568 Dr. Armstrong and Prof. Armstrong. Studies on [June 13, 



in solutions containing up to 12 per cent, glucose and from 81*6 to 80*9 in 

 solutions containing 16-30 per cent. 



Moreover, the addition of /3-methyl glucoside in advance serves to reduce 

 the amount of glucose converted. Thus, when glucose alone was used 

 (1 grm.), the amount converted was 0826 grm. When an equal weight 

 of glucoside was present, only - 709 was converted and when 3 grm. of 

 glucoside was used to 1 grm. of glucose, only 0'392 of the latter was etherified 

 (ibid., p. 1G38). 



It thus appears that the synthetic activity of the enzyme is affected in the 

 same way as its analytic activity by changes in concentration. It is to 

 be hoped that Bourquelot and Vardon will also determine whether the 

 influence of the /3-glucoside on the synthetic activity of the enzyme be in any 

 way a preferential effect.] 



But these are all conclusions at variance with the doctrine of the text- 

 books. So far as we are able to judge, the analytic activity of enzymes is 

 exercised more nearly in the manner first pointed out by Duclaux in 1898 

 and subsequently in 1902 by Adrian Brown and also by Horace Brown and 

 Glendinning : in each successive interval of time, the enzyme determines the 

 hydrolysis of the same amount of the hydrolyte ; the observed departures 

 from this rule may be attributed to the influence of the products of change. 



The mental picture of the process we have been led to frame involves the 

 following suppositions. 



Firstly, that a colloid surface in water is necessarily a hydrolated surface, 

 i.e. a surface to which molecules of hydrone — the fundamental molecule of 

 water — are attached in such manner that their activity at the surface is 

 greater than the average activity of the water in the neighbourhood. 

 Secondly, that as a consequence of this property of the surface the hydrolyte 

 is absorbed* from the solution, so that the colloid surface remains highly 

 charged with the hydrolyte probably almost up to the point at which the 

 supply in the solution is exhausted. Our assumption being that the enzyme 



* We venture to think that this term is sufficient for all purposes and that it is 

 undesirable and unnecessary to introduce a special term (absorption) both because the 

 uninstructed reader cannot attach any special meaning to this latter different from that 

 conveyed by the familiar term and because the meaning which it is sought to give to it 

 is not in reality different from that conveyed by the familiar term : no distinction is 

 drawn by implying that a substance is sucked in towards a body in a solution rather than 

 from a solution by a body, the process being one in which solution and surface are 

 reciprocally concerned. The growing tendency to introduce special terms which the 

 reader cannot understand unless specially instructed, whose meaning cannot be discovered 

 easily, is to be deprecated on all grounds. 



