LONGEVITY IN WARM CLIMATES. 769 



under six years of age. There cannot therefore 

 be a rational doubt, that the general diffusion of 

 sound practical knowledge of the animal eco- 

 nomy among the people, would augment the aver- 

 age duration of life at least 50 per cent. 



In regard to the mean duration of human life 

 in the warm and tropical portions of Asia, Africa, 

 and America, our information is exceedingly im- 

 perfect. But from all the best accounts I have 

 been able to collect from books of travels, there 

 is reason to believe, that in southern Asia, north- 

 ern Africa, and central America, it does not ex- 

 ceed thirty years. For the Hindoos, Arabs, 

 Egyptians, and southern Chinese, are said to be 

 old at fifty, and rarely live beyond seventy years, 

 if we except the Brahmins and the wealthier 

 classes in general, who avoid the noxious influ- 

 ence of a burning sun, and resort to frequent ab- 

 lutions with cold water by which health is pre- 

 served, and life often protracted to eighty, or even 

 to one hundred years in some cases, especially in 

 the extra tropical portions of India, China, and 

 Africa. It is seldom, however, that man arrives 

 at the age of one hundred, even in the north of 

 China, where life is longer than in the southern 

 provinces. For we are informed by Sir John 

 Sinclair, that when in the year 1784, the Emperor 

 Kien Long ordered all the centenarians in his 

 dominions to be numbered, only four could be 

 found. (Code of Health, vol. i. p. 89.) 



In the temperate climate of south Africa, the 



