106 THE DESCENT OF MAN. [Part I. 



mit their bad qualities. Melancholic and insane persons 

 are confined, or commit suicide. Violent and quarrel- 

 some men often come to a bloody end. Restless men who 

 will not follow any steady occupation — and this relic of 

 barbarism is a great check to civilization 16 — emigrate to 

 newly-settled countries, where they prove useful pioneers. 

 Intemperance is so highly destructive, that the expecta- 

 tion of life of the intemperate, at the age, for instance, 

 of thirty, is only 13.8 years; while for the rural laborers 

 of England at the same age it is 40.59 years. 17 Profligate 

 women bear few children, and profligate men rarely 

 marry ; both suffer from disease. In the breeding of do- 

 mestic animals, the elimination of those individuals, though 

 few in number, which are in any marked manner inferior, 

 is by no means an unimportant element toward success. 

 This especially holds good with injurious characters which 

 tend to reappear through reversion, such as blackness in 

 sheep ; and with mankind some of the worst dispositions 

 which occasionally without any assignable cause make 

 their appearance in families, may perhaps be reversions 

 to a savage state, from which we are not removed by very 

 many generations. This view seems indeed recognized in 

 the common expression that such men are the black sheep 

 of the family. 



With civilized nations, as far as an advanced stand- 

 ard of morality, and an increased number of fairly well- 

 endowed men are concerned, natural selection apparently 

 effects but little; though the fundamental social instincts 

 were originally thus gained. But I have already said 

 enough, while treating of the lower races, on the causes 



16 'Hereditary Genius,' 1870, p. 317. 



17 E. Ray Lankester, 'Comparative Longevity,' 1S70, p. 115. The 

 table of the intemperate is from Neison's ' Vital Statistics.' In regard to 

 profligacy, see Dr. Farr, " Influence of Marriage on Mortality," ' Nat 

 Assoc, for the Promotion of Social Science,' 1858. 



