278 BOTANICAL GAZETTE [APRIL 
contrast with the strong acceleration evident for sodium and potas- 
sium chlorides even at much higher concentrations. The points 
of maximum acceleration for calcium and magnesium chlorides, as 
here determined, occur at a concentration of m/64 for the former 
and of m/8 for the latter. From these points the acceleration 
falls with the gradual decrease in salt content to m/4096 calcium 
chloride, which accelerates but slightly, and to m/8192 magnesium 
chloride, which is apparently without influence. No retardation 
at low concentrations, as in the case of the monovalent salts, is 
here apparent. 
The effect of the salts of the heavy metals on diastatic action 
(with the possible exception of mercury) have not received as much 
attention as those of the alkalies or the alkaline earths, which are 
so uniformly present in the environment of most organisms. From 
table VII it is apparent that the chlorides of iron and copper, as 
used in this investigation, retard diastatic action markedly even when 
present in very smal] quantities. Acceleration occurs in very dilute 
solutions, as compared with the accelerating concentrations of the 
other salts, the region of acceleration being found to lie between con- 
centrations of m/2048 and m/8192 for cupric chloride, and between 
those of m/2048 and m/32,768 for ferric chloride, with maximum 
accelerations at m/2048 and m/8192, respectively. WOHLGE- 
MUTH,” working with salivary diastase, found that colloidal solu- 
tions of these metals in comparatively dilute concentrations 
retarded diastatic action. He did not find the strong accelera- 
tion which is so apparent in the present investigation, possibly 
because of the fact that his metals were in colloidal condition, 
or because of the few concentrations that he employed. Accord- 
ing to the data here presented, calcium chloride appears to be 
exceptionally effective in accelerating diastatic action, which is in 
accord with the findings of LisBonNE,” working upon the effect 
of this salt in restoring the activity of dialyzed salivary and pan- 
creatic amylases in the presence of demineralized starch. 
23 WOHLGEMUTH, J., Untersuchungen iiber Diastasen. Biochem. Zeitschr. 9: 10~- 
42. 1908. 
23 LISBONNE, MArcet, Influence des chlorures et de phosphates sur la sacchari- 
fication de l’amidon déminéralisé par les amylases salivaire et pancréatique. Compt. 
Rend. Soc. Biol. 70: 207-209. 1911. 
