THEORY OF LIFE 115 



Gravity is not momentarily of concern. 



The viscosity of the medium, a very important 

 factor when the displacement of colloid particles or 

 other particles or units of molecular dimensions are 

 under consideration, for merely the moment pos- 

 tulated may be considered a negligible factor, since — 

 as it will appear — the units whose movements are 

 followed are electrons. 



The inquiry, at the critical moment postulated, 

 then, is not concerned with the mean free path of 

 particles within the range of dimensions that are 

 associated with colloidal phenomena, the Brownian 

 movement of which (with introduction of the van't 

 Hoff factor i) obeys the gas law. Obviously, ques- 

 tions of equilibrium to which Gibbs*s phase rule 

 would apply, are not directly involved. Nor, at the 

 critical moment, does the inquiry pertain to the 

 problem of valency, or the association of atoms to 

 form molecules. 



Though the importance of light and sunshine to 

 life is well known, and the large place of radiation 

 appears from the photochemical facts, the photo- 

 electric effect, the Compton effect (serving as an 

 interpretation), the activation of certain unfer- 

 tilized eggs by specific rays, the lethal effect of sun- 

 shine on bacteria, etc., the problem of radiation 

 need not enter at the critical moment. Radiation, 



