1913] GODDARD—SOIL FUNGI 203 
In table VIII are also included some analyses of the medium to 
determine whether it took up an appreciable amount of fixed nitro- 
gen by remaining exposed to the air of the laboratory. One culture 
was analyzed immediately after being made up, another after 
being kept during the last development period (70 days) under a 
bell jar, to which air could enter only over a U-tube containing 
concentrated H.SO,. A third was exposed for 70 days to laboratory 
air, which could enter freely through the cotton stopper. The 
analyses of these cultures show clearly that no fixed nitrogen, 
which was detectible by the method of analysis, was taken up 
from the air. 



TABLE VIII 
DEVELOPMENT PERIOD 70 DAYS 
Dry wt. of |  Nof Nof | Total N of | N fixation 
No Fungus mycelium | mycelium filtrate culture control) 
mg. mg. mg. mg. mg. 
a 5 . d e 
I BON oe Wee ewan Pale she de lc alco Ue et eae eee fe $2 ee are ana gy 
2 | Myceliophthora......... 3.0 0.07 1.26 1.33 0.15 
3 te) ROCIO fo views i 4 0.07 I.19 1.26 0.08 
4 | Pachybasium........... Fk 0.00 1.12 Tits —o.06 
Bed FONT oe I 0.07 1.26 1.33 0.15 
6 Medium immediately after 
THARING OD ole oe ee a ee eee 10 45-0. 
7 | Medium after standing 1 
med Fe Cat ct, bk a aoe pee ee ee AD aniees 
8 | Medium under bell jar 70 
MAYES 1.50 leat es 







Table VIII shows a further point of some interest, viz., that 
the nitrogen which was shown to be present in the dextrose used 
is not available for the fungi, since approximately the same quantity 
is shown in the filtrates in which fungi have been cultivated as in 
the medium itself before inoculation. F urthermore, the spores 
introduced in inoculation do not add an appreciable quantity of 
nitrogen. 
INVESTIGATION IV 
This was carried out with cultures exactly similar to those in 
the previous investigation; but instead of being aerated, they 
were kept under bell jars from which all air was excluded, except 
that entering through a U-tube containing concentrated sulphuric 
