76 INFECTION AND IMMUNITY 



as complete as that following a more severe attack 

 contracted in the usual way. This method seems to 

 have been practised by Eastern nations long before it 

 \vas introduced into Europe. It was extensively em- 

 ployed in Turkey early in the eighteenth century, and 

 was introduced into England through the influence 

 of Lady Mary Wortley Montagu. No doubt the 

 mortality from smallpox was greatly diminished by 

 these inoculations ; but they were attended by the 

 disadvantage that the disease was propagated by 

 them, inasmuch as inoculated individuals became a 

 source of infection for others. Inoculation was still 

 practised in England for some time after the demon- 

 stration of the protective value of vaccination, but in 

 1840 it was prohibited by an act of Parliament. 



There is some evidence that vaccination as a pro- 

 tection against smallpox was practised to a limited 

 extent prior to the time of Jenner. Thus Humboldt 

 has stated that it was known at an early period to the 

 Mexicans. But its introduction as a reliable method 

 of protecting against smallpox is due to the patient 

 researches of the renowned English physician, whose 

 attention was first attracted to the subject in 1 768, 

 although it was not until 1796 that he made his first 

 vaccination in the human subject. His first public 

 institution for the practice of vaccination was estab- 

 lished in 1799, and the following year the practice 



