17, 4 Chatterjee: An Atypical Ameba 391 
RESUME AND CONCLUSIONS 
I have discovered an amceba causing fatal dysenteric lesions 
in man and differing from Entameeba histolytica in the following 
essential points: (1) The nucleus is massive—not karyosomic; 
(2) there is marked distinction between ectoplasm and endo- 
plasm; (3) chromidia are absent. 
The lesions caused by this organism differ from those familiar 
in dysentery of Entameba histolytica origin, in that the small 
intestine is attacked—a phenomenon heretofore absolutely un- 
known in dysentery of entamebic origin. Furthermore, the 
peculiar peritoneal involvement is a unique thing. 
The ameba differs in important morphological details from 
both Entameba nana and Vahlkampfia (Ameba) limacz. 
In asserting that this ameba is a new species I suffer under 
the difficulty that I have to draw my deduction from a single 
case. To ascertain whether it is a purely local variety hitherto 
unobserved, I have studied many permanent preparations that 
I have made from numerous stools from dysentery patients as 
well as from pus from liver abscesses, which I have had the op- 
portunity to examine during the past six years that I have 
been studying the intestinal protozoa. In no specimen studied 
could I find any ameba showing a nuclear or cytoplasmic struc- 
ture similar to that of the ameba I have found. Other workers 
in India who have studied the structure of amcbe found in 
human feces and who have used recent staining methods, among 
them Cragg(1) and Knowles and Cole, do not mention having 
come across any variety of amceba other than Entameba histoly- 
tica and E. coli. 
Therefore, it seems evident that this is a new species. The 
next question is, to what genus it should be assigned. Ac- 
cording to Schaudinn and to Doflein, the genus Entameba is 
characterized by a parasitic mode of life, movement by “Lap- 
pige” [lappenformige?] pseudopodia and by transmission to 
other hosts in cysts. This ameeba can then be classified under 
the genus, although I have not been able to demonstrate the 
encysted stage. 
I designate this ameeba Entameba paradysenteria sp. nov. 
This name, of course, may later be dropped if the organism is 
determined to be a species already described. 
