64 R. H. T\TIITEHEAD 



cell. However, they may be located in any portion of the cell- 

 body; often some are found in the vicinity of the nucleus, occa- 

 sionally in apparent contact with the nuclear membrane. It can 

 be determined that they lie in vacuoles, though some of the small- 

 est granules appear to be located at the nodal points of cytoplas- 

 mic threads. It would seem that the number of the granules 

 varies with different individuals. Thus in one cat there were 

 few ceils observed that contained more than two or three gran- 

 ules; in this animal the number and size of the cells also seemed 

 decidedly below the average. 



A very clear picture was obtained with Wright's blood stain. 

 The sections were stained twenty-four hours in a dilute solution 

 (one part of dye to forty of distilled water), the excess of dye was 

 washed out with distilled water, and the sections were then dehy- 

 drated in acetone, cleared in xylol, and mounted in neutral balsam. 

 The granules were stained red, the chromatin took the methylene 

 blue, and the general cytoplasm was stained blue or pinkish blue 

 (fig. 2). Sections of this material stained with Altmann's solu- 

 tion of acid fuchsin gave essentially the same appearances so far 

 as the granules were concerned; but in this case the picture was 

 not so clear owing to the fact that both the cytoplasm and the 

 granules were stained by the acid fuchsin; the granules, however, 

 were a much deeper red. I would call especial attention to the 

 fact that in none of the preparations mentioned above were any 

 mitochondrial structures demonstrated in the seminal epithelium. 



Iron haematoxylin gave a somewhat different picture (fig. 3). 

 Here the spongioplasmic framework was well stained in many 

 cells, so that' it sometimes presented the appearance of threads 

 of small granules (mitochondria) . In such cases granules might 

 be present in somewhat confusing number; but the distinction 

 between the two sorts could usually be made owing to the fact 

 that the granules were larger than the spongioplasmic structures, 

 were more regularly spherical, and were contained in vacuoles, 

 whose walls were furnished by trabeculae of the spongioplasm. 

 In these preparations mitochondrial structures were seen also 

 in the seminal epithelium, threads of bacilli-like grains in the 

 Sertoli cells being brought out with especial distinctness. 



