[Vor. 8 
76 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
vated series. Five cc. of Fehling’s solution, prepared according 
to the standard formula, were added to four of these tubes at a 
time, and the tubes immersed immediately in an actively 
boiling water bath for 10 minutes. 'The amount of reduction 
was determined by the Bertrand method as described by Shaffer 
(14), N/50 KMnO, being used in the titrations. The results 
were all obtained in duplicate. These differed from each other 
by not more than .03 ec. of N/50 KMnO, In all cases the 
H-ion concentrations of the control and active solutions were 
taken at the beginning and end of the period of incubation. 
These were found to remain constant during the time of the 
experiment. The H-ion concentration was shifted somewhat in 
several instances after the enzyme dispersion was added, this 
being due to the presence of alkali or to the presence of salts 
which affected the original buffer solution. 
Intracellular amylase.—The dry fungous mats were powdered 
in a mortar, and 2.5 gms. were again ground with about an equal 
amount of powdered Pyrex glass. The enzyme was extracted 
from this mixture with 125 cc. of doubly distilled water for 12 
hours. An extraction of from 1 to 4 hours was found to yield 
a dispersion of weaker amyloclastic activity. This dispersion 
was filtered and its activity tested at different H-ion concentra- 
tions in à manner similar to that discussed for extracellular 
amylase, except that 44 cc. of the buffer solution, 5 cc. of enzyme 
extract, and 1 cc. of 5 per cent soluble starch were used. The 
enzyme activity was tested exactly as described above. 
Ex AL DATA AND DISCUSSION 
The experimental data will be discussed under the following 
topics: ! 
(1) An analysis of the cultures, embodying the effect of the 
H-ion concentration upon the dry weight of the fungus and the 
effect of the growth of the fungus upon the final H-ion concen- 
tration of the culture solution, together with notes on some 
cultural characteristics of the organisms. 
(2) The influence of H-ion concentration of the NaOH- 
H,PO, solutions upon the activity of the amylase produced in 
culture solutions having different H-ion concentrations. 
(3) The effect of the H-ion concentration of the culture me- 
dium upon the accumulation of amylase. 
