EPITHELIAL MOVEMENT 561 



(fig. 1). The movement is of an amoeboid character. As a rule 

 the cells have a strong tendency to cling to their own kind and 

 thus extend in sheets, although under certain conditions active 

 movement of isolated cells is also to be seen. 



In the majority of cultures movement into the medium or 

 along the endothelial surface (or both) takes place according to 

 the consistency of the culture medium. The fact, that the epi- 



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Fig. 8 Experiment 238, 1. Epithelial movement on fibers of asbestos; culti- 

 vated forty hours in serum. At the extreme left cells are to be seen moving 

 along cover-slip. Note the adaptation of single cells to asbestos fibers. X 450. 



thelium moves along the epithelial or endothelial surface is very 

 important from various points of view; such a movement may 

 easily be overlooked in the culture of non-transparent tissue, such 

 as skin. 



In the preparations in which serum is used, no migration of 

 the epithelium into the medium takes place. There is mainly 

 a movement of cells over the tissue, especially on the endothelial 

 surface. 



