208 
Journal of Agricultural Research 
Vol. XXI, No. 4 
The concentration on which the greatest yield of fungous material was 
produced by a certain organism was not necessarily the optimum 
concentration for any of the other fungi. 
(4) The different organisms varied greatly in the amount of glucose 
required to produce 1 gm. of dry weight. Likewise the amount required 
to produce 1 gm. of dry weight of the same fungus differed with the 
concentration of the solution. 
(5) The “economic coefficient” was found to be much higher in many 
cases than that given by Kunstmann and Ono; the maximum of 28.88 
and the minimum of 1.44 being reached by Mucor racemosus on a 30 and 
50 per cent solution, respectively. The highest “economic coefficient” 
for some fungi was on the weaker solutions. Tor other organisms, 
however, the order was reversed. 
(6) Some of the organisms—namely, Fusarium acuminatum, Sclero- 
tium bataticola , and Sphaeronema fimbriatum —had little or no influence on 
the hydrogen-ion concentration. Rhizopus tritici, Diplodia tubericola , 
Mucor racemosus , Penicillium sp., and Botrytis drierea , on the other 
hand, increased perceptibly the acidity of the solution. 
(7) All of the fungi studied grew in solutions with a maximum osmotic 
pressure varying from 81.33 to 101.46 atmospheres. Fusarium acumina¬ 
tum and Mucor racemosus increased the concentration, whereas, the 
other fungi in general decreased it. In a few cases where a consider¬ 
able amount of sugar was consumed the concentration was actually 
increased. In general, the decrease in the osmotic concentration was 
not in proportion to the sugar consumed, so that it is possible that 
compounds such as organic acids, alcohol, etc., were formed from 
the sugar which would themselves influence the osmotic concentration. 
literature CITED 
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