MESENCHYME CELLS OF TISSUE CULTUEES . 441 



of some of the fine granules and fat globules, if the latter were 

 present. The cytoplasm, in the later stages, sometimes became 

 more or less vacuolated. These vacuoles were of a different 

 type from those that take the neutral red. They were difficult 

 to see and did not take up the neutral red. 



In fixed material many of the cells showed a peculiar, finely 

 granular, deeply staining area in the cytoplasm (figs. 1, 4, 6, 9, 

 11, 12, 14), seeming to indicate that the cytoplasm, probably 

 endoplasm, had become denser in certain areas and on fixation 

 had coagulated into a finely granular mass. These areas did 

 not appear to have any definite location. In some cells they 

 were near the nucleus, in others some distance away; in some 

 instances on the same side of the nucleus as the centrosphere, in 

 others on the opposite side; they occurred in cells with or with- 

 out centrospheres, in young daughter cells, in older cells, and even 

 in dividing cells. They were present in some cells with nuclear 

 shrinkage, in others they were absent. The condition of the 

 fixed cytoplasm of these areas reminds one very much of that 

 usually seen in dividing cells. 



No changes were observed in the centrosphere. 



CHANGES IN THE GRANULES AND VACUOLES 



The granules and vacuoles that had previously taken the neu- 

 tral red stain retained their usual condition until after the 

 nuclear and mitochondrial alterations had taken place, then 

 there was either a gradual loss or a rather sudden disappearance 

 of the red color. In the former case the vacuoles and granules 

 seemed to otherwise remain unaltered and could be seen unstained. 

 With the disappearance of the red color from the vacuoles and 

 granules the cells lost the last vestige of life. The vacuoles and 

 granules of dead cells never took up the neutral red, although 

 the cytoplasm sometimes became diffusely stained if the neutral 

 red was sufficiently concentrated. 



In the living cell the dye was evidently held in some peculiar 

 chemical or physical combination in the granules and vacuoles 

 and accumulated there until the saturation point was reached, 



