No. «. 



DEPARTMENT OF AGRICULTURE. 



335 



or amides, which in part become converted into ammonia. Thus 

 it may be said that ammonia production is almost a universal func- 

 tion of bacteria. 



In the following table is shown the production of ammonia by 

 several common species of soil bacteria grown in beef broth at room 

 temperature: 



Table III. 



IBS 



^ c 



<u b 



aj p p 



* S 



JO O 





Bacterium mycoldes 



Bacillus subtills, 



Bacillus pulvinatus — 



Variety A 



Variety B 



Bacillus No. 6 



Bacillus No. 7, 



Microspira temfls 



Bacterium fermentatlonis. 



9.18 

 6.4S 



1.02 



0.30 

 2.40 



0.30 



20.06 

 18.35 



10.20 

 6.78 

 6.44 



19.72 



8.50 



45.60 

 46.20 



18.30 

 22.00 

 38.10 



27.90 



21.0 

 21.4 



8.4 

 10. J 

 17.6 



12.9 



In the above table it is seen that the highest quantity of am- 

 monia was produced by Bacteriurn mycoides and Bacillus subtilis, 

 the latter organism converting 24.4 per cent, of the total nitrogen 

 of the medium into ammonia in thirty days. Both of these species 

 are abundantly and constantly present in soils, and are important 

 factors in the ammonification of organic matter. 



It is also noted that there is a marked difference in the ability of 

 the different species studied to produce ammonia, and in the rate of 

 its development; one form Microspira tenuis producing none after 

 a period of thirty days. Complete absence of ammonia production is 

 however the exception. 



( 5 . ) Nitrification. 



The subject of nitrification is one which has received a large share 

 of attention from scientific men, and the literature thereon is very 

 voluminous, extending over a period of twenty-five years. 



In 1871-75, Sir J. H. Gilbert found that the drainage waters from 



