362 Chittenden and Smith — Diai^tatic Action of Saliva. 



B. 40 c.c. of the above diluted saliva required 6*8 c.c. 0-05 per 

 cent, HCl to saturate the proteids present = 0-0074 per cent, com- 

 bined HCl. 



Two digestions each were made with A and B, using quantities 

 of the above salivas equivalent to 4 and 2 c.c. of the original saliva. 



Wt. Cii in one-eighth. Total amt. sugar formed. 



20 c.c. A, 00913 gram. 0-.3720 gram. 



23-4 B, 0-0987 0-4016 



10 c.c. A, 0-0850 gram. 0-3472 gram. 



11-7 B, 0-0940 0-3832 



starch converted. Starch converted. 



20 c.c. ^, 33-49 per cent. 10 c.c. ^, 31-26 per cent. 



23-4 B, 36-15 11-7 B, 34-49 



Increase, 2 66 per cent. Increase, 3 23 per cent. 



It is seen that the addition of the acid in this instance causes a very 

 decided increase in the diastatic activity of the saliva. The amount 

 of combined acid present in the 100 c.c. of digestive mixture in the 

 two cases was 0-0017 and 0-0008 per cent, respectively, yet the pres- 

 ence of this small amount of combined acid manifestly acts as a stim- 

 ulant to the diastatic ferment.* Even still smaller percentages of acid- 

 proteid matter have an equally decided action on the salivary ptyalin. 

 The following series of experiments illustrate this point and at the 

 same time are confirmatory of the preceding one. 



Series XV. 



A. 40 c.c. filtered saliva were neutralized and diluted to 200 c.c. 



B. 50 c.c. of the above diluted saliva required 4-75 c.c. 0-05 per 

 cent. HCl to saturate the proteids. The solution was distinctly acid 

 to litmus paper and contained 0-0043 per cent, combined HCl. 



Four digestions were made with both A and jB, using quantities 

 of saliva in each case equivalent to 4, 2, 1 and 0*5 c.c. of the original 

 saliva. 



wt. Gu in one-eighth. Tolal amt. sugar formed. 



20 c.c. A, 0-0925 gram. 0-3768 gram. 



21-9 B, 0-0959 0-3912 



10 c.c. A, 00827 gram. 03368 gram. 



10-95 B, 0-0876 0-3576 



5 c.c. A, 00671 gram. 0-2744 gram. 



5-6 B, 0-0751 0-3064 



2-5 c.c. ^, 0-0305 gram. 0-1296 gram. 



2-75 B, 0-0375 0-1568 



* Doubtless these percentages of combined acid are too high, since as before men- 

 tioned some of the acid added probably reacts with the phosphates naturally present 

 iu the saliva. 



