398 INTERNAL SECRETION 



persistence of those morphological and biological characters which 

 are the property of the male sex, is undoubted. 



The part played by Leydig's cells in the general effects 

 produced by the genital hormone is still very obscure. 

 Castration leads to changes in the growth of the bones ; to modi- 

 fications in the structure of certain internal secretory organs, as, 

 for instance, the hypophysis ; and to profound metabolic altera- 

 tions which are, to a certain point, independent of sex and may 

 be reduced by the exhibition of homosexual or even heterosexual 

 genital gland extract. Up to the present, there is no evidence 

 to show that the hormone which produces these results is 

 elaborated in the cells of Leydig. In Simmond's experiments, 

 the animals frequently put on fat after exposure of their testicles 

 to the Rontgen rays, but there is no evidence to show that the 

 changes in the metabolism of fat are not due solely to the destruc- 

 tion of the generative parts. Further investigation is required, 

 especially of those effects produced by the genital gland which 

 are independent of sexuality, before the significance of the in- 

 dividual tissues of the testicle can be understood. It appears by 

 no means improbable that several hormones of different origin 

 are supplied by the testicle to the blood-stream. 



Very little is known concerning pathological changes in the 

 cells of Leydig. According to Ancel and Bouin, this tissue 

 hypertrophies in acute disease, in prolonged cachexia it atrophies. 

 These investigators found that, in experimental intoxication or 

 infection, the cells of Leydig were hypertrophied at the commence- 

 ment of the condition, while in the final stages and in very severe 

 illness they were atrophied. They regard the hypertrophy of the 

 interstitial gland as a protective measure on the part of the 

 organism. This finding is confirmed by Voinov, but he regards 

 the increase in the number of Leydig's cells as a protective re- 

 action on the part of the genital gland. It seems probable, from 

 the observations which have been made-up to the present, that 

 the multiplication of Leydig's cells is in some manner dependent 

 upon the behaviour of the semiferous tubules. Hyperplasia and 

 hypertrophy of Leydig's cells are accompaniments of both im- 

 perfect development and secondary atrophy of the seminiferous 

 tubules (Diirck). Hansemann believed that the cells of Leydig 

 -are concerned in the production of testicular tumour. 



Ovary. In discussing the internal secretion of the ovary it 

 is necessary to consider this function in its relationship to three 

 different tissues : (i) the Graafian follicles; (2) the corpus luteum ; 

 and (3) those peculiar stroma cells which Bouin described col- 

 lectively as the glande inter stitielle de I'ovaire. 



Of these tissues, the two first have long been known, and 

 investigation has revealed the nature of their interrelationship with 

 one another. The third has recently become the subject of con- 

 siderable attention. The epithelioid cells in the interstitial tissue 



