VOL. XXXII.] PHILOSOPHICAL TRANSACTIONS. 6l5 



has considerably exceeded the medium we have determined, by taking in 42 

 years. 



There is another method, which, if put in practice in several large towns, or 

 parishes, and for a sufficient number of years, would enable us to come at a 

 nearer and still more certain computation of the proportion between those that 

 recover, and those that die of the small- pox : which is, to send a careful per- 

 son once a year, from house to house, to inquire what persons have had the 

 small-pox, and how many have died of it, in the preceding year. This has 

 been done by Dr. Nettleton the last year, at several towns in Yorkshire, &c. 

 and the same was done at Chichester for the same year, to the 15th of October 

 last, by a person of credit, whose account was communicated to me by my 

 learned and ingenious friend, Dr. Whitaker. Such another account has been 

 transmitted to me from Haverfordwest, in South Wales, by the learned Dr. 

 Perrot Williams, physician in that place. The sum of these accounts is as 



follows : 



Sick of the Small-pox, Died. 



Several towns in Yorkshire 3405 . . 636 



Chichester 994 .. l68 



Haverfordwest 227 .. 52 



Total 4626 . . 856 



From which it appears, that, on a medium between these accounts, there 

 died of the small-pox almost 19 per cent, or nearly 1 in 5, of persons of all 

 ages that underwent that distemper. Which is the more to be remarked, as 

 out of 82 persons, who had the small-pox by inoculation the same year, and 

 in the neighbourhood of the same places, not I miscarried. 



Mr. Mather observes, in his letter mentioned above, that out of more than 

 5000 persons, that had the small -pox at Boston in New England, within little 

 more than half a year, near 900 died, which is more than 1 in 6; and this ac- 

 count added to those from Yorkshire, Chichester, and Wales, reduces the pro- 

 portion of those that die of the small-pox, to somewhat more than 18 per cent, 

 so that the hazard of dying of that distemper, to those who are taken ill of it, 

 is that of 1 in between 5 and 6, or something above 2 in 11. 



The result therefore of these computations is, that if the same proportions 

 should still continue, as have hitherto been determined by observation, we must 

 expect, that of all the children that are born, there will some time or other, 

 die of the small-pox, 1 in 14. That, of persons of all ages taken ill of the 

 natural small-pox, there will die of that distemper, 1 in 5 or 6, or 2 in 1 1. — 

 That of persons of all ages inoculated, without regard to the healthiness or 



