LIVER CELLS FROM CHICK EMBRYO 293 



near the base of the cell, most of the cytoplasm being therefore 

 in the distal part. A few granules often occurred in or near the 

 base of the cell. Frequently there was an accumulation of the 

 granules in some one part of the cell (figs. 11, 13); the position 

 of this accumulation however, was not constant, and the gran- 

 ules were also often found scattered throughout the cytoplasm 

 (figs. 9, 10, 14, 18). Fat globules and mitochondria were present 

 in usual amounts. These granules seem to be similar in all 

 respects to the granules described in the fibroblasts of cultures 

 by Dr. Lewis^ and called by him degeneration granules. As in the 

 fibroblasts, they tend to accumulate in the liver cells in proportion 

 to the age of the culture and are most numerous in the cells 

 which are degenerating. 



Fat 



Free fat globules derived from the explants were present in the 

 media of all the cultures and were distributed throughout the 

 entire drop. They were especially abundant about the explant 

 and diminished sharply in number as their distance from the 

 explant increased (fig. 15). Considerable correlation was found 

 between the ages of the embryos from which the explants were 

 taken and the amount of free fat present in the medium. Increas- 

 ing amounts of free fat globules accumulated in the media with 

 the increasing age of the embryo from which the explants were 

 taken. Explants from five day embryos gave up very little fat, 

 while explants of sixteen day embryos gave up an enormous 

 amount (figs. 3, 15). Occasionally the number of fat globules 

 was so great as to make impossible the examination of the liver 

 cells. After the first twenty-four hours of cultivation there was 

 no perceptible increase in the amount of free fat in the medium. 



A similar correlation was found between the age of the embryo 

 and the number and size of the fat globules in the liver cells of the 

 growth (figs. 2, 3, 7, 12, 14, 16, 17, 18). The cells of cultures 

 of five day embryos had very few fat globules, some none at all. 

 The cells of cultures of six to twelve day embryos showed in- 



' Lewis, W. H. 1919 Degeneration granules and vacuoles in the fibroblasts 

 of chick embryos cultivated in vitro. Johns Hopkins Hosp. Bull., vol. 30, p. 81. 



