76 THE AMOEBAE LIVING IN MAN 



be considered later. His only real discovery of any importance was 

 that the mature cysts of this species are typically 8-nucleate : they do 

 not contain the indefinite numbers of nuclei attributed to them by the 

 earlier Italian workers. 



For nearly a decade Schaudinn's work was generally accepted and 

 "confirmed." The work of E. L. Walker (1911), followed by his later 

 publication with Sellards (1913), then for the first time placed our 

 knowledge of this organism on a sound scientific foundation. He 

 proved conclusively that it is a distinct species, and by experimentally 

 infecting human beings showed that it is non-pathogenic. From this 

 date onwards little of importance has been discovered. Walker's work 

 will be considered in greater detail later, but it is necessary to notice 

 it here on account of its capital importance in the history of our 

 knowledge of this species. 



A few further words must now be said about the nomenclature of 

 this amoeba. I have already discussed the subject very briefly elsewhere 

 (1918), and have had to refer to it previously in the present work: but 

 I cannot evade the question here. The present position is briefly this : 

 "Amoeba coli" Losch (1875), was not Entamoeba colt but Entamoeba 

 histolytica — using these names to denote the species here described under 

 them. "Amoeba coli" Grassi (1879a) was, however, chiefly — if not 

 entirely — Entamoeba coli : and so were Entamoeba coli Casagrandi et 

 Barbagallo (1895 a), Entamoeba hominis Casagrandi et Barbagallo (1897), 

 and Entamoeba coli Schaudinn (1903). The organism has been called 

 E. coli by almost every worker since, and it is generally recognized by 

 no other name. Now Schaudinn was unable to decide whether Losch 

 studied the form which he himself called £. coli or that which he called 

 £. histolytica. His inability to do so can be explained by supposing 

 that he had not studied Losch's paper properly, or that he had not 

 studied the amoebae of man properly — either or both of which may 

 account for his singularly unfortunate pronouncements on the question : 

 for there can be no doubt that Losch's " Amoeba coli " was Schaudinn's 

 Entamoeba histolytica, and not his Entamoeba coli. There is not a 

 vestige of evidence that Losch ever saw the latter species.* Con- 

 sequently, Schaudinn was in error when he founded his species E. coli 

 as a part of Losch's species "Amoeba coli." As already noted in 

 discussing £. histolytica, Schaudinn ought to have called this form 

 Entamoeba coli — using the specific name first given to it. The first 

 specific name available for the non-pathogenic species would then have 

 been hominis — proposed by Casagrandi and Barbagallo (1897). ^'^ 

 own "Entamoeba coli" would then naturally have been called Entamoeba 

 hominis, and there would have been no further trouble. However, 

 he made his mistake and nobody corrected him at the time. But it 

 will create endless confusion if the name Entamoeba coli is now trans- 

 ferred to the dysentery amoeba ; and, as 1 have already stated, I should 

 consider such a change— on the grounds of priority, or for any other 



* As already noted on an earlier page, Mesnil (1918) believes that Losch studied 

 a mixture of species, and that the name coli can be given to one of these — the harmless 

 one, as proposed by Schaudinn. M. Mesnil's judgement — for which I have the greatest 

 respect — is so rarely at fault that I have, since reading his remarks, re-read the whole 

 of Losch's paper with the greatest care : but I am still unable to find the slightest 

 evidence in support of his reading. 



