THE COMPOSITION OF THE SOIL 147 



Morrow 1 has shown that the figures for the distribution of 

 nitrogen given by the van Slyke method are unreliable in 

 presence of ferric chloride, which always occurs in soil ex. 

 tracts. Potter and Snyder have studied the amino-nitrogen 

 in soil. 2 



1 Soil Sci., 1918, 5, 163. 



ijourn. Amer. Chem. Soc., 1915, 37, 2219, and Journ. Ag. Res., 1916, 6, 61. 



10 



