314 THE PHYSIOLOGY OF REPRODUCTION 



that Pfliiger is correct in supposing that the internal secretion 

 of the testis acts as a direct stimulus upon the cells of the frog's 

 arm, and so induces the development of the sexual pad and the 

 hypertrophy of the muscle. 1 



There is some evidence to show that, after one-sided castration, 

 the remaining testis is capable of undergoing a compensating 

 hypertrophy. 2 If this is so, it affords an additional indication 

 that the testis is an organ of internal secretion. 



THE CORRELATION BETWEEN THE OVARY AND THE 

 OTHER FEMALE ORGANS AND CHARACTERS 



It has long been known that the ovary, like the testis, exerts 

 a profound influence over the metabolism, and that the ex- 

 tirpation of this organ, no less than castration in the male, 

 leads to very distinct results. In the human female double 

 ovariotomy, if carried out before puberty, besides preventing 

 the onset of puberty and the occurrence of menstruation, produces 

 noticeable effects on the general form and appearance, as may 

 be seen in adult women in semi-barbarous parts of Asia, where the 

 natives perform this operation upon young girls. Such women 

 are said to be devoid of many of the characteristics of their sex, 

 and in certain cases to present resemblances to men. 



In some female animals, also, the removal or incomplete de- 

 velopment of the ovaries has been said to lead to the appearance 

 of male characters. For example, Rorig 3 records three cases in 

 which female deer possessed horns, and were found upon exami- 

 nation to show abnormalities in the ovaries. Darwin 4 also states 

 that female deer have been known to acquire horns in old age. 5 



1 See also Nussbaum, " Hoden und Brunstorgane," &c., Pfluger's Arch., 

 vol. cxxvi., 1909. For further references to the literature of testicular 

 transplantation, see Boruttau, " Innere Sekretion," Nagel's Handbuch der 

 Physiologic des Menschen, Braunschweig, 1906. 



2 Ribbert, " Beitrage zur kompensatorischen Hypertrophie," &c., Arch. f. 

 Entwick.-Mechanik, vol. i., 1894. 



3 Rorig, " Ueber Geweihentwickelung," &c., Arch.f. Entwick.-Mechanik, 

 vol. x., 1900. 



4 Darwin, Variation in Animals and Plants, Popular Edition, London, 

 1905. 



6 Smith (F.) (Veterinary Physiology, 3rd Edition, London, 1907) states that 

 female cats, whose ovaries have been removed while young, acquire a head of 



