NATURAL HISTOEY OF MAN. 493 



of human life existing around us. With every allowance 

 for the thousand causes ever controlling or retarding their 

 influence, it seems certain that the higher grades of intellec- 

 tual and social existence continually tend in themselves to still 

 higher elevation. That some part of this effect is due to 

 hereditary transmission (a simple name for a most mysterious 

 fact) we cannot refuse from analogy to believe. We are 

 further called upon indeed, both by reason and analogy, to 

 admit a line of ultimate limit to all such deviations, assigned 

 doubtless to us, as to other forms of created beings, by the 

 great Creator of all. But in our ignorance where this limit 

 lies, such admission does in no way interdict the effort to make 

 the nearest approach to it which the human faculties render 

 possible. 



We have hitherto spoken only of those physical conditions 

 of the human being, by which we consider the unity of the 

 species to be vindicated, and which go yet further to render 

 probable the derivation of the whole from a single stock. 

 We must not let the argument stop here. The proof rises 

 in value and certitude as we admit the intellectual and moral 

 endowments of man into the question. It is very true that 

 from this source as well as from physical configuration, argu- 

 ments have been derived and strongly insisted upon, by those 

 who maintain the specific inferiority of certain races. The 

 mental faculties of the Negro in particular have been placed 

 in pointed contrast with those of the European ; and the in- 

 ference thence drawn that the former is incapable of reaching 

 the intellectual standard of the latter, or an equal grade of 

 social life. The advocate for identity of species has been 

 called upon to produce instances from the Negro race of any 

 high attainments in civilisation, literature, or philosophy; 

 and in default of these, summary judgement has been taken 

 against the whole race in question. 



On a subject of this kind, however, we must not be governed 



