392 BIOLOGY OF THE PROTOZOA 



as the cause of bacillary dysentery. Thus by the end of our second 

 period two important points had been established, viz.: the occur- 

 rence of two types of amebae in the human intestine, and the 

 occurrence of at least two types of dysentery due to different kinds 

 or organisms. 



3. Period of Taxonomic Chaos. — It is quite evident from the fore- 

 going that the term taxonomic chaos with propriety might be 

 applied to the entire history of dysentery. It is particularly applic- 

 able, however, to the first decade of the present century when, 

 owing to the prestige of Schaudinn, incorrect interpretation of the 

 life history of Endamoeba dysenteriae {histolytica) resulting from his 

 work stood in the way of progress for more than a decade. In his 

 paper on the reproduction of certain rhizopods Schaudinn (1903) 

 described the life histories of the foraminiferon Polystomellina crispa, 

 Lam., the testate rhizopods Centropyxis aculeata, Ehr., Stein, and 

 Chlamydophrys stercorea, Cienkowsky, and the parasitic amebae 

 of the human intestine. In connection with the first three he was 

 convinced that chromidia give rise to the nuclei of gametes (see 

 p. 69) and thus play an important role as germinal chromatin. 

 It is not surprising, therefore, that he ascribed an important part 

 to what he termed chromidia in the parasitic amebae. In respect 

 to these chromidia the life histories as he interpreted them in 

 Endamoeba coli and E. dysenteriae (histolytica) are complicated. 1 In 

 this account emphasis was laid by Schaudinn on : (1) The structural 

 differences in nuclei of E. coli and E. histolytica; (2) formation of 

 encysted amebae with 8 nuclei, giving rise to 8 spores, in E. coli 

 but absence of all cysts in E. histolytica; (3) reproduction by periph- 

 eral, chromidia-holding buds in E. histolytica but not in E. coli; and 

 (4) infection by spores of E. coli and by "resistant buds" in E. his- 

 tolytica; (5) pathogenicity of E. histolytica and harmlessness of 

 E. coli. 



In this same year (1903) Huber made observations and experi- 

 ments which, had they received the attention they merited (see 

 Dobell, 1919), would have saved subsequent confusion. From a 

 case of typical amebic dysentery he observed amebae and their 

 cysts, the former infecting cats when introduced per anum, the 

 latter infecting cats per mouth. The cysts were reported as con- 

 taining 1, 2 and 4 nuclei but never more than 4. In the glamor 

 of Schaudinn's prestige this latter important point was ignored. 

 Viereck (1907) and Hartmann (1907) found them and, since the 

 cysts had 4 nuclei and Schaudinn had stated that E. histolytica does 

 not form cysts, they regarded them as a new species of Endameba. 

 The former named it E. tetragena, the latter E. aj'ricana. Hartmann 

 recognized E. aj'ricana as the same as E. tetragena which had been 

 published somewhat earlier in the year. The observations were 



1 See Calkins Protozoology, 1909, p. 296. 



