80 EVOLUTION AND MAN S PLACE IN NATURE 



ment, will guard against interpretation of facts exclu 

 sively by reference to struggle for existence, conse 

 quent on the relations of numbers to the food-supply. 

 Granting Darwin s induction that a struggle for 

 existence inevitably follows from the high rate at 

 which all organic beings tend to increase/ 1 &quot; allowance 

 must be made for wider modification of organism 

 than this implies, as well as for limitation in repro 

 duction as life advances in the scale. Life is too rich 

 in variety to find adequate explanation of its history 

 in the mere balancing of numbers with food-supplies. 

 Life s potentiality, appearing in the laws of growth, of 

 adaptation, and of heredity, presents attraction for 

 the most exacting and most daring scientific investiga 

 tion. In no life is progress to be explained exclusively 

 by reference to amount of food -supply. Differentiation 

 goes on more freely and more widely in form, than 

 this would suggest. Darwin has said that the term 

 struggle for existence must be used in a large and 

 metaphorical sense ; so must environment be read 

 much more largely than could be suggested by mere 

 dependence on materials for nutriment. 



When the distinction between animal life and 

 rational is specially considered, the difference in 

 relation to environment becomes more marked than 

 at any prior stage. Dependence on environment 

 continues for the highest life, as in the history of 

 lower forms, but it differs greatly in degree and 

 manifestation. In the case of the animals, we see 

 them mastered by environment ; in the case of man, we 

 witness a mastery over environment impossible in the 

 history of lower life. Of this mastery, evidence lies 



1 Origin of Species, p. 46. 



