190 The Descent of Man. Part I. 



whilst most cf the others fail to breed. The males and females 

 of some sjDecies when confined, or when allowed to live almost, 

 but not quite free, in their native country, never unite ; others 

 thus circumstanced frequently unite but never produce offspring ; 

 others again produce some offspring, but fewer than in a state 

 of nature ; and as bearing on the above cases of man, it is 

 important to remark that the young are apt to be weak and 

 sickly, or malformed, and to perish at an early age. 



Seeing how general is this law of the susceptibility of the 

 reproductive system to changed conditions of life, and that it 

 holds good with our nearest allies, the Quadrumana, I can 

 hardly doubt that it applies to man in his primeval state. Hence 

 if savages of any race are induced suddenly to change their 

 habits of life, they become more or less sterile, and their young 

 offspring suffer in health, in the same manner and from the same 

 cause, as do the elephant and hunting-leopard in India, many 

 monkeys in America, and a host of animals of all kinds, on removal 

 from their natural conditions. 



We can see why it is that aborigines, who have long inha- 

 bited islands, and who must have been long exposed to nearly 

 uniform conditions, should be specially affected by any change 

 in their habits, as seems to be the case. Civilised races can 

 certainly resist changes of all kinds far better than savages; 

 and in this respect they resemble domesticated animals, for 

 though the latter sometimes suffer in health (for instance 

 European dogs in India), yet they are rarely rendered sterile, 

 though a few such iustances have been recorded. 47 The 

 immunity of civilised races and domesticated animals is 

 probably due to their having been subjected to a greater extent, 

 and therefore having grown somewhat more accustomed, to 

 diversified or varying conditions, than the majority of wild 

 animals; and to their having formerly immigrated or been 

 carried from country to country, and to different families or 

 sub-races having inter-crossed. It appears that a cross w T ith 

 civilised races at once gives to an aboriginal race an immunity 

 from the evil consequences of changed conditions. Thus the 

 crossed offspring from the Tahitians and English, w T hen settled 

 in Pitcairn Island, increased so rapidly that the island was soon 

 overstocked ; and in June 1856 they were removed to Norfolk 

 Island. They then consisted of 60 married persons and 131 

 children, making a total of 194. Here they likewise in- 

 creased so rapidly, that although sixteen of them returned to Pit- 

 cairn Island in 1859, they numbered in January 1868, 300 souls; 



17 'Ya-riat 3n of Animals,' &c., vol. ii., p 16. 



