1921] 
KARRER—H-ION CONCENTRATION AND AMYLASE ACTION 93 
with the organism. In Colletotrichum it occurred in the cultures 
having an initial H-ion concentration of Pa 7.0 and a final one 
of Pa 7.9, and in Fusarium in the cultures of P 3-4 which finally 
were Pa 7.2-7.8. The results with Penicillium did not cover 
conditions which were contrast- 
ing enough to furnish any con- 
clusions. 
SUMMARY 
The activity of amylase pro- 
duced by fungi grown in Czapek’s 
solution containing starch and 
having different degrees of acid- 
ity and alkalinity has been stud- 
ied for Fusarium sp., Colletotri- 
chum Gossypii, and Penicillium 
italicum. The activity of the 
enzyme as produced under these 
conditions was measured in 
NaOH-H,PO, buffer solutions 
having H-ionconcentrationsfrom 
Pa 3.0 to Py 11.0. An attempt 
has been made to determine the 
effect of the reaction of the cul- 
ture solution upon the accumu- 
lation of amylase by the various 
organisms. 
From the results obtained the LE $5 T 7 
following conclusions can be Fig. 14. Total action of extra- and 
drawn: intracellular amylase produced by 
Penicillium italicum grown in Czapek’s 
1. A relation, which varies with solution of Pu3.0 (..) and Pu 45 
(—). 
the organism, seemed to exist be- 
tween the H-ion concentration of 
the medium and the accumulation of extra- and intracellular 
amylase. 
2. In Fusarium sp., maximum total accumulation was pro- 
duced in the solutions having an initial of Py 4.5 and a final 
reaction of Py 7.8, whereas in Colletotrichum Gossypii a culture 
