(510 ) 
found as maximum temperatures for Saccharomyces sphaericus about 
60° C., for Phajus grandiflorus 67°, and for emulsine 70° C. 
After this the optimum temperatures for the enzyme action were 
fixed, for Indigofera by searching between 55° and 65° the maximum 
intensity of indigo-formation, testing all temperatures from 55°, 57°, 
59° C. and so on. The strongest inversion was found at 61° C. 
both for powdered crude enzyme and for enzyme-solution in 10 pCt. 
common salt and 10 pCt. calcium chloride. Changes in the degree 
of alkalinity or acidity within the narrow confines between which 
enzyme action is at all possible, deplace the optimum temperature but 
little). A difference in temperature of 1°C. was only to be observed 
between 61° and 62°; at 62° C. the decomposition was certainly a 
little feebler, but between 60° and 61°C. there existed some doubt. 
At lower temperatures distinct differences in the intensity of the 
decomposition could only be noted at intervals of 2° C. 
The enzyme of Polygonum, examined in the same way between 
35° and 45° C., gives the most copious production of indigo at 
42° C., with a rapid decrease in action above, a slow one below 
that point. 
1. Indigofera. 
. Phajus. 
. Polygonum. 
me O9 DO 
. Saccharomyces 
sphaericus. 
5. Emulsine, 
') Mr. van DerLpeN found upon addition of acid both for Indigofera and Polygonum 
a rising of 1° in optimum, which however disappeared when the employed solutions 
of crude indican were diluted with an equal volume of water and then, before the 
addition of enzyme, were brought to the same acidity. 
