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inextinguishable curiosity about the universe and the way it works; in other words, of most men and some women.

I propose, therefore, to try in the first place to summarize Samuel Butler's theory, and to indicate some of the reasons for its forty years of disrepute. In the second place I shall describe the nature of the evidence that has so triumphantly vindicated what was in Butler no more than an inspired guess.

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The controversy to which the discovery of evolution gave rise turned upon the causes of variations in species. That such variations had occurred and continued to occur was obvious. If they had not, if, in other words, all offspring exactly resembled their parents, the world would still be peopled by amoebas and jellyfish. There were two contemporary explanations in the field that of Darwin and that of Lamarck. Darwin's was no explanation at all. He said, in effect, that he could not tell why variations occurred; all that he could affirm was that those that were suited to their environment survived. Lamarck ascribed to the influence of external environment what Darwin left to chance. The environment changed, and the species either adapted itself to the change or it did not.

If it did, it survived; if not, it perished. Darwinism was the orthodox view when in the eighteen-sixties Butler first took the field as a convinced Lamarckian. He contended for purpose and progress in evolution, affirming that the adaptation of the organism to its environment was spontaneous, springing from within, rather than automatic and determined by influences exerted from without. More than this, any organism that had succeeded in slightly modifying itself by this purposive response handed on the modification to its offspring. Thus the offspring started, so to speak, where the parents left off, and by developing the

inherited modification achieved a still greater measure of racial differentiation. Thus a characteristic laboriously acquired by a parent appeared as a habit in the offspring, the offspring performing automatically and unconsciously activities which in the parent represented hardly won acquisitions.

The connecting thread in this process was memory. The offspring does what its parents did, and does it more easily because it remembers what they did. But how, it may be asked, can a child remember the activities of its parents? Because, says Butler, it is its parents. Butler proceeds to explain this startling announcement by a disquisition on the subject of identity. There is some sense, though a remote one, in which a man of eighty is the same person as a boy of six, so that he can say, 'I am the person who at the age of six did so and so.' In precisely this same sense, whatever it is, the boy of six is the same as the prenatal embryo from which he developed, the prenatal embryo as the germ cell from which it developed, and the germ cell as the parents' bodies of which it once formed part. Therefore there is as much identity between a parent and a child as between a child and an old man. The thread of continuity in virtue of which we assert this identity is memory, the baby chicken knowing that the first thing it must do with its beak is to peck its way out of the shell, because it remembers performing this action on countless previous occasions when it was in the persons of its ancestors. What is more, it knows that it must grow a horny piece of cuticle in the front of its face, and knows how to grow it, because it has done it so often before, and grows it accordingly without knowledge or effort. Actions which have been repeated in this way on a vast number of occasions become habitual, and are performed instinctively, without conscious attention.

Our remote ancestors learned with difficulty to circulate their blood and to grow their hair and nails. We have performed these processes so frequently that we can now go through them without thinking about them, our energy and attention thus being set free for other purposes. New acquisitions obtained by this released energy and attention will, in due course, appear in our remote descendants as inherited habits, with the result that there will one day be born a generation of babies who will know the multiplication table by instinct.

Thus we have a formula for progress in evolution. Evolution is creative and purposive: the life force acquires new faculties in the process of reacting to its external environment, and these new faculties appear as inherited endowments in its later manifestations. Life is not automatically determined by its environment. It grows and expresses itself in response to, and in a sense in spite of, its environment. One day, as in the last play of the Back to Methuselah Pentateuch, it will master its environment completely, and, ceasing to struggle to overcome matter, will proceed to uninterrupted contemplation.

This is all very well in its way; the formula of creative evolution constructs an imposing edifice, with space for many of the nobler aspirations of man. But there is one foundation-stone upon which the whole structure rests. This is the doctrine that characteristics acquired by parents can be inherited by offspring. Can they in fact, or can they not? The nineteenth century was on the whole inclined to say that they cannot. There was, as its men of science were never tired of pointing out, a complete lack of evidence, and there was the germ-cell theory of Weismann.

As regards the lack of evidence, take an acquired characteristic or rather, since you can never be sure that you

have found one, manufacture one for yourself by cutting off the tails of a pair of mice. Their offspring will have tails of the normal length. As for Weismann, he proved conclusively, as it was then thought, that the germ cell, although part of the parents' bodies, was screened from all the influences that affected the parents' bodies. The parent was, in short, merely a sort of postman, handing on a letter that had been entrusted to him by his parents, but having no power to alter its contents. If this were so, nothing that happened to the parent could possibly alter the writing of the letter, and that it was so nearly everybody until a few years ago believed.

The evidence upon which the modern belief in the importance of environment in determining characteristics is based will be found admirably summarized in a little book, by Professor Jennings, entitled Prometheus, in the 'To-day and To-morrow' series. Some of this evidence supports the belief in the inheritance of acquired characteristics, but the support is negative rather than positive, since it chiefly takes the form of a disproof of Weismann's theory that the germ cell is unaffected by the adventures that happen to the parent. That positive evidence is not wanting, however, the experiments to which I shall refer in a moment show.

Although my concern here is mainly with conclusions, a word on the machinery of inheritance may not be out of place. It is now established that the substances passing from parents to offspring which form the offspring's inheritance are a number of packets of chemicals. These packets of chemicals, called genes, are ranged like beads along a thread; the thread with the beads upon it is called a chromosome. The chromosomes normally exist in pairs, but only one member of any pair goes to form the germ cell from which

the offspring develops, the other and corresponding member being contributed by the other parent. The embryo cell contains an enormous number, running into several hundreds, of different kinds of genes surrounded by a kind of jellylike substance or plasm. The cell develops as the result of the interaction of the genes (a) with each other, (b) with the surrounding plasm, (c) with the oxygen, food, and other chemicals introduced into the cell from outside, (d) with the physical effects produced by external environment. All these factors taken together make the individual what he is; change any one of them, and he will be a different person.

Two considerations of importance emerge. In the first place, any single characteristic that the individual may possess will normally be the product of a considerable number of different genes. Mendelism is responsible for the widely held view that, as a general rule, any particular characteristic is due to the presence or absence of one particular factor. Characteristics so produced were known as 'unit characters.' 'Unit characters,' however, no longer exist. It is now generally recognized that a characteristic, such as red hair, may be and usually is due to the collocation of some hundreds of genes. Change any single one of these, and the characteristic will disappear. Since the particular chromosomes together with their genes which go to form the germ cell of the embryo appear to be chosen almost at haphazard from the available supply of chromosomes in the parents' bodies, it would appear that there is no way of securing that an offspring shall have any particular set of desired characteristics. The number of different combinations of genes that with any two parents may go to the formation of one offspring is for all practical purposes infinite. This fact goes far to

disprove the practicability of any form of eugenics - at least so far as the determination of inherited factors is concerned.

Now let us turn to environment. The effect of recent experiments is enormously to increase its importance. A change in any one of the genes may, as we have seen, produce different characteristics; but so also may a change in any one of the influences to which the genes are subjected. What a man inherits, in short, is not a set of characteristics, but a very large number of potential sets; which of these sets will in fact materialize depends entirely upon his environment. man's inheritance, therefore, is not what he is born with, but what under such and such conditions he may become. Thus the distinction between heredity and environment goes by the board.

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All characteristics are in a sense hereditary, since if the potentiality for them were not present in the genes they could not have developed; all characteristics are also environmental, in the sense that given any other environment they would have been different. In other words, every characteristic is a product both of heredity and of environment, differing both with the genes and with the influences to which they are subjected.

The changes in characteristics which have recently been produced in animals by suitably changing their environment are very startling. We normally think of a fish as having two eyes. If, however, you put him in the right kind of environment you can cause him to produce an offspring with one eye only in the middle of its face. A certain Dr. Kammerer, of Vienna, has carried out experiments of the most detailed character with salamanders and toads. There are two sets of salamanders in Europe. The first, salamander (1), is black, has two young,

which at birth closely resemble their parents, and normally inhabits cool Alpine uplands. The second kind of salamander, salamander (2), is black with yellow spots, and produces about thirty young, who when born have gills like fishes, pass the first six months of their life in water, and live in the warm moist lowlands. Dr. Kammerer subjected a number of salamanders (1) to the normal environment of salamanders (2). Result: in the second generation salamanders (1) produced quantities of gilled offspring who began life in the water. Similarly salamanders (2), if transferred to the normal conditions of salamanders (1), produced offspring who began to behave like those of salamanders (1), each successive generation inheriting more of the salamander (1) characteristics of their parents, and becoming increasingly like salamanders (1) and less like salamanders (2). Salamanders (2) when placed in black walled cages contracted the area of their yellow spots and produced offspring who, beginning life with spots of the size possessed by their parents, grew in course of time entirely black. In other words, the offspring not only inherit the characteristics acquired by the parents, but, inheriting them at the stage of development at which the parents, so to speak, left them, proceed to develop them a stage further on their own account.

Dr. Kammerer made similar experiments on toads, of which the results bear out the conclusions arrived at from a consideration of the salamanders; and these results have been paralleled by Dr. Durkhen, of Breslau, who has experimented with the color of the pupa of white butterflies. Dr. Kammerer's salamanders were brought to England in 1923, appeared in the flesh to many eminent biologists, and convinced all but the most obstinate.

Since his departure, however, many who believed in his presence have relapsed into professional skepticism, and will wish to write letters of disbelief to the Spectator to say so.

Finally Dr. Kammerer, by suitably changing its environment, has induced the blind cave-newt Proteus to develop an eye in one generation.

What is the bearing of these experiments upon the time-honored controversies upon which I have briefly touched? It seems to be clear:

1. That Weismann's germ-cell theory is wrong, and that organisms are affected by what happens to their parents.

2. That, therefore, some characteristics acquired by parents can be and are transmitted to offspring.

3. That the offspring inherit the characteristic at the stage at which the parent left it and carry it a stage further.

4. That, therefore, Samuel Butler was right in his controversy with Darwin and Weismann, evolution being progressive, and each generation, provided the environment remains substantially unchanged, raising itself upon the shoulders of those which have preceded it.

5. That it is impossible to predict what characteristic an offspring will develop in a new environment, and that there is, therefore, no reason to suppose that the offspring of a Russian Jew who is born in America will behave either like a Russian or like a Jew.

6. That, therefore, in a very real sense human nature can fundamentally change, and war is not, therefore, ineradicable.

7. That nevertheless eugenics in the sense of the purposive breeding of desired types is for all practical purposes impossible, owing to the haphazard selection of those genes which go to form any particular offspring.

ART IN AMERICA A CENTURY AGO1

BY WILLIAM ROBERTS

It is not easy to-day to realize the general conditions, the manners and customs, of the United States a century ago. It is not that there is an absence of contemporary printed records; these are in fact extremely voluminous, mostly written by British visitors, and in nearly every case the object of violent and acrimonious protest from the Americans of the time. A century ago the United States was in the early stages of a kind of evolution that differed from any sort of evolution that had ever taken place in any other country. The inhabitants were for the most part British in tradition and instinct, but the 'little differences' that led to the Revolution in the late eighteenth century, and the war of 1812, left the Americans with very little love for the mother country. It was, therefore, particularly exasperating to be visited by their own cousins and to be held up to be criticized by them. Their sensitiveness to criticism amounted almost to an obsession. No traveler, with the best intentions in the world, could say the right thing, or could say it in the right way, and it must be admitted that a good many travelers just set down what they considered plain, unvarnished truths, and let them go at that.

A century ago these frank books of travels in the United States had the American at a disadvantage; there were few literary men in the States who could take up the cudgels, and the defense 1 From the National Review (London Tory monthly), February

fell largely on the newspapers. Journalism, like other things in the States, was in its immature stage of existence, and the newspaper man was on the constant lookout for something with which to feed the prejudices of the public. The New York Herald - long 'the disgrace and the curse of the country . . . entirely owned and conducted by foreigners' - did not appear until 1835, but it had many early prototypes. The American suffered not only from the stranger within his gates, but also from the heavy artillery of the Edinburgh and Quarterly reviews, which were long anti-American, and often scandalously so.

The stupidity of this anti-American policy was keenly felt in Great Britain by those who realized, not only that the Americans were of the same origin as ourselves, but that the mere force of circumstances would one day place the United States among the great nations of the earth. Blackwood's Magazine, in the person of Christopher North, was one of the earliest of British literary organs to realize the senselessness of the very general anti-American feeling in this country. In Blackwood, of which he was editor, of December 1824 he printed, under the title of 'A Summary View of America,' an extremely long article of thirty-five pages that was in effect a running commentary on a book of that title recently issued in London. The article is signed with initials only, A. C., and the personality of the writer was unknown even to the editor. The bona fides of the writer were,

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