Variolation

I'm reading Smallpox: The Fight to Eradicate a Global Scourge by David Koplow, so I'm brimming with variola information.

Variolation was a form of smallpox inoculation in which scabs or pus from smallpox victims were powdered and inhaled or inserted under the skin to confer immunity. This method of inoculation was centuries old already when it came to Europe from Asia around 1720. Variolated persons suffered from a mild case of the disease (1 or 2% mortality), but could still infect others with full-blown smallpox (25 to 60% mortality).