With regard to the medico-legal aspects, Kiernan ("Responsibility in Active Algophily," Medicine, April, 1903) sets forth the reasons in favor of the full and complete responsibility of sadists, and Harold Moyer comes to the same conclusion ("Is Sexual Perversion Insanity?" Alienist and Neurologist, May, 1907). See also Thoinot's Medico-legal Aspects of Moral Offenses (edited by Weysse, 1911), ch. xviii. While we are probably justified in considering the sadist as morally not insane in the technical sense, we must remember that he is, for the most part, highly abnormal from the outset. As Gaupp points out (Sexual-Probleme, Oct., 1909, p. 797), we cannot measure the influences which create the sadist and we must not therefore attempt to "punish" him, but we are bound to place him in a position where he will not injure society.
It is enough here to emphasize the fact that there is no solution of continuity in the links that bind the absolutely normal manifestations of sex with the most extreme violations of all human law. This is so true that in saying that these manifestations are violations of all human law we cannot go on to add, what would seem fairly obvious, that they are violations also of all natural law. We have but to go sufficiently far back, or sufficiently far afield, in the various zoölogical series to find that manifestations which, from the human point of view, are in the extreme degree abnormally sadistic here become actually normal. Among very various species wounding and rending normally take place at or immediately after coitus; if we go back to the beginning of animal life in the protozoa sexual conjugation itself is sometimes found to present the similitude, if not the actuality, of the complete devouring of one organism by another. Over a very large part of nature, as it has been truly said, "but a thin veil divides love from death."[[105]]
There is, indeed, on the whole, a point of difference. In that abnormal sadism which appears from time to time among civilized human beings it is nearly always the female who becomes the victim of the male. But in the normal sadism which occurs throughout a large part of nature it is nearly always the male who is the victim of the female. It is the male spider who impregnates the female at the risk of his life and sometimes perishes in the attempt; it is the male bee who, after intercourse with the queen, falls dead from that fatal embrace, leaving her to fling aside his entrails and calmly pursue her course.[[106]] If it may seem to some that the course of our inquiry leads us to contemplate with equanimity, as a natural phenomenon, a certain semblance of cruelty in man in his relations with woman, they may, if they will, reflect that this phenomenon is but a very slight counterpoise to that cruelty which has been naturally exerted by the female on the male long even before man began to be.
Krafft-Ebing, Psychopathia Sexualis, English translation of tenth German edition, pp. 80, 209. It should be added that the object of the sadistic impulse is not necessarily a person of the opposite sex.