34 CELLULAR 



5.43 to I. In the case of large cells in tap water, 

 however, they report that sodium and potassium 

 were more nearly equal, and in small cells in 

 culture solution sodium predominated over 

 potassium. 



In these cases the sap could be extracted with- 

 out contamination or alteration. Where this is 

 not possible we cannot be sure of its composition. 

 Ordinary ash analyses, made without extracting 

 sap, do not tell us whether substances are present 

 in soluble or insoluble form, whether they are 

 located within the cell or in intercellular spaces. 

 But such analyses may nevertheless give us some 

 idea of the general situation. 



Ash analyses show a decided predominance of 

 potassium over sodium throughout the flowering 

 plants and mosses. In the case of marine algae 

 such analyses frequently show a preponderance 

 of sodium over potassium, but this might be due 

 to sea salts held in the cell walls or adhering to 

 the surfaces of the plant. 



The analyses of animals are less consistent 

 than those of flowering plants but in the major- 

 ity of cases potassium seems to predominate over 



