VELOCITY OF REACTION 187 



which the reaction is proceeding, each falling short of the true or 

 absolute equilibrium point. For example, a catalyst which by reason 

 of its properties and concentration has a power represented as at 

 AA 1? will when the reaction is proceeding in the direction from left 

 to right (X to XJ carry the reaction up to the point a, and the system 

 will be in equilibrium there, and when the reaction is proceeding in 

 the opposite direction (X x to X) will carry the reaction up to a 19 

 and leave the system in equilibrium there. Hence it is quite erroneous 

 to speak of these equilibrium points in incomplete reactions as false 

 equilibrium points, for under the given conditions the system is as 

 truly in equilibrium as it would be if all resistance to reaction were 

 removed and it had reached the absolute equilibrium point in the 

 absence of a catalyst. 



Barth, and later Duclaux, found that in the earlier part of the 

 reaction induced by invertase upon cane sugar, when moderately 

 concentrated solutions were used, the amount of the sugar 

 hydrolysed was not proportional to its concentration. Thus Barth 

 observed that, using the same amount of invertase, and varying 

 the concentration of sugar, between 5 per cent, of sugar and 

 I") per cent, practically the same amount was hydrolysed in equal 

 time. Below 5 per cent, the amount hydrolysed increased with the 

 concentration, but not proportionately, so that the percentage 

 hydrolysed was less, and with percentages higher than 15 the 

 absolute amount hydrolysed actually fell off. Duclaux further 

 showed that with the same concentration of enzyme and sugar, the 

 amount hydrolysed up to the point at which 20 per cent, had been 

 inverted was simply proportional to the time, so that the curve 

 representing the progress of the reaction up to this point was a 

 straight line and not a logarithmic curve. At a later stage, as a 

 result according to Duclaux of the retarding action of the products 

 of reaction, the curve began to obey the logarithmic law. Henri 

 later showed, however, that even in this portion Duclaux' s results 

 do not give the logarithmic law, the constant K all the time increas- 

 ing with the progress of the reaction. 



In an extensive series of experiments on the inversion of cane 

 sugar by invertase, Henri showed that the value of K calculated 



on the basis K= log continually increased throughout the 



reaction. 



He based on the fact that the value of the constant increased 



