172 Rerort OF DEPARTMENT OF BACTERIOLOGY OF THE 
inhibition increased with the further addition of the alkali up 
to —10%, where it was total. 
Acids° — A very slight addition of hydrochloric acid seemed 
favorable to the action of the enzym, a reaction of +0.5% 
being about the optimum. The difference between this and the 
neutral solution was, however, slight. When the reaction was 
+2.5% or above there was great inhibition and at +5% it 
‘was practically complete. | 
Various organic acids were tested also, the’ results in detail 
being as follows: 
Strength 
of 
Acid. titration. Effect. 
he vii myc sla paige +0.8 percent. retarded slightly. 
CEES EE ARES +151 . “greatly. 
FUE, ae, ae +8.0 complete inhibition. 
Acetic. +0.2 . no effect. 
OREN Rati at +0.5 « «« 
OP wer eee +1.0 ‘ retarded greatly. 
iets Wiglyemge aa Aen +10.0 rs complete inhibition. 
POrMiCwae tee tect +0.15 no effect. 
aS es +0.4 p 3 . 
Gab nah: ee +0.75 ‘3 retarded greatly. 
ics Swit ee. Cas AT a Tha complete inhibition. 
MATT ASTC 25 6 ears tls +0.14 a no effect. : 
ct See CRORES RE ae +0.55 e “(possibly slight retarding). 
PU SOL Pee Se +505 i almost full inhibition. 
IE Ra i i ade +0.2 ¢ no effect. 
wiht VE a ed aie +0.8 i sabi 
he Pe ae ve +8.0 7 almost full inhibition. 
CTU week ob ote eee +0.2 no effect. 
eel sheer eae +0.8 E Mm atreee 
gee Gt wee Wey sae +8.0 “ almost full inhibition, 
From these results it will be seen that these organic acids in 
no case aided the action; that where the acidity, as shown by 
titration, was +0.5% and less they were practically without 
effect; that +-1.0% and above distinctly inhibited in all cases 
where it was tried, and that from +5% to +10% led to com- 
plete inhibition. Here again it should be noted that even this 
large amount represents only a very mild degree of acidity, 
viz., 0.5% more or less by weight. 
These acids were made up by weight and titration strength determined 
afterward. One per cent. gravimetric solutions titrated respectively as 
follows: hydrochloric +50; acetic +20; tartaric +11; citric +15.5; 
malic +15.5; formic +15. 
