C. Dobell 
307 
countries at least it seems unnecessary to look beyond the native 
population for the “reservoir” of amoebic dysentery. It is not, of 
course, excluded that E. histolytica, though now a distinct species 
proper to man, may possibly have been acquired by him originally 
from a closely similar parasite of amphibia. This, however, is a mere 
guess which can never be tested, and is based solely on the striking 
similarity of E. histolytica and E. ranarum at the present day. 
Taking all the foregoing points into consideration it seems, therefore, 
justifiable to draw the following conclusion: Entamoeba histolytica 
Schaudinn and Entamoeba, ranarum G-rassi are probably distinct species; 
and consequently the frog, in all probability, is not a “reservoir” of 
human amoebic dysentery. 
% 
Note on the specific name of the Entamoeba of 
Human Amoebic Dysentery. 
In the foregoing pages I have called the Entamoeba which causes amoe¬ 
bic dysentery in man E. histolytica. As, however, a number of workers 1 , 
notably in France, have recently reintroduced the name E. dysenleriae 
for this organism—professedly in deference to the Rules of Nomencla¬ 
ture—I wish to state briefly my reasons for not adopting this name. 
Everybody competent to judge now agrees that there is but a single 
species 2 of Entamoeba which has been proved to cause dysentery in man. 
This is the species which was called Entamoeba histolytica by Schaudinn 
(1903), E. tetragena by Yiereck (1907), E. africana by Hartmann (1907), 
E. minuta by Elmassian (1909), and probably by several other names by 
other workers. All the specific names proposed since 1903, when the 
name histolytica was introduced, are, of course, no longer valid, now that 
the identity of the organisms concerned is recognized. There is no diffi¬ 
culty, therefore, in deciding the claims to priority of the names just cited. 
The real difficulty regarding the nomenclature of the intestinal 
amoebae of man was introduced by Schaudinn in his attempt to clear 
up the confusion which existed when he wrote. Up to that date (1903) 
there was great confusion, not only in the nomenclature, but also 
concerning the facts. It was generally supposed that there was but 
a single species of amoeba—the “ Amoeba coli ” of Losch -parasitic 
in the human bowel. By some it was considered pathogenic, by 
1 Cf. Brumpt (1913), Alexeieff (1914), Mathis and Mercier (1916), etc. 
2 Of this species there are, however, several different varieties or strains, distinguishable 
morphologically by the size of their cysts. Cf. Wenyon and O’Connor (1917), Dobell and 
Jepps (1917). 
