66 Chittenden and Painter—Influence of Therapeutic 
In a second series, larger percentages were used with the following 
results : 
Total amount Starch 
(NH4)3AsOq. Wt. Cu in 4. reducing bodies. converted. 
0 0-1712 gram. 0°3500 gram. 31°50 per cent. 
0:05 per cent. 071475 0°3004 27°03 
0-10 071147 0°2332 20°98 
0°50 0°0165 0:0368 3°31 
1:00 The solution became clear but no reducing bodies were formed. 
With this salt, a very decided stimulation of the ferment is to be 
observed in the presence of small percentages, while increased 
amounts of the salt ultimately stop diastatic action. 
Potassium antimony tartrate. 
Two series of experiments were tried with this salt, with the fol- 
lowing results: 
Total amount Starch 
K(Sb0O)C4H4Og. Wt. Cu in ¥%. reducing bodies. converted. 
0 0:1540 gram. 0°3144 gram. 28°29 per cent. 
0:001 per cent. 0°1610 0°3288 29°59 
0°005 0°1660 0°3392 30°52 
0-010 0-1760 073600 32°40 
0°050 01760 0°3600 32°40 
0-100 071745 0°3568 31-11 
0°200 0°1750 0°3580 32°22 
0 0°1545 0°3152 28°36 
0°10 0°1850 0:3788 34:09 
0°30 0°1640 0°3352 30°16 
0°50 0°2565 0°5304 47°73 
1:00 0-1570 0°3204 28°83 
2:00 071232 0°2504 22°53 
5:00 0°0470 00976 8-78 
Here we have an illustration, more forcible than with any other 
salt, of the power possessed by many substances of both increasing ~ 
and diminishing the action of the ferment. One* of us has for some 
time held that the addition of very small quantities of hydrochloric 
acid to neutral saliva tends to increase the amylolytic power of the 
ferment; that this takes place even when the proteids present are 
completely saturated with the acid, or in other words when there is 
present a very small amount of free acid, provided the acid-proteids 
are not present in too large an amount. It is well known that free 
hydrochloric acid, when present to the extent of a few thousandths 
of one per cent. completely stops the action of the ferment. Langley 
* Chittenden and Smith, Trans. Conn. Acad., vol. vi, p. 360. 
a 
