358 Chittenden and Sinith — Diastatic Action of Saliva. 



Still other experiments of the same nature liave sliown like results, 

 and even more marked. Thus, while neutral saliva without peptone 

 converted in one instance 1S"16 per cent, starch into sugar, a like 

 quantity of the normally alkaline saliva (z=0"002 per cent. Na.^Co, in 

 the digestive mixture) with O'l per cent, peptone converted 31'90 

 per cent, starch into sugar. 



Increasing the percentage of carbonate to a point where previous 

 experiment had shown almost complete stopping of the action of the 

 ferment, it was found that O'l per cent, of neutral peptone would, in 

 the above dilution, bring the diastatic action up, almost to that of 

 the neutral saliva. 



Series XIII. 



Thus, 20 c.c. of saliva were neutralized and diluted to 100 c.c, 10 

 c.c. used in each digestion. 



NasCOa 0-005^ NaaCO;, 0-005^ Na^COs 



Peptone, Peptone. 0-10$? Peptone. 



Wt. Cu in one-eighth, 00803 gram. 00181 gram. 0-0708 gram. 



Total amt. sugar, 0-3272 00800 0-2896 



Starch converted, 29-45 per cent. 720 per cent. 26-07 per cent. 



With 0'025 and 0*050 per cent, sodium carbonate, 0"l per cent, 

 peptone availed but little : there was slight diastatic action, but not 

 enough sugar formed to make the determination of it of any value. 

 These results would seem to indicate that one action of the peptone 

 in an alkaline solution is to combine with the alkaline carbonate and 

 form a compound of quite different power: thus, with 0-050 per cent, 

 sodium carbonate a corresponding larger percentage of peptone is 

 required to increase the diastatic power. In addition to this action, 

 however, there is still manifest the direct stimulating action of the 

 proteid matter on the ferment ; seen in one case in the increased per- 

 centage of sugar formed in the alkaline solution over the amount 

 formed in neutral solution by the same saliva under like conditions. 



As to the union of peptone and the alkaline carbonate we have a 

 strong indication of a combination in that the presence of peptone 

 tends to diminish somewhat the destructive action of small per- 

 centages of sodium carbonate in diluted saliva. 



Thus, while 10 c.c. of neutralized, dilute saliva (1 : 5) warmed for 1 

 hour with 0*05 per cent, sodium carbonate converted after neutraliza- 

 tion 25*05 per cent, starch into sugar, the same amount of saliva 

 warmed for the same length of time with the same percentage of 

 sodium carbonate, plus 0*4 per cent, peptone converted after neutral- 

 ization 32*68 per Qent. of the starch. 



