INTRODUCTION. 13 



for whether among the other species of man which he assumes, 

 there are conditions analogous to our ideas of justice and 

 morality, and if so, of what quality, would require a separate 

 investigation, which would also apply to religious and aesthe- 

 tical notions, etc. If there be various species of mankind, 

 there must be a natural aristocracy among them, a dominant 

 white species as opposed to the lower races who by their 

 origin are destined to serve the nobility of mankind, and may 

 be tamed, trained, and used like domestic animals, or may, 

 according to circumstances, be fattened or used for physiolo- 

 gical or other experiments without any compunction. To 

 endeavour to lead them to a higher morality and intellectual 

 development would be as foolish as to expect that lime trees 

 would, by cultivation, bear peaches, or the monkey would learn 

 to speak by teaching. Wherever the lower races prove useless 

 for the service of the white man, they must be abandoned to 

 their savage state, it being their fate and natural destination. 

 All wars of extermination, whenever the lower species are in 

 the way of the white man, are then not only excusable, but 

 fully justifiable, since a physical existence only is destroyed, 

 which, without any capacity for a higher mental development, 

 may be doomed to extinction in order to afford space to higher 

 organisms. 



To such or similar conclusions, the theory of specific differ- 

 ences among mankind leads us. Thus there are different and 

 more comprehensive interests attached to the question of the 

 unity of the human species, than to the probably unsolvable 

 problem of descent from one pair or several pairs, or the con- 

 test about permanence or mutability of races. 



On these grounds it would be an erroneous conception, 

 which, however, is not rare among naturalists, to think that 

 on physical considerations alone, for or against the permanence 

 of types, we can decide on unity of species j for whatever side 

 we take on the question of the mutability of the external man, 

 we should have to declare against specific differences, if it were 

 to turn out that they all possess the same qualities which 

 arrived at different degrees of development, determined only 

 by external circumstances and mode of life. Though some 



