THE WONDER OF LIFE 623 



which these facts represent may not be exhausted by 

 formulae in terms of matter and motion, but for the theore- 

 tical purposes of description, and for the practical purposes 

 of anticipation and mastery these formulae suffice. The 

 facts may be treated as parts of a mechanism, on the view 

 that all are ' merely comphcated cases of change of con- 

 figuration in a system of mass particles '. The processes of 

 the physical order are marked, as every one knows, by their 

 rigid uniformity of routine, their monotonous sequences, 

 which are hke chains of iron. They can be described with 

 extraordinary precision — on which we stake our lives 

 every day — by means of formulae which have only a few 

 factors in them. At present, these factors seem to be not 

 more than five — ^the ether, the electron, the atom, the 

 molecule, and the mass, energy being ' involved in the 

 construction of any of these out of any other '. The 

 question with which vitalists are chiefly concerned is 

 whether these concepts are adequate for a useful descrip- 

 tion of the activities of organisms — ioi a description which 

 will make the facts of life more intelligible, by showing 

 them to be particular cases of something more general. 

 For that is what ' making a thing intelhgible ' usually 

 means. It must be quite clearly understood that as 

 material systems in space, organisms ' conform to the laws 

 of the physical universe ' : gravity afiects a bird just as 

 it affects a stone, the properties of a hydrogen atom are 

 the same whether it forms part of a scholar or of his mid- 

 night oil, capillarity is as inexorable in a blood vessel as in 

 a glass tube ; but what the vitalist says is that all the 

 available knowledge of chemical and physical happenings 

 within the organism does not begin to answer the distinc- 

 tively biological questions. 



