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MARGAEET R. LEWIS AND WARREN H. LEWIS 



stages of the formation of network in the living cell. These 

 networks continually change shape (figs. 6, 7). New branches 

 appear, old ones change shape or position or break away, and 

 at times the entire network may break down into loops, threads 

 and granules without any apparent change on the part of the 

 cell. From our observations it appears that the network is 



Fig. 8 Mitochondria from a 3-day culture of intestine from a 7-day chick; 

 osmic vapor and iron hematoxylin; X 2250 diam.; various forms of mitochondria, 

 which come from the breaking down of a network, into loops, rings, threads, etc. 



very unstable and rapidly breaks down into granules, loops and 

 threads. Figure 8 shows such loops and rings in a fixed specimen. 

 There has been some discussion as to which shape of mito- 

 chondria is the more primitive. Meves ('08) claimed that in 

 the twenty-hour chick embryo the mitochondria are present 



