and Toxic Agents on the Amylolytic Action of Saliva. 83 
power of the four mixtures, expressed in the percentage of starch 
converted, was as follows: 
A. B. Cc. D. 
28°72 22°35 23°04 20°23 
With zinc sulphate, somewhat similar results were obtained: 
A. B. C. 
SENT 2 SO nee ee 2¢c.¢. PONG: 2¢.¢. 
IG OMe ea tise te ee 18 16 16 
PNSOT SON Se sap Seacue 0 2 2 
20 20 20 
Revicenta/Z0 SO, ease = = 0 0°05 0°05 
B was warmed at 40° ©. for 30 minutes and C for 1 hour; then 2 
c.c. of the zinc sulphate solution were added to A, and all three 
~ mixed with starch paste and water to 100 ¢.c. Each now contained 
0°01 per cent. zine sulphate and all three were then warmed at 
40° C. for 30 minutes, to determine the activity of the ferment. A, 
converted 22°24 per cent. of the starch, 6 11°88 per cent. and C 
10°98 per cent. 
These experiments would therefore indicate, on the part of the 
metallic salts experimented with, a destructive action towards the 
ferment, though loss of amylolytic power under the conditions of the 
experiments might also be due to more complete precipitation of the 
ferment in the more concentrated solution and under longer exposure 
to a temperature of 40° C. At the same time it is to be noticed, that 
any metallic-proteid compound formed with the above salts, has a far 
less destructive or retarding action than the free salt. Of these, the 
destructive action of mercuric chloride is most pronounced. 
Potassium permanganate acts, doubtless, by direct destruction of 
the ferment through oxidation, while many of the alkali and alkali- 
earth salts produce their retarding effects by simple clogging of the 
digestive fluid; but the fact that 0°5 per cent. of one salt, as potassium 
antimony tartrate, for example, increases the amount of starch con- 
verted 68 per cent., and 0°5 per cent. of another salt, as magnesium 
sulphate, diminishes the amount of starch converted by 65 per cent., 
plainly indicates that there is something in the presence of these salts, 
dependent upon chemical constitution, that controls the action of the 
ferment. 
