July 17, 1916 Influence of Calcium and Magnesium on Plant Growth 607 



magnesium as was added in the seed. Now, in pots 199 to 202, where 

 a small amount of easily available calcium had been applied, the per- 

 centage in the plants was materially increased. 



Attempts were made to grow wheat and cowpeas in paraffin, so that 

 they would have no access to calcium and magnesium. However, this 

 permitted but little growth, and analyses of the total plants thus grown 

 showed their calcium and magnesium contents to be equivalent to the 

 amount present in the seed. 



TABLE XIII. Analysis of wheat and soybeans grown in extracted sand series K 



SOYBEAN PLANT 



WHEAT PLANT 



a The containers in this series were tall Jena beakers holding 1,350 gm. of sand. 



From Table XIII it can be seen that the plants contained more calcium 

 and magnesium than was added in the seed, thus showing their power 

 to obtain these two elements from sand that had been previously extracted 

 with acid. 



