552 IOiWA ACADEMY OF SCIENCE Vol. XXIV, 1917 
NO. 47. 
Gelatine. 
1 hour. 
2 hrs. 
4 hrs. 
6 hrs. 
Standard 
8.9 
13.2 
15.3 
Gelatine 
15.5 
21.8 
21.4 
Hydrolyzed gelatine 
16.0 
18.1 
22.2 
As the number of free 
amino groups in 
the g 
elatine molecule 
becomes greater the stimulating power appears to increase. 
NO. 48. 
Serum Albumin. 
1 hour. 2.5 hrs. 4.5 hrs. 
Standard 1.8 4.6 7.3 
Albumin 16.1 21.8 24.7 
Hydrolyzed albumin 19.2 24.1 27.8 
This protein acts similarly to the gelatine and its decomposi- 
tion products. 
The amines of the methane series also have the power of stim- 
ulating the digestive power of ptyalin. Three were tried, 
methylamine, CH 3 NH 2 ethylamine, CoH 5 NH 0 and diethylamine, 
(C S H 5 -) S NH. 
NO. 143. 
2 hrs. 4 hrs. 6 hrs. 
Standard 8.5 13.0 15.0 
Methylamine 21.6 24.4 24.4 
Ethylamine .21.1 23.8 24.4 
Diethylamine 21.6 23.9 24.9 
Hence the activating effect is due to the nitrogen and not to 
the NITo as a group, since the derivatives of the group act as 
powerfully as the group itself. Trials were made also with the 
pentavalent nitrogen of the ammonium radical. Both ammonium 
salts of strong and weak acids were employed. 
In all the experiments the reactions of the solutions were made 
neutral to litmus, with the amino compounds as well as with the 
ammonium salts. 
Inasmuch as different samples of saliva were used the results 
from one series cannot be exactly compared with those of an- 
other; consequently several must be given. 
