CHAPTER IX. 



On the Causes of the Varieties of the Human Species, 



Having examined the principal points in which the several 

 tribes of the human species differ from each other 5 namely, 

 the colour and texture of the skin, hair, and iris, the fea- 

 tures, the skull and brain, the form and proportions of the 

 body, the stature, the animal economy, the moral and intel- 

 lectual powers, I proceed to enquire whether the diversities 

 enumerated under these heads are to be considered as cha- 

 racteristic distinctions coeval with the origin of the species, 

 or as the result of subsequent variation ; and in the event 

 of the latter supposition being adopted, whether they are 

 the effect of external physical and moral causes, or of native 

 or congenital variety. The very numerous gradations which 

 we meet with, in each of the points above mentioned, are 

 almost an insuperable objection to the notion of specific 

 difference ; for all of them may be equally referred to original 

 distinction of species ; yet if we admit this, the number 

 of species would be overwhelming. On the other hand, 

 the analogies drawn from the animal kingdom, and ad- 

 duced under each head, nearly demonstrate that the characte- 

 ristics of the various human tribes must be referred, like the 

 corresponding diversities in other animals, to variation. 

 Again, I have incidentally brought forwards several argu- 

 ments to prove that external agencies, whether physical or 

 moral, will not account for the bodily and mental differences 

 which characterize the several tribes of mankind ; and that 

 they must be accounted for by the breed or race ^, This 

 subject, however, requires further illustration. 



* See sect. ii. chap, ii, p. 277, and following; chap. iv. p. 357, and fol- 

 lowing ; chap. vi. p. 406. 



