ENTAMOEBA COLI 221 



creases in the cyst wall, or disturbance of the cytoplasm. In some cysts 

 the structures called chromophile ridges are undoubtedly chromatoid 

 bodies. Such statements as " chromatoidal body exhausted in the forma- 

 tion of chromophile ridge," made in connection with the cyst reproduced 

 at Fig. 102, 2, are quite incomprehensible. It is probable that Kofoid 

 and Swezy were dealing in some cases with mixed infections of E. coli and 

 E. histolytica. The writer (1922a, 1925) stated his reasons for regarding 

 the name Councilmania lafleuri as a synonym of Entamoeba coli. In a 

 later communication Kofoid, Swezy, and Kessel (1924) reaffirm their 

 belief in Councilmania lafleuri, and bring forward a number of further 

 observations which they consider establish the validity of the species. 

 After carefully reading their paper, the writer still believes that there is 

 no justification for the genus Councilmania, and that the characters which 

 distinguish C. lafleuri from E. coli fall within the range of variation of 

 E. coli itself. Gunn (1922) has examined some of the cases from which 

 Kofoid and Swezy described C. lafleuri. He has found that the amoebse 

 present were actually E. coli. 



Having discovered similar " budding cysts " in rats and mice, E. muris 

 and E. decumani are placed in the genus Councilmania as C. muris and 

 C. decumani by Kofoid, Swezy and Kessel (1923), while it is also claimed 

 by Kessel (1923a) that rats and mice can be infected with C. lafleuri, and 

 that the amoeba retains its characters in these animals. Apart from the 

 " budding " through a pore in the cyst, which the writer believes is a rupture, 

 the main points which, it is claimed, distinguish the genera Entamoeba and 

 Councilmania are the character of the cytoplasm and its inclusions, the 

 clear pseudopodia, the type of movement, and finally the dispersed karyo- 

 some. There is very great difficulty associated with the identification and 

 counting of chromosomes in nuclei of the type possessed by these amoebae, 

 so that the chromosome number quoted for C. lafleuri, C. muris, C. decumani, 

 E. coli, and E. histolytica (8, 6, 4, 6, 6) cannot be accepted as finally estab- 

 lished. Kofoid and Swezy (1921a) state that they have encountered jE. 7nuris 

 in man. E. muris of rats and mice so closely resembles E. coli of man that 

 the writer is at a loss to know how they arrived at their diagnosis, especially 

 as Kofoid, Swezy and Kessel (1923) adopt the view that the amoeba belongs 

 to the genus Councihnania. 



Entamoeba gingivalis (Gros, 1849) Brumpt, 1910.— This amoeba, which 

 is parasitic in the human mouth, was first seen by Gros (1849) in Russia. 

 He gave it the name Amoeba gingivalis, which was emended by Brumpt 

 (1910a) to Eutanujeba gingivalis. The organism was seen by Steinberg 

 (1862), who gave it the name Amiba buccalis, and by Grassi (1879), who 

 named it Amoeba dentalis. Doflein (1901) referred to it as Amoeba hartu- 

 lisi, and Kartulis (1906) as Entamoeba maxillaris. It has been described 



