270 BOTANICAL GAZETTE {APRIL 
is not proportional to the original amount of starch. The present 
investigation is therefore not directly comparable with such investi- 
gations as those of KjELDAHL,? KELLERMAN,”? McGuIcaAn," and 
others, who measured diastatic activity by determining the amount 
of a reducing sugar formed in a given time. For a more complete 
bibliography on the effects of salts on diastatic action, the reader 
is referred to EFFRONT,” GREEN,™3 OPPENHEIMER," EULER," as 
well as to the literature cited here. 
Experimentation 
The water, diastase, and starch used in this work were tested 
for neutrality in the course of the investigation, and it was found 
that while the water and starch-paste were neutral to phenolph- 
thalein, the diastase solution was strongly acid, requiring 1.2 cc. 
of o.or normal hydrate to neutralize 2 cc. of the stock solu- 
tion. Thus each tube of mixture as actually used possessed an 
acidity equivalent to 1/1660, or 0.000602 normal. Several series 
were carried out by neutralizing or partially neutralizing (with 
sodium hydrate) this acidity of the diastase, and a strong retarda- 
tion was evident when even a small quantity of the alkali was 
added. Thus the use of 5 cc. of 0.0005 alkali diluted to 20 cc. 
by the addition of the usual amounts of diastase solution, starch- 
paste, and water (reducing the acidity of the mixture to 0.000477 
normal) caused a retardation of 13 per cent as compared with the 
control without the alkali. With a further decrease in the acidity 
to 0.000352 normal, there was apparently but little action of the 
diastase, and when the original acidity was completely neutralized, 
9 KyELDAHL, Recherches sur les ferments producteurs de sucre. Compt. Rend. 
Lab. Carlsberg 1: 109-157. 1879 
% KELLERMAN, Kart F., The effects of various chemical agents upon the starch- 
converting power of taka diastase. Bull. Torr. Bot. Club 30:56-70. 1903. 
™ McGuican, H., The relation between the rg corned of salts and 
their antifermentative properties. Am. Jour. Physiol. 10:444-451. 
1 EFFRONT, JEAN, Enzymes and their applications. SR s ae New 
York. 1902 
%3 GREEN, J. REYNOLDS, The soluble ferments and fermentation. Cambridge 
University Press. 1901. 
14 OPPENHEIMER, Kart, Die Fermente und ihre Wirkungen. Leipzig. 1910. 
15s EuLer, Hans, Allgemeine Chemie der Enzyme. Wiesbaden. 1910. 
