W. J. V. OSTERHOUT 283 



2. Tests of the cell sap show that in a balanced solution of NaNOs 

 plus Ca(N03)2 there is a slow penetration of NO3 and that the cell 

 remains in a normal condition, but in pure NaNOs there is rapid 

 penetration accompanied by injury. 



3. Inasmuch as determinations of electrical conductivity give the 

 same result it may be concluded that this method gives reliable infor- 

 mation regarding permeability. 



4. While observations on recovery from plasmolysis give similar 

 results, the method is less satisfactory. 



