LIFE: ITS NATURE, ORIGIN, AND MAINTENANCE.^ 



By E. A. ScHAFER, LL.D., D.Sc, M.D., F.R.S., 

 Professor of Physiology in Edinburgh. 



PREFACE. 



In the following essay, which formed the presidential address to the 

 British Association at its meeting in Dundee in 1912, I have tried to 

 indicate in clear language the general trend of modern biochemical 

 inquii'ies regarding the nature and origin of living material and the 

 manner in which the life of multicellular organisms, especially that of 

 the higher anhnals and man, is maintained. I have also stated the 

 conclusions which it appears to me may legitimately be drawn from 

 the result of those inquiries, without ignoring or minunizing such 

 difficulties as these conclusions present. 



There is, it may be admitted, nothing new in the idea that living 

 matter must at some time or another have been formed from lifeless 

 material, for in spite of the dictum OTYine vivum e vivo, there was cer- 

 tainly a period in the history of the earth when our planet could have 

 supported no kind of life, as we understand the word; there can, 

 therefore, exist no difference of opinion upon tliis point among 

 scientific thinkers. Nor is it the first time that the possibilit}' of the 

 synthetic production of living substance in the laboratory has been 

 suggested. But only those who are ignorant of the progress which 

 biochemistry has made in recent years would be bold enough to 

 affirm that the subject is not more advanced than in the days of 

 Tyndall and of Iluxlej^, who showed the true scientific instinct in 

 affirming a belief in the origilial formation of life from lifeless material 

 and in hinting at the possibility of its eveniual synthesis, although 

 there was then far less foundation upon which to base such an opinion 

 than we of the present day possess. The investigations of Fischer, 

 of Abderhalden, of Hopkins, and of others too numerous to mention, 

 have thrown a flood of light upon the constitution of the materials 

 of which living substance is composed; and, in particular, the epoch- 

 making researches of Kossel into the chemical composition of nuclear 



> An address delivered to the British Association for the Advancement of Science, at its meeting at Dun- 

 dec in September, 1912. Reprinted by permission from pamphlet copy printed by Longmans, Green & Co., 

 London, 1912. 



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