MITOCHONDRIA IN TISSUE CULTURES 381 



Vacuoles 



There are two distinct types of degeneration of the cells of 

 the tissue cultures. The cell either suspends activities, rounds 

 up and dies, or else the cell continues its usual activities but the 

 cytoplasm becomes filled up with vacuoles and the mitochondria 

 become small granules (fig. 22). In a healthy cell a vacuole is 

 often seen to come and go in the cytoplasm, but when several 

 vacuoles remain in the cytoplasm degeneration has begun and 

 the cell never again resumes its normal appearance, but con- 

 tinues to accumulate vacuoles until most of the cytoplasm is 

 used up and only a network which contains scattered granules 

 remains. 



Fig. 22 Cell from a 3-day culture of intestine from a 7-day chick embryo; 

 the cell has a number of vacuoles near the nucleus, most of the vacuoles contain 

 one or more granules; X 1580 diam. 



In the fixed and stained preparations the vacuole appears 

 either as a clear space often difficult to differentiate from the 

 fat globule space, or it appears as a clear space within which is 

 a faintly stained granular substance (gray with Heidenhain's 

 iron hematoxylin or red brown with Bensely's anilin fuchsin, 

 methylen green stain). 



In the living cell these vacuoles are distinctly different from 

 the fat droplets. They appear to be fluid spaces not at all 

 refractive, in fact, they resemble a hole in the cytoplasm. Small 

 dancing granules which vary in number from one to many may 

 be suspended in the fluid of the vacuole or closely attached to 



THE AMERICAN JOURNAL OF ANATOMY, VOL. 17, NO. 3 



