444 



riod of old age. Whatever regimen may have been followed, man at 

 that age is truly old, and cannot but be aware of it. 



CCLXI. Of the jirobabilities of human life. Man dies at all ages 5 and 

 if the duration of his life Surpasses that of the lower animals, the grcai: 

 number of diseases to which he is liable, renders itmuch more uncertain, 

 and is the cause why a much smaller number arrive at the natural term 

 of existence. It has been attempted to discover what are the probabili- 

 ties of life, that is, to ascertain, from observation, how long a man may 

 expect fo live,, who has already reached a determinate age. From late 

 accurate observations of the age at which a number of persons have .died* 

 and from a comparison of the deaths with the births, it has been ascer- 

 tained) that about one-fourth of the children that are born, die within 

 the first eleven months of life : one-third between twenty-three months 5 

 and one-half before they reach the eighth year. Two-thirds of mankind 

 die before the thirty-ninth year, and three-fourths before the fifty-first; so 

 that, as Buffbn observes, of nine children that are born, only one arrives 

 at the age of seventy-three ; of thirty, only one lives to the age of eighty; 

 while out of two hundred and ninety-one, one only lives to the age of 

 ninety; and in the last place, out of eleven thousand nine hundred and 

 ninety-six, only one drags on a languid existence to the age of a hundred 

 years. 



The mean term of life is, according to the same author, eight years, 

 in a new-born child. As the child grows older, his existence becomes 

 more secure, and after the first year, he may reasonably be expected to 

 live to the age of thirty-three. Life becomes gradually firmer up to the 

 age of seven, when the child, after going through the dangers of denti- 

 tion, will probably live forty-two years and three months. After this pe- 

 riod, the sum of probabilities, which had gradually increased, undergoes 

 a progressive decrease; so that a child of fourteen cannot expect to live 

 beyond thirty-seven years and five months ; a man of thirty, twenty-eight 

 years more ; and, in the last place, a man of eighty-four, one year only. 

 From the eighty-fifth to the ninetieth year, probabilities remain station- 

 ary, but after this period, existence is most precarious, and is painfully 

 carried on to the end. Such is the result of observation, and of calcula- 

 tions on the different degrees of probability of human life, by Halley, 

 Graunt, Kersboom, Wargentin, Simson, Deparcieux, Dupre de St. Maur, 

 Buffon, d'AIembert, Barthez, and M. Mourgues, who has just published 

 his observations, collected at Montpelier, in the course of a great number 

 of years, and with the most scrupulous accuracy*. 



* From the observations made during more recent periods, it would appear that the 

 mean duration of human life has experienced an increase of nearly five years in the 

 greater number of European countries. This may be in some measure owing to the 

 introduction of vaccination, but perhaps the chief causes may be found in the progress 

 of science and civilization, giving rise to a general improvement in the habits of life, 

 particularly with regard to ventilation and cleanliness ; to better habitations; a more 

 ample supply of food, clothing, and fuel; greater sobriety; a more general cultivation 

 of the soil, and consequent removal of the sources of several diseases; to improved ma- 

 nagement of children ; and to the advanced state of medical knowledge. 



The same causes that conduce to longevity must, of course, increase the population of 

 a country. The suppression of monastic celibacy, and the more equal distribution of 

 landed property, consequent on the revolution in France, have tended to increase the 

 population of that country, notwithstanding the destructive wars in which she has been 

 engaged. Copland 



