526 Dr. E. E. Armstrong and Mr. R J. Caldwell. [Apr. 5, 



If acceptance can be accorded to the arguments put forward in 

 this communication, some progress will have been made towards 

 unravelling the very complex phenomena presented by fermentative 

 changes. 



[D 1820, 7050, 8010.] 



" Studies on Enzyme Action. IV. — The Sucroclastic Action of 

 Acids as contrasted with that of Enzymes." By Edward 

 Erankland Armstrong, Ph.D., Salters' Company's Research 

 Eellow, and Robert John Caldwell, B.Sc, Clothworkers' 

 Scholar, Chemical Department, City and Guilds of London 

 Institute, Central Technical College, Communicated by 

 Professor H. E. Armstrong, F.R.S.. Received April 5, — Read 

 April 28, 1904. 



D 1820 Milk sugar, hydrolysis by acids. 



1) 7050 Hydrolysis of sugars by acids and by enzymes contrasted. Nature of 

 active system and explanation of influence of concentration and of 

 temperature. 



. D 8010 Enzyme action contrasted with, that of acids. 



Not only are the various bioses hydrolysed at very different rates 

 by enzymes but they are also known to differ in their behaviour 

 towards acids : cane sugar being hydrolysed with the greatest facility, 

 whilst maltose is acted upon but slowly. The experiments described 

 in this communication were instituted primarily with the object of 

 ascertaining the behaviour of milk sugar, of which nothing was known. 



The hydrolysis of cane sugar under the influence of acid was 

 carefully investigated by Wilhelmy as far back as 1850, with the aid 

 of the polariscope, then a new instrument. It was shown by him that 

 nversion follows the logarithmic law 



K = log , 



t a-x 



which at a later date became regarded as the general law of mass 

 action. Subsequent workers have studied the action more in detail, 

 but the object of several of the latter inquiries has been rather to 

 determine the relative activities of different acids and to study the 

 application of the ionic hypothesis in such a case of hydrolysis. 



Maltose has been shown by Sigmond* to exhibit the same general 

 behaviour as cane sugar towards acids, whilst affording very different 

 constants. 



The only other glucose derivative which has been studied is salicin.f 

 * 'Zeit. Phys. Chem.,' vol. 27, p. 385. 

 f Noyes and Hall, 'Zeit. Phys. Chem.,' vol. 18, p. 240. 



