TESTICLE AS GLAND OF INTERNAL SECRETION 497 



or two mikrons in diameter, often in clusters. They lie, for the most 

 part, in the peripheral portions of the cells, but may be found anywhere 

 in the cytoplasm. Each granule is contained in a distinct vacuole, as 

 is evident in very thin sections two or three mikrons thick. It is inter- 

 esting to note that in the case of cells which contain many fat globules, 

 they and these granules lie in these same vacuoles. These granules are few 

 in the rodents, fairly, numerous in the dog and sheep, and abundant in the 

 cat, pig and man. They first appear in the pig embryo of 23 mm., after 

 which time they are regularly present. In the undescended testis of a 

 cryptorchid pig they are very numerous. Hence they are probably not re- 

 lated to spermatogenesis, since in such testis the seminal epithelium is 

 undeveloped or atrophied. 



The staining reactions of these granules and their sensitiveness to 

 acetic acid call to mind the zymogen granules of the pancreas. On the 

 other hand, the reaction for prozymogen, which usually can be had in. cells 

 which produce zymogen, could not be obtained. Our knowledge of the 

 zymogen is so imperfect that it does not seem safe either to affirm or to 

 deny the zymogenic nature of the granules; but, without any reference 

 to their chemical nature, we may regard them as an internal secretion 

 of the interstitial cells. 



Discussion of Results 



The various theories as to the function of the interstitial cells are 

 that they act as nurse-cells, passing their fat and pigment through minute 

 canals in the walls of the tubules to be received by the Sertoli cells and 

 there used as pabulum in the formation of spermatozoa. Reinke thinks 

 crystalloids are an internal secretion while others think the fat itself is 

 the internal secretion of the interstitial cells, and is poured into the gen- 

 eral circulation through the lymphatics. Loisel has advanced the theory 

 that the interstitial cells manufacture an internal secretion out of their 

 fat, and that this secretion produces the secondary sexual characters of 

 the male. 



Effects of Various Factors on the Testicle 



I. Captivity. The phenomena of degeneracy are observed with ex- 

 treme frequency in the testicles of animals in captivity. All sections of the 

 seminiferous tube undergo various alterations, and can be seen at diverse 

 stages of their degeneration. 



The degeneracy is observed as much in quiescent cells as in cells under- 

 going active karyokinesis. 



(A) The quiescent cells present protoplasmic lesions of two very 

 different types; the vitreous degeneracy and the granular transformation. 



