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Studies on the Processes Operative in Solutions (XXX) and 

 on Enzyme Action (XX). — The Nature of Enzymes and of 

 their Action as Hydrolytic Agents. 



By E. Frankland Armstrong and H. E. Armstrong, F.R.S. 



(Eeceived June 13,— Eead June 26, 1913.) 



Our object in the present communication is to utilise the experience 

 gained in the course of two convergent series of inquiries carried on during 

 the past 12 years in the hope of arriving at a satisfactory solution of the 

 problems of hydrolysis whether effected either by ordinary agents — acids or 

 alkalies — or by enzymes. 



The nature of the hydrolytic process has been discussed broadly in 

 Part XXIV of the one series and the phenomena attending the dissolution 

 of salts in water and the behaviour of saturated solutions towards precipi- 

 tants has since been considered in Part XXA' of the same series : much that 

 has been said in these two communications will be of consequence in the 

 present discussion. The views put forward with regard to the composition of 

 water (S. VI)* and with reference to the part played by the class of 

 substances which we have termed collectively hormones^ in altering the state 

 of water and of substances dissolved in it, will also be found to have a 

 bearing on the problems presented by enzymes. The present communication, 

 it should be stated, is in the main an amplification of the views expressed in 

 Part II of the Studies on Enzyme Action.! 



The interpretation of the phenomena we shall offer will also involve 

 taking into account the views on residual affinity of the negative elements in 

 particular and on the nature of the process of chemical change advocated by 

 one of us in a communication brouo-ht under the notice of the Societv in 

 1886 and in a Presidential Address to the Chemical Society in 1895. 



The present communication, in fact, is the outcome of an inquiry, lasting 

 over a long period, carried out with the object of arriving at a rational 

 solution of some of the most fundamental of chemical problems — especially 



* It will be convenient to refer to communications of the one or the other series as 

 papers of the S. and E. series respectively. 



t 1 Koy. Soc. Proc.,' 1910, B, vol. 82, p. 588. Of. ' Annals of Botany,' 1911, vol. 25, 

 p. 507. As used originally by Bayliss and Starling, the term hormone had a restricted 

 significance ; we have applied it more generally to compounds which penetrate the 

 differential septa of animal and vegetable structures. 



| Ibid., 1904, vol. 73, p. 500. 



2 t 2 



