With the exception of 8 (Indian seamen) all were Europeans from 64 countries, the majority from the far east and Africa. The diagnosis was made from rectal ulcer scrapings and feces. Complicating conditions and clinical symptoms are discussed. Treatment by injection with the following drugs was investigated: (1) Emetine bismuth iodide; effective on cysts; 7% relapses; tends to render Endamoeba histolytica emetine-fast. (2) Emetine periodide; better tolerated than E.B.I. but not efficacious; 46% relapses. (3) Auremetine, a compnd. of auramine, an aniline dye; quite toxic, all relapsed. (4) Quinoxyl (synonyms: yatren, chinofon, anayodin), a combination of oxyquinoline-sulfonic acid and iodine, a potent non-toxic drug; produces best results in resistant cases when used in combination with E.B.I.; treatment well tolerated if minutiae of dosage and timing are observed. (5) Enterovioform; results inconclusive; soothing action on mucous membrane, but no effect on amoebae. (6) Chaparro amargosa, extract of Castela bark used extensively in Mexico; results inconclusive. (7) Conessine, kurchine hydrochloride, and kurchi bismuth iodide; no cures. 19 references.