M. Flourens on the Natural History of Man. 357 



of the human species on the different points of the surface of 

 the globe. 



Tte study of these three parts of the physical history of 

 man, formed the subject of my lectures of late years. But I 

 cannot finish this article, without examining a question which 

 is at this day much controverted; — I mean, if the different 

 races of men form a single species, or if, forming different 

 species, they constitute what is called in natural history a ge- 

 nus. A simple glance at the definition of the word species 

 Avill be sufficient to cause all difficulty on this point to vanish. 



Buffon defines species, — ^" A succession of similar individu- 

 als which reproduce each other." M. Cuvier also defines spe- 

 cies, — " The imion of individuals descended from each other 

 or from common parents, and of those who resemble them as 

 much as they resemble each other." Now, it is easy to see 

 that this definition, given by Buffon and M. Cuvier, is com- 

 plex, and that it unites two very distinct facts, viz. the fact of 

 reproduction or of succession, and the fact of resemblance. 



Here the fact of the resemblance is completely subordinate 

 to that of the succession ; and Buffon and Cuvier afterwards 

 agree in this themselves. " The comparison of the resem- 

 blance of individuals is only," says Buffon, " an accessory idea, 

 and often independent of the first (the idea of constant suc- 

 cession by generation)." " The apparent differences of the 

 races of om' domestic species," says M. Cuvier, " are stronger 

 than those of any savage species of the same genus." 



Besides, the appreciation of resemblance is always more or 

 less arbitrary. One naturalist often finds a resemblance im- 

 portant which another naturalist considers slight. The foun- 

 dation of all natural history (for the foundation of all the na- 

 tural history of organized beings is the positive determination 

 of the species) would only repose, then, on an arbitrary ap- 

 preciation. 



The idea of resemblance, as Buffon says, is only an accesso- 

 ry idea. It is, in other words, a subsidiary means which na- 

 turalists employ for want of the only decisive means, the fact 

 of the succession ; but when the decisive means, the fact of 

 the succession is known, the subsidiary means ought to be ex- 

 cluded. 



