What is eugenics? / by Leonard Darwin.

  • Leonard Darwin
Date:
1932
Catalogue details

Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: What is eugenics? / by Leonard Darwin. Source: Wellcome Collection.

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    DOMESTIC ANIMALS 3 differences in the individuals selected in consequence for breeding purposes generation after generation. The contrast between cats and dogs is also instructive. The cat's nature leads it to wander out at night, and its habits make control over its breeding very diíñcult; and such breeding is, therefore, but little attended to. In consequence, as compared with dogs, fewer different breeds of cats have been produced, with less marked differences between them. Then, again, cats are chiefly useful for killing mice at home. This they can do in their master's absence, because he does not want to eat the mice himself. Hence obedience to a caU has not been bred into them. Lastly, what brings the cat home in the morning after its wanderings in the dark is the desire for shelter and warmth. It was those cats which felt this desire for comfort most strongly who least often deserted the camp to become wild animals. The result of this unpremeditated selection going on for ages has been the production of the comfort- loving, imsympathetic animal we аП know so well. The effects of selection in bygone times are also seen clearly in our cattle of to-day. In the days of our ancestors of long ago, the poor тИкет was often killed for food, while the cow producing more milk was retained to supply the family. It was only the better milkers, therefore, who had calves; and these calves passed on to their descendants their powers of producing milk in bigger quantities. No doubt this kind of unintentional selection in some degree improved the breed in regard to milk-giving. In our day, however, dehberate selection is being carried on with the greatest forethought and care. A bull is valued for breed¬ ing purposes in accordance with the milking quahties, not only of its female ancestors, but also of the cows which he has already produced as his offspring. African savages have tame cows which are known to have produced not more than two or three pints of milk a day ; and this may be more than that produced by wild cattle. A good milker may now produce forty pints a day, this increase in amount being the result of deliberate care taken in breeding.