They discovered that if a very small amount of pus from a blister was injected into a healthy person, the person would contract smallpox but survive 99% of the time.
Waligundua kuwa ikiwa mtu mwenye afya nzuri atawekewa kiasi kidogo cha usaha toka kwenye lengelenge, mtu huyu atapata ndui lakini atashinda 99% ya mara zote.