What is eugenics? / by Leonard Darwin.

  • Leonard Darwin
Date:
1928
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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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    8 WHAT IS EUGENICS? and if both of these offspring grew up and in time also reproduced their kind in like manner, numbers would be kept just even. As a rule, however, every animal has more than two offspring, generally many more. And when, in the past, numbers have not been increasing, all the offspring over two must on the average have been got rid of before pairing, somehow or other. How has this been brought about ? This keeping down of numbers has been the result of what has been called the struggle for existence. This is not a very good name ; for the killing off of animals in fights with other animals has not been the most important way in which their numbers have been held in check. Many more have died as the result of accident, disease, and want of food. Some have failed to get a mate, and have consequently left no progeny behind them. The result of these innumerable deaths and failures has been that the numbers of the different races of animals have been kept from altering greatly. Now, some of these animals were slightly superior to their fellows in some way which gave them an advantage in this so-called struggle for existence. It was these shghtly superior animals who had the best chance of survival and of reproducing their kind, and who most often did so. They were picked out by what has been called natural selection. Life has existed on this earth for perhaps a thousand million years. During all this time the best or the fittest animals have been selected, as it were, in this way for breeding purposes. We have seen how our savage ancestors, without always giving the matter any thought, generally bred from the dogs who actually succeeded best in the chase. The result of this partly unpremeditated selection was that in the course of a few thousand years a wolf-like animal slowly changed into a dog something like our greyhound. The survival of the beings best fitted to their surroundings during an unthinkably long period of time has led in a somewhat similar manner to some lowly animal gradually giving rise to man.
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