420 AMYLOLYTIC ACTION OF SALIVA. 



From these data it will be seen, as has already been pointed 

 out by Chittenden and Smith, that free hydrochloric acid, 

 especially when it reacts for any length of tune, is destructive 

 to the enzyme of the saliva, even with extreme dilution of the 

 acid. 



With reference to the retarding effect of alkalies upon 

 salivary digestion as ascertained by Kiibel, we recall that 

 Chittenden and Smith * also pointed out the inhibitory reaction 

 in the case of sodium carbonate. But in this instance they 

 likewise emphasize the importance of considering the dilution 

 of the saliva and consequent changes in the amount of 

 proteid present, before any definite statement can be arrived 

 at for definite strengths of alkali. 



In discussing the fate of the saliva in the stomach during 

 digestion, it will hereafter be necessary to take into consider- 

 ation the investigation of Cannon f on the absence of move- 

 ment in the fundus, if the observations on the cat and dog be 

 applicable to other animals and man also. The food is not 

 readily mixed with the gastric juice hi this portion of the 

 organ, and consequently an acid reaction does not develop for 

 some time. Salivary digestion may thus presumably proceed 

 for some time in this region without marked retardation. 



SUMMARY. 



The chief object of this note has been to point out that it is 

 impossible to designate any percentage of acid or alkali which 

 inhibits salivary digestion in a definite degree. The character 

 of the action is dependent also upon the absolute amount of 

 saliva and the attendant variation in the quantity of proteid 

 matter present. Whenever free hydrochloric acid is present, 

 inhibition more or less complete is certain to result. 



* Chittenden and Smith, Studies, etc., p. 33. 

 t Cannon, Amer. Jour. Phjsiol., 1898, i. p. 379. 



