Page:The Negro a menace to American civilization.djvu/85

Rh you surely would not breed from white cats with cross and ill-tempered natures to get them. And, if you wanted black cats with an area of white on the chest, you would certainly select parents so marked, a dozen or more individuals, and by careful selection and not too close interbreeding, the desired marking will be produced in an ever-increasing proportion of cases. The same thing would happen in nature were such cats left to themselves to breed, and the white area on the chest proved to be a strong sexual and attractive character; but in such a case it would take ever so much longer, the balance of the environment being the same, and food and climate favorable. After studying thousands of such cases, Darwin was again led to say that " Man may select and preserve each successive variation, with the distinct intention of improving and altering a breed, in accordance with a preconceived idea; and by thus adding up variations, often so slight as to be imperceptible by an uneducated eye, he has effected wonderful changes and im- provements. It can, also, be clearly shown that man, without any intention or thought of improving the breed, by preserving in each successive generation the individuals which he prizes most, and by destroying the worthless individuals, slowly, though surely, induces great changes. As the will of man thus comes into play, we can understand how it is that domesticated breeds show adaptation to his wants and pleasures. We can further understand how it is that domestic races of animals and cultivated races of plants often exhibit an abnormal character, as compared with natural species ; for they have been modified, not for their own benefit, but for that of man."