STUDIES OF THE INTERSTITIAL CELLS OF LEYDIG. 

 No. 2. — Their Postembryonic Development in the Pig. 



R. H. WHITEHEAD, M. D. 



Medical Department, University of North Carolina. 



With 5 Text Figures. 



In a recent article ^ I presented the results of a study of the embryonic 

 development of the interstitial cells of Leydig in the pig. In the present 

 article I wish to give a brief account of the findings in a study of their 

 postembryonic development in the same animal. The methods employed 

 were the same as those described in the first article, to which I may refer 

 also for the more important facts in the literature of the subject. 



The youngest pig in my series was one month old. In sections of the 

 testis at this age, compared with one from the embryo pig near term, the 

 cross-sections of seminal tubules are somewhat more numerous and closer 

 together, and the masses of interstitial cells are proportionally smaller. 

 Beneath the albuginea the cells are much reduced in size, and are ar- 

 ranged in a few more or less parallel rows, separated by small bundles 

 of connective-tissue fibres. In the deeper portions of the gland, however, 

 the cells are still of about the same size. Three main types of cells can 

 be observed, as follows (Fig. 1) : 



1. Cells with cytoplasm condensed around an eccentric nucleus, while 

 the periphery is extensively vacuolated. The vacuoles have more or less 

 uneven, ragged margins. Some of them hold inclusions which vary in 

 size; the largest of these have the granular appearance and staining 

 reactions of the cytoplasm, while others are more hyaline in appearance. 

 Occasionally structures entirely similar to these inclusions are found 

 between the cells. 



2. Cells whose cytoplasm is condensed around an eccentric nucleus, 

 while their periphery is much clearer, containing only a few scattered 

 cytoplasmic threads. 



»Amer. Jour. Anat., Vol. 3, No. 2, 1904. 

 American Jourxal of Anatomy. — Vol. IV. 



