ENTAMOEBA COLI 75 



and non-dysenteric persons. Further, they identified the organism 

 which they studied with Losch's " Amoeba coH," though it was 

 really Grassi's "Amoeba coU," and not Losch's organism. At first 

 (1895a) they named their amoebae Entamoeba colt — the new generic 

 name being proposed in ignorance of the similar name (Endauioeba) 

 previously introduced by Leidy (1879). In their second publication 

 (1897), however, they renamed the species completely, calling it Ent- 

 amoeba hominis. Pestana (1917) has recently attempted to revive this 

 name. 



It may be noted that Casagrandi and Barbagallo (1897) introduced 

 the name E. hominis in a most irregular manner. It occurs only twice 

 in their publication — first as an implied synonym of "Amoeba coli 

 (Losch) " in the title of their paper, and a second time in the summary 

 of their conclusions (p. 163), where it is again implied that it is syn- 

 onymous with "A. coli." There can be little doubt that these authors 

 actually studied the species here considered ; but it seems probable 

 that they also saw, and confused with it, other species. For example, 

 they found individual amoebae as small as 5 /a in diameter, and these 

 cannot have been £. coli. They also saw amoebae containing red blood 

 corpuscles, and these must have been E. histolytica. They found cysts 

 with diameters dosvn to 8^, and these were, in all probability, those of 

 E. histolytica or E. nana. They did not describe the nuclei m the 

 cysts correctly — even as regards their number; for they stated that the 

 cysts may contain "from i to 11 and more," although they figured some 

 typical 8-nucleate specimens. Certain of their other observations will 

 be considered later: for the present it will suffice to note that their 

 " E,ntamoeba coli" or " E. hominis" was, for the most part, the organism 

 here described under the first of these names. 



Schaudinn (1903) restudied and redescribed this organism, adding 

 numerous details — mostly wrong — to the earlier accounts. He con- 

 sidered that the amoebae studied by Quincke and Roos (1893) were all 

 uncertain species, because " infections of cats " . . . " cannot be 

 used as a specific criterion "* — which shows how superficial was his 

 knowledge of the amoebae of man and of the work of these authors. 

 Casagrandi and Barbagallo (1897), however, he allows to have studied 

 his own " harmless form " from man with accuracy. Since they 

 identified their amoeba with the " Amoeba coli " of Losch, Schaudinn 

 considered that this specific name {coli) should be used for the species 

 which they described. He accepted, also, their generic name Entamoeba 

 in place of Amoeba: and he concluded that the correct name of 

 this organism is "Entamoeba coli (Losch) emend. Schaudinn." This 

 determination was not justified by the facts, as can easily be shown. 

 Nevertheless, the organism has borne this name ever since. 



Schaudinn's contributions to our knowledge of Entamoeba coli con- 

 sisted chiefly in the discovery of a " schizogony " in the free amoebae 

 and an "autogamy" in the cysts — both, in all probability, non-existent. 

 He also confirmed the observations of earlier workers in regard to the 

 structure and general appearance of the organism and its cysts, and as 

 to its non-pathogenicity. The more important of his statements will 



* This is, of course, true as a general statement. But in the present case it so 

 happens that this criterion is a good one : and moreover it was by no means the only 

 one used by Quincke and Roos. 



