400 ESSAYS AND OBSERVATIONS 



cafion to a pretty careful inquiry, has acci- 

 dentally furniQied a new argument in favour 

 6f inoculation, and a further proof of the 

 great benefit of it. Long ufe has ihewn it 

 to be immediately a real fecurity agalnft the 

 prevailing malignity of a very mortal dif- 

 temper ; and the prefent inftance affords a 

 ftrong prefumption that it is, in its confe- 

 quences, no lefs a prefervative from many 

 difeafes incident to a period of life the moft 

 fatal to mankind. 



As to the theory in the objedion, it is 

 more philofophical perhaps to argue thus : 

 The fever of the fmall-pox, communi- 

 cated in the infant-ftate, not only deftroys 

 or expells the latent feeds of difeafes, before 

 they are, by time and accidents, perfedted and 

 put into adion, but caufes fuch an altera- 

 tion of the humours as may make them 

 lefs fufceptible of any morbid impreffions : 

 and the velTels being fo foon accuftomed, be- 

 fore they become rigid, to certain motions and 

 extenfions, the body is rendered ever after 

 more paffive to the impulfes of any fubfe- 

 quent diftemper ; which therefore will be 

 attended with lefs danger. This is agree- 

 able 



