SEASONAL CHANGES IN INTERSTITIAL CELLS 485 



Another part of a testis was fixed in Carnoy's fluid (6:3: 1) 

 and stained with iron hematoxylin and also with Mayer's 

 haemalum and eosin. 



A third and smaller section was fixed in Meves' ('08) modifica- 

 tion of Benda's fixer for four and one-half days both with and 

 without the subsequent pyrohgneous-chromic acid and potassium 

 dichromate mordantage. This material was also dehydrated, 

 cleared and embedded rapidly according to the schedule described 

 •for the modified Zenker's material. It was stained for mito- 

 chondria with sodium alizarinsulphonate and crystal violet ac- 

 cording to the technique employed by Meves and Duesberg ('08) 

 and also as used by Wildman ('13). Sections were also mounted 

 unstained in balsam without any cover glass to demonstrate the 

 fatty globules which develop in the peripheral cytoplasm of the 

 interstitial cells and which are blackened by the osmic acid of 

 the fixer. 



All sections were cut 4 /x and 6 m thick. Those cut 4 ^i thick 

 were used almost entirely and comparable figures in the accom- 

 panying plates are from such sections. 



On account of the large size of the testis, especially at certain 

 seasons of the year, and the soft consistency of the structures 

 within the tough tunica albuginea, it is difficult to get small 

 pieces, even with the sharpest razor, for fixers that penetrate 

 poorly, without disturbing the relationship of the interstitial 

 tissue to the tubules. As a consequence the osmic acid stained 

 preparations used to demonstrate the fatty globules in the 

 peripheral cytoplasm of the interstitial cells, had to be taken 

 near the cut surface of the block where sucb disturbance had 

 occurred to a greater or less degree. 



There is a strong tendency for the interstitial tissue to draw 

 away from the tubules in material fixed in both Carnoy's and 

 Zenker's fluid. This is especially true at certain seasons when 

 the interstitial tissue is very loose. The heat of the paraffin 

 bath may also have contributed to these artifacts. These de- 

 fects, however, serve to bring out even more clearly the relative 

 interstitial cell development at the various seasons and do not 

 invalidate the cytological details. 



THK AMERICAN JOURNAL OF ANATOMY, VOL- 22, NO. 3 



