Féré (_L'Instinct sexuel_, p. 241) has sought to explain away some of these phenomena, in so far as they may be brought against the theory that the secretions and excretions of the sexual glands are the sole source of the sexual impulse. The persistence of sexual feelings after castration may be due, he argues, to the presence of the nerves in the cicatrices, just as the amputated have the illusion that the missing limb is still there. Exactly the same explanation has since been put forward by Moll, _Medizinische Klinik_, 1905, Nrs. 12 and 13. In the same way the presence of sexual feelings after the menopause may be due to similar irritation determined by degeneration during involution of the glands. The precocious appearance of the sexual impulse in childhood he would explain as due to an anomaly of development in the sexual organs. Féré makes no attempt to explain the presence of the sexual impulse in the congenital absence of the sexual glands; here, however, Mundé intervenes with the suggestion that it is possible that in most cases "an infinitesimal trace of ovary" may exist, and preserve femininity, though insufficient to produce ovulation or menstruation. It is proper to mention these ingenious arguments. They are, however, purely hypothetical, obviously invented to support a theory. It can scarcely be said that they carry conviction. We may rather agree with Guinard that so great is the importance of reproduction that nature has multiplied the means by which preparation is made for the conjunction of the sexes and the roads by which sexual excitation may arrive. As Hirschfeld puts it, in a discussion of this subject (_Sexual-Probleme_, Feb., 1912), "Nature has several irons in the fire."