352 Chittenden and Smith — Diastolic Action of Saliva. 



c. Influence of 0"30 per cent, sodium carbonate. 



Saliva alone. Saliva + NazCoa = 30j^. Difference. 



Starch, 40-27 per cent. 10-83 per cent. 29-44 per cent. 



40-23 9-87 30-36 



" 3715 9-52 27-63 



" 38-80 9-79 29-01 



" 37-55 1001 27-54 



" 38-36 9(;0 28-76 



Glycogen, 29-11 693 



The action of the sodium carbonate is here very marked and very 

 constant. 



We have repeated tliis series of experiments in part, varying the 

 conditions only by using neutralized saliva, so that the percentages 

 of alkali present niiglit be exact.* 



It is evident from these results that the presence of a definite per- 

 centage of sodium carbonate will produce approximately a constant 

 diminution in the diastatic action of the saliva. This result, how- 

 ever, is constant only when the saliva acts in the above dilution. 

 Diminish the amount of ferment — or rather dilute the saliva — and 

 then the above peicentages of alkali produce quite a different result. 

 The above results were obtained where the dilution of the saliva was 

 as 1 : 4. Adding now neutralized saliva to the alkaline mixtures of 

 starch and water in such proportion that 10 c.c. of the original saliva 

 are present in 100 c.c. of digestive mixture; i. e., a dilution of 1 : 10, 

 the results are different. 



The following figures were obtained with the above dilution, the 

 mixtures being warmed at 40° C. for 30 minutes. 



Series IX. 



Per ceht. NajCoa. Wt. Cu in one-eighth. Total amt. sugar formed. 



0-0998 gram. 4064 gram. 



0-005 0-0898 0-3(i64 



0-025 0-0437 0-1816 



0-050 0-0277 0-1184 



0-100 0-0182 00808 



0-300 00105 0504 



0-500 0-0091 ()-()448 



* The standard solutions of sodium carbonate were made from the chemically pure, 

 anhydrous salt. 



