BY R. GREIG-SMITH. 



Experiment iv. 



745 



Milligrams of naphthalene added 

 to 100 grams soil. 



Ammoniacal nitrogen formed from 2 grams 

 of dried blood in 6 days; milligrams. 



None. 



1 



10 



50 



250 



60 

 60 

 58 

 35 

 23 



It is clear, that when 1% of dried blood is contained in soil, 

 naphthalene acts as a depressant, so far as ammonification is con- 

 cerned. In the experiments with soil and naphthalene, the latter 

 showed itself to be an accelerant of bacterial growth, and, in- 

 ferentially, of the rapidity of decay. The sets of experiments 

 are, therefore, at variance. In an endeavour to find the cause of 

 the variance the following was obtained. 



Experiment v. 



Milligrams of naphtha- 

 lene added to 100 

 grams soil. 



Ammoniacal nitrogen 



formed from 2 grams 



dried blood in 4 days 



at 21°; milligrams. 



Bacteria in millions per 

 gram of dry soil. 



The result shows that, under the conditions of the experiment, 

 there is no difference in the bacterial counts; and that, in the 

 presence of dried blood, the stimulating action of naphthalene is 

 not evident. 



As it would be interesting to know what ammonification occurs 

 when unmanured soil is used, a similar experiment, without the 

 blood, was made. This extended over 14 days, and the result 

 showed that no ammonia had been formed from the organic 

 matter of the soil; that is to say, no ammonia was detected, 

 upon distilling the soil-extracts with magnesium oxide. In 



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