THE TESTICLE AND THE OVARY 339 



and by Pe/ard, and stating that the hypertrophy of such tissue 

 {e.g. after the removal of one whole testis and a great part of the 

 second one), when such hypertrophy occurs, is due to local conditions 

 of nutrition (i.e. of blood supply), and is not truly compensatory. 

 The two views are not necessarily inconsistent, since with other 

 organs of internal secretion (e.g. the pancreas) it is known that a 

 small portion of gland tissue will suffice for the needs of the 

 organism, and yet such organs will sometimes undergo what appears 

 to be a compensatory regeneration. Moreover, if a minute portion 

 of gland tissue is really in every way adequate, it is difficult to 

 understand why the glands in question (whether testis, or pancreas, 

 or any other endocrine organ) should be as large as they normally 

 are. It is not unreasonable to assume, therefore, that the endocrine 

 organ of the testis when artificially reduced tends to undergo an 

 hypertrophy to its normal bulk, but that this hypertrophy is 

 dependent upon local nutritive conditions or blood supply. It must 

 be pointed out, however, that some investigators (Kyrle, 1 Kohn, 

 Stieve, etc.) are disposed to deny an endocrine function to the 

 interstitial tissue, suggesting that it exercises a trophic function 

 in connection with seminiferous cells, or hold with Pe/ard that 

 the testicular hormone is produced by the germinative tissue or 

 the cells of Sertoli. That a condition in which the male sexual 

 characters have failed to develop may be associated with the 

 presence of interstitial cells is not unknown, but Lipschiit/ 2 has 

 pointed out that the mere existence of these cells is insufficient, 

 and that to be effective the interstitial tissue must be in a state 

 of functional activity, whereas this is not always the case. 



It has already been mentioned that, according to Ancel and 

 Bouin and others, there is a foetal interstitial gland in the testis 

 of the developing horse and also in the chick. It would seem 

 probable that this gland is responsible for the development of the 

 pre-natal sexual characters in the manner postulated by Lillie in 

 his theory of the " free-martin." This theory has recently received 

 remarkable confirmation from the experiments of Minoura, who 

 was able to produce artificial " free-martins " in the chick by graft- 

 ing portions of reproductive gland, obtained from other individuals, 

 on to the chorio-allantoic membrane during the progress of develop- 

 ment. This work is described below in the chapter on the Deter- 

 mination of Sex (p. 695). 



1 Kyrle, "Ueber die Regenerationsvorgiinge ini tier- und inenschlicher 

 Hoden," Sitzunysb'r. A lead. ITiss. HYw, vol. cxx., 1911. See also Kohn, Arch, 

 f. Entwick.-Mechanik, vol. xlvii., 1920; Stieve, Ergebn. <L Annf. >/. L'ntwicL, 

 vol. xxiii., 1921 ; and Tiedje, Dent*. mcd. Woch., No. 13, 1921. 



2 Lipschiitz, " Ralentissement exp&imentale de la Masculinisation," C. R. de 

 la, Soc. de Biol., vol. Ixxxvi., 1922. 



