VELOCITY OF REACTION. HOMOGENEOUS SYSTEMS 43 



increased again, and reached the value of 0.022 if 6 c.c., 

 and of 0.109 if 6.75 c.c. of i n. HC1 was present in 100 c.c. 

 of the liquid. These circumstances seem to indicate that 

 some alkali present in the original culture was neutralised 

 by the first addition of the hydrochloric acid, which there- 

 after exerted its destructive action. The slight difference 

 between the action of sodium hydrate and ammonia leads 

 to the conclusion that the bases act by setting some 

 alkaline substance in the bacterial culture free. The in- 

 feriority of the ammonia might be explained by its fee- 

 bleness, which allows an equilibrium with the base from 

 the culture to be reached before all the base has been set 

 free. 



Even the presence of weak acids, e.g. of acetic acid, 

 accelerates the destruction of the vibriolysin. Thus 9 c.c. 

 of i n. CH 3 COOH in 100 c.c. of culture gives a reaction- 

 constant 0.064, its action corresponding to that of 6.5 c.c. 

 i n. HC1. The weak acid exerts much less influence than 

 a strong one, which was to be expected, the neutralised base 

 being of less strength than ammonia, so that a noticeable 

 hydrolytic action must occur. 



The reaction-constant is, considering the great errors 

 of observation, practically proportional to the amount of 

 base added (if the alkalinity exceeds o.oi n.); but 

 for the action of the acids no such regularity is found, 

 even if we calculate from the neutralisation point, which 

 ought to nearly coincide with the point of minimal con- 

 stant of reaction. 



The content of alkali in the natural solution of vibriolysin 

 explains another fact found by Madsen ; namely, that the 

 constant of reaction depends on the initial concentration 



