LIFE AND EXPERIMENT 



commonly distinguish a living thing from a non-living; both 

 the organization and these characteristics should claim more 

 attention from those — be they biologists, mathematicians, 

 physicists or chemists — who study the living state, than 

 they have up to now received. Having agreed that there 

 exists no chemistry peculiar to living things and that 

 physical properties are possessed by the living and by the 

 non-living as well, we have remaining the task of evaluating 

 the differences. 



It is not implied that only similarities have been studied 

 and never the differences of the two regions. Nevertheless, 

 those differences which set apart a living thing from a non- 

 living should be studied more extensively as such. I can 

 not see how they can be investigated by physico-chemical 

 methods in the sense of Loeb, that is, by resolution into 

 ultimate particles, by methods suitable for pure compounds 

 used in the chemist's laboratory, or by any other that does 

 not maintain the integrity of the living state. Biology 

 should develop its theories by a method of work adapted to 

 the peculiarities of the living thing and therefore quite 

 distinct from those used in pure physics and pure chemistry. 

 This statement does not imply that we should discard 

 entirely for biology the use of physical and chemical means. 

 Surely, no one would set himself against the use of the 

 microscope or any other most refined apparatus, and of 

 reagents, drugs, dyes, etc., the common equipment in the 

 study of the living thing. Biologists count, measure and 

 weigh and seek to detect cause and effect. But whatever 

 means we employ should be adapted to that particular level 

 which the living thing occupies in the natural world. 



In an investigation which aims to explain the state of 

 being alive, the first prerequisite is the appreciation of the 

 limits which circumscribe this state. In the utilization 

 of physico-chemical means, then, we need to recognize the 

 extent to which we change the living state; and, if we go 



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