DEFINITION OF SPECIES. 359 



great advantage even to chemistry itself, now 

 become so vast and accurate a science. 



Independently of all general methods of 

 classiilcation, whether natural or artificial, 

 plants, as well as animals, are distinguished 

 into Genera*, Species, and Varieties. 



By Species are understood so many indi- 

 viduals, or, among the generality of animals, 

 so many pairs, as are presumed to have been 

 formed at the creation, and have been perpe- 

 tuated ever since ; for though some animals 

 appear to have been exterminated, we have 

 no reason to suspect any new species has 

 been produced ; neither have we any cause 

 to suppose any species of plant has been lost, 

 nor any new one permanently established, 

 since their first formation, notwithstanding 

 the speculations of some philosophers. We 

 frequently indeed see new Varieties, by which 

 word is understood a variation in an esta- 

 blished species ; but such are imperfectly, or 



* Our scientific language in English is not sufficiently 

 perfect to afford a plural for genus, and we are therefore 

 obliged to adopt the Latin one, genera, though it exposes 

 us sometimes to the horrors of hearing of " a new ge- 

 nera" of plants. 



