1918] REED—WHEAT SEEDLINGS 377 
has not benefited the plant by excluding sodium, especially in view 
of the amount found in the tops, but rather has rendered it harm- 
less within the plant. 
A second set of cultures was made in which the ratios of sodium 
to calcium were identical with some of those employed by OsTEr- 
HOUT. The pure NaCl and CaCl, solutions were each 0.004M. 
Fic. 1.—Effect of calcium and magnesium salts upon toxicity of sodium chloride 
to wheat plants: culture solutions were jar 1, 4000 p.p.m. NaCl; jar 2, 4000 p.p.m. 
NaCl plus 30 p.p.m. CaSO,; jar 3, 4000 p.p.m. NaCl plus 30 p.p.m. CaO; jar 4, 
4000 p.p.m. NaCl plus 30 p.p.m. Mg(HCQ;),. 
This is much less than the concentration of NaCl employed in the 
first series, being 230 p.p.m. of NaCl instead of 4000 p.p.m. This 
series of cultures was continued for 16 days, at which time 100 rep- 
resentative plants were withdrawn from each culture, weighed, and 
analyzed, giving the data shown in table II. 
