ON PROOF 273 



It would seem plain that the general law of the 

 structure of living matter and the definition of life and 

 of death are amenable to proof in the laboratory of 

 the physicist. But because the problem of the 

 structure of living matter (no less than the problem 

 of the structure of inert matter) ultimately is a prob- 

 lem of atomic physics, the physicist is the only one 

 who has the tools, or who, finding his tools inade- 

 quate, can contrive tools, to test for the law and the 

 definitions. Of all who heretofore have testified con- 

 cerning the problem of life in one or another of its 

 aspects, not one has the tools for this investigation. 

 This question of direct experimental proof of the 

 theory then cannot be answered by the paleontol- 

 ogist (whose facts in every way satisfy the demands 

 of the theory), the comparative anatomist and the 

 embryologist — who have been the chief witnesses on 

 the question of descent; nor by the physiologist, nor 

 the cytologist, nor the psychologist, and by neither 

 the biochemist nor the physical chemist. The biolo- 

 gist, as such, does not have the means of approach 

 to the problem involved in this question of proof. 

 Proof can be supplied only by the physicist. 



The work required certainly is not less difficult, but 

 perhaps is more difficult, than any that yet has been 

 done in physics. That living matter presents peculiar 

 difficulties to direct research is, of course, well known. 



