But a dysgenic factor in an animal _is_ a dysgenic factor, and that is all there is to it. There are no two sides to the question. But if anything goes to show the difference between animals and human beings, and to demonstrate why principles of eugenics, as derived from a study of animals, can never be _fully_ applicable to human beings, it is these considerations which we now have under discussion. To repeat, neuroses, neurasthenia, psychasthenia, and the various forms of neuropathy and psychopathy are dysgenic factors. But people suffering from these conditions often are among _the world's greatest geniuses_, have done some of the world's greatest work, and, if we prevented or discouraged marriage among people who are somewhat "abnormal" or "queer," we should deprive the world of some of its greatest men and women. For insanity is allied to genius, and if we were to exterminate all mentally or nervously abnormal people we should at the same time exterminate some of the men and women that have made life worth living. And what is true of mentally abnormal is also true of physically inferior people. An inferior horse or dog _is_ inferior. There is no compensation for the inferiority. But a man may be physically inferior, he may be, for instance, a consumptive, but still he may have given to the world some of the sweetest and most wonderful poems. A man may be lame, or deaf, or strabismic, he may be a hunchback or a cripple and altogether physically repulsive, and yet he may be one of the world's greatest philosophers or mathematicians. A man may be sexually impotent and absolutely useless for race purposes, yet may be one of the world's greatest singers or greatest discoverers. In short, the eugenic problem in the human is not, and never will be, as simple as it is in the animal and vegetable kingdoms. If we want to strive after healthy, normal mediocrity, then the principles of animal eugenics become applicable to the human race. If, on the other hand, we want talent, if we want genius, if we want benefactors of the human race, then we must go very slow with our eugenic applications. =Drug Addiction or Narcotism= Addiction to drugs, whether it be opium, morphine, heroin or cocaine, is a strongly dysgenic factor. The addiction to the drug is of itself not transmissible, but the weakened constitution or degeneracy which is generally responsible for the development of the drug addiction is inheritable. A few cases of drug addiction are external; that is, the patient may have a good healthy constitution, no hereditary taint, and still because during some sickness he was given morphine a number of times he may have developed an addiction to the drug. But those cases are rare. And such cases, if they are cured and if the addiction is completely overcome, may marry.