[88 The Descent of Man. Part 1. 



Lastly, Mr. Macnamara states 44 that the low and degraded 

 inhabitants of the Andaman Islands, on the eastern side of the 

 Gulf of Bengal, are " eminently susceptible to any change of 

 " climate : in fact, take them away from their island homes, and 

 " they are almost certain to die, and that independently of diet 

 " or extraneous influences." He further states that the inhabit- 

 ants of the Valley of Nepal, which is extremely hot in summer, 

 and also the various hill-tribes of India, suffer from dysentery 

 and fever when on the plains ; and they die if they attempt to 

 pass the whole year there. 



We thus see that many of the wilder races of man are apt to 

 ,iuffer much in health when subjected to changed conditions 

 or habits of life, and not exclusively from being transported to 

 a new climate. Mere alterations in habits, which do not appear 

 injurious in themselves, seem to have this same effect ; and in 

 several cases the children are particularly liable to suffer. It 

 has often been said, as Mr. Macnamara remarks, that man can 

 resist with impunity the greatest diversities of climate and other 

 changes; but this is true only of the civilised races. Man in 

 his wild condition seems to be in this respect almost as sus- 

 ceptible as his nearest allies, the anthropoid apes, which have 

 never yet survived long, when removed from their native 

 country. 



Lessened fertility from changed conditions, as in the case of the 

 Tasmanians, Maories, Sandwich Islanders, and apparently the 

 Australians, is still more interesting than their liability to 

 ill-health and death; for even a slight degree of infertility, 

 combined with those other causes which tend to check the 

 increase of every population, would sooner or later lead to 

 extinction. The diminution of fertility may be explained in 

 some cases by the profligacy of the women (as until lately with 

 the Tahitians), but Mr. Fenton has shewn that this explanation 

 by no means suffices with the New Zealanders, nor does it with 

 the Tasmanians. 



In the paper above quoted, Mr. Macnamara gives reasons for 

 believing that the inhabitants of districts subject to malaria are 

 apt to be sterile ; but this cannot apply in several of the abovo 

 cases. Some writers have suggested that the aborigines of 

 islands have suffered in fertility and health from long continued 



toI. i., p. 272. I owe the census of of the above-named works. I have 



the several years to the kindness of omitted the census for 1850, as J 



Mr. Coan, at the request of Dr. You- have seen two widely different num- 



mans of New York ; and in most bers given. 



cases I have compared the Youmans ** * The Indian Medical Gazette, 



figures with those giren in several Nov. 1, 1871, p. 2-40. 



