The facts of which I have just given a summary lead directly to a most striking instance of disharmony exhibited in the order of the development of the human reproductive apparatus. Puberty declares itself in a woman by the beginning of menstruation at a time when girls still possess infantile characters and when the bones of the pelvic basin are not yet fully developed. Obviously there is a disharmony between puberty and the general maturity of the body, that is to say, the nubile condition. This disharmony becomes still more evident upon a closer examination of the phases of development of the different reproductive functions. In the human race, reproduction is brought about by the union of the sexes suggested by sympathy or mutual love. The sexual union makes it possible for the male elements or spermatozoa to reach the eggs and fertilise them by passing into them. It might have been expected that the different steps in the process would have been attuned so as to act in harmony. As a matter of fact there is no such relation. The different factors of the sexual function develop independently and unharmoniously. Love and the sexual sense in the human race appear before the other factors in the process. Ramdohr,[109] in the eighteenth century, stated that little boys frequently exhibit amorousness towards women. They are capable of being strongly affected by jealousy and by desire of exclusive possession of the coveted woman. This fact is well known, and has been related of famous personages. Thus Dante, at the age of nine, fell in love with Beatrice; Canova was in love when he was little more than six years of age, and Lord Byron was in love with Mary Duff at the age of seven.[110] Sexual excitability appears at an age when there is no question but that the sexual elements are undeveloped. In infants still in the cradle, observers have noticed movements and attitudes showing the presence of sexual excitability. Curschmann and Fürbringer,[111] both competent clinicians, have noticed these feelings in children under the age of five. Later on in life, the development of the sensibility is more common, and is practically universal among boys before the time at which the spermatozoa are ripe. This disharmony is the cause of onanism, which is common everywhere among boys. Before ordinary sexual congress is possible for them, boys experience the characteristic pleasure of the sexual sensations, and by a kind of natural instinct learn self-gratification. Onanism is sometimes defined as a “gratification of the sexual desire by unnatural means.”[112] But it is man’s constitution itself that permits the development of the sensation precociously, before the development of sexual maturity. Letourneau is right when he says that such sexual aberrations are abnormal, but not unnatural, as they occur among animals.