CHAPTER I. 



INTRODUCTORY. 



IT is scarcely more than a century since the several 

 sciences to which we apply the general name of Natural 

 History, began to rouse themselves from a sleep into 

 which they had fallen nearly two thousand years before. 

 The middle ages of Natural History are peculiarly the 

 dark ages, and the darkness was dense as it was long. 

 Throughout this long period observers were scarce ; theo- 

 risers and commentators, critics of subjects which they 

 could not comprehend, were numerous ; and the body 

 of naturalists occupied themselves in specious dreams. 

 Here and there, like the flashes which cheer the dark- 

 ness of the polar winter, noble minds rose above their 



B 



