VELOCITY OF REACTION. HOMOGENEOUS SYSTEMS 53 



the inversion. This is not the place to enter upon a discus- 

 sion of this peculiar view. 



Regarding the influence of temperature on the action of 

 invertase on cane sugar we possess some old observations 

 of Kjeldahl. 1 They give an optimum at about 52.5 and 

 fji= 9080. They are reproduced in the table: 



Temp. o 18 30 40 45 48 50 52.5 55 60 65 70 C. 

 Vel. obs. 17 60 113 179 228 250 260 267 260 179 21 o 

 Vel. calc. 21 (60) 112 181 (228) 261 285 318 353 436 534 651 



In a recent memoir 2 Henri analyses the hydrolysis of 

 maltose by means of maltase. In this case the reaction- 

 product is glucose, and the constant of reaction increases 

 with the progress of the reaction. Henri's formula 



1C = -log - gives a very nearly constant value for K. 



t d X 



This constant decreases as the quantity of maltose in- 

 creases. For the first three hours it is, for instance, for 

 solutions of the following concentration, 2 per cent sol. 

 K= 368 icr 5 , 4 per cent sol. K 164 io~ 5 , 6 per cent sol. 

 K= 1 06 icr 5 . It is nearly inversely proportional to the 

 quantity of maltose present. It would therefore be reason- 

 able to put 



where K^ is a new constant, and (a x) the concentration 

 of the maltose. But as the maltose as well as the glucose 

 has a retarding influence on the process, it would be more 

 rational to put 



1 Kjeldahl: cited from Duclaux, Traite de microbiologie, 2. 177 (1899). 



2 Victor Henri: " Recherches physico-chimiques sur les diastases," 

 Archive di Fisiologia, 2. i (Nov. 1904). 



