600 



T. J. MURRAY 



aerobic conditions. The process in general proceeds better in 

 richer soils. It is best with the greenhouse type and poorest 

 with the clay. Casein is more easily broken down than blood 

 meal. Blood meal is ammonified to a greater extent under 

 aerobic and anaerobic conditions in sterile inoculated soil than 

 in fresh soil. The soils kept under anaerobic conditions gave a 

 strong disagreeable odor, showing that other processes were 

 going on. This was not noticeable with the soils kept under 

 aerobic conditions. 



Experiment III. Ammonification in solution. Ammonia in milligrams per 100 

 cc. of solution. 



Urea bouillon 



One hundred cubic centimeters of the solutions in 250 cc. 

 Erlenmeyer flasks were inoculated, respectively with 2 grams of 

 soil of each type. One inch of sterile paraffin oil was added to 

 half of them, the other half being kept under aerobic conditions. 



Ammonification in solution goes on under anaerobic conditions 

 as well as under aerobic conditions. The urea is more easily 

 ammonified than the peptone. The ammonification of urea pro- 

 ceeds better under anaerobic conditions than under aerobic con- 

 ditions. The ammonification of peptone proceeds just as readily 

 in the presence as in the absence of air. Larger amounts of 

 ammonia were formed in solution than in soil. 



It was thought that an excess of air might inhibit or increase 

 the amount of ammonia formed. A preliminary experiment was 

 carried out by bubbling washed air through 100 cc. of Dunham's 

 solution inoculated with 2 grams of garden soil (greenhouse). 



