382 



CHEMICAL DYNAMICS 



evanescent in comparison with that of the substrate and so forth. 

 If we try to generalize Henri's equation by removing these 

 simplifying assumptions we obtain equations which are, mathe- 

 matically speaking, unmanageable. The surprising thing is, 

 therefore, not that Henri's equation fails to adequately repre- 

 sent Abderhalden and Koelker's results, but that, if the con- 

 ditions in the system are as complex as those which Henri depicts, 

 any simple relation can be found which will express the progress 

 of the reaction with any approach to fidelity. 



Computing the average values of 100 & 3 calculated from the 

 equation (iv) for the various ferment-concentrations employed 

 by Abderhalden and Koelker we obtain: 



from which it is evident that the velocity-constant of hydrolysis, 

 when computed from Henri's equation, far from being directly 

 proportional to the ferment-mass is actually greater the more 

 dilute the ferment. It appears distinctly within the bounds of 

 possibility that the intensity of the hydrolysing activity of the 

 ferment is relatively greater the more dilute its solution. This, 

 in turn, suggests the possibility that the ferment may exist both 

 in an active and inactive form (active and inactive, that is, with 

 respect to the acceleration of hydrolysis). The proportion of in- 

 active ferment would, of course, depend, not only upon the total 

 mass of ferment in the system, but upon the mass of uncombined 

 active ferment. If this were the case then k and e in Abder- 

 halden and Michaelis' equation, accepting Henri's derivation of 

 the equation, might be expected to be functions, not only of the 

 total ferment mass and of the relation between the mass of free 

 active ferment and that of the substrate and products respec- 

 tively, but also of the relation between the proportion of ferment 

 in the inactive condition and the mass of the uncombined active 

 ferment (Cf. Chap. XVII). 



On the other hand, it is possible that the coincidence between 

 Abderhalden and Michaelis' equation and that of Henri is merely 

 formal, that, as Abderhalden and Michaelis suggest, the true 



