298 RUTH STOCKING LYNCH 



Tn twent3'-eight cultures made from embrj^os varying from 

 six to twelve days' incubation an unusually large amount of 

 debris was present. These cultures included ten planted in 

 media without any stain, nine planted in trypan blue media, 

 eight planted in media containing both trypan blue and neutral 

 red, and one in a neutral red medium. The cultures showing 

 debris were usually discarded on the third day after planting 

 as worthless for liver cell growth. They seldom showed growth 

 of any kind, still more rarely any growth of liver cells. One 

 culture showed a good growth of liver cells which was finally 

 entirely hidden by debris. 



In eight sets plants were made of the subcutaneous tissue of 

 the same embryo from which the liver tissue was taken and 

 planted at the same time in the same media, for comparison with 

 the liver in regard to the occurrence of debris. These sets were 

 made from embryos of seven to twelve days' incubation and the 

 tissues were washed in three dishes of media before planting in 

 order to remove all free blood. Sixty-three per cent of the liver 

 cultures and ten per cent of the connective tissue cultures showed 

 debris. In the liver cultures the debris, which was often present 

 on the first day after planting, increased with the age of the cul- 

 ture. In the five connective tissue cultures in which it was 

 present on the first day after planting, no increase in amount 

 occurred as the culture aged ; on the contrary, no debris was to 

 be found on the second day after planting in any of these five 

 cultures. 



This debris behaves in man}' respects like fibrin but we are still 

 uncertain as to its exact nature. 



SUMMARY 



Cultures were made from the liver of chick embryos from 

 5 to 18 days' incubation. The best growths were obtained from 

 embryos of 5 to 12 days. No liver cells proper were obtained 

 from embryos older than 1() days. 



Four types of cells (liver cells, endothelial cells, mesothelial 

 cells and wandering cells) migrated out from the explants in 

 varying numbers; some cultures contained only one, or two, or 

 three types. 



