314 ALWIN M. PAPPENHEIMER 



in some cells closely aggregated, in others less numerous. They 

 may extend out into the cell processes; usually there is a narrow 

 zone at the surface of the cell which contains fewer granulae. 

 They are often grouped in linear alignment about a fat vacuole, 

 or in the long axis of the cell and especially in the protoplasmic 

 processes where the protoplasmic fibrils run parallel. The gran- 

 ulae do not always stain with the same intensity in the same 

 cell, but this may be due to uneven penetration of the stain or 

 decolorizing agent through the plasma (figs. 5 and 6). 



In most of the cells there is an area adjacent to the nucleus 

 where the protoplasm is denser and the granulae and fat, drops 

 are absent. Although centrosome or cy tasters were not seen in 

 these preparations, it is probable that this denser granule-free 

 area represents the cytocentrum. 



WTien the cultures are fixed in bichloride-acetic acid, the cyto- 

 plasmic granulae are very indistinctly brought out by the Heiden- 

 hain stain. The nucleus on the other hand,, instead of appearing 

 homogeneous as in the formalin preparations, shows finely dis- 

 tributed chromatin clumps. The only mitotic figures seen in 

 these cells during the course of the work, were in a specimen 

 fixed in bichloride-acetic acid. The chromatin threads of the 

 dividing cells (prophase and diaster stage) were very large and 

 distinct. 



The cytoplasmic granules of the cells were also demonstrated 

 by the Altmann-Bensley method, the loosening and retraction of 

 the clot being prevented by preliminary fixation in 10 per cent 

 formalin. The stained preparations however were unsatisfactory 

 since the decolorization of the fuchsin in the plasma clot was 

 impossible, and only a few cells which by fortunate chance, lay 

 within the retraction zone, were available for study. 



By this method, smaller rounded cells filled with fuchsinophile 

 granules were also seen. The granulae in part show swelling 

 and disintegration, but may persist in this altered form even 

 after the cell has degenerated. 



The granulae of the large cells may be brought out clearly by 

 the use of vital stains, the most successful of those tried being 

 Janus green and methylene-blue GG. With the former stain, 



