PHYSICAL EVOLUTION 221 



the physical conditions of life, side by side with the competition 

 between man and man, in which even now the question of life or 

 death is often involved, there is going on a struggle between 

 nations. Even during times of peace there is a race for the most 

 habitable or wealth-producing parts of the earth, and the question 

 who shall occupy them is decided largely by the amount of 

 armed strength that the rival claimants among the nations have 

 to show. In fact it is a state of perpetual war in which the 

 combatants, as a rule, instead of coming to actual blows display 

 their forces, upon which the weaker retires, ruminating on 

 enlarged military or naval programmes. Though it can never 

 happen that any of the European nations, even in the event of a 

 great war, ending in the complete victory of one side, will 

 disappear in the sense that it will have no descendants, yet the 

 number of its descendants depends very largely on wars and 

 menaces of war. The country that secures the best of the 

 earth will send out more colonists than the country that has 

 to send its sons to live among foreigners and speak a strange 

 language. 



National prosperity and strength lead to rapid multiplication : The moral 

 and national strength depends as much on moral evolution as on factor 

 physical and intellectual evolution. The citizens must be ready 

 to make sacrifices for the common good : the rich must see that 

 the poor are lifted out of squalor. Without this, hard conditions 

 may make the breed physically strong, but the nation will be 

 weak. National strength is the resultant of two factors which 

 find it difficult to go in harness together : of a hard environment, 

 that makes the component units of the nation hard as itself, and 

 of a spirit of mutual help that in days of wealth and science 

 tends to soften all that is hard. 



Sexual Selection works side by side with Natural Selection, Sexual 

 supplementing it and making it more drastic. I have written at Selection 

 length on its working among mammals and birds and here it is 

 only necessary very briefly to recall the conclusions arrived at. 

 The result of sexual selection, e.g. among migratory birds, is that 

 the best pair with the best and the worst are left to pair with the 

 worst. And thus the hand of Natural Selection falls very heavily 



