13 
ration losses, 1 gram of monomagnesium phosphate was al-^o added, 
as recommended by Lohnis and Green. 1 After bringing the moisture 
to about 25 per cent and incubating at 28° C. for four days, the 
ammonia was determined as before with the following results: 
Amount of ammonia formed from varying quantities of casein. 
[Average of 2 samples.] 
Amount of 
casein 
added. 
N found as 
Per cent of 
total N re- 
Amount of 
casein 
added. 
N found as 
Per cent of 
total N re- 
ammonia. 
covered as 
NH 3 . 
ammonia. 
covered as 
NH 3 . 
Gm. 
Mg. 
Gm. 
Mg. 
0.2 
12.0 
48.4 
1.5 
'111.7 
60.1 
.4 
25.5 
51.4 
2.0 
151.0 
60.9 
.6 
43.5 
58.2 
2.5 
192.3 
62.0 
.8 
58.2 
58.7 
3.0 
244.1 
65.9 
1.0 
70.7 
57.0 
1 1 sample only. 
The percentages of total nitrogen recovered as ammonia increased 
as the amount of casein increased, varying from 48.4 per cent with 
0.2 gram to 65.9 per 
cent with 3 grams (see 
fig. 1). Loss of am- 
monia by evaporation 
was not important, 
since the percentage 
yields were greatest 
where the greatest 
concentration of am- 
monia occurred. 
Since almost no nitri- 
fication took place in 
any instance, it seems 
reasonable to believe 
that, as the amount 
of casein added is in- 
creased, a decreasing percentage of the total nitrogen present would 
be consumed by the bacteria and consequently higher percentage 
yields of ammonia be obtained. The yield from 1 gram (57 per cent) 
agrees closely with that recovered in preceding series. 
SERIES VII AMMONIFICATION OF CASEIN DURING DIFFERENT LENGTHS 
OF TIME. 
This series was begun at the same time as Series VI, using the same 
soil. One gram each of casein, calcium carbonate, and magnesium 
phosphate was mixed with 100-gram portions of soil, sterile water 
60 
50 
40 
30 
SO 
/O 
' 
7 O. 
2 
a a 
6 a 
e l 
o /.. 
r ?.< 
? 2. 
5 3.0 
Sj G&AA4S OF CWS£W /=VP£S£NT 
Fig. 1.— Diagram showing the ammonification of different amounts 
of casein. 
i Loc. cit. 
