The Scottish Naturalist. 09 



ciles of life, the following questions occur. Do they arise from 

 admixture of species nearly allied, producing intermediate 

 species?. Are they the diverging ramifications of the living 

 principle under modifications of circumstance ? Or have they 

 resulted from the combined agency of both ? Is there only one 

 living principle ? Does organized existence, and perhaps all 

 material existence, consist of one Proteus principle of life, 

 capable of gradual circumstance-suited modifications and aggre- 

 gations, without bound under the solvent or motion-giv- 

 ing principles, heat or light? There is more beauty and 

 unity of design in this continual balancing of life to circum- 

 stance, and greater conformity to those dispositions of nature 

 which are manifest to us, than in total destruction and new 

 creation. It is improbable that much of this diversification is 

 owing to commixture of species nearly allied : all change by this 

 appears very limited, and confined within the bounds of what 

 is called species. The progeny of the same parents, under 

 great difference of circumstance, might in several generations 

 even become distinct species, incapable of co-reproduction. 

 The self-regulating adaptive disposition of organized life may 

 in part be traced to the extreme fecundity of nature, who, as 

 before stated, has, in all the varieties of her offspring, a prolific 

 power much beyond (in many cases a thousandfold) what is 

 necessary to fill up the vacancies caused by senile decay. As 

 the field of existence is limited and pre-occupied, it is only the 

 hardier, more robust, better-suited-to-circumstance individuals, 

 who are able to struggle forward to maturity j these inhabiting 

 only the situations to which they have superior adaptation, and 

 greater power of occupancy than any other kind : the weaker, 

 less-circumstance-suited, being prematurely destroyed. This 

 principle is in constant action. It regulates the colour, the 

 figure, the capacities and instincts : those individuals of each 

 species whose colour and covering are best suited to conceal- 

 ment or protection from enemies, or defence from vicissitude 

 and inclemencies of climate — whose figure is best accom- 

 modated to health, strength, defence, and support — whose 

 capacities and instincts can best regulate the physical energies 

 to self-advantage according to circumstances, in such immense 

 waste of primary and youthful life — those only come forward to 

 maturity, from the strict ordeal by which nature tests their 



