SECT. IV.] GROUNDS FOR CLASSIFICATION. 221 



tion, that at a remote time the human organism was more 

 plastic under external agencies, just as every individual and 

 every people has a juvenile period before their transition from 

 the natural to the civilized state, in which they are more 

 plastic than at any later period. 



We conclude, therefore, that there are no fixed and definitely 

 limited forms which can be considered as specific differences ; 

 but that if the human species is zoologically to be brought 

 under some chief divisions, it is a mere classification furnished 

 to us by striking analogies. Lesson 1 observes very justly, 

 " On ne devrait en effet adopter les distinctions de races ou 

 d'especes 2 que com/me des moyens artificiels destines d preciser nos 

 idees dans V etude de I'homme, et d le rendre plus facile" J. 

 Miiller 3 expresses himself in a similar sense when he says, t ' that 

 a rigid division of mankind is impossible. The given forms 

 differ in typical peculiarities; but there is no certain scien- 

 tific principle for fixing the limits specifically. It might 

 be more proper to distinguish all peoples as constant and 

 extreme forms of variations, than to distribute them into 

 races. This seems impossible, nor does science require 

 such a division ; to attempt it leads unavoidably to an arbi- 

 trary assumption." Tartars and Finns will always occupy 

 an unknown position between the Mongolian and Caucasian 

 race ; Papuas and Alfurus between Malays and Negroes, etc. 

 The impossibility of a rigid separation is confirmed by an expe- 

 rimental study of race-characters, and also by the fact that 

 only small collections of skulls exhibit decidedly different 

 forms ; whilst large collections fill up the gaps between them, 

 showing continued transitions from one form into every other. 

 If, in order to oppose the argument founded upon the 

 above facts, many originally different human species are 

 assumed in that part of Africa situated between the tropics, 

 all difficulties are removed, inasmuch as such assumptions 



1 " Voyage medical autour du monde," p. 156, 1829. 



2 As regards species, this is an error, though it is true with respect to races. 

 The question in relation to the first has been awkwardly treated, for they 

 have disputed whether species were created or were only by us introduced in 

 nature. Species are, no doubt, objective realities, not merely thoughts or 

 models according to which nature acts. 



3 "Handbuch der Physiol.," ii, 114. 



