CHEMICAL ASPECTS OF LIFE — HOPKINS 131 



tions with disease, are now the subject of intense study, awaken 

 deep curiosity with respect to this question. We cannot yet claim 

 to know whether or not they are living organisms. In some sense 

 they grow and multiply, but, so far as we yet know with certainty, 

 only when inhabitants of living cells. If they are nevertheless 

 living, this would suggest they they have no independent power of 

 obtaining energy and so cannot represent for us the earliest forms 

 in which life appeared. At present, however, judgment on their 

 biological significance must be suspended. The fullest understand- 

 ing of all the methods by which energy may be acquired for life's 

 processes is much to be desired. 



In any case every living unit is a transformer of energy however 

 acquired, and the science of biochemistry is deeply concerned with 

 these transformations. It is with aspects of that science that I am 

 to deal and if to them I devote much of my address my excuse is 

 that since it became a major branch of inquiry biochemistry has had 

 no exponent in the Chair I am fortunate enough to occupy. 



As a progressive scientific discipline it belongs to the present cen- 

 tury. From the experimental physiologists of the last century it 

 obtained a charter, and, from a few pioneers of its own, a promise 

 of success; but for the furtherance of its essential aim that century 

 left it but a small inheritance of facts and methods. By its essential 

 or ultimate aim I myself mean an adequate and acceptable descrip- 

 tion of molecular dynamics in living cells and tissues. 



II 



When this association began its history in 1831 the first artificial 

 synthesis of a biological product was, as you will remember, but 3 

 years old. Primitive faith in a boundary between the organic and 

 the inorganic which could never be crossed was only just then realiz- 

 ing that its foundations were gone. Since then, during the century 

 of its existence, the association has seen the pendulum swing back 

 and forth between frank physico-chemical conceptions of life and 

 various modifications of vitalism. It is characteristic of the present 

 position and spirit of science that sounds of the long conflict between 

 mechanists and vitalists are just now seldom heard. It would almost 

 seem, indeed, that tired of fighting in a misty atmosphere each has 

 retired to his tent to await with wisdom the light of further knowl- 

 edge. Perhaps, however, they are returning to the fight disguised as 

 determinist and indeterminist, respectively. If so the outcome will 

 be of great interest. In any case I feel fortunate in a belief that what 

 I have to say will not, if rightly appraised, raise the old issues. To 

 claim, as I am to claim, that a description of its active chemical 



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