Genetics and eugenics : a consideration of the relation of animal experimentation top human inheritance and infant conservation / by Raymond Pearl.

  • Pearl, Raymond, 1879-1940.
Date:
[1912?]
Catalogue details

Licence: In copyright

Credit: Genetics and eugenics : a consideration of the relation of animal experimentation top human inheritance and infant conservation / by Raymond Pearl. Source: Wellcome Collection.

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    scientific analysis, because such a large portion of the pertinent and necessary data is lacking. As an illustration of the difficulty I need only mention here the inheritance of skin colour in man. One would be inclined to say off-hand that it ought to be the simplest of matters to find out in this country (the United States) of all others, just how pigmentation is inherited in crosses of black and white races. Yet the question of whether skin colour segregates (in the Mendelian sense) in such crosses is’ a matter by no means definitely settled, and to all appearances not likely to be for some time to come, because of its complications and the impossibility of controlled experimentation. The statistical method is practically the only one by which the inheritance of many human characters can be directly investigated. This is unfortunate in several ways, but chiefly because it means that—in so far—the only sort of direct know¬ ledge of human inheritance which we are able to get is just the sort which is not very useful. More than anywhere else it is true that in regard to human inheritance it is knowledge respecting the individual rather than the mass which we want, and which is most useful. Let the meaning be clear here : We wish to find the basic general laws of human inheritance. But the real, compelling, human reason why we want to know these is so that we may be able to predict with precision what will happen in the individual case. The statistician will tell us that all this is nonsense—a chimerical dream—because in inheri¬ tance the results are determined by an indefinitely vast number of small causes all acting together, and hence anything like accurate prediction of results in the individual case is quite out of the question. This argument has plausibility and has carried weight. Latterly, however, it has lost much of its force. It is perfectly true that by statistical methods it is apparently impossi¬ ble to get at any general law whereby one can predict the coat colour of offspring, horses or dogs (for example) following particular, individual matings. Yet it is evident that the diffi¬ culty here does not inhere in the nature of the case but rather in the nature of the methods. By direct and “individualistic ” methods of research a general law has been worked out where-