MICROBES AS EMPIRE BUILDERS 283 



who, four centuries ago, numbered no more than the present inhabi- 

 tants of Greater London, has increased nearly fifty-fold. The 

 greatest world-force to-day, it seems certain to maintain its 

 position, for the sword as a means of founding permanent empires 

 went out of date with the coming of civilization, and the regions 

 that disease can lay waste are all occupied, not by mere conquerors, 

 but by colonists rooted in the soil and resistant to every disease 

 that is likely to afflict them. No other race in the world has such 

 room for growth and expansion as the Anglo-Saxon. 



