a sufficiently general support to render them worthy of consideration not only by biologists, but by politicians of whatever outlook.