50 Chittenden and Cummins—Amylolytic Action 
With 0°5 per cent. neutral peptone. 
Total amount 
Na )CO3. Wt. Cuin 4. reducing bodies. Starch converted. 
0 071388 gram. 0°2828 gram. 25°45 per cent. 
0-001 per cent. 0°1443 0°2942 26°47 
0-002 071431 0°2918 26°27 
0°003 0°1485 0°3030 2°27 
0°004 071404 0°2860 25°74 
0°005 071406 0°2864 25°77 
0-010 071317 0°2682 2413 
It is thus seen that the presence of 0°5 per cent. of neutral peptone 
entirely prevents the retarding action of the several percentages of 
sodium carbonate, except in the last experiment of the series where 
slight retardation is apparent. It is to be remembered here that 
even 0°005 per cent. of sodium carbonate alone, almost completely 
stops the action of the ferment. What at first sight appears to be 
strange in this last series of experiments, is that the first three per- 
centages of sodium carbonate cause a gradual increase in amylolytic 
action over that of the neutral fluid plus like percentage of peptone. 
The explanation of this, however, is quite simple. In studying the 
influence of neutral peptone on the action of the ferment (15 c. ¢. 
malt) it was found that the greatest acceleration of amylolytic action 
was obtained with the smallest percentage of peptone, and moreover 
that ferment action diminished in proportion as the peptone was 
increased. Now peptone undoubtedly prevents the action of sodium 
carbonate on the ferment by combining with it, forming an alkaline 
carbonate-proteid compound, possessed of but little retarding action ; 
hence in the above experiment the first action of the smallest percen- 
tages of sodium carbonate is to diminish the amount of free peptone, 
thus causing slight acceleration; further on, however, the increased 
amount of alkaline-proteid body formed, counteracts the accelerating 
influence of the free peptone, when gradual retardation commences ; 
finally, increase in the percentage of sodium carbonate leads to the 
presence of free sodium carbonate, when amylolytic action comes to 
a sudden standstill. This point being reached, increasing the per- 
centage of peptone prevents the stoppage of ferment action. This 
is well illustrated by the following series of experiments, using larger 
percentages of both peptone and sodium carbonate, but 15 c. c. of 
the malt extract, as before. 
