CYTOPLASM OF ANIMAL AND PLANT CELLS. 7 



2. Impermeability or partial permeability to water, dyes, and 

 crystalloids is a property of all portions of protoplasmic gels. 



3. The rate of penetration of protoplasm by dyes and crystal- 

 loids is, in general, inversely proportional to the concentration of 

 the living gel. 



4. The best vital stains known penetrate such highly con- 

 centrated protoplasm as the epithelial and striped muscle cells 

 of Nee turns very slowly. 



5. The interior portions of the cytoplasm of the starfish egg 

 and probably the striped muscle cell of Necturus exhibit the 

 same sort of osmotic properties as the surface. 



6. The cell-walls, and not the protoplasm of many plant 

 cells, prevent the entrance of dyes. 



