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THOUGHTS ON SPECIES. 



By Brackenrtdge Clemens, M.D. 



{Reprinted from the Journal of the Philadelphian Academy of 

 Natural Sciences.*) 



In the endeavour to form a conception of what constitutes 

 species, our ideas must be separated from the . individual, 

 which is merely the representative of species in some one of 

 its special states or conditions. Every mature or perfected 

 being has had an anterior organic history included in the 

 history of its structural progression, from a collection of 

 simple cells to a natural body, possessing individual and 

 distinctive characteristics. No one of its states or conditions 

 constitutes species ; neither the perfect insect, nor the pupa, 

 nor the larva, nor the ovum, fulfil in themselves the con- 

 ception involved in this term, but simply represent the 

 various relations the individual maintains to physical and 

 animated nature, and during the continuance of which its 

 structural and peculiar biography is written. The perfect 

 being is the temporary expression of a thought or conception 

 involved in the series of actions which constitute in their 

 entity a special and definite creation, and in this state has 

 reached the acme of its perfectibility, a point beyond which 



* [In the original Memoir this forms a portion of the Introduction to 

 a Synopsis of North American Sphingida.'] 



