Ch. V. of pursuing the opposite Mode. 307 



plan for the extermination of the casual small-pox, 

 draws a frightful picture of the mortality which 

 has been occasioned by this distemper, attributes 

 to it the slow progress of population, and makes 

 some curious calculations on the favourable effects 

 which would be produced in this respect by its 

 extermination.* His conclusions, however, I fear, 

 would not follow from his premises. I am far 

 from doubting that millions and millions of human 

 beings have been destroyed by the small-pox. But 

 were its devastations, as Dr. Haygarth supposes, 

 many thousand degrees greater than the plague,f 

 I should still doubt whether the average popula- 

 tion of the earth had been diminished by them. 

 The small-pox is certainly one of the channels, and 

 a very broad one, which nature has opened for the 

 last thousand years, to keep down the population 

 to the level of the means of subsistence ; but had 

 this been closed, others would have become wider, 

 or new ones would have been formed. In ancient 

 times the mortality from war and the plague was 

 incomparably greater than in modern. On the 

 gradual diminution of this stream of mortality, the 

 generation and almost universal prevalence of the 

 small-pox is a great and striking instance of one 

 of those changes in the channels of mortality, 

 which ought to awaken our attention and animate 

 us to patient and persevering investigation. For 

 my own part I feel not the slightest doubt, that. 



* Vol. i. part ii. sect. v. and vi. 

 t Id. s. viii. p. 164. 



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