EPITHELIAL MOVEMENT 



551 



utmost degree, the cells along the periphery became loose and 

 isolated. 



The appended tables give some examples of the frequency of 

 various types of epithelial movement in plasma (table 1) and in 

 serum (table 2), respectively. 



Fig. 3 Experiment XLIX, 2. Silver impregnation, demonstrating the bound- 

 aries of individual cells. Drawn from a part of actively moving border closely 

 attached to the lower surface of cover-glass. Cultivated in serum; three days' 

 growth. G, advancing border. X 450. 



3. Velocity of epithelial movement 



The velocity of cell movement in vitro exhibits a considerable 

 variation under different circumstances, and, as stated before, 



THE JOURNAL OF EXPERIMENTAL ZOOLOGV, VOL. 26, NO. .3 



