212 A. W. GREENWOOD 



Much has already been written regarding these rod-Hke bodies 

 present in the cytoplasm of the Sertoli cells in P h a s c o - 

 1 a r c t u s . I do not propose to discuss at much length the 

 theories already advanced, but will give my conclusions 

 arrived at by a study of these bodies, and the results of experi- 

 ments undertaken by me to determine if possible their nature. 

 The experiments were undertaken with the view to ascertaining 

 whether the rods served a nutritive function. The fact that 

 these rods were found only in the Sertoli cells led me to believe 

 that possibly these rods were a source of nutriment, or con- 

 nected in some way with the supply of nutriment to the develop- 

 ing spermatozoa. 



Below I give the results of some digestion experiments under- 

 taken to prove this point if possible. 



Fresh material was cut by means of a freezing microtome. 

 Owing to the difficulty of picking up the rods in unstained 

 material, the tissue was stained. The stains used were neutral 

 rod and methyl green. 



The sections after staining were submitted to the action of 

 a weakly acidic mixture of pepsin and glycerine. Cells with 

 rods were picked out and their position marked by means of 

 a micrometer eyepiece. Then the microscope was placed in 

 an electric oven and kept at a constant temperature of 30° Centi- 

 grade. The progress of the action was watched from time to 

 time. The accumulation of the products of digestion after a time 

 tended to stop the action and only partial digestion took place. 

 In all cases of partial digestion the rods were still visible. With 

 the use of more of the digestive fluid complete digestion of the 

 cytoplasm occurred. In this case, with complete digestion, the 

 cells moved about in the fluid and were difficult to find again. 

 In the majority of the experiments the rods were identified 

 even after complete digestion, but in some cases thej^ could 

 not be found. 



The same experiment was carried out, using an alkaline 

 mixture of zymine and glycerine. Again, here the rods were 

 still visible after partial digestion ; but in the case of complete 

 digestion, owing to the difficulty of picking up the rods in the 



