▁and ▁assist ed ▁by ▁Arthur ▁Charles ▁and ▁Albert ▁Fish er ▁ref ined ▁this ▁process ▁into ▁ 1 9 3 3 ▁to ▁consist ently ▁produce ▁highly ▁pure ▁ins ul in . ▁Charles ▁and ▁Fish er ▁prepared ▁a ▁new ▁international ▁standard ▁for ▁ins ul in , ▁the ▁first ▁in ▁cry st all ine ▁form . ▁In ▁ 1 9 3 6 , ▁Fish er ▁and ▁Scott ▁built ▁upon ▁the ▁work ▁of ▁Hans ▁Christian ▁H aged orn , ▁one ▁of ▁B ant ing ▁and ▁Best ' s ▁original ▁Dan ish ▁collabor ators ▁( al ong ▁with ▁August ▁K rog h ), ▁to ▁form ulate ▁prot am ine ▁z inc ▁ins ul in . ▁This ▁was ▁the ▁first ▁long - act ing ▁alternative ▁to ▁regular ▁ins ul in . ▁ ▁Pre vent ing ▁di ph ther ia : ▁ 1 9 2 4 - 1 9 2 7 ▁ ▁Initial ly ▁established ▁in ▁ 1 9 1 4 ▁to ▁produce ▁the ▁di ph ther ia ▁ant ito x in , ▁the ▁Con n aught ▁Labor ator ies ▁continued ▁to ▁prior it ize ▁the ▁er adic ation ▁of ▁di ph ther ia . ▁Though ▁the ▁institution ' s ▁efforts ▁had ▁made ▁the ▁ant ito x in ▁freely ▁available ▁to ▁the ▁public , ▁the ▁disease ▁remained ▁one ▁of ▁the ▁leading ▁public ▁health ▁thre ats ▁to ▁children ▁under ▁ 1 4 . ▁The ▁objective ▁was ▁to ▁move ▁from ▁treatment ▁to ▁prevent ion . ▁ ▁In ▁ 1 9 2 4 , ▁John ▁G . ▁Fitz G er ald ▁visited ▁the