256 THE CAUSATION OF DISEASE. 



portion to the rigour of the E ; or, to put it in another way, 

 the greater the struggle against the E the higher the efficiency 

 of S. This truth is well exemplified in the common affairs of 

 life. Every one is aware that the efficiency of a railway 

 service, for instance, is heightened by opposition. Organic 

 evolution is indeed entirely due to rigour of E, and, so soon as 

 that rigour is diminished, evolution ceases and dissolution begins. 

 Examples illustrating this truth are so numerous and obvious 

 that there is no occasion to mention any. 



An adequate supply of food, then, being within the reach 

 of every member of a civilized community, the E is thus far 

 rendered more easy, and this will tend to check the progress 

 of evolution, inasmuch as a number will continue to live who 

 would otherwise die. 



It must not be supposed, however, because the population 

 of civilized communities is increasing and the food supply 

 adequate for all, that therefore the struggle for existence — 

 using this term in the most literal sense — is less among civilized 

 than among primitive communities. The very fact that civilized 

 communities are possessed of such enormous wealth and such 

 abundant food supplies, as compared with primitive commu- 

 nities, shows that, taking one individual with another, the 

 actual struggle must be far greater in the former, for the 

 increased wealth is the outcome of increased labour. Most 

 civilized men, having the capacity and the need for work, do 

 it voluntarily, and play an active part in the great social 

 machinery, so that, as a matter of fact, they struggle hard for 

 existence, and, as a result of this struggle, man is still evolv- 

 ing to something higher than a mere bread-winner. But, 

 although in this sense the struggle for existence is greater in 

 civilized than among primitive communities, yet in another 

 sense it is less severe, seeing that in all civilized communities 

 there is a large number of individuals physically and morally 

 incapable of providing for themselves, and such being, by the 

 forbearance of their brethren, permitted to live, evolution to 

 that extent suffers. 



The E of civilized man is rendered less rigorous in other 

 ways. The individual may be surrounded by the most " easy " 

 E which it is within the power of man to create. In the first 



