310 THE PHYSIOLOGY OF REPRODUCTION 



that the constant administration of fresh testicular substance 

 might have led to a different result. 



Bouin and Ancel x have shown in the horse and other animals 

 that when the vasa deferentia are ligatured the spermatogenetic 

 tissue of the testis ceases to be functional and gradually under- 

 goes degeneration, while the interstitial cells remain unaffected. 

 They point out, further, that those cells have a distinctly 

 glandular appearance, and that their presence suffices for the 

 development of the secondary sexual characters. Consequently 

 they draw the conclusion that the testis is an organ producing 

 an internal secretion which is elaborated by the interstitial cells 

 and not by the spermatogenic tissue. These investigators state, 

 further, 2 as a result of a series of experiments upon guinea-pigs, 

 that the subcutaneous injection of extract prepared from the 

 interstitial tissue of the testis arrests the effects which castration 

 otherwise would produce upon the rest of the generative system 

 and upon the skeleton. 3 Their results, therefore, differ from those 

 of Walker. In another paper Bouin and Ancel 4 state that the 

 injection of similarly prepared testicular extract in guinea-pigs 

 tends to promote growth. In the horse they found that the 

 development of the interstitial gland substance of the adult 

 coincided with the first occurrence of spermatogenesis ; but that 

 there was also a foetal interstitial gland, which disappeared at the 

 end. of gestation, and a slightly developed gland composed of 

 xanthochrome cells, which was only found in the immature 

 animal. 5 



1 Bouin and Ancel, " Recherches sur les Cellules interstitielles du Testicule 

 des Mammiferes," Arch, de Zool. Exper., vol. i., 4th series, 1903. 



2 Bouin and Ancel, "Action de 1'Extrait de Glande interstitielle du 

 Testicule," &c., C. R. de VAcad. des Sciences, vol. cxlii., 1906. 



3 Castration in early life, as already mentioned, is said to lead to a 

 prolonged retention of the cartilaginous unions between the bones, especially 

 in those of the limbs. 



4 Bouin and Ancel, " Sur 1'Effet des Injections de 1'Extrait de Glande 

 interstitielles du Testicule sur la Croissance," C. R. de la Soc. de Biol., 

 vol. Ixi., 1906. 



6 Bouin and Ancel, " La Glande interstitielle du Testicule chez le Cheval," 

 Arch, de ZooL Exper., vol. iii., 4th series, 1905. According to Lecaillon 

 the interstitial tissue in the mole's testis is functionally active during the 

 breeding season, when the testis is sixty-four times larger than during the 

 resting period. (" Sur les Cellules interstitielles du Testicule de la Taupe con- 

 siderees en dehors de la Periode de Reproduction,'' C. R. de la Soc. de Biol., 

 vol. Ixvi., 1909). 



