Decembeb 11, 1914] 



SCIENCE 



843 



and interaction of the parts of the system. 

 SimOarly with life and its manifestations : the 

 complexity of organisms and of organic proc- 

 esses, so far from making us despair of the 

 adequacy of physico-chemical analysis in deal- 

 ing with yital phenomena, seems in fact to the 

 reviewer the surest witness to their essential 

 adequacy. For these vital processes, however 

 complex and mysterious, are unfailingly con- 

 stant in their normal manifestation; one has 

 only to reflect on what is continually happen- 

 ing in the body of a healthy man in order to 

 realize this; and the stability of conditions 

 thus shown surely has the same basis as have 

 the stability and constancy of the simpler non- 

 vital processes which we everywhere find as 

 components of the vital. The basis of this 

 stability is simply the exactitude with which 

 natural processes repeat themselves under 

 identical conditions.^ If this were not the case, 

 how could a physico-chemical system of the 

 vast complexity of (e. g.) the human organism 

 ever exhibit stable existence or constant 

 action? It is impossible to doubt that the 

 constancy with which complex physiological 

 processes operate is conditional on the con- 

 stancy of the simpler component processes — 

 those which form the subject-matter of physico- 

 chemical science. Constancy in the char- 

 acter, mode of action, and interconnection of 

 the component substances and processes is evi- 

 dently indispensable to the constancy or stabil- 

 ity of the product of their integration, the 

 living organism. We find in fact that mys- 

 terious and unintelligible physiological proc- 

 esses, e. g., the regeneration of the lens in the 

 eye of a salamander, recur under appropriate 

 conditions with the same constancy as the 

 simplest and most intelligible, say the forma- 

 tion of a retinal image by that same lens. It 

 is clear that if we admit the adequacy of 

 physico-chemical methods in the one case we 

 must be prepared to do so in the other. 



Second, it is to be noted that the organic 



2 Just why there is such repetition is rather a 

 philosophical than a scientific question; but it 

 seems probable that it is at bottom an expression 

 of the homogeneity of the conditions of natural 

 existence, space and time. 



processes show evidence by their very limita- 

 tions that the underlying mechanisms are 

 strictly physico-chemical in character. Thus 

 vitalists call especial attention to the instances 

 of development and form-regulation which 

 have so far baffled all attempts at physico- 

 chemical analysis. " Does not this mean," 

 Johnstone asks, "that in biology we observe 

 the working of factors which are not physico- 

 chemical ones ? " The limits to the regulative 

 power are less frequently cited by vitalists; 

 yet surely evidence of this kind is equally 

 relevant. Why, if an entelechy can restore 

 the amputated arm of a salamander, can not 

 it perform a similar miracle in the case of a 

 man? The fact is that nothing is proved by 

 citing such cases. But on the whole they 

 seem clearly to imply that the properties of 

 the organism are throughout the properties of 

 physico-chemical systems, differing from in- 

 organic systems simply in their complexity. 

 The reviewer knows of no facts which, viewed 

 without prepossession, necessitate or even 

 unequivocally favor the contrary view. Those 

 vitalists who maintain that material systems 

 are incapable, without the aid of an entelechy, 

 of developing the characteristics of life — and 

 who even hold that fundamental physical laws 

 like the second principle of energetics are 

 evaded by organisms — must adduce evidence 

 of a less doubtful kind in support of their 

 thesis. The peculiarities which organisms ex- 

 hibit appear to the reviewer to lead to precisely 

 the contrary conclusions, and to indicate that 

 stable and constantly acting physico-chemical 

 systems may exhibit a degree of complication, 

 both of composition and of behavior, to which 

 literally no limits can be assigned. 



Another mode of reasoning popular among 

 vitalists, and equally fallacious from the phys- 

 ico-chemical standpoint, is that an entelechy 

 can, without the performance of work, guide 

 or coordinate toward a definite end processes 

 which themselves require the performance of 

 work. This view implies that in the organism 

 molecular movement may be directed, retarded, 

 or accelerated at the will of the entelechy. 

 But in Newton's first law of motion it is surely 

 made clear that any deviation in the move- 



