1918] Waynick: A Statistical Study of Nitrification in Soil 269 



Attention is called to the fact that variations in other products of 

 microorganic activity and in the chemical constituents of different 

 samples of the same soil may be as large or even larger than those found 

 in the present study; and that a much more comprehensive study of 

 variability than the one herein reported is now being carried out. 



The writer wishes to express his indebtedness to Dr. C. 1>. Lipman 

 for suggestions offered during the progress of the work, and to Dr. L. 

 I). Batchelor for helpful suggestions in the preparation of the manu- 

 script. Also to Mr. Douglas Wright. Jr.. for aid in taking the samples 

 and in making the calculations. 



'& 



Transmitted April IS, 1918. 



