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number on the fingers of one hand the investigations of any importance that deal with this problem. Beyond the fact commented on by Darwin that changed conditions of life tend to enhance variability, very little was known about the production of variations through environmental changes until the experiments of Tower showed that in the Colorado potato beetle a high temperature and an unusual degree of humidity during the period of maturation of the sex cells resulted in the production of well-marked mutations which bred true to type. The stability of these new mutations indicated that they owed their origin to changes in the germ plasm brought about by changed external conditions. In the evening primrose, Enothera lamarckiana, and a few other plants stable mutations have been produced by the action of chemicals injected into the ovary, and by treating the plants with rays emanating from radium.

The experiments thus far performed afford a certain amount of evidence for the conclusion, to which one would naturally be disposed on a priori grounds, that the kinds of variations that arise in organisms are conditioned by the nature of environmental forces. If this be true, we are naturally led to enquire how the changing environment to which civilization exposes the human race affects the trend of variations that arise in the germ plasm. With our unnatural indoor life, the unwholesome living conditions of a large part of our wageearning population, the increasing drift of people into large cities, our alcoholism, and our numerous diseases, it can hardly be expected that the germ plasm of the race will escape being affected in some way. But how? Here we are compelled to confess practically complete ignorance. Were we to judge by analogy with what has happened with our domestic animals, which are relatively degenerate from the standpoint of physical vigor and general intelligence, the probable outcome would not be reassuring. We might be disposed to infer that germinal variations arising in response to agencies which impair the vitality of the body would probably give rise. to inferior progeny. The disastrous effects of lead poisoning upon the children of workers in lead, even when the father alone is affected, may be an indication of the kind of influence which might be anticipated from the action of an unwholesome environment. We know too little, however, of the permanence of the transmitted effects of lead poisoning to base anything more than a very tentative supposition on these results.

With regard to the important question of the hereditary in

fluence of alcohol our knowledge, although still very unsatisfactory, affords some ground for more or less probable inference. While statistics show that epilepsy, insanity, and feeblemindedness occur with much more than average frequency among the offspring of parents addicted to alcohol, this correlation may be due to the fact that parental alcoholism is so often the result of a neuropathic constitution, and that it is the inheritance of this constitution, and not the effect of parental intemperance, that disposes the children of alcoholics to various forms of nervous malady and mental defect. Statistics may discover correlations but they are seldom adequate for establishing causal connections. As the method of experiment to which recourse must usually be had in the endeavor to ascertain causes can not well be applied to human beings, the most promising field of enquiry is afforded by experiments on animals. If alcohol were found quite generally to produce hereditary defects in animals, we should have a strong argument in favor of its producing similar results also in man.

Of the investigations that have yielded indications of the injurious hereditary effects of alcohol, the recent work on guinea pigs by Stockard and his colleagues is the most noteworthy. The animals employed were bred and shown to be capable of producing normal offspring before they were subjected to the influence of alcohol. Control experiments with untreated animals were also carried on side by side with animals to which alcohol was given, and the offspring of the two sets carefully compared. Without describing the methods of experimentation or giving the details of the results, it may suffice to state that the alcoholized guinea pigs gave rise to a much larger proportion of still-born offspring and offspring which lived but a short time than did the controls. It is particularly noteworthy that when the male parent alone was given alcohol the percentage of defective offspring was strikingly large, although the largest proportion was obtained from the matings in which both parents were alcoholized. It was further shown -and this is particularly significant in relation to our problem-that when the offspring of alcoholized parents were bred without being subjected to alcohol they gave rise to a large percentage of defective animals. Deformities such as an eyeless guinea pig, animals with a reduced number of digits, dwarfs, and many other kinds constituted 5.23 per cent. of ordinary alcoholic strains, and 14.81 per cent. of inbred alcoholic strains, while no deformities appeared among the animals bred from normal parents.

These experiments, unlike most previous studies, were car

ried out on an extensive scale and with due checks and controls, and they seem to afford strong evidence for the conclusion that alcohol administered to guinea pigs gives rise to defects in the progeny which are capable of being transmitted to subsequent generations. Recently Pearl has applied Stockard's methods to the domestic fowl, but instead of obtaining evidence of inherited injury he found that the progeny of the treated birds were slightly above the controls in fecundity and apparent vigor. These results are not necessarily inconsistent with those obtained by Stockard, since the germ plasm of the fowl may be much less easily affected by alcohol than that of the guinea pig. Further experimental work on this important topic is much to be desired before we can be entirely justified in drawing conclusions concerning the hereditary influence of alcohol in man. At present, all that we are warranted in inferring is that alcoholism in man is a more or less probable source of hereditary defect.

The same guarded conclusion should be drawn, I believe, in regard to other so-called "racial poisons." The terrible consequences which luetic infection entails upon following generations are primarily due to the transfer of pathogenic germs from parent to offspring, instead of to heredity in the proper sense of this term. Nevertheless, it is a distinct possibility that the toxins carried in the bodies of the unfortunate victims of this common malady may injure the germ plasm in such a way as to give rise to strains with a true hereditary defect. We may have similar suspicions that the same result may be produced by tuberculosis and other diseases; but unfortunately in regard to most of these questions we can only indulge in speculation. Did we know what agencies give origin to our strains of imbeciles, lunatics and morons we might be able to nip in the bud one of the most serious of our social evils. We may have a shrewd suspicion that our modern régime with all its institutions which conspire to sap the vitality of the race is continually adding new strains of such undesirables. When experiments on the causes of variability in the lower animals have yielded us a large body of well-organized knowledge, instead of the meager and scrappy information which we now possess, we shall doubtless be in a position to draw conclusions of a high degree of probability regarding the trend of variability in man, and possibly to bring this variability in a measure under control.

Any consideration of the influence of social amelioration upon the evolution of racial qualities has to take into consideration the question of how the trend of variation in human

beings will probably be affected. If, as seems not improbable, intemperance, disease, and possibly bad living conditions are productive of hereditary defect, our racial welfare may not be seriously menaced by the reduced action of selection which would probably follow upon the institution of social and economic reforms. On the contrary, the race may be freed from sources of continued contamination which act as a check upon its progress. A social system which presumably favors the "beneficent working of the survival of the fittest" by creating conditions of life that lead to a high death rate among the less successful types, may not only fail to eliminate these types, as we have attempted to show, but may be a means of actually creating the inferior variations which it is supposed to destroy.

Our aim thus far has been to show that the realization of Utopian dreams of a state of society in which the evils of poverty, intemperance, severe individual struggle and warfare have been relegated to the past does not necessarily entail biological decadence. In fact, there are reasons for believing that such a consummation would do away with many of our present sources of racial deterioration. Would it also set into operation any agencies which would promote racial advancement?

If the cure for democracy is more democracy, it may also be true that the cure for the cure for the racial evils of civilization is more civilization. An enlightened society, possessing a knowledge of the principles of its own evolution, and mindful of the welfare of future generations, may accomplish much in the direction of eugenic progress. The control of the birth rate which mankind is now exercising from prudential considerations, or the more laudable motive of giving better advantages to a few children rather than mere maintenance to many, might, in such a society, be utilized more for social and less for individual ends. With parenthood placed upon a voluntary basis we might reasonably expect that the less desirable stocks would show an increased tendency toward elimination and that the rearing of children would be undertaken in greater measure by the classes more amenable to the influence of the sense of racial obligation.

Alfred Russel Wallace entertained great hopes of race improvement through the financial emancipation of women. When women are no longer tempted to marry for support they will, according to Wallace, be more apt to select only superior types of men to be the fathers of their children. As a means of race improvement doubtless marriage selection has magnificent possibilities. But when we reflect upon the frequency

of marriage among the Jukes and Kallikaks on the one hand, and the low marriage rate of women graduates of colleges on the other, it must be admitted that, as a factor in race progress, marriage selection at present is a miserable failure. Mere economic reform can not be relied upon to improve matters greatly unless it is accompanied by a general diffusion of education; and education will avail little unless it includes the inculcation of a sense of responsibility for the hereditary qualities of future generations. Education is eugenically of value chiefly as affording a basis for the development of a "eugenic conscience" which is now sadly lacking in most people of culture. It is a hopeful sign, however, that here and there among people who have inherited a generous measure of desirable traits eugenic considerations have led to the rearing of larger families. One is therefore encouraged to have sufficient confidence in human nature to believe that the spread of eugenic education, so that people of superior endowments will have the matter of their obligations to the race brought squarely home to them, will not fail to have an effect in checking the evils of our present differential fecundity.

Racial improvement has doubtless very intimate relations to the improvement of the economic conditions which now oppress a very large proportion of mankind. A society with wellmarked castes will probably make little progress if it includes an ignorant and poverty-ridden proletariat. Under a régime which affords better educational advantages and a higher standard of living for the less successful classes, the relatively high birth rate of those who multiply through sheer lack of restraint would probably be reduced. Economic reform is by no means the panacea for racial and social ills that it is apparently taken to be by many socialistic theorists, but it would afford conditions under which the operation of eugenic ideals would doubtless be more effective than under our present social order. Greater equality in the distribution of wealth would tend to bring about greater equality in the birth rate of different classes. With a higher general standard of education and a diffusion of the sense of obligation to transmit socially valuable qualities to future generations, conditions might possibly be changed so that a greater relative fecundity would come to characterize the more vigorous, intelligent, and public-spirited members of the community. Should society succeed in restoring the correlation between fecundity and the possession of superior qualities a correlation which our present civilization has pretty effectually subverted-humanity would once more be on the highway of racial advance.

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