Chittenden and Smith — Diastatlc Action of Saliva. 359 



The peptone present had evidently in some way prevented the 

 destructive action of the alkaline carbonate, and the most plausible 

 explanation seems to be the probable formation of an alkaline-pro- 

 teid body. 



Influence of free acid and of aeid-proteid matter on the diastatic 



action of saliva. 



The influence of dilute acid solutions on the diastatic action of 

 saliva is naturally a point of considerable physiological importance. 

 In view of the rapid passage of the salivary secretions into the 

 stomach, we need to 'have accurate knowledge of the exact influence 

 of free acid and acid-reacting fluids on the ferment and its diastatic 

 activity. 



In considering this question we do not need now to take into 

 account the older observations of Jacubowitsch, Lehmann, SchilF, 

 Watson, Briicke, Hammarsten and othei's, since these led to no 

 agreement of opinion and more recently acquired knowledge has 

 rendered necessary difl^erent methods of procedure. 



In 1881 it was announced by one of us* that the ferment of saliva 

 was destroyed on being warmed for two hours with gastric juice 

 containing 0'2 per cent, hydrochloric acid; also that the same treat- 

 ment with 0-2 per cent, hydrochloric acid alone caused great destruc- 

 tion of the ferment, so that on neutralization diastatic action was 

 greatly diminished. At the same time it was pointed out that much 

 smaller percentages of acid, even 0-025 per cent.,f diminished the 

 diastatic action of the ferment very materially. Shortly after this 

 similar results were obtained independently by Langley,J who in an 

 interesting paper on the destruction of ferments in the alimentary 

 canal, pointed out that ptyalin from the parotids of a rabbit was 

 destroyed by digestion with a small amount of gastric juice, and 

 also that weak solutions of the ferment were more or less destroyed 

 by heating at 40° C. with 0-014 per cent, hydrochloric acid. In 

 comparing these latter exj^eriments with the preceding it is to be 

 remembered that the former were made with 25 c.c. of filtered human 

 saliva, a much stronger solution doubtless, both as regards the fer- 

 ment and the albuminous matter present. 



Later it was pointed out by one of us,§ that peptones have a very 



* Chittenden and Griswold, Amer. Chem. Jour., vol. iii, 305. 



f Irrespective of the proteid matter. 



\ Journal of Physiology, vol. iii, No. 3. 



§ Chittenden and Ely, Amer. Chem. Jour., vol. iv, 114. 



Trans. Conn. Acad., Vol. VI. 45 Maech, 1885. 



