64 Chittenden and Painter—Influence of Therapeutic 
The hindering action of the copper salt is nearly as pronounced as 
that of mercuric chloride and even more so than the bromide and 
iodide of mercury. 
Lead acetate. 
With this salt, the smaller percentages experimented with show a 
slight stimulating action; but the larger percentages fail to retard 
the amylolytic action of the ferment as the preceding salts. 
Pb(CgH309)2+38Hy,0. Wt. Cuin 4. reine names. Bes 
0 0°1630 gram. 03332 gram. 29°98 per cent. 
0°0003 per cent. 071642 0°3356 30°20 
0:0005 0°1635 0°3340 30°06 
0°0010 071635 0°3340 30°06 
0-0020 0°1595 0°3256 29°30 
0:0050 071395 0:2840 25°56 
0:0100 0°1402 0°2856 25°70 
A second series of experiments, with still larger percentages of the 
lead salt, gave the following results: 
Total amount Starch 
_Pb(C2H302)2+8H,0. Wt. Cu in ¥. reducing bodies. converted. 
0 0°1742 gram. ' 0°3564 gram. 32°07 per cent. 
0°05 per cent. 071735 0°3548 31°93 
O10 cI. 0°1720 0:3516 31-64 
0°30 0°1657 0°3384 30°45 
0°50 ; 0°1555 0°3172 28-54 
1:00 4 0°1375 0°2800 25°20 
3°00 0°0785 0°1600 14-40 
5°00 0:0490 0°1016 9°14 
Thus, the presence of even five per cent. of lead acetate fails to 
completely prevent amylolytic action. 
Arsenious oxide. 
Owing to the comparative insolubility of this substance in neutral 
fluids, small percentages only could be experimented with. With 
these, the following results were obtained : 
Total amount Starch 
As,03. Wt. Cu in ¥4. reducing bodies. converted. 
0 0°1475 gram. 0°3004 gram. 27°03 per cent. 
0-0003 per cent. —0°1507 0°3072 27°64 
0:0005 0°1537 0°3136 28°22 
0°0010 0°1475 0°3004 27°03 
0°0020 0°1579 0°3204 28°83 
0°0050 0°1390 0°2832 25°48 
0°0900 01605 0°3276 29°48 
Although the results obtained do not wholly accord with each 
other they still plainly show that arsenious acid, to the extent pres- 
