CUTICLE, NAILS, HAIR AND FEATHERS. $75' 



powers, is adequate to reproduce a similar set of in- 

 dividuals. Every species of living beings owes its 

 origin to a series of events connected together as 

 cause and effect, operating intimately on matter, 

 and yet liable to be easily removed from the whole 

 material world. There is no visible law of necessary 

 operation, affording security for the permanence of 

 any organized species. The mode of its introduc- 

 tion in the former history of things, or of its sup- 

 posable re-introduction at a future epoch, eludes 

 inquiry, excepting in so far as the history of organic 

 remains shews that organization, in its forms and 

 laws, has undergone revolutions which force us to 

 recognize the operation of causes to us unseen, be- 

 ing removed from the range of all that we can dis- 

 cover by the most acute reflections on such laws as 

 fall within our view. 



The naturalist, therefore, in extending his inqui- 

 ries, dwells at greatest leisure on objects which his 

 senses can discover. Every thing else is general. 

 These alone are particular. In these inquiries, he 

 can only make more or less near approaches to a 

 knowledge of the nature of organic assimilation. 

 He cannot reach this knowledge itself. He can- 

 not any farther estimate the functions of the parts, 

 than by observing them in a stage as near as possi- 

 ble to the accomplishment of their object, and by 

 instituting a due examination of the nature of the 

 change that is effected. 



s 2 



