1921] X 
KARRER—H-ION CONCENTRATION AND AMYLASE ACTION 65 
initial activity of malt amylase was found to be in a solution 
neutral to methyl orange, but a solution alkaline to this indicator 
showed maximum total digestion of starch to maltose and glu- 
cose. Fernbach and Wolff (06), working along the same line, 
found maximum amyloclastic and saccharogenic activities in 
solutions neutral to methyl orange. A secondary phosphate 
added to these solutions caused a depression of activity, while 
a primary phosphate produced either no effect or slight acti- 
vation. The latter effect was ascribed to a failure to secure 
complete neutrality in the control solution. An analysis of 
their conclusions will show that the results are compatible with 
more recent work, since the range of color change in methyl 
orange is from about Px 3 to Px 5. 
Kellerman (’03) studied the effects of various chemical agents 
' upon the activity of Taka diastase by determining the reduction 
of the solutions with Fehling’s solution. He concluded that 
at a concentration of N/10 all of the inorganic acids employed 
completely checked the activity. A dilution of N/1000 gave 
marked acceleration. The results with malt diastase were 
somewhat different in that acceleration did not occur until an 
N/5000 dilution was reached. Organic acids gave, in general, 
results similar to inorganic acids, but malic and acetic acids did 
not completely check hydrolysis at N/10 dilution. Acetic 
acid gave no acceleration until a dilution of N/2500 was reached. 
These differences were not explained by the author, but were, 
no doubt, due to differences in the ionization of the acids. With- 
out any exception, the alkalis used seemed to be detrimental or 
slightly so, even up to N/10,000 dilution. 
Cole (703) reached the following conclusion as to the activity 
of ptyalin: “The hydrolysis of starch is accelerated by the 
presence in the solution of electro-negative ions (anions) other 
than OH ions and depressed by electro-positive ions (kations) 
and by hydroxyl ions." For example, the chlorine ion in HCl is 
the factor which increases the action, and in low concentration of 
acid the depression due to the H ions is not sufficient to show 
itself against the acceleration of the chlorine ions. Although 
his conclusions seem to be based upon insufficient data in some 
instances and his interpretations do not altogether agree with 
recent researches, he demonstrated that a low concentration of 
