Human Physiology. 7 



hundred people to the square mile. There are tropical 

 countries that can sustain one thousand to the square mile. 

 If we take the actual population of some of the Belgian 

 provinces as a. fair average of the capacity of land under high 

 culture to support inhabitants, the earth might feed twenty- 

 five times its present population twenty-five billions. For ages 

 to come, therefore, the population question which has given so 

 much trouble to political economists, is only a question of 

 emigration, colonisation, the distribution of surplus popula- 

 tions, and the subjugation and cultivation of man's heritage. 



The life of each generation of men is reckoned at thirty 

 years. In a thousand years, therefore, thirty-three generations 

 thirty-three thousand millions pass through this stage of 

 being. 



In considering the present and probable future condition 

 of man on the earth, it is not necessary to take much account 

 of the savage tribes which are disappearing from America, 

 Australia, Sosth Africa, and the Islands of the Pacific Ocean. 

 In a few generations these COUP tries will be entirely peopled 

 by descendants of English, Scotch, Irish, and German emi- 

 grants, with lesser intermixtures of the Scandinavian and Latin 

 races of Europe. The Chinese and Japanese may help to 

 people the western shores of America; China and India may 

 rise to a higher phase of civilisation, or sink before the more 

 energetic populations of the Sclavonic or Anglo-Celtic races. 

 The problem of the civilisation or extinction of the Negro 

 tribes of Africa will be settled during the coming century. 



I propose in this work to consider the condition of man in 

 the highest civilisation to which he has attained, and I shall 

 therefore take England as an example of the highest develop- 

 ment of human industry, commerce, wealth, and moral and 

 political power and greatness. Other nations, no doubt, are 

 in advance of England in certain particulars. Education is 

 more general and thorough in Germany and Switzerland, and 



