of Diastase of Malt, as modified by various conditions. 59 
all but completely destroyed the ferment by 30 minutes warming at 
40° C. ; 
In conclusion then, we have to notice a greater susceptibility on 
the part of this ferment to the action of acid-proteids and free acid 
than the salivary ferment. Whether this latter point constitutes 
any real difference, it is hard to say, since the apparent increase in 
amylolytic action noted in the presence of traces of free acid in the 
case of saliva (0°0001—-0:0006 per cent. free HCl) involve such small 
quantities as to make the results somewhat questionable,* since such 
very small additions of acid might perhaps be used up by the phos- 
phates or other salts present. But taking the evidence of the results 
and comparing them with results obtained in like manner with the 
diastase of malt, it would certainly appear that the latter is more 
susceptible to the action of free acid than the salivary ferment, 
though both are very readily destroyed by a few thousandths of one 
per cent. of free HCl. 
In other respects, the ferment of malt behaves similarly to the fer- 
ment of saliva; both act better in a neutral than in an alkaline 
solution; proteid matter too, prevents the retarding action of alka- 
line carbonate and thus, as in the case of saliva, the action of a given 
percentage of sodium carbonate on diastase is dependent in part, 
upon the concentration of the fluid and the consequent amount of 
proteid matter present. Neutral peptone, moreover, exerts a direct 
stimulating effect on the amylolytic action of neutral diastase. 
Greatest amylolytic action, as in the case of saliva, is, however, ob- 
served in the presence of proteid matter partially saturated with acid, 
but larger percentages of acid-proteids may cause complete destruc- 
tion of the ferment. The accelerating action of proteid matter is in 
great part due to its power of combining with both acid and alkaline 
carbonate, but in addition we cannot but recognize a direct stimula- 
tion of the ferment, as in the action of neutral peptone on a neutral 
solution of diastase. 
Lastly, it is evident from these results, that diastase taken into the 
stomach must sooner or later be completely destroyed, by either the 
free acid or the large percentage of acid-proteids; but in the first 
stage of digestion, in the absence of free acid and under the protect- 
ing influence of proteid matter the conversion of starch into sugar 
may still go on, though soon destined to feel the effects of the 
gradually increasing percentage of combined acid. 
* See Chittenden and Smith, Trans. Conn. Acad., yol, vi, p. 370, 
