126 
W. GLEN LISTON AND C. H. MARTIN. 
to agree absolutely in regard to all their essential features. 
In both these types it seems rather difficult to stain the 
nucleus satisfactorily, and moreover, there seems to be 
evidence for a series of remarkable morphological changes 
in the structure of the nucleus of this form, the significance 
of which is not at present clear to me (PL 18, figs. 22-24). 
From the observations on the live cultures it is evident that 
the nuclear division is amitotic, and neither from such 
observations nor from the stained films is there any evidence 
whatever in this type for the occurrence of endogenous 
budding. Until more time has been spent on this form, and 
fresh material obtained of it, it is impossible to estimate to 
what extent it may differ from Schaudinn’s Entamoeba 
histolytica. 
As regards the other two amoebae, that from the monkey’s 
rectum (PJ. 18, figs. 31, 32) was on the stained fiims a roughly 
spherical form, with rather darkly staining cytoplasm, 
measuring about 15 /ul in diameter. The cytoplasm contained 
numerous vacuoles. In the nucleus the chromatin was chiefly 
condensed in the large central karyosome v and in a distinct 
peripheral zone of fairly large granules. The amoeba 
cultivated from Bombay tap-water (PI. 18, fig. 30) measured 
about 16 by 10 /a ; its cytoplasm was clear, and in some cases 
markedly vacuolated. The nucleus showed the chromatin 
massed in a central karyosome. 
Although I am sure that further work on these forms would 
lead to interesting and valuable results, yet I feel that there 
is already evidence amply sufficient to prove Major Liston’s 
main contention that the larger amoeba from liver-abscess is 
quite a distinct type, different from the other small form 
here described; in fact, when one regards the simple method 
of reproduction by endogenous buds seen in this form, it 
may be doubted whether it ought to be included in the amoebae 
at all, but having regard to our present ignorance of this 
form, it may be appropriate to leave it for the present in the 
group which Schaudinn has pithily described as “ ein 
Sammeltopf der heterogensten Elemente.” 
Lister Institute, 
April 4th, 1911. 
