1921] 
KARRER—H-ION CONCENTRATION AND AMYLASE ACTION 79 
either of the other organisms. The best results were obtained 
under acid conditions from Py 2.5 to 4.5. At P4 8.0 only a few 
hyphae were produced from the spores. Visible growth ap- 
peared at the end of about 4 days, and the mycelium grew on the 
surface of the liquid forming a rather thin, felt-like mass. No 
spores were produced in the culture solution having a concen- 
tration of P, 3.0, but there was abundant production in most of 
the natural Czapek’s solution cultures of P, 4.5. 
Amylase activities.—As stated above, the results of the experi- 
ments on amylase activity will be discussed from two stand- 
points: the effect of the buffer solution of various H-ion concen- 
trations upon the activity of the amylase produced in the diff- 
erent culture solutions, and the effect of the H-ion concentration 
of the culture medium 
upon its accumulation in 
the mycelium and the 
culture solution. The 
data will be presented in 
the form of tables, also 
of curves where the ab- 
scissae are the H-ion con- 
centrations of the buffered 
solutions in which enzyme 
activity was measured, 
and the ordinates, the 
cubic centimeters of the 
N/50 KMnO, solution 
which represent the rela- 
tive amounts of starch 
hydrolyzed and therefore 
the extent of enzyme pro- 
duction. As shown in 
)a 
g. 2. Action of extracellular ( an 
intracellular (- - -) amylase produced by Fusar- 
tables r-1v, the results of jum sp. grown in Armée solution of Pg 4.5. 
the inactivated or control 
series were subtracted from the active series in order to produce 
these amounts. The extracellular amylase curve denotes hy- 
drolysis with 2 cc. of culture solution and the curve of intracellular 
amylase with 1 cc. of 2 per cent mycelium dispersion or .02 gm. 
of the powdered mycelium. 
