194 
Journal of Agricultural Research 
Vol. XXI, No. 4 
of fungi could thrive in concentrated solutions of glucose ranging from 
1.6 to 2.6 molecular and i.6 and i.8 molecular sucrose. 
With two exceptions the fungi studied by the writers grew on solutions 
of glucose from approximately 42 to 50 per cent concentration. The two 
exceptions, Botrytis cinerea and Sphaeronema fimbriatum, made a fair 
growth on solutions of approximately 38 and 25 per cent, respectively. 
The actual loss in the amount of sugar is somewhat significant and 
differs considerably with the different fungi. The greatest consumption, 
if it may be so expressed, occurs in the 10 per cent concentration. In 
a 10 per cent concentration Diplodia tubericola reduced the percentage 
of sugar from 9.4 to 1.2; Mucor racemosus from 9.4 to 5.2; Sclerotium 
bataticola from 9.6 to 2.2; and PenicUlium sp. from 9.26 to 3.16. In 
general, the percentage of sugar actually consumed by the organisms 
just named decreased as the concentration of the solutions increased. 
On the other hand, Rhizopus tritici and Botrytis cinerea used more sugar 
at the higher concentrations, while Sphaeronema fimbriatum produced 
no change. 
total, amount of glucose present 
Although the study of Table I shows quite clearly that considerable 
glucose is converted by the action of some of the fungi, yet this does 
not show exactly what has occurred, since the figures are expressed in 
percentages and certain factors are not considered. For example, no 
account was taken of the amount of evaporation or of the difference in 
the quantity of solution present in the flasks. Table II shows more 
accurately the amount of sugar remaining in each flask at the end of 
the experiment. These figures were obtained by multiplying the num¬ 
ber of grams of dextrose in each 100 gm. of solutions—namely, per¬ 
centage of dextrose present—by the total number, of grams of the 
medium present and dividing the result by 100. The amount of sub¬ 
strate in each flask was determined by deducting the combined weight 
of the flask and dried fungous growth from that of the solution, flask, 
and mycelium. In the Rhizopus tritici experiment, which was the 
first one conducted, not enough solution of all strengths was prepared 
to permit of the addition of 150 cc. to each flask; hence the control 
flask in some cases contained 100 cc. or even less. This causes what 
would at first appear to be a great inconsistency in the amount of dex¬ 
trose present in the control as compared with that in the inoculated 
flasks. This is especially evident in series VI, where the total amount 
of dextrose in the control was 41.82, while the average for the inoculated 
flasks was 78.74. It is, however, also noticeable in series III, IV, and V. 
