10 



E. J. LUND 



to remain in a uniform condition, might perhaps account for the 

 visible difference in the vacuoles in this and similar cases. But 

 a conception of this process may more properly be obtained if we 



--v- n 







B 







^^^- 



ly-^ 









7,yac;^iir^ 



B 



Fig. 2 Shows the resorption of the liquid included with the yolk grains during 

 formation of the vacuole. A, food vacuole just separated from base of gullet; 

 B, the same, five minutes after separation. 



Fig. 3 Showing the independence of vacuoles with respect to resorption of 

 liquid contents. The larger Vacuole containing a partially digested Paramecium 

 is not affected by the resorption of the fluid in the vacuole containing the fresh 

 yolk grain. B drawn 5^ minutes after A. 



think of it as a process of imbibition of the liquid by the colloidal 

 cytoplasm, accompanied by changes in the permeability of the 

 vacuole membrane. The problem here must be similar to that 



