12 
bean cake meal, cottonseed meal, and linseed meal were almost the 
same, being equal to 34.1 per cent of the total nitrogen added. Thus 
it is shown, in common with the findings of others, that the carbon 
nitrogen ratio may greatly affect the accumulation of ammonia in 
soils. 
The low yields of ammonia in the presence of carbohydrates have 
been attributed to stimulation of the ammonia-consuming organ- 
isms, whereby ammonia is reconverted into organic forms, and to the 
formation of metabolic by-products, probably of an acid nature, 
which exercise an inhibitory influence on ammoniflcation; but, as 
shown by Lipman et al., 1 the depressing effect of carbohydrates 
can not be prevented by adding calcium carbonate. It is probable 
that the energy derived by the ammonifying organisms themselves 
from the nonnitrogenous matter is of considerable importance. It 
is true these organisms can satisfy their energy requirements from 
amino compounds of various sorts, but it does not follow that a part 
of it could not be derived more advantageously from carbohydrates. 2 
The fact that bacteria split off ammonia from nitrogenous substances, 
thus eliminating a portion of the nitrogen present, is in itself evidence 
of their demand for nonnitrogenous matter. 
It should be borne in mind that the nonnitrogenous constituents 
of the above materials were made up of different chemical compounds 
including fats and carbohydrates. The exact effect of fats is not 
known, but different carbohydrates produce widely different effects. 
In general, soluble carbohydrates more markedly depress ammonifl- 
cation than insoluble forms. 3 The nature of nitrogenous constitu- 
ents in these materials also differs considerably, and the rate at 
which they undergo hydrolysis, with the exception of casein, has not 
been extensively studied. As will be shown later, the products of 
acid hydrolysis vary considerably. Since hydrolysis is probably 
essential as preliminary to ammoniflcation 4 any differences in the 
rates of hydrolysis would probably be reflected in the rates of ammoni- 
flcation. 
SERIES VI AMMONIFICATION WITH VARYING AMOUNTS OF CASEIN. 
In the preceding series the yields of ammonia from practically the 
same amounts of casein varied from 50.2 per cent to 56.9 per cent of 
the total nitrogen added. In the following series the concentration 
-of casein was varied and the same amounts of soil and calcium car- 
bonate were used throughout. For the purpose of reducing evapo- 
i New Jersey Stas. Rpt. 1911, pp. 193-212. 
2 See J. G. Lipman et al., New Jersey Stas. Rpt. 1909, pp. 166-169. 
a See Lipman et al., New Jersey Stas. Rpt. 1911, pp. 193-212. 
< The fact that peptone has frequently been found to ammonify more rapidly than dried blood or cotton- 
seed meal may be due in part to its being a partially hydrolyzed substance. 
