‘THE CONSTITUENTS OF THE ASH OF PLANTS 179 
its molecule. It is probably an indirect effect arrived at 
through faulty nutrition set up in the absence of the metal. 
Fia. 89.—PLants oF BucKWHEAT CULTIVATED IN VARIOUS NUTRITIVE 
SoLvurions, 
1, normal solution containing all necessary salts ; 2, solution containing the same 
salts as 1, except potassium compounds; 3, solution of same composition as 1, 
except that sodium salts have,been substituted for potassium compounds; 4, 
solution of same composition as 1, except that no calcium salts are present ; 
5, solution containing no compounds of nitrogen, 
At first sight it seems as if the absence of inorganic salts 
may be effective by interfering with the maintenance of the 
turgid condition of the cells, as all the compounds men- 
tioned have osmotic properties. It is evident, however, 
it 
