350 SPARKS FROM A GEOLOGIST'S HAMMER. 



reach, and building the organism according to a certain 

 pattern; and there are the external conditions in the 

 presence of which these activities are carried on. What- 

 ever influence the environment may exert, it can obvi- 

 ously be no more than a conditioning influence, since 

 whatever is done with the organic structure is done in 

 the organism and through physiological processes and in- 

 strumentalities. Now, whatever may be the nature of 

 the forces acting within, it is conceivable that they may 

 be conditioned or determined in their activity by the 

 quality and quantity of food, water, air, warmth and rest. 

 These belong to the environment. Variations in the sup- 

 ply of these requisites depend on two classes of influences. 

 These are the natural influences arising from daily, sea- 

 sonal, periodical and secular changes in the supplies 

 and from the movements and migrations of the animal. 

 These variable factors have been taken into the account by 

 the older transmutationists, Lamarck and St. Hilaire, and 

 by the later Darwinists. Then there are the artificial 

 influences (as we may style them) arising from the con- 

 tests of individuals for the possession of the requisites of 

 life. They might be styled the volitional conditions, in 

 distinction from the non-volitional or cosmical conditions. 

 These contests constitute the "struggle for existence," 

 which is the peculiar feature of Darwinian derivative 

 doctrine. The outcome of this struggle is always the 

 " survival of the fittest," and a concomitant tendency of 

 the specific type to improve. It is thus that the envi- 

 ronment of cosmical or volitional concomitants may deter- 

 mine, promote or limit the organic activities of animals 

 that have come into the world and entered upon the 

 struggle for self support. Undoubtedly the outcome of 



