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1913.] Processes Operative in Solutions and Enzyme Action. 579 



proportion. In the case of the highest proportion, the retardation was at 

 first very great, but it is obvious that recovery then set in. The effect of the 

 alkaline salt, M/5, Na 2 HP04, was prejudicial from the beginning. 



It was noticed that the solution became cloudy on mixing the enzyme with 



























































































































































— I 























* 





























































O 20 40 60 60 100 120 



MINUTES 



Fig. 5. 



the strong solution of the acid phosphate but that it afterwards became clear. 

 Evidently the enzyme was at first in large part neutralised and " coagulated " 

 but as alkali was formed it became redistributed and as the acid phosphate 

 served to neutralise the alkali produced in the- change the enzyme preserved 

 its activity to a greater extent than it did when no phosphate was present.] 



Influence of the Products of Change and of other Substances. — In these 

 studies, stress has always been laid on the influence which certain of the 

 products of change exercise in retarding the action of an enzyme and the 

 special influence of one or the other of the products of change has often been 

 advanced as an argument of consequence in favour of the conclusion that the 

 enzymes are strictly specific agents. 



This, in fact, is to be regarded as a principal argument in favour of the 

 hypothesis now advocated and we have therefore been led to reconsider very 

 carefully the evidence brought forward in this connexion at an early stage 

 of this inquiry. We now desire to amend it in important particulars, 

 having in the interval arrived at the conclusion that it is necessary to be 

 very careful in interpreting the effects produced by various substances and 

 not to regard them always as specific influences. 



In the first place, it is necessary to take into account the manner in which 

 the proportion of the hydrolyte present influences the result and to realise 



