56 Chittenden and Cummins—Amylolytic Action 
All of these results show acceleration under the influence of small 
percentages of combined acid, followed, as the percentages are in- 
creased, by decided retardation, thus agreeing with the results pre- 
viously obtained with the salivary ferment. 
The destructive action of small percentages of acid-peptone on the 
ferment is not great in the presence of an excess of peptone, but as 
the peptone approaches saturation its destructive power is increased, 
and when completely saturated with acid, a moderate amount of 
peptone so combined will quickly and completely destroy the fer- 
ment. ‘This is plainly shown in the following series of experiments : 
i 2. 3. 4. 
Malt extract..-..... 15. ¢. 1b 'c..e: , bcc. Lover 
Peptone sol.*______- 20 20 20 20 
HCl 0°1 per cent. ___- 0 1 2 4 
Fe Oa ery at eee = rl 14 13 ll 
50 50 50 50 
Pe ptone yee a= eres 0-1 per cent. 0O-l percent. 0-1 percent. 0°l percent. 
Combined HCl-_----.- 0 0-002 0004 0-008 
These mixtures were warmed at 40° C. for 30 minutes. 20 ¢. ¢. of 
the peptone solution together with 15 c.c. of the malt extract re- 
quired 4:0 c.c. of 0°1 per cent. hydrochloric acid to saturate the 
proteid matter, consequently in the above mixtures, 2 and 3 contained 
a large excess of uncombined peptone, while in 4 the proteid matter 
was just saturated. 
Neutralizing and equalizing mixtures were added to each as 
follows : 
if oe 3. 4. 
0°1 per cent. Na,CO; | --- 0 15¢ec. 3 «e 5°9 ce. 
01 a NaeCO;,2---- D9 ene. 4°4 2°9 0 
0°1 4 Cee so ASO 3°0 sil) 0 
The solutions were now, on being diluted to 100 ¢. ¢., in every re- 
spect equal. Their amylolytic power on being tested with starch 
paste was as follows: 
Total amount Starch 
No. Wt. Cuin ¥. reducing bodies. converted. 
1 0°1595 gram. 0°3258 gram. 29°32 per cent. 
2 01527 0°3118 28°06 
3 071239 0°2522 22°69 
4 trace. 
Hence, when the proteid matter present is only one-quarter satu- 
rated with acid, the acid-peptone so formed may exert some destruc- 
* The peptone solution contained 0°250 gram peptone in 100 c. c. water and was 
made neutral to test papers; 20 c. c. therefore contained 0°050 gram peptone. 
Vv 
