Chittenden and Smith — Diastatic Action of Saliva. 355 



the action of the ferment and not to its destruction. On the other 

 hand, 0-3 and 0-5 per cent, sodium carbonate under like conditions 

 and with the same strength of saliva cause a marked destruction of 

 the ferment, as the results of experiments 4 and 5 plainly show. 



We have repeated the above series of experiments with a saliva, 

 neutralized and diluted 5 times, using in each experiment 10 c.c. of 

 the diluted fluid, equal to 2 c.c. of the original saliva. The only 

 otiier deviation from the conditions already given consisted in wai'm" 

 ing the saliva with the alkaline carbonate for 1 hour instead of 30 

 minutes. We will not give the details of the experiment, as the 

 results were mostly negative. With this amount of saliva, 0-15 per 

 cent, sodium carbonate almost completely destroyed the ferment 

 in 1 hour's warming at 40° C, and even 0*05 per cent, of the alka- 

 line carbonate showed under these conditions a very great destruc- 

 tive action ; thus, after heating the diluted saliva with 0*05 per cent, 

 sodium carbonate for 1 hour at 40° C, and then neutralizing the 

 mixture it was able in 30 minutes to convert but 5*69 per cent, of 

 starch into sugar, while the same quantity of saliva simply warmed 

 with water, converted under like conditions 27'08 per cent, of starch 

 into sugar.* Under these circumstances, then, the destructive action 

 of dilute sodium carbonate is very great. To what is due this great 

 difference in the action of sodium carbonate of the same strength ? 

 Probably to the presence of the larger amount of albuminous matter 

 which in the less diluted saliva possibly combines with the alkaline 

 carbonate. It would follow, moreover, from our results, that any 

 proteid compound formed, has in itself no destructive action on the 

 ferment, even to a slight extent. 0*005 per cent, sodium carbonate 

 causes no destruction of the ferment in 1 hour's warming at 40° C. ; 

 that is, in saliva of this dilution. 



Influence of proteid matter on the diastatic action of saliva in 



nentral sohitions. 



It was formerly demonstrated by one of usf that the presence of 1 

 per cent, peptone tended to increase the diastatic action of saliva in 

 a neutral solution to such an extent that on an average about 4 per 



* The amount of destruction produced in saliva of this solution by the above per- 

 centage of sodium carbonate does not appear to be constant, since we have found in 

 several cases a much greater diastatic action after an hour's warming at 40° C. 

 than in the above instance, due prol)ably to the larger amoimt of ptyalin or proteid 

 matter present. 



f Chittenden and Kly, Amer. Cliem. .Jour., vol. iv, 107. 



