An analogy with the sexual friendship of youth may be traced in the case of old men, when, for instance, with the involution following old age, the latent amphisexuality of man appears. This may be the reason why so many men of fifty years and upwards are guilty of indecency. Homo-sexuality has been observed amongst animals to a considerable extent. F. Karsch has made a wide, if not complete, compilation from other authors. Unfortunately, practically no observations were made as to the grades of maleness or femaleness to be observed in such cases. But we may be reasonably certain that the law holds good in the animal world. If bulls are kept apart from cows for a considerable time, homo-sexual acts occur amongst them; the most female are the first to become corrupted, the others later, some perhaps never. (It is amongst cattle that the greatest number of sexually intermediate forms have been recorded.) This shows that the tendency was latent in them, but that at other times the sexual demand was satisfied in normal fashion. Cattle in captivity behave precisely as prisoners and convicts in these matters. Animals exhibit not merely onanism (which is known to them as to human beings), but also homo-sexuality; and this fact, together with the fact that sexually intermediate forms are known to occur amongst them, I regard as strong evidence for my law of sexual attraction. Inverted sexual attraction, then, is no exception to my law of sexual attraction, but is merely a special case of it. An individual who is half-man, half-woman, requires as sexual complement a being similarly equipped with a share of both sexes in order to fulfil the requirements of the law. This explains the fact that sexual inverts usually associate only with persons of similar character, and rarely admit to intimacy those who are normal. The sexual attraction is mutual, and this explains why sexual inverts so readily recognise each other. This being so, the normal element in human society has very little idea of the extent to which homo-sexuality is practised, and when a case becomes public property, every normal young profligate thinks that he has a right to condemn such “atrocities.” So recently as the year 1900 a professor of psychiatry in a German university urged that those who practised homo-sexuality should be castrated. The therapeutical remedies which have been used to combat homo-sexuality, in cases where such treatment has been attempted, are certainly less radical than the advice of the professor; but they serve to show only how little the nature of homo-sexuality was understood. The method used at present is hypnotism, and this can rest only on the theory that homo-sexuality is an acquired character. By suggesting the idea of the female form and of normal congress, it is sought to accustom those under treatment to normal relations. But the acknowledged results are very few.