ENTAMOEBA HISTOLYTICA 27 



to be quite unjustifiable. If Losch's name " coli " is accepted at all, 

 it must, according to the rules, be given to the dysentery amoeba, and 

 to no other : and it is not permissible to use its synonym " dysenteriae " 

 to replace it, and then to bestow " coli " upon another species. One 

 way out of this difficulty has recently been suggested by Mesnil (1918), 

 who thinks that Losch originally gave the name Amoeba coli to a 

 mixture of species — one of which was later called dysenteriae by 

 Councilman and Lafleur. Unfortunately there is no evidence that this 

 was the case. There is absolutely nothing to indicate that Losch 

 studied more than one species, and to my mind there can be no 

 doubt as to which this was — namely, the dysentery amoeba. Schaudinn 

 (1903), it is true, was "unable to decide" whether Losch studied the 

 pathogenic or the harmless species, and consequently gave his name 

 to the latter : but no experienced modern worker can share his doubts. 



Schaudinn (1903) displayed a singular lack of judgement in his 

 revision of the name "Amoeba coli." Beyond a doubt he should have 

 called the dysentery amoeba Entamoeba coli Losch and the non- 

 pathogenic species E. hominis Casagrandi et Barbagallo. This would 

 have created no confusion at the time, as people were then accus- 

 tomed to call the dysentery amoeba Amoeba coli,* Since Schaudinn 

 made his mistake, however, his names have been almost universally 

 adopted ; and they should now, in my opinion, be preserved at all costs. 

 I believe this can be done, moreover, without violation of the Rules 

 of Zoological Nomenclature, though it appeared to me impossible 

 when I last discussed the problem (1918). I now offer the following 

 solution : 



"Amoeba coli " Losch (1875) may be regarded as a descriptive term, 

 and not a binominal Linnaean name within the meaning of the code. 

 It was introduced in the following words : " Da die von mir beschrieb- 

 ene Amobe, so viel mir bewusst, iiberhaupt mit keiner der bisher 

 bekannten Formen vollkommen iibereinstimmt, so scheint es mir 

 gerechtfertigt, dieselbe bis auf Weiteres mit einem besonderen Namen 

 zu bezeichnen und nach ihrem Fundorte etwa Amoeba coli zu nennen " 

 (Losch, 1875, p. 208). The generic name is written with a capital — as 

 it would be, in any case, in German — but in ordinary type. There is 

 nothing to indicate that Losch did not employ it as a mere descriptive 

 term! — in the customary medical manner {i.e., like the ordinary names 

 of bacteriology, or Councilman and Lafleur's "amoeba dysenteriae"). 

 Undoubtedly many of the earlier workers regarded it in this light 

 {e.g., Councilman and Lafleur). The name Amoeba coli written in italic 

 type, and as a proper zoological name, seems to have been first used by 

 Grassi : and the organism to which he gave it was probably the non- 

 pathogenic form — not the dysentery amoeba — owing to a misidentifica- 

 tion. Consequently, I regard "Amoeba coli" Losch, 1875, as a 

 synonym of E. histolytica Schaudinn, 1903, but not a valid zoological 

 name; and Amoeba coli Grassi, 1879, as the first valid name given to 

 the organism which Schaudinn (1903) later called Entamoeba coli — as 



* Musgrave and Clegg (1904) say that the amoebae in human stools were "usually" 

 called Amoeba dysenteriae when large and containing red corpuscles, and Amoeba coli 

 when smaller, devoid of blood corpuscles, and believed to be non-pathogenic. The 

 earlier literature does not bear out this statement. 



t And with some hesitation, as the word " etwa " before it seems to imply. 



