1913] GODDARD—SOIL FUNGI 279 
the nitrogen-free cultures, and microscopic examination established 
the purity of these growths. 
The fungi tested in this series of investigations include all those 
previously given in the complete list, excepting Mucor stolonifer, 
Penicillium glaucum, P. bicolor, and Trichoderma Koningi. 
In the last four investigations, cultures were submitted to the 
most careful chemical analyses to determine the quantity of nitrogen 
in the culture at the beginning and at the end of the growth period. 
Proper controls were used in each case. 
In all the five investigations above mentioned, the results were 
entirely negative for all the 15 fungi tried, under the conditions of 
the investigations. The highest amount of nitrogen found in any 
culture in a nitrogen-free medium, after the method of analysis had 
been mastered, was 0.46 mg. in a socc. culture. A repetition 
of this culture under essentially the same conditions showed only 
0.11 mg. gain. One other result of 0.31 mg. gain was obtained, 
although the duplicate culture showed a gain of but 0.03 mg. 
Aside from these results mentioned, all the values for the nitrogen 
gain are well within the limits of error of the method. This error 
is somewhere about 0.14 or 0.21 mg. Indeed, it is doubtful if 
results can always be obtained as accurately as this. In the cul- 
tures of investigation V, containing ammonium nitrate, the highest 
nitrogen gain was 0.27 mg. in a socc. culture which contained at 
the beginning 0.22 mg. fixed nitrogen. 
CHEMICAL ANALYSES 
For the chemical analyses, different modifications of the 
Kjeldahl method were employed. In general, these methods were 
in accordance with the official methods of the Association of 
Official Agricultural Chemists of the United States. For nitrate- 
free media, the Gunning method was used, modified by the use of 
copper sulphate, according to the investigations by H1pBaRD (43) 
and in accord with the method used by TERNETZ (19; see HOPPE- 
SEYLER 44). For the analysis of media containing ammonium 
nitrate, the “Official Gunning modification to include the nitrogen 
of nitrates” was used, modified by the use of copper sulphate as in 
