(511) 
For aethyl-acetate-yeast the optimum lies at 44°, for Phajus at 
53° C., and for emulsine at 55° C.?), 
Particularly for emulsine the intensity of action is feeble, and the 
feebler it is, the more troublesome exactly to fix the temperature- 
optimum, as is clearly shown by the course of the curved line in 
the graphic representation. 
For the exact determination of the shape of the curved line 
which indicates the general relation between decomposition and tem- 
perature, temperatures above and below the optimum were sought, 
at which the quantities of indigo, formed after an hour’s action, 
were quite the same. In a_ system of coordinates with the 
temperatures as abscisses and the intensity of decomposition as 
ordinates, these points have then equal ordinates and by determining 
some such couples the whole course of the curve becomes known. 
When looking at the curves found in this way we see that 
the decrease of action above the optimum is much more rapid than 
the rising below and that the last rising is not proportioned to the 
temperature. 
At the same temperature the indican-decomposition by the various 
enzymes is operated with very unequal intensity. Proportionate ciphers 
between them were fixed as follows. In the experiments described 
before, so much of the enzymes to be compared was added to 10 ce. 
of indican-solution that at the optimum temperatures effects of equal 
intensity were observed. This proved to be the case when use was 
made of the following quantities of crude enzyme in milligrams: 
Indigofera 5, Polygonum 20, Saccharomyces sphaericus 40, emulsine 
100, which numbers stand to one another as 1:4:8:20. When all 
these quantities were doubled or reduced to the half, the propor- 
tions underwent no change. Consequently from these numbers follows 
that the intensity of decomposition for the different enzymes is ex- 
pressed thus: Indigofera 20, Polygonum 5, aethyl-acetate-yeast 2.5, 
emulsine 1. In the graphic figure the length of the ordinates is 
taken proportionately with these numbers. 
So we find that the curve of the Polygonum-enzyme is about 
uniform with that of the much stronger enzyme of Indigofera, but 
at O° C. they cross each other, so that at a still lower temperature 
the action becomes an inverse one. 
The great difference in intensity of action is also proved by the 
fact, that, for the manifest appearance of indigo in 10 cc. of the 
1) As is seen, the difference between the optimum and maximum temperature 13 
for all enzymes about 14° C, 
