LIVER CELLS FROM CHICK EMBRYO 283 



LIVER CELLS 

 Migration 



The time at which migrating cells first appeared varied greatly. 

 In some instances the first cells appeared within 4 hours after 

 planting; in most cases within 24 hom's; in a few not before 48 

 or more hours had elapsed. One culture, which eventually gave 

 rise to an extensive growth, had only a few migrating cells 72 

 hours after planting. There appeared to be some correlation 

 between the age of the embryo and the beginning of growth, the 

 explants from younger embryos tending to show migrating cells 

 earlier than explants from embryos of nine or more days' in- 

 cubation. Trypan blue cultures also were characterized by 

 early and rapid migration of liver cells. These cultures gave 

 extensive growth much more quickly than cultures grown in 

 media without the dye, one trypan blue culture reached the 

 climax of its growth within 18 hours after planting. In most cul- 

 tures the climax occurred 48 to 72 hours after planting; in some 

 cases, however the best growths appeared much later, even as 

 late as 144 hours. 



The best growth of liver cells obtained was 27m wide and 

 occurred 120 hours after planting. It was one of a set of ten 

 cultures taken from an embryo of eight days' incubation, which 

 gave the best growth results in the entire series of experiments. 

 Fresh bouillon was used in making up the Locke-Lewis solution 

 for this set. Of these ten cultures, eight showed extensive liver- 

 cell growth within 24 hours after planting; one showed extensive 

 growth only after 48 hours had elapsed; the tenth showed only 

 endothelium. Of the eight which showed wide growth within 

 24 hours, one was infected while staining with neutral red and 

 had to be discarded, and one did not grow any further. Of the 

 other six, one began to degenerate on the fifth day, four on the 

 sixth day, and the sixth was in fine condition on the sixth day 

 when it was fixed (figs. 19, 20). The one which did not show 

 good growth until 48 hours after planting did not begin to de- 

 generate until the seventh day. In many cultures degeneration 

 began at 72 hours ; in others the cells were in good condition after 



