Morality--not that learnt mechanically, but that which we feel as an internal necessity--has become, in the course of thousands of generations, an organized instinct. For this reason, like all other organized instincts, it is exposed to ‘perversion,’ to aberration. The effect of this is that an organ, or the whole organism, works in opposition to its normal task and its natural laws, and cannot work otherwise.[248] In perversion of taste the patient seeks greedily to swallow all that ordinarily provokes the deepest repugnance, _i.e._, is instinctively recognised as noxious, and rejected for that reason--decaying organic matter, ordure, pus, spittle, etc. In perversion of smell he prefers the odours of putrefaction to the perfume of flowers. In perversion of the sexual appetite he has desires which are directly contrary to the purpose of the instinct, _i.e._, the preservation of the species. In perversion of the moral sense the patient is attracted by, and feels delight in, acts which fill the sane man with disgust and horror. If this particular perversion is added to ego-mania, we have before us not merely the obtuse indifference towards crime which characterizes moral madness, but delight in crime. The ego-maniac of this kind is no longer merely insensible to good and evil, and incapable of discriminating between them, but he has a decided predilection for evil, esteems it in others, does it himself every time he can act according to his inclination, and finds in it the peculiar beauty that the sane man finds in good.