238 THE DESCENT OF MAN. Part I. 



Extinction follows chiefly from the competition of 

 tribe with tribe, and race with race. Various checks 

 are always in action, as specified in a former chapter, 

 which serve to keep down the numbers of each savage 

 tribe, — such as periodical famines, the wandering of 

 the parents and the consequent deaths of infants, pro- 

 longed suckling, the stealing of women, wars, accidents, 

 sickness, licentiousness, especially infanticide, and, 

 perhaps, lessened fertility from less nutritious food, and 

 many hardships. If from any cause any one of these 

 checks is lessened, even in a slight degree, the tribe 

 thus favoured will tend to increase ; and when one 

 of two adjoining tribes becomes more numerous and 

 powerful than the other, the contest is soon settled by 

 war, slaughter, cannibalism, slavery, and absorption. 

 Even when a weaker tribe is not thus abruptly swept 

 away, if it once begins to decrease, it generally goes on 

 decreasing until it is extinct. 31 



When civilised nations come into contact with bar- 

 barians the struggle is short, except where a deadly cli- 

 mate gives its aid to the native race. Of the causes which 

 lead to the victory of civilised nations, some are plain 

 and some very obscure. We can see that the cultivation 

 of the land will be fatal in many ways to savages, for 

 they cannot, or will not, change their habits. New 

 diseases and vices are highly destructive ; and it appears 

 that in every nation a new disease causes much death, 

 until those who are most susceptible to its destructive 

 influence are gradually weeded out ; 32 and so it may be 

 with the evil effects from spirituous liquors, as well as 

 with the unconquerably strong taste for them shewn by 

 so many savages. It further appears, mysterious as is 



31 Gerland (ibid. s. 12) gives facts in support of this statement. 



32 See remarks to this effect in Sir H. Holland's ' Medical Notes and 

 Reflections,' 1839, p. 390. 



