Summary

A study of the amebacidal activity in vitro of mapharsen and seven other compounds and three known amebacides is reported. Of the group of agents tested in vitro, mapharsen was most effective and killed E. histolytica in 1 to 20,000 to 1 to 30,000 dilution on 48 hours exposure. 2,4-dihydroxyphenylarsonic acid was effective in 1 to 8,000 dilutions against one strain of E. histolytica and N,N'-disodiumformaldehyde bisulfite-3,3'-diamino-4,4'-di(β-hydroxyethoxy)arsenobenzene in 1 to 3,000 dilution was effective against two other strains. Other drugs had no appreciable effect an amebae in similar concentrations.