LETTERS TO BROTHER JOHN. 171 



becomes gradually firmer up to the age of seven; 

 when the child, after going through the dangers of 

 dentition, will probably live forty-two years and 

 three months. After this period, the sum of pro- 

 babilities, which had gradually increased, under- 

 goes a progressive decrease; so that a child of 

 fourteen cannot expect to live beyond thirty-seven 

 years and five months; a man of thirtVj twenty- 

 eight years more ; and, in the last place, a man of 

 eighty-four but one year more. Such is the result 

 of observation, and of calculations on the different 

 degrees of probability of human life, by Halley, 

 Graunt, Kersboom, Wargentin, Simson, Depar- 

 cieux, Dupre de St. Maur, Buffon, D'Alembert, 

 Barthez, and M. Mourgues." De Lys* Richerand. 

 How is it, that of the whole number of children, 

 so few, so very few, live long enough to fulfil the 

 final cause of human existence ? 



Now if, in contemplating the system of man in 

 connexion with the other systems of nature, we be 

 able to discover any one very striking difference 

 wherein his system differs from all others, may we 

 not fairly presume that this difference between 

 them is the cause of the remarkable and otherwise 

 unaccountable anomaly above mentioned? 



We need not look far, nor ponder long, in order 

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