ES eg Se 
1913] HAWKINS—MALT DIASTASE 279 
In the present study with ferric chloride, at a concentration of 
m/4096 an acceleration was found slightly higher than any obtained 
with the various concentrations of copper and of calcium. It is 
interesting to note here the high concentrations of copper that are 
favorable to diastatic action, in comparison with the great toxicity 
of this salt toward plants as observed by KAHLENBERG and TRUE,”4 
STEVENS,”> DuGGar,”® LIvVINGSTON,”’ and others. 
A comparison of the different degrees of the acceleration of 
diastatic action resulting from the presence of the various salts 
used singly brings out the point that the effects of potassium 
chloride and of sodium chloride are much the same; which is in 
agreement with the work of KUEBEL, GRUTZNER, COLE, WOHLGE- 
MUTH, and others, for extract of pancreas and salivary diastase. 
Calcium chloride, as shown in the tables, accelerates more than do 
the salts just mentioned and also more than does magnesium 
chloride. This is not in accord with the results of WoHLGEMUTH, 
who, however, used only a single concentration of calcium and 
magnesium chlorides, this being the optimum concentration for 
sodium chloride as he found it, a consideration which probably 
accounts for the discrepancy here mentioned. 
EFFECT OF SALT COMBINATIONS 
The average ratios of diastatic efficiency furnish a means for 
attacking the problem which led to the present studies, whether 
or not two salts simultaneously present in a mixture influence 
each other’s effects on starch hydrolysis. While the data obtained 
in these experiments are not sufficiently complete to warrant. 
quantitative consideration of this problem, several points are at 
least qualitatively indicated. It is apparent that, since different 
concentrations of the same salt produce markedly different-effects 
* KAHLENBERG, Louis, and TruE, RopNey H., On the toxic action of dissolved 
salts and their electrolytic dissociation. Bot. Gaz. 22:81-124. 1896. 
*s STEVENS, F. L., The effect of aqueous solutions upon the germination of fungus 
Spores. Bor. Gaz. 26:377-406. 1898. 
UGGAR, B. M., vhanieoees ree nore ae reference to the germination of 
certain fungus spores. Bort. Gaz. 31:38-66. 190 
77 LIVINGSTON, Burton Pa peeran i of a green alga. Bull. 
Torr. Bot. Club 32:1-34. 1905. 
