▁ ▁History ▁ ▁Vari olation ▁ ▁Early ▁attempts ▁to ▁prevent ▁small po x ▁involved ▁deliber ate ▁in oc ulation ▁with ▁the ▁disease ▁in ▁hopes ▁that ▁a ▁m ild ▁case ▁would ▁confer ▁imm unity . ▁Origin ally ▁called ▁in oc ulation , ▁this ▁technique ▁was ▁later ▁called ▁vari olation ▁to ▁avoid ▁confusion ▁with ▁cow po x ▁in oc ulation ▁( v acc ination ) ▁when ▁that ▁was ▁introduced ▁by ▁Edward ▁Jen ner . ▁Although ▁vari olation ▁had ▁a ▁long ▁history ▁in ▁China ▁and ▁India , ▁it ▁was ▁first ▁used ▁in ▁North ▁America ▁and ▁England ▁in ▁ 1 7 2 1 . ▁Re ver end ▁Cot ton ▁M ather ▁introduced ▁vari olation ▁to ▁Boston , ▁Massachusetts , ▁during ▁the ▁ 1 7 2 1 ▁small po x ▁ep ide mic . ▁Despite ▁strong ▁opposition ▁in ▁the ▁community , ▁M ather ▁convinced ▁Dr . ▁Z ab d iel ▁Bo yl ston ▁to ▁try ▁it . ▁Bo yl ston ▁first ▁experiment ed ▁on ▁his ▁ 6 - year - old ▁son , ▁his ▁slave , ▁and ▁his ▁slave ' s ▁son ; ▁each ▁subject ▁contract ed ▁the ▁disease ▁and ▁was ▁sick ▁for ▁several ▁days , ▁until ▁the ▁sick ness ▁van ished ▁and ▁they ▁were ▁" no ▁longer ▁grav ely ▁ill ". ▁Bo yl ston ▁went ▁on ▁to ▁vari olate ▁thousands ▁of ▁Massachusetts ▁residents , ▁and ▁many ▁places ▁were ▁named ▁for ▁him ▁in ▁grat itude ▁as ▁a ▁result . ▁Lady ▁Mary ▁Wort ley ▁Mont agu ▁introduced ▁vari olation ▁to ▁England . ▁She ▁had ▁seen ▁it ▁used ▁in ▁Turkey