16 
by hydrolyzing the humus precipitate. The results are shown in the 
following table: 
Amid nitrogen in humus. 
Solutions 
slightly 
acidified 
and 
evaporated 
before 
distillation. 
Per cent 
of soil. 
Solutions 
slightly 
acidified. 
No evapo- 
ration. 
Per cent 
of soil. 
Not pre- 
cipitated by 
HCl. (a). 
Per cent 
of soil. 
Precipi- 
tated by 
HCl. (b\ 
Per cent 
of soil. 
Total. 
Soil No. 
a+b. 
Per cent 
of total 
soil 
nitrogen. 
Per cent 
of 
humus 
nitrogen. 
317 
0.100 
.073 
.059 
.039 
.033 
.025 
.020 
.026 
.009 
0.087 
.073 
.052 
.028 
.026 
.018 
.020 
.017 
.012 
0.095 
.074 
.056 
.040 
.031 
.022 
.025 
.014 
.008 
0.073 
.056 
.061 
.020 
.027 
.016 
.018 
.023 
.011 
0.168 
.130 
.117 
.060 
.058 
.038 
.043 
.037 
.019 
13.54 
16.88 
19.76 
13.15 
16.38 
17.43 
19.54 
18.97 
15.57 
21.70 
428 
22.03 
379 
26.65 
406 
26.55 
447 
26.98 
345 
25.85 
343 
33.86 
405 
42.53 
292 
32.76 
16.80 
28.77 
The relatively high percentages of amid nitrogen obtained from the 
original humus solutions is noteworthy, as is also the fact that the 
nitrogen bodies not precipitated by hydrochloric acid contained 
practically all of the amid nitrogen existing as such in the humus 
solution. On an average, the hydrochloric acid precipitate yielded 
upon hydrolysis practically the same amounts of amid nitrogen as 
were contained in the original humus solutions. The total amid 
nitrogen contained in the humus, when calculated to the percentages 
of the total soil nitrogen, presents some variation, and on the average 
amounted to 16.80 per cent of the total soil nitrogen. When such 
data were calculated to the basis of the humus nitrogen it was found 
that the relative amounts of amid nitrogen contained increased with 
a decrease in the humus nitrogen. In other words, relatively greater 
amounts of amids occurred in soils which contain a low percentage of 
humus nitrogen. This may be purely a coincidence, but is probably 
due to the fact that either in the preparation of the humus solution, 
or in the process of determining the amid nitrogen in it, a certain 
amount of hydrolysis took place which would tend to markedly 
increase the relative amounts of amid obtained from those humus 
solutions containing the smallest amounts of nitrogen. On an 
average, 28.77 per cent of the humus nitrogen was found to be present 
as amids. It will be recalled that the amid nitrogen obtained upon 
hydrolyzing the soils as a whole amounted to considerably smaller 
percentages of the nitrogen dissolved. 
BASIC NITROGEN. 
The basic nitrogen bodies in humus were determined by the phos- 
photungstic acid method, as already outlined. The results are re- 
corded in the following table: 
