1913] HAWKINS—MALT DIASTASE 285 
pronounced acceleration of starch hydrolysis is shown for all of 
the salts used at different concentrations; the highest acceleration 
found is for iron (291 per cent) and the next highest for calcium 
(269 per cent). Retardation of hydrolysis is shown at high con- 
centrations for all salts excepting sodium chloride and potassium 
chloride. For these two salts a pronounced retarding action (15 
per cent in both cases) is manifest at low concentrations, the great- 
est retardation occurring with concentration m/128. This retarda- 
tion in-weak solution seems not to have been considered heretofore. 
Combinations of two salts are shown to be sometimes more 
and sometimes less efficient in modifying diastatic action than 
are molecularly equal concentrations of their component salts. 
It is thus possible that enzymatic power, the magnitude of which 
is frequently to be related to the concentration of single salts in 
the medium, may in some cases at least be still more highly devel- 
oped than is possible through the influence of single salts, by the 
presence of a properly balanced salt combination. 
Jouns Hopkins UNIVERSITY 
BALTIMORE, Mp. 
