496 



V. D. LESPINASSE 







I 





like masses ; Jbut they do not run together into a large sphere, flattening 

 the nucleus out against the cell-wall, as is the case with the typical adi- 

 pose cell. Rather the arrangement is such as is found in developing fat 

 cells. This characteristic has led some to doubt if the fat is "ordinary 

 fat." The fat in the interstitial cells is for the most part a phosphated 

 lipoid material but cholesterin ester and neutral fat also are probably 

 present. 



The fat globules are dissolved by ether, absolute alcohol, xylol, etc., and 

 are stained by both osmic acid and Sudan III in short, give the usual' 

 microchemical reactions employed for the demonstration of fat in other 



tissues; so that they are un- 

 doubtedly ordinary fat. 



II. Pigment. This is not 

 a constant content of the inter- 

 stitial cells, but is very common 

 in the young testes of chickens. 

 In human material it is rather 

 rare. It is fatty, staining well 

 with Sudan III in frozen sec- 

 tions and faintly even in mate- 

 rial that has been treated with 

 alcohol. 



777. Crystalloids. The dis- 

 covery of crystalloids in the in- 

 terstitial cells aroused consider- 

 able interest as these crystal- 

 loids by some are supposed to 

 be the active internal secretion. 

 Crystalloids are present, how- 

 ever, in a very few animals, if, indeed, it is not limited to man. 



IV. Specific Granules. One finds certain definite granules quite con- 

 stantly present in the mammalian testis, including that of man. To 

 demonstrate them the tissue must be well preserved, and the fixing fluid 

 is of prime importance. Thus, they are quite sensitive to certain acids, 

 fluids containing much acetic acid or potassium bichromate, giving nega- 

 tive results. 



Absolute alcohol and 10 per cent formalin give very satisfactory 

 fixation. With Mann's methyl blue-eo'sin they stain red ; they are brought 

 out well by iron hematoxylin; but the most distinctive picture is furnished 

 by staining with Reinke's neutral gentian, as modified by Bensley. With 

 this stain the cytoplasm is colored orange, while chromatin and the granules 

 are stained violet ; so that an excellent contrast is obtained between the 

 granules and the cytoplasm in which they are imbedded. In such prepara- 

 tions the majority of the interstitial cells contain definite granules one 



Fig. 4. High power photomicrograph of the 

 nucleus of the interstitial cells to show the 

 chromatin rods of the nucleus. 



