Chittenden and Sinith — Dlastatic Action of Saliva. 375 



where the dilution is as 1:50 or 100, and is apparently out of all 

 proportion to the amount of alkalinity. 



3. Sodium carbonate retards the diastatic action of ptyalin in 

 proportion to the amount of alkaline carbonate present. The per- 

 centage of alkaline carbonate, however, which hinders diastatic action 

 can be designated only for definite mixtures and not in a general 

 sense, being dependent upon the dilution of the saliva and the 

 consequent change in percentage of proteid matter. 



4. The destructive action of sodium carbonate is modified materi- 

 ally by the dilution of the saliva ; becoming greater the more the 

 fluid is diluted. This result is due not to simple dilution but doubt- 

 less to the diminished amount of proteids. 



5. Neutral peptone has a direct stimulating efiect on the diastatic 

 action of neutral saliva. 



6. The presence of small percentages of neutral peptone tends to 

 raise the diastatic action of normally alkaline saliva, to a point even 

 beyond the action of the neutralized fluid ; due in part doubtless to 

 a loose combination of the alkali with the proteid matter, and also 

 to a direct stimulation of the ferment. Likewise peptone tends to 

 diminish in a similar manner the retarding action of the various 

 percentages of sodium carbonate. To accomplish this, however, the 

 amoimt of peptone must be proportionate to the percentage of 

 alkaline carbonate. 



7. Peptone tends to prevent the destructive action of dilute 

 sodium carbonate on salivary ptyalin, thus giving proof of the 

 probable formation of an alkaliue-proteid body. 



8. Saliva with its proteid matter saturated with acid appears to 

 have a greater diastatic action than when simply neutralized ; except 

 when the acid-proteids thus formed are above a certain percentage. 

 Small percentages of peptone saturated with acid, similarly increase 

 the diastatic action of neutralized saliva up to a certain point. In- 

 creasing the percentage of acid-proteids finally causes a diminution 

 of diastatic activity. 



9. The retarding influence of acid-proteids is out of all proportion 

 to their power of destruction. Large percentages however of acid- 

 proteids may cause almost complete destruction of the ferment. 



10. The most favorable condition for the diastatic action of ptyalin, 

 under most circumstances, appears to be a neutral condition of the 

 fluid together with the presence of more or less proteid matter. The 

 addition of very small amounts of hydrochloric acid, however, to 

 dilute solutions of saliva, giving thereby a small percentage of acid- 



Trans. Conm. Acad., Vol. YI. 47 March, 1885, 



