During an investigation of the methods used in the cultivation of E. histolytica, it was found that the number of organisms produced in vitro could be significantly increased by the addition of extracts of human feces to the culture fluid. This has been studied quantitatively in various commonly used media.
The use of fecal material in media devised for the purpose of cultivating human protozoa has been mentioned in the publications of Kartulis (1889), Boyd (1918–19) and Boeck and Drbohlav (1925). Kartulis used sterile emulsions of rabbit and pigeon feces in an attempt to cultivate his dysentery-producing amoebae. Boyd employed fecal material when he first successfully cultivated Trichomonas hominis. Boeck and Drbohlav tested the effects of aqueous extracts of human feces in Lock-Egg-Serum medium and found that the bacteria multiplied so rapidly that the medium soon ceased to be a favorable environment for the amoebae.