888 



TRANSACTIONS OF SECTION K. 



rate of hydrolysis of the cane-sugar is determined only by the amount of the 

 cane-sugar present at any moment.^ 



(3) We have now shown how the actual amount of chemical change going on 

 in a solution is determined by the 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 circumstances, but is affected by 

 variations of external conditions, always by temperature, and generally by the 

 presence of traces of so-called catalysts. 



TUpa 



K iK 5k 4-h. Sh. 6h. jk Sh. 

 Fig. 1. 



The relation to temperature we will postpone, and proceed to consider our 

 bird principle, the acceleration of reaction velocity by catalytic agents. 



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 hydrolysis of cane-sugar, so slow with pure water, goes at a fair velocity if a 

 few drops of a mineral acid are added to the solution, while the addition of a 

 trace of a particular enzyme (invertase from plant or animal) enormously 

 increases the rate of change, so that the whole 128 grammes of cane-sugar are soon 

 bydrolysed to hexose. The reaction progresses quantitatively in the same sort of 



' 128 grammes cane-sugar unite with 6-7 grammes water in hydrolysis, and in our 

 experiment nearly 1000 grammes of water are present, 



