388 



MARGARET R. LEWIS AND WARREN H. LEWIS 



stain like mitochondria. In the migrating fat cells which contain 

 few fat globules some of the mitochondria may be in the form 

 of threads or short rods but there is a coincident change in the 

 shape of the mitochondria with the accumulation of fat drop- 

 lets so that a cell which is crowded full of fat droplets contains 



<3»5K 





Fig. 2") Photograph of part of a 2-day culture of intestine from a G-day chick. 

 The explanted piece of intestine is from the region where the yolk-sac is attached, 

 and the cells on the left ot the culture are similar to those from cultures of the 

 yolk-sac; each endodermal cell has one or two large fat globules; on the right are 

 mesenchyme cells free or almost free from fat. 



only small granule shaped mitochondria. The fat droplets are 

 outlined by a row of granules which stain like mitochondria 

 (fig. 26 b). ^ 



The second type of fat is one or two small round refractive 

 granules foimd in almost all the cells of the growths. These 

 fat globules have not been observed to increase markedly in 



