Theories of Life, Mechanical and Vitalistic 329 



ever, state with some assurance, that at present we can- 

 not see how any known principles of chemistry or of 

 physics can explain the development of a definite form 

 by the organism or by a piece of the organism. Indeed, 

 we may even go farther, and claim that it appears to be 

 a phenomenon entirely beyond the scope of legitimate 

 explanation, just as are many physical and chemical 

 phenomena themselves, even those of the simplest sort. 

 To call this a vitaUstic principle is, I think, misleading. 

 We can do nothing more than claim to have discovered 

 something that is present in living things which we can- 

 not explain and perhaps cannot even hope to explain 

 by known physical laws" (p. 255). This seems to con- 

 cede the main claim of the vitaUsts. Yet, later on, we 

 find these words : '' To prevent misunderstanding, it may 

 be added that while, from the point of view here taken, 

 we cannot hope to explain the behaviour of the organism 

 as the resultant of the substances that we obtain from it 

 by chemical analysis (because the organism is not simply 

 a mixture of these substances), yet we have no reason 

 to suppose that the organism is anything more than the 

 expression of its physical and chemical structure. The 

 vital phenomena are different from the non-vital phenom- 

 ena only in so far as the structure of the organism is 

 different from the structure of any other group of sub- 

 stances ' (pp. 280 f.). This seems to concede the claim 

 of the physicochemical theory except for the reservation 

 regarding structure ; and this reservation is most wisely 

 made. For it is just this reservation which, from the 

 point of view of this work, completely neutralizes the 

 claim that an explanation is nothing other than a reduc- 

 tion of a whole to its elements. Such a claim leaves 



