Variolation
Smallpox quotes

The deliberate inoculation of an uninfected person with the smallpox virus (as by contact with pustular matter) that was widely practiced before the era of vaccination as prophylaxis against the severe form of smallpox .

variolation  Early form of vaccination in which part of the lesions produced by smallpox were used to try and trigger immunity to the disease http://www.immunisation.org.uk/glossary.html

The Chinese were the first to put this observation into practice through an early form of vaccination called variolation, which was carried out as early as the 10th century and particularly between the 14th and 17th centuries. The aim was to prevent smallpox by exposing healthy people to matter from the lesions caused by the disease, either by putting it under the skin, or, more often, inserting powdered scabs from smallpox pustules into the nose (see picture, below). http://www.immunisation.org.uk/history.html