Of all animals man is most subject to disease and defect in body and in mind. Sickly, or mal-formed wild animals are so rare as seldom to be seen. This is almost as true of domesticated animals, though epidemics sometimes sweep them off. Animals mentally defective are almost unknown. But man is assailed with a thousand ailments. Defective organs, functional disorders, chronic invalidism are common. Malformations of body, also of brain causing idiocy, stupidity, insanity and crime, are a hundred times more frequent in man than in lower animals, wild or domesticated. Why this difference? The answer is easy for anyone familiar with the laws of evolution. The sedulous sifting by natural selection of animals in the wild state has left no sickly or half-witted degenerates to burden the world with a like progeny. If at rare intervals the law of variation should drop a mal-formed specimen into Nature’s sieve it would be quickly eliminated along with the great mass of averages. Practically the same is true of domesticated animals where the watchful eye of man is substituted for Nature’s. As natural selection is hampered in its operation among domesticated animals by the interference of man, so is it limited on the human plane. There, we find virtually no selection, neither natural nor artificial. Hence the degeneracy--physical, mental, moral. Both Nature and man, in their respective fields of operation, select only a few of the best for propagating purposes--Nature eliminating the rest by death, and man by sterilization. But on the human plane man--acting mercifully toward the individual, mercilessly toward the race--does his best to thwart Nature. He prolongs the lives of weaklings, of the maimed-from-birth, of the deaf and dumb and blind, and of the mentally sub-normal. So far, all is well. But he permits these victims of an inferior ancestry to marry and procreate almost without limit. What then can we expect but for the world to be burdened with invalids, runts, and the mal-formed--cursed with morons, sub-morons, half-wits, quarter-wits, and predestined criminals? And worse for the entire race, this class shades upward by imperceptible degrees into all gradations, mingling its inferior strains with the best. It has always been so; therefore all of us, far more than wild animals, have a mixed ancestry, of the good and the less good.