It often happens that the genital sense is exalted, because it is the only one, or nearly so, which continues. This is frequently seen in idiots, and in those affected with dementia. The imbeciles, if left to themselves, “says Esquirol,” sometimes at the period of puberty become affected with onanism, nymphomania, or hysteria. Idiots also often indulge in the most unrestrained masturbation. This can readily be imagined: these individuals are in a measure isolated by the debility or weakness of their senses and intelligence. As they receive no external impressions, those which are inherent, exercise unlimited power. The internal senses are then much more regarded, because they speak alone. That which is in others only a desire, becomes in idiots a want: hence there are many who seem to live, merely to eat, drink, and indulge in licentiousness. When speaking of the effects of onanism on the mental faculties, we have shown that the venereal sense becomes heightened, as these other faculties are weakened. This fact may be remarked, whatever may have been the cause of derangement: for many individuals become affected with onanistic satyriasis, because they are imbecile or idiotic. Finally, idiocy may be the effect and cause of onanism. Sometimes the disease appears first, sometimes the habit--but as soon as they exist they strive continually to increase, and we are unable to say which of the two exercises the stronger influence on the other. Our remarks on idiocy are equally applicable to cretinism, which is a variety of this affection. The cretins, though small, goitrous, hideous and imbecile, are extremely salacious, and this feeling is allayed by intercourse between them, or by onanism. A remarkable fact which has been observed twice, once in a cretin and once in an idiot, may throw some light on the organic causes of the inverse progress followed by the external and internal senses in this kind of patients: it is the _hypertrophy of the ganglionnary nervous system_. One of these cases is recorded by M. Schiffner. He found, on the cadaver of a cretin, that the ganglions of the great sympathetic nerve, situated along the vertebral column, were unusually large. The sympathetic nerve of the left side, on a level with the 6th vertebra presented a ganglion the size of a hen’s egg. Before this case of Schiffner, in 1819, Cayre also, in a thesis on idiotism, had mentioned the excessive development of the ganglionnary system, in one born an idiot. The cervical ganglions were three times their usual size; those of the thorax were larger than in the healthy state, and this was the case also with the semilunar ganglions.