BACTERIA AS EMPIRE BUILDERS 187 



of greater proportions than all the mass of trivial gossip 

 about kings and queens and the accounts of futile dynastic 

 wars and stupid religious controversies which fill so large a 

 space in his written political history. In the latter as told 

 by historians, groping in obscurity and blinded by their own 

 preconceptions, men and events are often distorted out of all 

 proportions. A clever but prejudiced writer may pass base 

 metal into perpetual circulation as gold. Luther and the 

 Reformation are accepted as Divine by many people ; they 

 are reviled as diabolical by more. Cromwell was long 

 regarded as accursed ; to-day he is half deified. How many 

 of us are able to decide on grounds of fact, not of fiction, 

 whether the Roman Empire perished because the Romans, 

 becoming luxurious, sinned against our moral code, as ecclesi- 

 astic historians would have us believe, or because a disease 

 of monkish bigotry and stupidity clouded the clear Roman 

 brain and enfeebled the strong Roman hand, as Gibbon 

 would have us think. But the Natural History of Man 

 deals without obscurity and without uncertainty with greater 

 matters. Study it, and the mists clear away from much 

 even of political history. We see clearly how little the 

 conscious efforts of man have influenced his destiny. We 

 see forces, unrecognized, enormous, irresistible, unchanging, 

 working slowly towards tremendous conclusions forces so 

 irresistible and unchanging that watching them we are able 

 even to forecast something of the future. 



312. The mere political results of Man's evolution against 

 disease are of almost incalculable magnitude. The human 

 races of one half of the world are dying, and are being 

 replaced by races from the other half. Not all the wars 

 during all time taken together constitute so great a tragedy. 

 A quite dispropbrtionate part in this great movement has 

 been borne by our own race. It has seized on the larger 

 part of those regions in which the aborigines were incapable 

 of civilization and were undefended by malaria. In the great 

 void created by disease it has more room wherein to spread 

 and multiply than any other race. The world-predominance 

 of the future, therefore, seems assured to it. Our birth- 

 rate, it is true, is falling, and is likely to fall still more. 

 It is lower than that of many other peoples. But medical 

 men know that the fall is due to no loss of natural fecun- 

 dity; but merely to the inevitable spread of physiological 

 knowledge a knowledge which is being gradually acquired 

 and used by all civilized races. Other nations may dream 

 of foreign conquest, but the time for founding permanent 



