ENTAMCEBA COLI 



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Entamceba hominis Casagrandi and Barbagallo, 1897; Entamoeba coli Scliaudinn, 

 1903; Amoeba coli Brumpt, 1910; Entamoeba williamsi Prowazek, 1911; Entamceba 

 hartmanni Prowazek, 1912 (pro parte); Entamoeba brasiliensis Aragao, 1912 (pro 

 parte); Loschia coli Chatton and Lalung-Bonnaire, 1912 ; Entamoeba coli communis 

 Knowles and Cole, 1917 (^^ro parte); Endameba intestinivulgaris Aragao, 1917 ; 

 Endameba coli Craig, 1917; Endameba hominis Pestana, 1917 ; Councilmania lafleuri 

 Kofoid and Swezy, 1921. 



This amoeba is a harmless commensal of the digestive tract of man, 

 and is in no sense a tissue-invading amoeba like E. histolytica. According 

 to Dobell, it was first seen by Lewis (1870) in India, and was described 

 more accurately by Cunningham (1871). Grassi (1879-1888) gave various 

 descriptions of the organism, and erroneously believing it to be identical 

 with the form originally studied in dysenteric cases by Losch (1875), 

 gave it the name Amoeba coli, a name which shovdd have been employed 

 for the pathogenic form only. As has been explained above, Schaudinn 

 again committed this error, and though, 

 according to the strict laws of nomen- 

 clature, E. coli should be the name of 

 the pathogenic amoeba, its employment 

 in this sense would lead to endless 

 confusion, so that it is better to retain 

 the name E. coli for the harmless amoeba. 

 Grassi realized that the amoeba was a 

 harmless inhabitant of the human diges- 

 tive tract, for he found it not only 

 in sick, but also in healthy people. 

 Quincke and Eoos (1893) gave a good 

 description of E. coli, which they dis- 

 tinguished from E. histolytica, while 

 Casagrandi and Barbagallo (1895, 1897) 

 studied the same organism, which they 



named Efitamoeba coli. They took a retrograde step in assuming that 

 this was the only form which occurred in healthy as well as in dysenteric 

 subjects. Schaudinn (1903) clearly stated that there were two amoebse, 

 the one a tissue-invading form and the other a harmless commensal, and 

 his reputation as a protozoologist resulted in a universal acceptance of 

 this view, which had been previously put forward by Quincke and Roos. 

 Since Schaudinn's time numerous names have been given to amoebse which 

 are undoubtedly merely forms of E. coli. These have been fully discussed 

 by Dobell (1919), and it is unnecessary to enter into the matter here. 



Entamoeba coli is a very common parasite of the human intestine. In 

 tropical lands, or in other countries where sanitary arrangements are not 

 satisfactory, it is probable that no person escapes infection. Like E. histo- 



FiG. 99. — Entamoeba coli with In- 

 gested Cyst of E. histolytica 

 (x ca. 2,000). (After Wenyon 

 AND O'Connor, 1917.) 



