The term sadism is derived from the celebrated Marquis de Sade, a French author, whose obscene romances overflow with cruel voluptuousness. Certain reminiscences of sadism are common both in man and woman. At the moment of highest excitation in coitus it is not uncommon for one or other of the couple to bite or scratch in the ecstasy of their amorous embraces. Lombroso remarks on the brutal excesses of soldiers when excited after battle. This is so to speak an inversion of sadism as regards cause and effect. After the exaltation of combat, that of desire possesses the mind, as in the inverse direction exaltation of desire gives rise in certain cases to that of violence and thirst for blood.
Krafft-Ebing draws attention to the fact that love and anger are the two most violent effective conditions, and are at the same time the two powers which provoke the most motor discharges. This explains why they may be associated in the delirium of unbridled passions. To these facts is added an atavistic relic of the instinct of man's ancestors, the males of whom fought furiously to conquer the females by violence, which provoked desire in them, after the subjection of the object of their sexual appetite. True sadism can, however, only become effective by the combination of two causes: (1) by an exalted and absolutely pathological association of sexual desire with a sanguinary instinct, and with the desire to illtreat and overcome a victim; (2) by an almost absolute absence of moral sense and sympathy, combined with a violent and egoistic sexual passion. It is evident that the slight more or less sadic impulses which may involuntarily occur in the performance of normal coitus, are quite exempt from the second of these causes.
Krafft-Ebing maintains that sadism is usually, if not always, congenital and hereditary. Sadism is for a long time restrained by fear, education or moral sentiments. It is only gradually, when normal coitus cannot procure for the perverted sexual appetite the satisfaction it requires, that the sadist gives way to his passion; this gives the latter a false appearance of acquired vice.
The highest degree of sadism leads to assassination. In this way human tigers entice young girls into a wood and cut them to pieces. Some begin by forcing them to coitus, after frightening them, or half strangling them; others masturbate in their ripped up entrails. But some others have no desire for coitus, nor anything resembling it, their desire being satisfied only by the sight of the terror, suffering and blood of their victim, whom they torture before killing. Others again associate desire with the rage of a wild beast to such a point that they swallow parts of their victim's body and drink the blood.