Jound in cases of Dysentery from the Mediterranean 185 
diameter. The mature cysts contain four nuclei, as well as 
darkly staining masses of various shapes known as chromidial 
_or crystalloidal blocks. The tetranucleate cyst is characteristic 
and diagnostic, and the cysts are the infective stages. 
A patient showing acute symptoms of dysentery is not wholly 
infective, for he is often merely harbouring the large trophozoites 
of H. histolytica which, by animal experiments, have been shown 
usually to be non-infective when fed by the mouth. The stools 
of convalescent and recovered patients may still contain cysts, 
and so such persons may act as carriers of the disease. In return 
cases, or cases that have remained without treatment for a long 
time, a generation of smaller trophozoites is associated with or 
replaces the larger ones. These smaller forms are the senile or 
pre-cyst generation of Darling. These small entamoebae were 
described separately by Elmassian in 1909 as Entamoeba minuta, 
from a case of chronic dysentery in Paraguay. 
Follicular abscesses followed by ulcers, due to L. histolytica, 
occur in the large intestine. The entamoebae may invade the 
liver, producing abscesses in that organ. 
In the stools of sub-acute cases of amoebic dysentery which 
we have examined, uninucleate or tetranucleate cysts were 
observed. 
The dysentery-producing amoebae must be distinguished from 
Entamoeba colt, a parasite which may be found in the alimentary 
tracts of healthy persons. J. coli divides by binary fission or by 
schizogony into eight daughter forms. The cysts contain “eight 
nucle1 when mature. They measure about 15w to 20m in 
diameter, and so are slightly larger than those of HL. listolytica. 
The cyst wall of #. coli is thicker than that of H. histolytica, 
and the former cysts rarely contain chromidial blocks, while the 
trophozoites very rarely ingest red blood corpuscles. 
Flagellate Diarrhoea and Dysentery. 
The examination of the stools of a number of patients from 
Gallipoli, who showed dysenteric symptoms, revealed the presence 
of various flagellates. These Mastigophora include Trichomonas 
hominis (also called YT. intestinalis), Chilomastia (Tetramitus) 
mesmili, Giardia (Lamblia) intestinalis, and Cercomonas hominis. 
Most of these organisms are either complicated in structure or 
relatively little known. While some workers may consider some 
of these flagellates to be non-pathogenic, others have found them 
to be excitants of diarrhoea and dysentery. Among these latter 
workers are some of the principal parasitologists of South 
America and the French Colonies, while their publications are 
of recent date. 
