CHEMICAL NATURE OF CERTAIN GRANULES 65 



In material fixed in absolute alcohol the granules, in spite of 

 the distortion of the cells, were still quite evident and apparently 

 undiminished in number. 



In the previous communication it was stated that the granules 

 could not be stained in material fixed by solutions which contained 

 potassium bichromate in large proportion. This statement was 

 based on the negative results obtained with pieces of cat's testis 

 fixed in several fluids which contained that salt in considerable 

 amount. I am unable to say just where the error came in, but 

 the statement was certainly erroneous. Hanes' has demon- 

 strated the granules in pig's testis fixed in Zenker's fluid, and I 

 have myself repeatedly observed them in this material fixed by 

 Zenker. I have investigated the point anew in the cat's testis 

 as well as the pig's, and find that the granules, while present, are 

 more or less disfigured : they are apt to lose their regularly spher- 

 ical contour and appear as irregular lumps, or as spherules with 

 darkly stained periphery and lighter center. This disfiguration, 

 however, is possibly due to the acetic acid contained in the 

 Zenker's fluid. 



From the above we may conclude that the granules described 

 in formalin and absolute alcohol material are proteid in nature. 

 They may be stained with either basic (gentian violet) or acid 

 (acid fuchsin) dyes; but when given an equal opportunity at the 

 methylene blue and the eosin in Wright's stain take the eosin. 



In the course of a recent study of the lipoids of these cells* in 

 the cat it was noticed that along with the globules of lipoids the 

 interstitial cells frequently contained granules with an affinity 

 for Sudan III which, in respect of size and position, were indis- 

 tinguishable from the granules just described. The suggestion 

 presented itself that the granules really consist of a combination 

 of proteid and fatty material, and that in paraffin sections of 

 material fixed in formalin or absolute alcohol the fatty constituent 

 had been dissolved out, leaving only the proteid. It seemed 

 highly improbable that any fatty matter would remain in sections 



' F. M, Hanes. The relation of the interstitial cells of Leydig to the production 

 of an internal secretion of the mammalian testis. Jour. Exp. Med., March, 19n. 



■• R. H. Whitehead. A microchemical study of the fatty bodies of the intersti- 

 tial cells of the testis. Anat. Rec, vol. 6, 1912. 



