SOME CHEMICAL ASPECTS OF LIFE ' 



By Sir Feedekick Gowland Hopkins, Pres. R. S. 



The British Association returns to Leicester with assurance of a 

 welcome as warm as that received 26 years ago, and of hospitality as 

 generous. The renewed invitation and the ready acceptance speak 

 of mutual appreciation born of the earlier experience. Hosts and 

 guests have today reasons for mutual congratulations. The Associa- 

 tion on its second visit finds Leicester altered in important ways. It 

 comes now to a city duly chartered and the seat of a bishopric. It 

 finds there a center of learning, many fine buildings which did not 

 exist on the occasion of the first visit, and many other evidences of 

 civic enterprise. The citizens of Leicester, on the other hand, will 

 know that since they last entertained it the Association has cele- 

 brated its centenary, has four times visited distant parts of the 

 Empire, and has maintained unabated through the years its useful 

 and important activities. 



In 1907 the occupant of the Presidential Chair was, as you know. 

 Sir David Gill, the eminent astronomer who, unhappily, like many 

 who listened to his address, is with us no more. Sir David dealt 

 in that address with aspects of science characterized by the use of 

 very exact measurements. The exactitude which he prized and 

 praised has since been developed by modern physics and is now so 

 great that its methods have real esthetic beauty. In contrast, I have 

 to deal with a branch of experimental science which, because it is 

 concerned with living organisms, is in resj>ect of measurement on a 

 different plane. Of the very essence of biological systems is an in- 

 eludible complexity, and exact measurement calls for conditions here 

 unattainable. Many may think, indeed, though I am not claiming 

 it here, that in studying life we soon meet with aspects which are 

 nonmetrical. I would have you believe, however, that the data of 

 modern biochemistry which will be the subject of my remarks were 

 won by quantitative methods fully adequate to justify the claims 

 based upon them. 



1 Presidential address before the British Association for the Advancement of Science, 

 Leicester, 1933. Reprinted by permission from the Report of the Association for 1933. 



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