296 RUTH STOCKING LYNCH 



between contiguous cells. Very soon clear, blister-like sacs or 

 blebs began to protrude from the free cell edges and were alter- 

 nately retracted and extended from various parts of the free 

 edge of the cell. These blebs often contained one or more 

 granules in active movement. Meanwhile the boundaries be- 

 tween contiguous cells disappeared and the granular contents 

 of the cell became greatly crowded. Granules in cells at this 

 stage could be stained with neutral red and if previously colored 

 with either neutral red or trypan blue, or both, still retained their 

 color. After a varying length of time (never more than three 

 hours) the neutral red color faded, and if more was added to the 

 culture it was not taken up (figs. 18a, 18e). Very soon after 

 the neutral red faded the blebs disappeared and the cells were 

 left as irregular masses of shadowy granules surrounding more 

 or less misshapen and compressed nuclei. The trypan blue 

 staining was retained for a much longer time than the neutral red. 



WANDERING CELLS 



The wandering cells found in these cultures were usually small, 

 contracted, irregular cells with many clear, pointed processes. 

 Their cytoplasm was packed with fat globules which generally 

 hid all other details. Sometimes a few of these cells were 

 flattened; in these the clear nucleus and many angular granules 

 of all sizes could be made out. In the wandering cells of some 

 of the cultures irregular green masses were also present; these 

 were interpreted as bile granules which the cells had taken up 

 from the degenerating liver cells of the explant. In one culture 

 from an 11 day embryo every wandering cell found on the second 

 day of cultivation contained one or more bright green bodies. 



These macrophagic cells occurred in considerable abundance 

 in the cultures, especially in those which showed little or no 

 growth of liver cells or endothelial cells. They were scattered 

 all through and over the explant and growing edge, and usually 

 many were free in the culture, isolated from the other cells and 

 from each other. They moved about actively, throwing out 

 and retracting their processes. 



