THE GENERA OP' AMOEBAE LIVING IN MAN 17 



for E. histolytica. Although the grounds for the proposal are now 

 known to have been fallacious, the name was introduced for an easily 

 lecognizable organism ; and there seems to be nothing in the rules of 

 nomenclature which can. render it invalid. Moreover, Liihe's name 

 seems to be the first generic name available for the dysentery amoeba, 

 if it is decided to remove it from the genus Endamoeba (= Entamoeba) ; 

 and since E. coli and the other harmless forms related to it are co-generic 

 with E. histolytica, it follows that all these organisms might have to be 

 placed in the genus Poneraiiioeba. This would be a most unfortunate 

 interpretation of the laws of nomenclature ; for it would place all the 

 harmless species, which constitute the greater part of the group, in a 

 genus designed for, and designatory of,* the one exceptional species 

 which is known to be pathogenic. 



Chatton and Lalung-Bonnaire (191 2), believing E. histolytica to be 

 subgenerically distinct from the amoebae of the is. coli type, proposed 

 a new subgenus Viereckia to contain it. According to their nomen- 

 clature the organism should be called Loschia (Viereckia) tetragena. 

 From Chatton's later publications it may be gathered that he has 

 abandoned this view, for he now calls the dysentery amoeba Entamoeba 

 dysenteriae. The name Viereckia appears, in any case, to be a synonym 

 of Poneramoeba — if the dysentery amoeba is to be placed in a genus 

 apart. At the moment, however, there seem no adequate grounds for 

 separating it from other amoebae such as E. coli, E. ninris, or E. ranarmn. 



In my opinion it is most undesirable to change the names of the 

 amoebae living in man unless this course becomes absolutely necessary. 

 I propose, therefore, provisionally to retain the name Entamoeba Casa- 

 grandi et Barbagallo, 1895, for the organism to which it was given — 

 namely, E. coli — and for all those species which are clearly co-generic 

 (£. histolytica, E. gingivalis, E. muris, etc.) ; and to retain also the genus 

 Endamoeba Leidy, 1879, for the one organism — E. blattae — for which it 

 was proposed. It may be argued that Endamoeba and Entamoeba are 

 different spellings of the same name, or that they differ too slightly from 

 one another to be kept separate. This has already been urged by many 

 writers, and is doubtless justifiable. Nevertheless, nobody can say at 

 present whether the organisms originally called Endamoeba and 

 Entamoeba respectively are generically the same or different : and if the 

 difference is at present so slight and uncertain, then a slight difference 

 between their generic designations might not inappropriately express it. 

 Whether ultimately shown to be right or wrong, this course is, I think, 

 the one which will give rise to the least confusion at present. I cannot, 

 for my own part, accept with equanimity any drastic change in nomen- 

 clature which will certainly lead to confusion — however plausible a case 

 may be made for it by those who care more for the " correctness " of 

 names than for the codification of knowledge. What, for example, 

 should we gain by calling the dysentery amoeba, which every worker in 

 England has known for years as Entamoeba histolytica, by the new name 

 Poneramoeba coli ? And yet a very plausible case indeed can be made 

 out for this combination. 



I shall therefore continue to refer three of the common amoebae 

 of man — namely, E. coli, E. histolytica, E. gingivalis — to the genus 



* Poneratnoeba, from vovj\p6s^ causing pain, harmful. 



