THE CHARACTERISTICS OF HUMAN LIFE 57 



on construction of mechanical appliances. This is 

 the difference between polished stone for an arrow- or 

 axe-head, and the modern steam-hammer and tele 

 graphic apparatus. Thought has brought greater 

 mechanical force to our aid, turning even the forces 

 of Nature into service, making less demand on 

 muscular activity, in order to have freer egress for 

 human purpose. This is the distinctive feature in 

 industrial advance. It is thought against muscle; 

 the outcome shows greater resuTts by improved 

 instruments. These few illustrations of the part 

 played in the world by rational power may suffice. 



We are now prepared for comparative results, in 

 the first instance, in view of man s relation to the 

 animals most associated with him ; and next in view 

 of the distinction in his own life between functions 

 physical and rational, expressing the dualism noted 

 in his life. We seek reliable classification of the 

 functions, without as yet touching the theoretic 

 question as to the origin of the differences ob 

 served. 



The warrant for classifying man with animals is 

 clear. Human organism belongs in all respects to the 

 system of organic life, moulded on the same plan, 

 subject to the same laws of health, liable to the same 

 diseases, endowed with analogous sensibilities and 

 powers of locomotion. A man depends upon food, 

 air, and exercise, just as a dog does. In all organism 

 alike, there is tear and wear, as with machinery ; in 

 all, combustion by effort ; in all, need for renewal of 

 energy by nutriment. Physical energy, and physical 

 work, are strictly analogous through all Nature. 

 Distribution of life over the globe shows adaptation to 



