and Toxic Agents on the Amylolytic Action of Saliva. 67 
and Eves* make this divergence of action of one and the same sub- 
stance a ground for questioning the accuracy of such a view, for, say 
they, “since 0°0015 per cent. HCl decreases amylolytic action it 
seems very unlikely that 0°0005 per cent. should increase it.” The 
action of many neutral salts here experimented with, where both 
stimulation and retardation are obtained, plainly show that such a 
double action, dependent simply on quantity is not an impossible one, 
Stannous chloride. 
With this salt very marked results were obtained as follows: 
Total amount Starch 
SnClo Wt. Cu in ¥. reducing bodies. converted. 
0 0:1475 gram. 0°3004 gram. 27°03 per cent. 
0°0003 per cent, 0°1582 0°3232 29°08 
0°0010 The solution became clear, but no reduction. 
0°0050 The starch was not at all altered in appearance. 
Here there is stimulation, followed by rapid and complete stopping 
of amylolytic action. 
Zine sulphate. 
ZnSO4+7H20. Wt. Cu in ¥. roifouies Bodies: conentad: 
0 0°1495 gram. 0°3048 gram, 27°43 per cert. 
0:0003 per cent. 071490 0°3040 27-36 
0°0005 0°1510 0°3088 27°79 
00010 01475 0°3004 27°03 
0°0020 0°1440 0°2936 26°42 
0°0050 0°1360 0°2772 24-94 
0°0100 0°1260 0°2576 23°18 
0 071375 0:2800 25°20 
0°05 per cent. 00775 0°1480 13°32 
0°10 0-0650 0°1332 ; 11°98 
0°30 0°0450 0°0936 8°42 
0:44 0 
These two series of experiments plainly show a gradually dimin- 
ished amylolytic action, as the percentage of the zinc salt is in- 
creased, until with 0-4 per cent. a complete stoppage is effected. 
Kjeldahl+ found a like retarding action on the addition of zine 
sulphate to a malt extract. 
In this connection it is interesting to note that Sternberg} finds 
zinc sulphate devoid of germicide value, even when used in the 
proportion of 20 per cent. 
* Journal of Physiology, vol. iv, No. L. 
+ Jahresbericht fiir Thierchemie, 1879, p. 382. 
¢ Amer, Jour. Med. Sciences, April, 1883, p, 330. 
