44 LECTURES ON IMMUNITY 



and is nearly proportional to it. In reality the bouillon 

 in which the vibrions grow is slightly alkaline. Madsen 

 found at 47.8 C. that the original solution of vibriolysin 

 gave K \ =0.0198. The same solution, diluted to the con- 

 centrations 0.5 or 0.25, gave -/T 2 = 0.0072 and ./T 4 = 0.0039 

 respectively. These three figures are nearly in the pro- 

 portion 4:2:1, or as the corresponding concentrations, 

 which is easily understood if the alkali present exerts a 

 catalytic influence. 



Much more complicated is the influence which the addi- 

 tion of acids or of bases exerts upon the attenuation of 

 tetanolysin, which is also in itself alkaline. The velocity 

 of reaction K increases with the amount of alkali added, 

 but decreases at first if acid is added until it reaches a 

 very flat minimum, after which it increases again on 

 further addition of acid. This is evident by an inspection 

 of the following figures (valid at 49.83 C.) : 



98 c.c. of tetanolysin solution -f 2c.c. I n. NaOH ^=0.0112 



99 c.c. of tetanolysin solution + I c.c. I n. NaOH 0.0097 

 99.5 c.c. of tetanolysin solution + 0.5 c.c. I n. NaOH 0.0085 



100 c.c. of tetanolysin solution 0.0047 



99 c.c. of tetanolysin solution + I c.c. I n. ^SO* 0.0071 



98 c.c. of tetanolysin solution + 2 c.c. I n. H 2 SO* 0.0435 



This seems to indicate that the acid first added is bound 

 by some weak base in the bouillon ; and that the first 

 trace of alkali added is also bound, probably in setting 

 some weak alkali free in the bouillon. 



The figures for the reaction velocity in the presence of 

 2 c.c. i n. H 2 SO 4 in looc.c. are as follows, and indicate a 

 monomolecular process: 



