VELOCITY OF REACTION. HOMOGENEOUS SYSTEMS 99 



of p in the two cases of digestion of gelatin by means of 

 pepsin or of trypsin is very startling. In any case it is not 

 possible to retain the opinion that /-i is of the same order 

 of magnitude for all velocities of reaction, corresponding 

 closely to an increase in the proportion i : 2 for an increase 

 in temperature of ten degrees (fi = 1 1,850 at 20, p = 14,400 

 at 50, and /*= 17,200 at 80 C.). As most of Madsen's 

 determinations were carried out in the proximity of 50, we 

 may say that /* is between four and fourteen times greater, 

 that is, the increase for 10 C. may be from 2 8 = 8 to 2 13 = 

 8200 times the usual rate. 



