188 THE CLIMATIC FACTOR AS ILLUSTRATED IN ARID AMERICA. 



Immigrants from other regions, if such were really the bringers of the seeds of civilization, 

 did not degenerate rapidly, for their descendants must have been full of energy and initiative 

 for centuries before a culture so highly impregnated with local character could have devel- 

 oped. And finally the ancient people succeeded in conquering regions that now arc 

 unconquerably forested and feverish. 



In order to explain this strange contradiction between the past and the present two 

 possibiUties present themselves. The first is that the ancient inhabitants of Yucatan, in 

 spite of their lack of beasts of burden and tools of iron, could accompHsh all manner of 

 things which modern man can not. They could clear and cultivate the dense forest, they 

 could resist its debilitating fevers, they could work with constant energy in spite of the 

 enervating climate, and they could persist in doing all these things for centuries. In 

 other words, they were greatly superior to any modern race. This is the common, although 

 unexpressed assumption. The other possibility is that the rainfall was formerly less than 

 at present, so that regions now covered with forest then bore only jungle, that fevers were 

 less abundant than now, and that the climate was not so enervating. This second i)ossi- 

 bility seems to demand less radical assumptions than the first. It simply requires us to 

 believe that the same sort of thing has happened in Yucatan which we have reason to 

 believe has happened elsewhere. 



