ines ▁and ▁ant ito x ins ▁ ▁O pp osition ▁to ▁small po x ▁v acc ination ▁continued ▁into ▁the ▁ 2 0 th ▁century ▁and ▁was ▁joined ▁by ▁controvers y ▁over ▁new ▁v acc ines ▁and ▁the ▁introduction ▁of ▁ant ito x in ▁treatment ▁for ▁di ph ther ia . ▁In jection ▁of ▁horse ▁ser um ▁into ▁humans ▁as ▁used ▁in ▁ant ito x in ▁can ▁cause ▁hyp ers ens itivity , ▁commonly ▁referred ▁to ▁as ▁ser um ▁sick ness . ▁Moreover , ▁the ▁continued ▁production ▁of ▁small po x ▁v acc ine ▁in ▁animals ▁and ▁the ▁production ▁of ▁ant ito x ins ▁in ▁horses ▁prompt ed ▁anti - viv ise ction ists ▁to ▁opp ose ▁v acc ination . ▁ ▁Di ph ther ia ▁ant ito x in ▁was ▁ser um ▁from ▁horses ▁that ▁had ▁been ▁imm un ized ▁against ▁di ph ther ia , ▁and ▁was ▁used ▁to ▁treat ▁human ▁cases ▁by ▁providing ▁pass ive ▁imm unity . ▁In ▁ 1 9 0 1 , ▁ant ito x in ▁from ▁a ▁horse ▁named ▁Jim ▁was ▁cont amin ated ▁with ▁t et anus ▁and ▁killed ▁ 1 3 ▁children ▁in ▁St ▁Louis , ▁Missouri . ▁This ▁incident , ▁together ▁with ▁nine ▁death s ▁from ▁t et anus ▁from ▁cont amin ated ▁small po x ▁v acc ine ▁in ▁Cam den , ▁New ▁Jersey , ▁led ▁directly ▁and ▁quickly ▁to ▁the ▁passing ▁of ▁the ▁Bi olog ics ▁Control ▁Act ▁in ▁ 1 9 0 2 . ▁ ▁Robert ▁Koch ▁developed ▁t uber