No. 502] CHEMICAL MECHANICS IN LIVING PLANT 641 



combined effect of (1) the specific reaction velocity and 

 (2) the law of mass. We have next to point out that the 

 specific reaction coefficient is not the same under all cir- 

 cumstances, but is affected by variations of external con- 

 ditions, always by temperature, and generally by the pres- 

 ence of traces of so-called catalysts. 



The relation to temperature we will postpone, and pro- 

 ceed to consider our third principle, the acceleration of re- 

 action velocity by catalyiic agents. 



/0 >+ l»! I 1 1 j =1 



It has long been known that small additions of various 

 foreign substances may have a great effect in increasing 

 the rate at which a reaction is proceeding. Thus this hy- 

 drolysis of cane-sugar, so slow with pure water, goes at a 



