340 THE MULES. 



like the ancients, reside in the presence of uncon- 

 trouled animal nature, we have found that, like 

 them, though they believe in heterogeneous inter- 

 mixtures known to he untrue, they nevertheless 

 infer them from others which have every appear- 

 ance of reality; thus, we may instance the well 

 authenticated fact of the- American bison, in the 

 frenzy of defeat and expulsion, forcing his way to 

 seek companions among domestic cows, whose do- 

 mesticity in this case is an accident, not a cause : 

 we may point out likewise, in the rut of Indian 

 repudiated Axine bucks producing among the un- 

 speckled Porcine the intermediate well known breed 

 of spotted hog-deer, an instance where both species 

 are wild. 



" In Natural History," Cuvier remarks, " we 

 judge from the forces acting at present on the law. f 

 of nature, and not from those of a different charac- 

 ter which have ceased to operate, or are no longer 

 within reach of observation." To render this maxim 

 wholly admissible, it would be necessary to sub- 

 stantiate the facts: undoubtedly the period when 

 animals extended their habitation after primitive 

 distribution is in a great measure past, excepting 

 where the intervention of man continues to act ; yet 

 it is not wholly so, nor is it proved that the earlier 

 migrations of mammals were entirely without human 

 intervention. If the feral horse, stretching without 

 his instrumentality towards Tierra del Fuego and 

 to California, is not wholly free from objection, the 

 progress of the Bengal tiger to the reedy shores of 



