Ryder.] [May 16, 



chemico-physical basis. It is probably, therefore, not an unjustified as- 

 sumption to state that the acquisition of an increased mass in organic 

 bodies leads to an increased capacity to integrate and assimilate still further 

 additions to the original organized mass, and that if this process could go 

 on indefinitely without the intervention of death and a necessity for'oxy- 

 gen, the earth might be gradually transformed, in so far as its available 

 materials held out for such a purpose, into a few organized individuals. 

 Such a supposition is, however, absurd, since such masses, even were their 

 growth possible, would finally become helplessly immobile from their own 

 weight ; such a process would be self-destructive and incapable of indefi- 

 nite maintenance. 



If, however, the principle that successive increments in the mass of or- 

 ganized bodies, carried with it the implication that such increments imply 

 their capacity to increase more and more rapidly, under favorable condi- 

 tions, or as it may otherwise be expressed, are thus enabled to grow, in 

 virtue of such an inherent property, far beyond the bulk of their original 

 germinal mass, then this deduction must form the basis upon which the 

 phenomena of growth, reproduction and sex must finally be interpreted. 

 This principle affords also the physico-chemical or physiological reason for 

 the foundation of the IV^althusian principle that the production of organ- 

 isms would if unchecked outrun the available food production for a cer- 

 tain section of such organisms, as an aggregate namely, the animal 

 world. 



The foundation of the principle of Mai thus and of the Darwinian prin- 

 ciple founded upon it, therefore lies within the domain of ultimate biologi- 

 cal physics or the molecular dynamics of organized bodies. The main- 

 spring of the principle of natural selection, upon final analysis is not 

 itself a choice between two things but an inevitable consequence of the 

 innate molecular habit of living matter, if I may so express myself. It is 

 physical in that the chemical and physiological laws under which growth 

 or molecular integration can take place are themselves resolvable into 

 physical laws which can be coordinated under the principle of the conser- 

 vation of energy. 



This physical principle of continuous and continuously augmented inte- 

 gration and the consequent increase of the mass of living bodies is the 

 primary conditioning factor of growth by intussusception of similar mole- 

 cules. It initiates the struggle for existence, as the struggle due to motion 

 and the attraction of stellar bodies, maintains the latter in their harmo- 

 nious relations in space. 



This principle must, however, be further qualified in that the properties 

 of the molecular integrating factors of living organisms differ very widely. 

 Some forms (vegetal) under one set of conditions can integrate new and 

 more complex assimilable molecules by recombining binary compounds ; 

 other forms animals can assimilate only such new ternary molecules or 

 such as are very nearly similar to their own, while a third form, the sex- 

 ual, is probably the highest expression of this integration of similar mole- 



