326 The Theory of Genetic Modes 



series which represents vital growth and development 

 may turn out to be, no one can tell beforehand simply 

 from the formulas drawn from physics and chemistry, just 

 by reason of this fundamental inability of such formulas to 

 exhaust an irreversible series. The fact that it is irrever- 

 sible is itself the fact of genetic importance ; for it shows 

 that the later terms have some character which the earlier 

 have not. 1 



The second of our axioms, however, must also be true, 

 and it bears directly in the opposite direction toward 

 the confirmation of the claim of the physico-chemical 

 theory for those phenomena of life to which retrospective 

 and analytic formulas have legitimate application. The 

 data of all science are, as we have seen, subject to this 

 demand. Looked at as an accomplished fact, a life-phe- 

 nomena is as much a fact subject to the laws of cause and 

 effect and conservation of energy as are the phenom- 

 ena in any other cases involving physical and chemical 

 constituents. The alternatives are often considered : on 

 the one hand, the exclusive recognition of the categories of 

 regularity and uniformity upon which quantitative science 

 rests, that is, the recognition of the vital processes as 

 physical and chemical phenomena solely, and, on the other 

 hand, the reverse the introduction into the body of 

 every living cell of a ' somewhat ' altogether unamenable 

 to law, and not capable of being recognized by positive 

 science at all. But this antithesis is quite unnecessary ; 

 we are not shut up to these alternatives. 



As we have seen, the right of physics and chemistry 

 to the universal application of their formulas to their 



1 Yet fully admitting the right of quantitative science to show, if it can, 

 that it is reversible. 



