May 16,1921 Glucose as a Source of Carbon for Storage-Rot Fungi 191 
gillus and Penicillium grew well on Czapek’s nutrient solution, which 
contains its nitrogen and carbon in the form of sodium nitrate and cane 
sugar, respectively. Young (32) on the other hand, used ammonium 
nitrate as a source of nitrogen and cane sugar as a source of carbon for 
Aspergillus niger to good advantage. 
The results of various workers seem to indicate that no generalizations 
can be made as to the best source of nitrogen and carbon for fungi. 
They rather point to the fact that the various fungi differ in their require¬ 
ments and that the best source of both these elements must be ascertained 
for each organism. 
It is not claimed that the culture medium used for these investigations 
is the best for all the fungi studied. It is likely that a better medium 
might be found for each of the organisms. The nature of the work, 
however, required that the same substrate be used for all the fungi, and 
the modification of Czapek’s nutrient solution as here employed seemed to 
meet the requirements better than any other solution tried. Only one 
organism (Sphaeronema fimbriatum ) failed to thrive well upon it. 
PREPARATION OF CULTURES 
A sufficient quantity of medium was prepared at one time for an entire 
experiment, thus insuring an equitable distribution of the salts. The 
solution was steamed for 20 minutes in an Arnold sterilizer and then fil¬ 
tered to remove a slight precipitate which formed during the heating. 
A definite quantity by weight of this solution was then placed into each 
of seven large beakers, and the required amount of Baker’s C. P. dextrose 
was added to all but one to make approximately the following strengths 
of the carbohydrate: 00, 10, 20, 30, 40, 50, and 60 per cent. The solu¬ 
tions were then steamed in the beakers for 20 minutes and again filtered. 
One hundred fifty cc. of each solution were added to four 300-cc. Erlen- 
meyer flasks previously stoppered with cotton and weighed, thus making 
7 sets of 4 flasks each containing an approximately equal amount of 
solution with six different strengths of dextrose and one without sugar. 
These flasks were reweighed and sterilized by steaming for 20 minutes 
on three consecutive days. 
INOCULATION OF CULTURES 
Three flasks of each set were inoculated with a loop of a heavy spore 
suspension in sterile distilled water or with mycelium from young and 
vigorous cultures growing either on Irish potato cylinders or stems of 
Melilotus alba Desr. The fourth flask in each set not inoculated was held 
as a control. The cultures were incubated in the dark for two weeks at 
about 28° C. Notes were taken on the general character of the growth 
at the end of the first week and again when the experiment was terminated. 
