[Vor. 8 
32 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
To compare the result with that of organie compounds, 0.5 per 
cent casein was used in one flask, likewise one flask without a 
nitrogen-containing compound served as control. Each culture 
flask, Erlenmeyers of 125 cc. capacity, contained 25 cc. of the 
medium to be tested, and the incubator interval was 25 days. 
TABLE XX 
THE GROWTH OF THE STRAINS ON NITROGEN-CONTAINING CULTURE 
MEDIA. THE DECIMAL QUANTITIES REPRESENT DRY 
EIGHT IN GRAMS 
Potassium Potassium Potassium Casei No. N 
nitrite nitrate cyanide — -€ 
Strain 
Mycl. | Sel. | Mycl. | Scl. | Mycl. | Scl. | Mycl. | Scl. | Mycl. | Sel. 
P1 .040 0 .210 2 0 0 .910 3 Negl. 0 
P4 0 0 .050 1 0 0 .240 1 Negl. 0 
P7 0 0 170 0 0 0 .180 0 Negl 0 
B1 0 0 .020 0 0 0 .040 1 Negl. 0 
H .040 0 . 200 2 0 0 .930 3 Negl. 0 
B3 0 0 .020 1 0 0 .220 2 Negl. 0 
It is interesting that P1 and H are able to utilize nitrogen 
in the form of potassium nitrite to a certain extent, while the 
remaining strains can not. The filtrate of the potassium ni- 
trate solution in which P1 and H had grown exhibited a positive 
color test for nitrite. To what extent, however, this reduction 
of nitrate and utilization of nitrite may occur with these fungi 
has not been established. Slight reduction of nitrate was also 
observed in the potassium nitrate cultures infected with P4 and 
B1, but absolutely no reduction took place in P7. A solution 
of 5/100 M of potassium cyanide was rather toxic to all the fungi 
studied. In general, nitrogen in the form of casein would seem 
to be most available. 
The next experiment was made like the preceding, but with 
the following inorganic compounds: (1) 5/100 M ammonium 
nitrate, (2) 5/100 M. potassium nitrate, and (3) 5/100 M am- 
monium nitrate plus 5/100 M potassium nitrate. These com- 
pounds were used with 2 per cent glucose in a mineral solution 
as before. 
