MITOCHONDRIA IN TISSUE CULTURES 363 



All phases in the development of the cell, i.e., daughter cell, 

 growing cell, resting cell and dividing cell can be found with 

 any one of the above combinations of the mitochondria. How- 

 ever, it must not be forgotten that many cells contain part of 

 one kind of mitochondria and part of another and that any 

 one shape of mitochondria may turn into another at any time 

 during observation, and that no one shape of mitochondria 

 remains as such for a very long interval of time, but changes 

 into another. 



/Mil J^ ^'' 



80 



Fig. 13 A, cell from a 2-day culture of heart from a 7-day chick; practically 

 all the mitochondria are degenerated, those in the region of the central body 

 show most advanced stage of granular rings; X 790 diam.; b, degenerating mito- 

 chondria from mesenchyme cell of a 2-day culture of intestine from a 4-day 

 chick; X 920 diam.; c, cell from a 2-day culture of heart of a 5-day chick; all the 

 mitochondria have degenerated into granular rings; osmic acid vapor and iron 

 hematoxylin; X 790 diam.; d, process of degeneration in a single mitochondrium 

 produced by the action of acetic acid vapor on a living cell; e, effect of CO3 on 

 another mitochondrium in 2 minutes. 



Degenerate mitochondria 



Degenerate mitochondria of various shapes are occasionally 

 found in these preparations (fig. 13). A study of the cells of 

 the older growths shows that all the mitochondria do not neces- 

 sarily degenerate at the same time. Some cells are found which 

 contain many normal mitochondria, some partly degenerate, 

 and others entirely degenerate. 



