43 
a normal slope, was observed more than once on repeating the same 
experiment at py = 8.13. For instance on July 19th., 1917. Fig. 14. 
Figure 14. 
Vl 
0.6; 
0.5 
0.4 
0.3 
0.2 
0.1 
a SSL 
120 230 300 360 420 480 
minutes. 
10. Influence of the concentration of enzyme. 
In continuing the investigations of part 4 with smaller enzyme- 
concentrations it was first observed, that in the same conditions the 
same quantity of Soja-meal did not always give the same result. In 
preparing the necessary solutions the distilled water had been freed 
from carbonic acid by boiling in a tin coated copper flask. After 
this method of purifying the distilled water had been replaced by 
distilling the water once more in a Jena flask and glass condenser, 
rejecting the first part of the distillate, more regularity seemed to 
be obtained. Still, weighed off in such small amounts, the Soja-meal 
appeared to be not quite homogeneous. An explanation of this fact 
will be brought forward further on. 
Nevertheless important new results could be obtained in this way. 
For the sake of the necessary constancy of py the urea-concen- 
tration in these experiments was again 0,01 °/,. 
Taking the same unit as before the concentration of the urease 
was now 335. 
