lU(j studies of the Interstitial Cells of Le^alig 



These two processes, growth of the tubules and atrophy of the inter- 

 stitial cells, continue at such a rapid rate that in the five-months pig the 

 tubules greatly predominate over the interstitial cells (compare Figs. 

 3 and 4). The latter are now so reduced in size as to almost be identical 

 in appearance with the subalbugineal cells of the pig at one month. In- 

 dividual cells are shown in Fig. 5. Many of them are like the central 

 one in the figure, otliers entirely lack the distinct cell-boundaries and 

 are little more than naked nuclei, and others show distinct cell-boundaries 

 only at intervals, especially at the margin of a vacuole. 



Of the three adult testes at my disposal two were evidently pathological, 

 as the tubules in one case contained no sexual cells, and in the other 

 only a few spermatogonia ; probably they were ectopic testes, and need 

 not be considered here. The tliird one, however, was normal, and sper- 

 matogenesis was quite active. Sections show that the growth and con- 

 voluting of the seminal tubules have progressed still further, with the 

 result that there are very few Leydig's cells between the albuginea and 



Fig. 5. Types of Leydig's cells iu pig tive months old. x 800. 



the bases of the tubules, but they have been crowded against the lines of 

 attachment of the septa to the albuginea. In the deeper portions of the 

 sections the general appearance of the cells is quite similar to that found 

 in the five-months pig, with the exception that they are somewhat larger. 

 They do not contain any acidophile granules, nor could Eeinke's crys- 

 talloids be demonstrated in them. The subdivision of the groups of 

 Leydig's cells has increased, and in many situations there are none be- 

 tween adjacent tubules. 



While, of course, this study does not warrant conclusions as to the 

 function of Leydig's cells in the adult, we may at least inquire if it furn- 

 ishes any data in support of any of the hypotheses which have been 

 advanced as the result of histological investigation of adult conditions. In 

 favor of the theory of v. Bardeleben, that Leydig's cells replace Sertoli 

 cells as the latter are worn out in the performance of their function, I can 

 find no evidence in any of the preparations. After the basement membrane 

 of the tubules is laid down it forms a barrier which completely prevents 

 the passage of interstitial cells into the tubules. So also as to the view 



