628 INTERNAL SECRETION 



and the nipples develop to the form and size seen in the normal 

 female. The dimensions and shape of the body conform more and 

 more to the feminine type. The hair becomes smooth and silky, 

 in contrast to the coarse hair of the normal or even of the castrated 

 male. The psychical characteristics also become feminized, and 

 certain reflexes peculiar to the female make their appearance. The 

 feminized male is sought by normal males as if it were a true female. 

 A more general influence of the sexual organs on metabolism 

 seems also to be well established. The exact experiments of Loewy 

 and Richter on the metabolism of bitches before and after cas- 

 tration throw light upon the changes which follow that operation, 

 and afford decisive proof that they are connected with the absence 

 of substances specific to the ovary. They conclude that in the 

 castrated animal the oxidative energy of the cells is lessened. The 

 oxygen consumption sinks, even although protein is laid on and the 

 total amount of active tissue thus increased. Under certain cir- 

 cumstances this specific diminution of metabolism may be balanced 

 by conditions which cause an increase in the metabolism. The 

 lessening of the oxidative power is due to the loss of ovarian sub- 

 stance, for the administration of an extract of the ovary (oophorin) 

 not only neutralizes it, but actually causes an increase in the gaseous 

 metabolism to far above the original amount, while it has no effect 

 on the metabolism of the uncastrated animal. It is not the de- 

 composition of proteins, but of non-nitrogenous substances, which 

 is accelerated. Oophorin also brings about a notable increase in 

 metabolism in the castrated male dog, while, curiously enough, 

 extract of testicle causes only a small increase, due to a basic sub- 

 stance, spermin (C 5 H 14 N 2 ), which can be isolated from the testicle. 

 But the orchitic extract is not without influence in other ways. 

 It certainly increases the capacity for muscular work (Zoth and 

 Pregl), as tested by the ergograph (p. 726), and this distinct physio- 

 logical action is sufficient to encourage the hope that it may possess 

 some therapeutic value, although far from what has been claimed 

 for it by its more enthusiastic advocates. The only constituent of 

 extracts of the testicle made with salt solution which causes any 

 pronounced effect on the blood- pressure when injected into the 

 circulation is a nucleo-protein, the most plentiful of the protein 

 substances. The pressure falls, mainly owing to inhibition of the 

 heart, but partly through vaso-dilatation in the splanchnic area 

 (Dixon). 



Jlfhe testicles also influence the growth of the bones. In eunuchs 

 and in young men with atrophy of the testicles a tendency has been 

 observed for the long bones to go on growing far beyond the usual 

 period^ This has been shown by the Rontgen rays to be due to 

 delay in the ossification of the epiphyses. The same has been 

 observed in animals, and is supposed to be caused by the loss of 



