VELOCITY OF REACTION. HETEROGENEOUS SYSTEMS IO/ 



Another series of experiments seems to indicate that 

 the value of K is independent of the quantity of erythro- 

 cytes, but increases more rapidly than in proportion to the 

 quantity of serum. (It is rather peculiar that this behaviour 

 is not indicated in the figures given above.) 



Madsen, aided by Walbum and Nugochi, has carried out 

 a large number of experiments on the velocity of reactions 

 of different substances at different temperatures. Their 

 method consisted in determining the qualities of the same 

 agent, e.g. haemolysin, which were necessary to produce a 

 certain effect in a given time, e.g. 10 minutes. The lower 

 the temperature, the greater the quantity of the agent 

 necessary for the effect, generally speaking. Taking 

 ammonia as an illustration, we know that, if the quan- 

 tity exceeds greatly the amount necessary for complete 

 haemolysis in a very long time, the time necessary to 

 secure a certain effect is inversely proportional to the 

 quantity of ammonia used. If therefore, as the experi- 

 ments indicate, the addition of 0.085 c - c - of a solution of 

 ammonia to 8 c.c. of a i per cent suspension of erythro- 

 crytes from horse blood at 34.8 C. will give in 10 minutes 

 the same effect as 0.17 c.c. of the same solution at 29.7 C., 

 the other conditions being the same, we conclude that 0.085 

 c.c. of the ammonia would require 20 minutes at 29.7 C. to 

 attain the same effect as in 10 minutes at 34.8; i.e. the 

 velocity of reaction at 34.8 C. is double that at 29.7 C. 

 Generally speaking, the velocity of reaction is in these 

 experiments inversely proportional to the quantity used. 

 Evidently this conclusion is valid only for those cases in 

 which, as for ammonia, the rate of the reaction is propor- 

 tional to the quantity of reacting substance; but this seems 



