68 ON VARIETIES, RACES, SUB-SPECIES, AND SPECIES. 



author, or from the circumstances in M'hich he was placed, and 

 which were not sufficient, at the time, to enable him to give an 

 exact definition of the species described by him. It is clear that 

 the errors of which we have spoken might have been avoided, and 

 that they will in time be entirely effaced from our books : for, 

 thanks to the great number of naturalists, thanks to the many 

 travels undertaken for the purpose of advancing natural science, 

 errors committed by carelessness or ignorance are soon detected, 

 and species established from too small a number of individuals to 

 represent them completely, as has been the case with many exotic 

 species, will be sooner or later properly defined. 



Want of irrecision, 



Tiiere is a great difference between a species ill defined, in 

 consequence of what we call eiTors, and species which may be in- 

 exactly defined relatively to the absolute truth, and which we could 

 not know, in our present state of knowledge at least, with respect 

 to the two tilings essential to the notion of species ; the want of 

 precision of which we have to speak as possible, is very different 

 from errors, for want of precision, even if it be real, as we cannot 

 now prove it, can give us no riglit to argue as if it were 

 incontestable. 



Want of precision in defining a species, not considered by 

 naturalists as ill established, may arise from two opposite causes 

 — the definition may give the species too great an extent or may 

 confine it icithin too narrow limits. 



First Case. — Definition too large. 



A definition of a species is too large if it includes as races true 

 species, or in other words, if the individuals of these so-called 

 races have not all, without exception, proceeded from the same 

 male and same female : for example, those naturalists who make 

 man a genus composed of several species, accuse of this fault 

 those who consider man as one species comprehending races 

 which, according to them, have all sprung from one father and 

 one mother. 



Second Case. — Definilio7i too small. 



Notwithstanding the existence of the two opinions relating to 

 the human genus and human sj)ecies, the want of precision aris- 

 ing from a too confined, appears to be commoner than that 

 which arises from a too extended definition ; in our opinion the 

 number of species of which we speak, and which are described 

 among the species of botanists and zoologists, will rather decrease 

 than increase, because it might be found that the races now 

 referred to a single species are in fact so many distinct species ; 



