1921] 
MATSUMOTO—SPECIALIZATION IN RHIZOCTONIA 31 
With respect to the nutritive value of the media used, P1 and H 
grew best on casein, peptone, and asparagin, and less on legumin, 
while P7 grew best on peptone, legumin, casein, and asparagin 
in the order named. P4 grew best on peptone and casein, show- 
ing no apparent difference between the two, and much less on 
legumin and asparagin. This series of experiments was per- 
formed during the earlier part of the investigation. "Therefore 
the strain B1 had not then shown a high capacity for growth on 
liquid media. "The result with this strain on casein was, however, 
peculiar. B3 was also unable to grow well on any of the media 
with the exception of casein. As a whole, casein was the most 
desirable food material for the various strains. Amygdalin, on 
the other hand, was unsatisfactory as a source of nitrogen, thus 
bearing out, as far as this experiment may, Nageli’s supposition 
that nitrogen cannot be assimilated when in direct combination 
with carbon. Nevertheless, Pfeffer (799) found that certain 
fungi were able to grow when supplied with nitrites and might 
even obtain their nitrogen from amygdalin or potassium cyanide. 
Caffeine was not utilized by any of the strains. 
With respect to the nutritive value of nitrite and nitrate, 
Pfeffer also states that nitrites are assimilated by nitrite bacteria 
only, but that they do not serve as a source of nitrogen for mould 
fungi; yet Winogradsky's observations are not in accord with 
this view. Many investigations have been made on the compara- 
tive value of nitrate and ammonia compounds. It has also been 
observed that the nitrogen requirements of certain fungi may 
depend largely upon the source of carbon. For instance, as 
shown by Fischer, Bacillus coli may utilize nitrate in the presence 
of glucose, but if glycerin is substituted for glucose it does not 
thrive on nitrate. In the case of Aspergillus Czapek showed 
that the amino acids were preferable to peptone in the presence 
of glucose. 
Although I have not been able to pursue extensively a study 
of this interesting subject as it relates to Rhizoctonia, the follow- 
ing data are interesting as far as they go. In a solution con- 
taining 2 per cent maltose, .025 per cent magnesium sulphate, 
and .025 per cent potassium monophosphate, there were dis- 
solved in different flasks potassium nitrate, potassium nitrite, 
and potassium cyanide to make concentrations of 5/100 M. 
