300 BOTANICAL GAZETTE [OCTOBER 
6 similar 50 cc. cultures, having about the same quantities of com- 
bined nitrogen supplied to them, are reported to fix quantities of 
nitrogen all the way from 44.9 to 193.6mg. This discrepancy is 
even more striking if we use the figures in column 10 of her ‘‘ table I,” 
which represent total amounts of nitrogen fixed. Here the results 
for the same 6 cultures as those above referred to vary between 
33-3 and 205.1 mg. LaTHAm’s explanation that this is due to 
passing beyond the optimum or critical point in the supply of 
combined nitrogen in the culture hardly seems satisfactory, espe- 
cially with the scant evidence at hand on this point. Furthermore, 
the great excess in the nitrogen gain over that reported for fungi 
by any other investigator, great even when compared with bacteria, 
would seem to require creditable confirmation before being finally 
accepted. 
It might also be possible to reject some of the earlier work when 
methods of sterilization, inoculation, and pure cultures were so 
poorly perfected. However, the same cannot be said of the pains- 
taking work of FRrorticu (11), TERNETz (19), and others, where 
accurate methods are reported and analytical data are fully given. 
It must be admitted, at the same time, that the weight of negative 
evidence is increasing, and it seems likely that few if any fungi 
will be found to have nitrogen-fixing power, unless, perhaps, it 
may be in the case of the mycorhiza forms, regarding which more 
evidence is much needed. 
This investigation does not seem to add weight to the osaliall 
tions suggested by PENNINGTON of the conflicting results on this 
question, namely, that difficulties with the Kjeldahl method of 
analysis have led to variations in reports, and that differences in 
the strains of fungi used, suggested by THom’s (33) work, might 
have led to different results. As seen from previous data of 
paper, the method of analysis seems capable of giving a limit of 
error which is far less than the differences in the results of differ- 
ent investigators. Such accuracy, however, could not be depended 
upon except in the hands of a skilled chemist, or at least one who 
had acquired considerable practice with the method. As to the 
second explanation, a good deal more work needs to be added to 
that of Taom along the line of modification through different culture 

