912 



Journal of Agricultural Research vol. vi, No. 23 



/qooOjOOO 



3,000,000 



6, 000,000 



4,000,000 



a, 000,0 00 



4,000,000 



2,000,000 



/O /S 20 2S SO J& 40 



/MCHES Or WAT£/? APPL/ED 



Fig. 6. — Curves of the number of colonies of bacteria developing from cropped plots 'with varying quan- 

 tities of manure. 



