266 BOTANICAL GAZETTE [APRIL 
development of the eggs of Fundulus; and OsTERHOUT,’ working 
with plants, has shown the same kind of antagonism between the . 
salts of magnesium and of potassium. That caJcium and potassium 
influence each other in their effect upon certain bacteria has been 
brought out by Lipman.’ 
In a theoretical consideration of the possible causes of chemical 
stimulation, it is suggested that, since many vital phenomena seem 
to be dependent upon enzymes, it is possible that the influence 
of chemical substances upon the activity of plants and animals 
may be due in some measure to the action of such substances in 
accelerating or retarding enzyme activity. With these ideas in 
mind, it was undertaken to study the relation between the catalytic 
action of some enzyme and the concentration in the medium of 
certain salts, to determine, if possible, whether enzyme catalysis 
is influenced independently by two salts simultaneously present 
in the medium, or whether either salt increases or decreases the 
accelerating or retarding influence of the other upon such catalytic 
reactions. 
__ The studies here reported bear upon this question and were 
carried out in part in the new Laboratory of Plant Physiology of 
the Johns Hopkins University, at Homewood, and in part in the 
Biological Laboratory of the Johns Hopkins University. The 
writer is greatly indebted to Professor BurToN E. LIvINGSTON, 
under whom this investigation was conducted, for his many helpful 
suggestions and criticisms. 
Materials 
The enzyme chosen for investigation was, for practical reasons, 
malt diastase (Merck’s ‘diastase of malt absolute’’), and the salts 
used were chlorides of sodium, potassium, calcium, magnesium, 
copper, and iron (Kahlbaum’s ‘‘chemically pure” salts were exclu- 
sively used). The activity of the diastase was measured in terms 
of the length of time required for it to render a starch paste (of 
washed maize starch) powerless to give color reactions with iodine. 
4OsterHout, W. J. V., The antagonistic action of magnesium and potassium. 
Bot. GAz. 45:117-124. 1908. 
. 
Pe e ‘7 1 14 mmont 
fication by Bacillus subtilis. Bor. Gaz. 48: 105-125. 1909. 
