The New Heredity



I HAVE a friend who goes in strongly for genealogy. He claims to have traced his ancestry back to Clovis — or is it only to Charlemagne? I forget; but it does n’t matter. If my friend knew more about the actual characteristics of his famous but unknown ancestor, it would matter more.

The British Museum Library is infested by a lot of dry and dusty men, tracing genealogies for English and American — especially American — patrons. The Library assistants know them as ‘ searchers.’ They are searching for names, and a few facts about the men and women who bore these names: the dates and places of their birth and death; the number and sex and names of their children; their occupations and positions and honors and titles — especially their honors and titles.

These searchers sometimes speak of their profession as the study of heredity. Their work, and that of a few physicians who interested themselves in a mild way in trying to trace the recurrences of some disease or malformation in a family stock, constituted much of the study of heredity as it existed before the days of Francis Gabon, cousin of Charles Darwin, anthropologist, founder of the modern eugenics movement, and most scientific student of human heredity in the nineteenth century.


No biological subject seems to me more interesting or more important to the student of human life than heredity. Why are we like our parents? Why are we unlike them? Does heredity count for more, or for less, than environment and education in determining what we are and what we do? How can we distinguish the effects of heredity from the effects of environment and education?

It is said that fifty members, in five generations, of the Bach family were notable musicians. Anyway, if not fifty, there was an unusual lot of them. Was this because they taught each other music so well? Or because the capacity for being a good musician was inherited in this family strain? Among the 1200 known members of the notorious Jukes family there were 310 professional paupers, 440 physical wrecks from debauchery, 55 prostitutes, 60 habitual thieves, 7 murderers, and 130 other convicted criminals. Was this because of poverty, lack of education, and continuously bad environment, or was there an inherited mental defectiveness, weakness of will, and trait of bestiality in the strain? The environmentalists accept one answer, the hereditarians the other. The truth is that one cannot answer certainly these questions about the Bach and Jukes families without a careful collection and analysis of many facts. And we have not all these facts just now before us.

But we can find clearer cases. I once — no, not once but several times, as behooves the careful student — divided into three lots of one hundred each the three hundred silkworms hatched from a single clutch of eggs. To one lot of these brother and sister worms I gave, from the first meal of mulberry leaf after hatching to the last one before pupation, all the food that each worm could eat; to the second, I gave to each worm exactly half this ration; and to each member of the third lot, exactly one fourth of the optimum ration. When the cocoons were spun, I had three lots of cocoons of three different sizes (amount of silk produced). The lot of big cocoons came from the best-fed worms, the middle-sized cocoons from the worms on half-ration, and the little cocoons from the ones on quarterration. Some of the latter died during the experiment; their food allowance was hardly a living ration. I used to remember my silkworms sometimes during the Belgian relief work.

Finally, when the moths came from the cocoons, they also could be readily grouped into three lots, one of big moths, one of middle-sized moths, and one of dwarf moths. These lots corresponded with the different rations the worms had had.

Now, no one would hesitate to declare that these differences among cocoons and moths were produced by the varying environment — that is, food supply — to which the silkworms had been exposed.

But I tried another experiment. I took a number of silkworms from each of several just-hatching clutches of eggs laid by different moth-mothers, and reared all of these worms as one lot, each member of which got just as much food, and at just the same time, carefully weighed out from the same gathering of mulberry leaves, as every other member. Also, all these worms lived under exactly the same other conditions, as temperature, light, atmospheric humidity, and everything else that constitutes silkworm environment.

But when the cocoons were spun, and when the moths issued from the cocoons, neither cocoons nor moths were of the same size. There was no cocoon or moth so little as those that were produced by the nearly starved worms of the first experiment; but there were some plainly smaller than the average, and some plainly larger than the average. Yet all had come from worms reared under as nearly identical environment as possible. But they had come from different mothers and fathers. These parent moths had varied among themselves, some larger, some smaller. And their offspring also varied in size, despite an identical upbringing. It seems safe to attribute these differences to heredity.

In still another experiment, I selected just-hatched worms from ten different lots of eggs laid by silkworm moths, all of the same species but of ten different artificially developed races, the worms of each race producing cocoons characterized by special size or shape or color of silk (white, pale yellow, golden, salmon, greenish). I reared all these worms under identical conditions of food supply and temperature and light and atmosphere. But each worm produced a cocoon of shape, size, and color characteristic of its race. This again is heredity in its familiar wider manifestation of racial persistence, or kind producing kind.


But let us get back to human beings. Observing this more complex animal, can we find cases where the respective influences of heredity and environment can be distinguished as clearly as among our silkworms?

There is a well-attested record that of 480 direct descendants, in five generations, derived from the mating of a normal father and a feeble-minded mother, 143 were known to be feebleminded, while a considerable number of others had a doubtful mental status. Of 496 direct descendants, in five generations, however, from the same normal father mated with a normal mother, all but one were of normal mentality.

Now I should say that it is quite certain that the feeble-minded mother had handed on feeble-mindedness to many of her posterity directly by heredity. One does not become feebleminded by environment, even though a person of normal mentality may become outranked in mental achievement by others of similar mentality but of better education.

Goddard’s careful detailed studies of the genealogical history of 327 families represented by inmates in the Vineland (New Jersey) Training School for Feeble-minded, and numerous other similar studies by other careful investigators, prove conclusively the heritability of feeble-mindedness. Similarly, the studies of Galton, Pearson, and others, on English men of genius and high-ranking Oxford students, equally prove the heritability of unusual mental ability. But the proved differences in mental achievement, associated with presence or absence of education on the part of different persons of apparently similar native mental endowment, show that achievement — that is, what we do — varies not only with inherited capacity, but also with opportunity (environment) for this capacity to be most effectively exercised.

The Maoris of New Zealand, a Polynesian race, have added little to human knowledge during their history, and, since their contact with Caucasians, have mostly died. But some of the remaining ones have taken advantage of the opportunities for education offered them by the English occupation of their islands, and have become very capable individuals, comparing favorably with the Caucasian colonials.

This is a good example of the influence of environment and education in determining what we can do. But it does not prove that this influence is all-powerful. The black race of Africa has certainly not contributed much to human civilization, even when brought into contact with a highly developed education. The race seems to have an inherited incapacity, as a race, for high mental achievement. I recognize of course the brilliant, although infrequent, individual exceptions.

But inherited differences in mental capacity are by no means limited to differences of race. Go into any school in this country. Pay attention only to those pupils of similar race. Not only is there an equal opportunity for education before them, but the teachers are trying to compel every pupil to accept the opportunity. Some obstinately refuse to do so. But most of them, through inclination or coercion, try to learn their lessons. But do all do equally well? Conspicuously not. What are the reasons for this variance? One will be admitted by all teachers to be the principal one. It is the different inherent capacity of the pupils. Some try and can; some try and cannot. They are naturally different in mental capacity and character; born that way; that way by heredity.

What, then, is this mysterious, ever-present, powerful influence that plays so large a rôle in determining what we can do and cannot do? This powerful influence in human life that spells happiness and pride, or dismay and grief, to parents? This potent life-factor, so important to us as individuals and, from a larger point of view, even more important to us as members of a community, nation, or race? This influence that may spell greatness or littleness to a whole people? What has science to tell us, us laymen fathers and mothers of children in whose achievement and happiness — and happiness comes chiefly from achievement — we are even more interested than in our own, and to us laymen members of a nation for whose development and future we have a great concern ? What has science to tell us of the why and how of heredity? Can it tell us enough, so that in the light of such knowledge we may hope to make the best use of our control of environment to encourage and reinforce favoring heredity and to restrain and offset unfavorable heredity, to the end of strengthening the nation and advancing human progress?

Well, the answer to the last question is certainly yes, even though the answer to the first question, that is, What is heredity? may not be any more enlightening than the answers scientific men give us to the questions, What is gravitation? What is electricity? We do not know, satisfyingly, what electricity is, but we know enough about what it does to enable us to manage it, that is, make good use of it, and avoid letting it do us much harm. That is about what we know of gravitation — and of heredity.

Heredity affects not only our mental capacity but our physical makeup, including the color of our hair and eyes, the normality or abnormality of our bodies, our bodily strength and weakness and resistance or nonresistance to disease and poisons. And it equally affects all the characters of all our domestic animals and plants. By virtue of our selective control of the mating and reproduction among these plants and animals, we have, if we exercise this control under the guidance of our present-day knowledge of heredity, a powerful instrument in our hands to make them contribute ever more enormously to our comfort and advantage. And we can similarly use this knowledge to assure a greater happiness and progress among our own kind. We can discourage such matings as are practically certain to produce children doomed to unhappiness and suffering, or to be serious burdens on society.


But you may not care to accept these assertions without some explanation and illustration of the definiteness of our present-day knowledge of heredity, its mechanism, methods, and power. It is certain that we have gained more of a scientific knowledge of heredity in the latter third of the last century, and in this past fifth of the present century, than had been gained in all time before. Is this new knowledge really sufficient and sufficiently definite to be useful?

We need not concern ourselves here with the history of our growing understanding — with some misunderstanding — through the centuries of the mechanism and methods of inheritance. Heredity has always been recognized as one of the major factors in organic evolution; hence it has always been a subject of special interest to evolution students. But we may give our first attention to the sudden and important increase of our knowledge of heredity in the beginning of the second half of the nineteenth century. For it was then that the ‘new heredity’ began.

It began with the work and writings of that Francis Galton to whom I have already referred — an excellent example of the personal advantage which comes through being derived from a family stock in which unusual mental capacity has been a conspicuous hereditary feature.

Galton opened a new field in heredity study by paying attention to the inheritance of mental traits. Observation of inheritance, before Galton, had chiefly concerned itself with physical characters. Galton studied the inheritance of mental ability in Oxford students and distinguished English families. From these studies he formulated a general law of ancestral inheritance, to the effect that an individual derives on the average one half of his inheritance from his two parents, one fourth coming from each; one fourth of his inheritance from his four grandparents; one eighth from his eight great-grandparents; and so on, by diminishing fractions, until the sum of this infinite series reaches 1, or the total inheritance of the individual.

He also formulated a second generalization, which he called the law of filial regression. This may be expressed by saying that the children of parents who vary from the mean of the population vary similarly, but to less extent than the parents. ‘The stature of adult offspring must on the whole,’ he says, ‘be more mediocre than the stature of their parents; that is to say, more near to the mean or mid-type of the general population.’

Galton treated heredity statistically. He determined averages, and his laws indicate general, or average, results.

These generalizations, or laws, of Galton, based on the examination and statistical treatment of many data, mark a distinct step forward in the study of heredity. But they give us little information — and that little is somewhat discredited by the more recent revelations of the heredity students — about the probabilities of the inheritance of specific characters, and the hereditary make-up of specific individuals. They do not indicate just what special traits we may expect to derive, or may not expect to derive, from the parents, or the grandparents, or greatgrandparents. Nor do they tell us what will be the hereditary fate of a given individual with a given ancestry. And it is precisely that kind of information that we most desire. If one of the parents is feeble-minded and the other normal, or if both parents are normal but a grandparent is feeble-minded, or if both parents are feeble-minded but all four of the grandparents are normal-minded, will the child or children be feebleminded, or not?


In the eighteen-fifties and -sixties, an Augustinian monk, Gregor Mendel, living in a cloister in Brünn, Austria, made a series of experiments in hybridizing various races of garden peas in the cloister garden. He published the results of his experiments, together with a theoretical explanation of them, in the obscure journal of the local natural history society of Brünn. Here they lay, practically unobserved, certainly unappreciated, until 1900 when three famous European botanists, one in Holland, one in Germany, and one in Austria, all working independently along lines tending to lead them to conclusions similar to Mendel’s, all independently, and practically simultaneously discovered Mendel’s work and made it known to the world. For thirty years an epoch-making discovery in science had lain hidden! Now Mendel, Mendelism, and Mendelian inheritance are names as familiar to biologists as Darwin, Darwinism, and Darwinian selection. And in time they will be as familiar to laymen.

Mendel made the beginning of the more important part of the ‘new heredity.’ Many followers have developed this new heredity into a fascinating and imposing special science. It is already in the way of answering precisely those questions about inheritance that we most want answered. It deals with the inheritance behavior of specific traits of plants, animals, and man, and with the inheritance of specific individuals. And it reveals much of the actual physical mechanism of heredity.

Mendel, in his own work, crossed different races of peas — he worked also with some other plants—which differed plainly and characteristically in such specific and immediately contrasted details as height of stem, character of seed coat, form of the pods, and so forth. He crossed a race with tall stem and one of low stem, a race with wrinkled seeds and one of smoothly round seeds, and so on, and noted the outcome in every one of the offspring produced by each cross-mating. He then mated these hybrids among themselves and similarly recorded the results for all of the second-generation offspring. He followed in detail the inheritance of his various pairs of contrasting characters through several generations, always noting the results in all of the individuals produced by each mating.

Mendel arrived at several definite and surprising and important results — results not limited to garden peas but holding for other plants, for animals and for man. One of these results is that, given a definite knowledge of the presence or absence in the germ cells of given parents of some physical or chemical determiner of a certain trait or traits, — and this can be determined from a knowledge of two or three ancestral generations, — definite prophecy can be made as to the outcome of the children of these parents with regard to this trait, either when the two parents are alike, or when they differ in regard to the possession of this trait.

Another result is the clearing-up of the old mystery concerning the passingon of a trait by parents not possessing it, that is, in bodily or mental manifestation. The explanation of this depends upon the fact, also first clearly indicated by Mendel’s work, that the possession of the determiner of a trait in the germ cells does not necessarily assure the bodily development of the trait in the person producing, or produced from, such germ cells. For example, a normal-minded mother and father of a certain germinal character and history can produce feeble-minded children; and a feeble-minded mother of a certain germinal character and history can produce normal-minded children. The germinal and bodily possessions of an individual may differ; and it is the germinal rather than the bodily character and history of a given individual that is of prime importance in understanding and prophesying the hereditary possibilities of that individual and his offspring.

Let me show this by an experiment that I have made repeatedly.

If we make a cross-mating between two silkworm moths of different artificially developed races, one of these races producing exclusively golden silk (cocoons) and the other white silk, we shall get a family of about three hundred brother and sister silkworms which, when cocooning time comes, will spin not pale yellow (color-blend) cocoons, nor yellow and white blotched (color mosaic) cocoons, nor some golden cocoons and some white cocoons, but all of them will spin golden cocoons like the cocoons of the golden-silk-spinning race to which one of the parents belonged. And it makes no difference whether this parent was the male or the female parent. It is the hereditary trait, golden silkspinning, that dominates over the hereditary trait, white silk-spinning, not one parent over the other. The dominance seems complete, and, as regards physical or bodily manifestation, it is. But let us carry the experiment a step further.

If we mate two of these goldencocooning offspring of the golden X white cross we shall get a family of silkworms which will not all spin golden cocoons, as both their parents did, but three fourths of the young will spin golden cocoons and one fourth white cocoons, and this proportion will be nearly exact. If now, two of these white spinners, which are the offspring of two golden-spinning parents, are mated together, all the offspring produced by them will spin white cocoons, while the off spring of two of the golden-spinning children of the golden-spinning parents will again divide in the proportion of three golden spinners to one white spinner.

That is, although the golden-spinning trait is dominant, in bodily manifestation, over the white-spinning trait, when a pure golden race is crossed with a pure white race the germ cells of the offspring produced by this crossing will still carry the white-spinning trait, which is able again to manifest itself under certain conditions.

Mendel, whose results in crossing his races of garden peas differing in various contrasted traits, such as tall and dwarf stem, smooth and wrinkled seed-coat, and so forth, were just like these silkworm results, offered a theoretical explanation of this behavior which indicates what the conditions are which make the recessive trait appear again after its apparent extinguishing by the dominant trait. And this explanation so well accounts for the happenings that it may be accepted as the true one.

It assumes that hereditary traits are represented in the germ cells by specific physico-chemical determiners, which are brought together in the fertilized egg cell produced by any mating, pure or cross, and handed on in the male and female sex cells produced by the offspring of the cross, without destroying or materially influencing each other; although, when two kinds of determiners representing contrasting traits, such as yellow-and-white-silk spinning or high-and-dwarf stem of pea plant, are in the egg cells, one of these contrasting characters is dominant over the other as regards actual bodily manifestation.

Now, applying this explanation to the pea and silkworm experiments, let us see how it accounts for the results.

When a moth of the pure white-silk race is crossed with a moth of the pure golden-silk race, the offspring will all spin golden cocoons, because golden is dominant over white in the struggle for manifestation; but half of the germ cells of these hybrid golden-silk spinners will carry the determiner for golden, and half the determiner for white. When these golden-spinning hybrids are mated together, the differing sex cells should meet, by the law of probabilities, in the following proportions: male cell carrying golden with a female cell carrying golden in one fourth of the cases; male carrying golden with female carrying white, or female carrying golden with male carrying white, in one half of the cases; and male carrying white with female carrying white in one fourth of the cases. Now the results of these junctures in the fertilized egg cells from which the young develop should be that, in all the cases where golden meets golden, the developing young should spin only golden cocoons and produce sex cells containing only golden determiners; in all the cases where white meets white, the young should spin only white cocoons and produce sex cells containing only white determiners; but in all the cases where golden meets white, the young should spin only golden cocoons (because golden dominates white in bodily manifestation where the two traits meet), but these young should produce sex cells, one half carrying golden and one half carrying white determiners.

That is, although all of the young produced by mating a moth of the pure golden race with a moth of the pure white race should spin golden cocoons, only three fourths of the young produced by a mating of these hybrids should spin golden cocoons, while one fourth should spin white, and these whites mated together should produce young spinning only white; but the goldens mated together should produce again a certain proportion of whites, because only one third of these goldens are germinally pure, the other two thirds possessing both germ cells representing white and germ cells representing golden. Which is just what happens.

This is only the beginning of the new-heredity story, which has been worked out by much careful experiment on plants and animals, and much painstaking observation and ancestry-tracing of human beings, by the students of Mendelian inheritance. In some cases, the first hybridization produces a blend between the crossed characters, because neither character is actually dominant over the other; but crossings of the blend-generation result in a breaking-up among the offspring into some (actually one fourth) showing one of the original traits, some (another one fourth) showing the other, and the rest (one half) showing the blend again. The one fourth showing one of the original traits are germinally pure for that trait, and, mated together, produce offspring showing only that trait; and similarly with the one fourth showing the other original trait. But the blends are germinally impure, that is, they produce in equal numbers sex cells carrying one trait and sex cells carrying the other, and, when mated together, they produce offspring, one fourth manifesting only one trait and germinally pure for that trait, one fourth manifesting only the other trait and also germinally pure for it, and one half showing blends and germinally impure.

But it would take too long, and carry us into too much detail for this general paper, to go on with the story. It is sufficient to affirm that the facts of Mendelian inheritance and their explanation have carried us a long way in our attempts to reach the goal of being able to prophesy, with a high degree of confidence, what will be the specific hereditary outcomes of matings of plants and animals and men in which contrasting specific traits are involved. The principles and the mechanism of Mendelian inheritance are well determined. But the behavior of each trait has to be worked out for each species of plant or animal, or for man. Golden color may be dominant over white in the silk of silkworms; but because we know this, we cannot say that golden is dominant over white in flower petals. It may be in one kind of flower and the reverse may be the case in another.

The actual determinations can be fairly easily worked out in plants, and in those animals susceptible to experiment. In the case of man, however, planned and controlled experimentation is impossible. Here advantage must be taken of unplanned experiment (miscellaneous matings), and of family (genealogical) records which have paid more attention to physical and mental characteristics than to names, dates of interesting happenings, and honors and titles. There must be a new kind of genealogical searching.

Much has already been done in this way. The hereditary behavior of a number of human pathological conditions, like six-fingeredness, web-fingeredness, dwarfism, color-blindness, night-blindness, and the like; and a number of diseases, and especially disease diatheses, as diabetes and Huntington’s chorea; and some less important but interesting physical characteristics, as eye-color and hair-form; and finally, and very importantly, several mental traits, as feeble-mindedness and epilepsy have been pretty clearly worked out. But only a beginning has been made. And, despite the sweeping claims of the Mendelians, there is undoubtedly much heredity that is not Mendelian in character.


Fortunately, our fate as regards both personal and social achievement and happiness is not all determined by heredity. I say fortunately, for despite the good fortune of the individual who finds himself naturally endowed with a sound body and unusual mental capacity and despite the good fortune of a race or nation or any social group which includes in its ranks a large number of such naturally endowed individuals, it would be a calamity beyond reckoning if heredity were to be the sole arbiter of our fate. Such a condition would rob millions of hope. It would, too, absolve all of us of personal responsibility for our own outcome and that of the race. Or it would at least restrict this personal responsibility to the simple brutal one of preventing any individuals except those of a certain standard of physical and mental fitness from participating in racial increase.

But heredity, despite all the claims for it made by the convinced hereditarians, is by no means the only factor, although it is a very important one, in the determination of human achievement and, hence, happiness. There is nurture as well as nature to be taken into account: that is, environment and education as well as inheritance. But it does behoove any nation ambitious for national achievement and solicitous for the individual health and happiness of its people to pay serious attention to all possibilities of having its succeeding generations well-born. As a matter of determined fact, most civilized nations are not now having their succeeding generations well-born. The birth rate of these nations is a selective birth rate, and it is not one based on good selection. Karl Pearson pointed out some years ago that one fourth of England’s population was producing each year one half of the new births, and that this ultraprolific fourth was exactly that part of the total population least well-endowed by heredity and social heritage.

The analysis of our own annual birth rate also indicates an unfortunate and menacing disproportion between the ill-born and the well-born. It is not merely the decline in birth rate, which we show in company with the nations of Western Europe, that is so disturbing; but it is the fact that this decline is selective, and is most marked in those classes or parts of the population which we can least well afford to have reduced. Holmes paints a gloomy picture of this in his recent book, The Trend of the Race. ‘We are losing the elements of our population that belong to native American stock,’ he declares. ‘We are losing the elements of our population that have achieved success financially, socially, and in the field of intellectual achievement. The elements of the population that are of subnormal mentality exhibit at present the highest degree of fecundity.’

With regard, in particular, to this matter of inherent, that is, inherited, low mental capacity, the revelations of the application of the ingenious tests for intelligence, devised with much care and after much preliminary experimentation by competent psychologists, to 1,700,000 drafted American soldiers, show us amazing facts. Certain persons in discussion of these data have tried to make them show more than they really do show. These drafted men may be taken as a fair sample of our people: they represent all social classes, all degrees of education, and all kinds of professional, business, industrial, and agricultural activities. The tests of the mental capacity of these drafted soldiers showed that 4.5 per cent of the examined men could be rated as of ‘very superior intelligence,, 9 per cent as of ‘superior intelligence,’ 16.5 per cent as of ‘ high average intelligence,’ 25 per cent as of ‘average intelligence,’ 20 per cent as of ‘low average intelligence,’ 15 per cent as of ‘inferior intelligence,’ and 10 per cent as of ‘ very inferior intelligence.’

In a democracy like ours, such a representation of mental levels within the population gives one food for serious thought. What of the future of the republic? What of the future of the evolution of the race if this evolution is to continue to be determined, as it now is chiefly being determined, by the further accumulation and use of knowledge and the passing-on of this knowledge by social heritage to succeeding generations? Are we going to be capable, mentally capable, of making the most of the opportunities for racial progress which social evolution puts into our hands? The facts set out, and the implications of these facts indicated in such a book as Goddard’s Human Efficiency and Levels of Intelligence should have a hearing by every man or woman of responsibility in this country — not simply that we may enjoy, as some naturally do enjoy, a certain anxiety and pessimism, but that we may be informed, and hence well oriented, in facing our great task of making the best of the situation; our task of exerting, wisely and along the lines most promising of useful results, our efforts to use the environmental and educational means that are really in our hands to give ourselves more power of achievement, and hence more happiness, and to assure a continuing human progress.

However conflicting may be the definitions of human progress, we do have a sort of racial consciousness of what we hope human kind may attain to. In this hope for the highest humanness, and in the expression of our goal to be reached, we may be idealist in the highest degree; but in the actual striving to reach the goal and realize the hope, we must be sternly realist. There are definite physical and biological preconditions to be achieved. This realist struggle can only be successful if carried on in the light, and with the guidance, of scientific knowledge. That is why we must know the worst and the best about the power of heredity, and at the same time, the worst and the best about the limitations and the possibilities of environment and education.

I received recently an advertisement from a gentleman of impressive head, — he had his picture on his advertising circular, — that asked the interesting question, Should I like to be another Michelangelo or Leonardo da Vinci. It suggested that, if I should, the gentleman would explain how I could have my wish — probably for a certain consideration. He gives lectures to aspiring audiences on how to make yourself about anything you would like to be.

Now this gentleman is an ardent environmentalist. He believes, I imagine, that the principal thing about being born is the mere matter of being brought alive into the world, and thus made an object to be moulded into any wonderful shape by environment and education. Any child can become anything any other child can, provided a similar advantage of an identical environment. There are many people — educators, prison reformers, mystics — who believe this, and preach and practise feverishly on the basis of this belief. Heredity is negligible in their scheme of things. There is even a school of scientific anthropologists in this country, and represented in most other countries in which scientific anthropologists occur, who go nearly as far. If they do not quite say that any man can be or do what any other can do or be, provided an identical environment and education, they do believe that any living human race, or considerable group, can reach the status — evolutionary status, we may call it — of any other group, if it can have a similar environment ; and they declare that the differences among races as we note them to-day are chiefly owing to differences in environment and the controlling influence of this varying environment.

It is certainly true that one cannot be at all sure, without some experimental evidence, that a so-called backward race is backward because of inherent (hereditary) incapacity, or because of lack of opportunity to use a possessed capacity. I have already referred to the Maoris of New Zealand, who have not added much to human progress, but who, when the Caucasian colonials set up schools which they could attend, fell little behind the representatives of a highly civilized race in their school work.

But it is not with races that we are now especially interested: it is with ourselves. How much can we do in determining the fate of our children by submitting them to carefully chosen environment and education? How much influence does inevitable variation in environment have in determining the final fate of our children? The answers are, I firmly believe, and with all appreciation of the significance of our modern knowledge of heredity, that environment has a large influence in determining the outcome of any given person, and that we can do much to help determine the fate of our children by controlling their environment in the mother-body, in the cradle, in the school and playground, and, indeed, through all their life.

There need be no doubt about this, despite all our new understanding of the great rôle that heredity plays in human fate. In fact, this very new understanding assures us of the great rôle that environment and education also play in human and animal and plant fate. There is, indeed, no heredity or, better, no result of heredity without environment. The fertilized egg cell, with its inheritance determiners, can come to nothing without a certain necessary environment for itself and for the embryo and the adolescent into which it is to develop. There can be heredity only when there can be environment, and specific environment at that. The two are inseparable: they inevitably coöperate. One without the other is nothing.

There can never be two identical heredities, or two identical environments. There is always some slight physical or (and) chemical variation in the inheritance determiners; and there is always some variation in the conditions that constitute environment. This is because the physicochemical conditions in the world are constantly changing with time, and time does not repeat itself. Hence there is always some variation even in the brother and sister plants and animals and men which come from the fertilized eggs produced by any single pair of parents; and more variation in the young from eggs which come from various parents of the same species. All the worker bees in a hive come from eggs produced by a single female, the queen. These bees are reared under conditions as nearly alike for all as it is possible to find in nature. The temperature and humidity and food conditions are, as nearly as they can be, alike for all the young bees developing at the same time in a given time—and there may be thousands.

Yet I have never failed, in repeated trials, to find marked, measurable variations, and other easily definable structural variations, in the fully developed bees issuing from their birth cells at the same time. And with these structural variations, there were undoubtedly physiological and psychological variations which, because I do not know bees well enough, I could not readily detect. Some of these variations were due to differences, slight but inevitable, in the physicochemical inheritance determiners; more of them were due to environmental variation, such as slight differences in the cell-shape, the food provided by the nurses, and so on.

But if the bees differ from each other because inevitable differences of environment have their influence in determining the outcome of personal development, how much more must human beings differ from each other, among whom the environmental differences attending development are, comparatively, enormous. Fortunately we can, in some measure, control and determine this environment. Therefore it is for us to find out what results any given environmental conditions produce, and then to eliminate as far as possible the bad conditions and seek earnestly to establish the good ones. Personal and social effort can do much for the unborn embryo, and more for the babes and child and adolescent.

Over the surface of the cerebral hemispheres of the human brain there is spread a thin superficial layer of nerve cells, blood vessels, and supporting tissue called the cerebral cortex. It varies from one and a half to five millimetres in thickness, and the total number of nerve or brain cells in it is about nine millions. But, taken all together, these nerve cells weigh only about thirteen grammes, and make only about a cubic inch of matter. Yet, in a just-born child, this thin layer of gray brain-matter, this trivially small part of the whole body is the clean surface on which is to be painted, slowly, in enduring pigments, the influencing picture of nature and human life which the new individual is to carry till death. This picture will largely determine its behavior as child, adolescent, and adult. To the formation of this picture all the sense organs will contribute; also, all the inferences based on the observations made by the senses. The whole social heritage of the human race will add to the making of this picture, in a degree determined by parents, playmates, teachers, and books.

The substance of this surface on which the picture is painted, and hence an important element in determining the character of the picture itself, is the physical basis of intelligence and memory: this substance, and the picture painted on and into it, is the very scat of human personality. The blood and lymph and the hormones (gland secretions) will affect this substance; every reaction of the rest of the body will be registered on it. Up to the inherent (inherited) limits of its possibilities, it will be influenced by any and all of the elements of the environment which may, by chance or deliberate determination, be brought to bear on the individual from beginning to end of his life.

What better chance could we ask, to build the kind of man or woman we want out of the child under our control. Just one, perhaps. This is, that that qualifying clause, up to the inherent (inherited) limits of its possibilities,’ should be wiped out. But the word ‘limits,’ which sounds discouraging, has, after all, its encouragement. Limits can be broad as well as narrow , high as well as low. And if the child is born with large possibilities, these large possibilities can be realized if the proper environment and education are given it. If the possibilities are more limited, there is still necessity for a suitable environment and education to permit the child’s development up to the very verge of these limits, and in the special way which these limits impose.

Perhaps the principal fault with our present system of education is that it takes too little into account these inherited differences in individual capacity: it is too blind to the fixed levels of mental capacity which characterize the various groups in school and college classes. And hence it is wasteful and inefficient in its attempts to offer the needed environmental (educational) conditions necessary to the fullest development of our youth. When the use of mental tests among school children had revealed clearly that some children were inherently less intelligent than others, — this had, of course, been revealed before, even if less exactly, by simple observation, — it was realized that it would be advantageous to establish ‘backward’ classes; and this was gradually done in most schools. But now we know that it is no less advantageous to provide special opportunities for ‘ forward ’ pupils — to establish ‘forward’ as well as ‘backward’ classes.

This has been criticized as undemocratic, as favoring the smart at the expense of the stupid. But it is not at the expense of the stupid. It is as much to their advantage as to the advantage of the smart, for it relieves them of trying to do the impossible, and hence of becoming hopeless because of failure to achieve it. And it gives them opportunity to make the very most of their possibilities. It is democratic in the highest degree to give to every child the opportunity to make the most and best of himself. It is undemocratic, unfair to the child and harmful to the nation, to limit the child of superior intelligence to the pace of the child of average intelligence, to say nothing of the pace of the child of inferior intelligence. And our present school-system does just that. Equal opportunities for all children to make the utmost out of their varying inherent mental-capacity, through suitable environment and education, is real democracy in education.

And everything I have just said applies as well to college and university students as to school children. We see to-day, in our great institutions of higher learning, the efforts and time of administrators and professors, and the money and equipment of the institutions, devoted largely to attempts to hold backward and average and forward students to the same work and standards. The backward are lifted and pushed, and the forward restrained, to make all conform to the average. The result is discouragement and bitterness among the backward, and deadening of interest and idleness among the forward. These seek relief in athletics and extraneous student activities, where all forwardness is recognized and rewarded.

Fortunately, the colleges are aw akening to the situation. The problem of the gifted student is being recognized, and first attempts to solve it are being made. But both secondary and college education need a vigorous shaking out of their ruts. They must cut with tradition and join hands with modern knowledge. They must appeal to present-day scientific psychology and present-day knowledge of heredity for a new orientation and grounding. Education is environment. It should be good environment, helpful not harmful environment, if the race is to make the most of itself. This is simply a biological truism. That it may be good environment, educators must have personal knowledge of science, or personal faith in it, and personal resolution to make their practice conform to their know ledge and faith. We are incredibly wasting money, effort, and time, and sacrificing individuals and society by our present-day educational methods, because these methods were established before the days of the new knowledge of heredity, and because we have had a wrong conception of democracy in education.

The time has come to do better. But it will take a mighty effort to do it. If the professional educators will not do it of their own free will, — and, as one of them and knowing the breed pretty well, I am fearful of them, — then they must be made to. The biologist stands aghast at what he sees happening. He knows what the consequences of flouting Nature are. The fate of plants, animals, and men is determined by heredity and environment. It takes the best of both to assure the best fate. Shall man, who has some power over his heredity and much power over his environment, not use this knowledge and this power to give himself the best fate possible? If he does not, he is worse than foolish; he is criminally responsible to his children and his children’s children.