PHYSICAL AND CHEMICAL METHODS 25 



in, the experimenter must never forget that the living being 

 forms a complete organism. It has a personality, and the 

 biological phenomenon as a whole is not simply due to the 

 summation of elementary chemical phenomena, but to the 

 order in which these phenomena occur in time and space. 

 This order appears to be the expression of a pre-determined 

 purpose. 



Sir Frederick Gowland Hopkins, one of the founders of 

 modern bio-chemistry, wrote the following lines in 1925 

 {Lancet)^ in an article protesting against the term 'protoplasm' 

 taken as a definition of the elementary living substance: 



'There is no such thing as living matter in a specific sense. 

 The special attribute of such systems from a chemical 

 standpoint, is that these reactions are organized, and not 

 that the molecules concerned are fundamentally different 

 in kind from those the chemist meets elsewhere.' 



The phenomena of life considered in their different aspects 

 and intimate nature are thus simultaneously characterized by 

 special forms which distinguish them as 'life phenomena' and 

 by an identity of laws which incorporates them with the 

 other phenomena of the cosmic world. It must be admitted 

 that, if there are special procedures in all vital phenomena, 

 at the same time they all obey the laws of mechanics, physics, 

 and ordinary chemistry. 



We have written, it must, purposely. This is not a profession 

 of faith, for all professions of faith, be they vitalistic or 

 materiaUstic, are unscientific. But itjs important to orient 

 research by means of a hypothesis, and it is impossible actually 

 to avoid this one. That experiments should absolutely con- 

 firm or invahdate it, is immaterial to a man of science, or 

 rather, to be exact, should be immaterial. Passions, which 

 have nothing in common with science, have weighted the 

 scales alternately on the vitalistic and mechanistic sides without 

 any real benefit, for it is not by speeches but by experiments 

 that human knowledge is advanced. There is much to be said 



