VELOCITY OF REACTION. HOMOGENEOUS SYSTEMS 51 



behaves the catalytic action of a colloidal solution of plati- 

 num on hydrogen peroxide. 



In an analogous manner, according to Euler's measure- 

 ments, the catalase extracted from lard saponifies a con- 

 centrated solution of ethyl-butyrate (at 35C). q is the 

 quantity of butyric acid set free after t minutes, as deter- 

 mined by titration with barium hydrate. 



The reaction is clearly monomolecular, as is indicated 

 by the constancy of K. A more complicated formula was 

 found empirically by Henri 1 to be valid for the inversion 

 of cane sugar by means of invertin extracted from yeast 

 cells. 



Henri's formula is the following : 



a x 



It differs from the formula for monomolecular reactions 

 by the expression (a -f- x} instead of simply a in the nom- 

 inator after log. As example I quote the reaction of 4c.c. 



solution of diastase with 0.5 n. sugar at 25 C. '- i s the 



inverted sugar proportional to the initial quantity of cane 

 sugar. 



1 V. Henri: Zeitschr. f. ph. Ch. 39. 194 (1901). 



