184 
Coccidia parasitic in man 
Outside the human body, the protoplasm of the oocyst segments into two 
round sporoblasts which soon become ovoid and develop into spores, which 
are similar in structure to those of other species of the genus. The spore 
measures about 12/x to 14/x in length, 7/x to 9/x in breadth. The sporocyst is 
fairly thick, and contains, when the spore is mature, the four vermiform 
sporozoites characteristic of the genus, and a large granular sporocystic 
residue. (Cf. Text-fig. 1, B.) Very frequently one or two small and irregular 
bodies are to be seen at the narrower end of the oocyst. They are present 
before the segmentation of its contents (cf. fig. 1, PL VIII), and therefore do not 
represent a true oocvstic residuum, which is absent in I. hominis. The sporo¬ 
zoites are long and narrow. Their internal structure is difficult to make out, 
but each probably possesses a nucleus situated subterminally. 
Wenyon and O’Connor (1917) have recorded that an abnormal develop¬ 
ment may sometimes occur in which the oocyst forms “ only a single sporocyst 
containing 8 sporozoites.” I have seen a similar abnormality very rarely in 
I. bigemina from the cat. 
Occurrence. The oocysts of this species were found by Wenyon (1915) 
in the faeces of patients invalided to England from Oallipoli, and suffering 
from dysentery and other intestinal ailments. They had previously been 
noticed in the same class of cases by Woodcock (1915) and Low (vide Wenyon, 
1915). Wenyon found altogether fifteen infected cases among 556 examined 
(Wenyon, 1916); and one further case was subsequently found in completing 
the examinations of this w r hole series of 775 patients (Dobell and Stevenson, 
1917). Woodcock (1915) and Woodcock and Penfold (1916) have recorded in 
all ten further infections found in the same class of cases 1 , and I have recorded 
one (Dobell, 1916). All the infected persons had served in the Eastern Mediter¬ 
ranean War Area; and most, if not all, of them had been on the Gallipoli 
Peninsula. Somewhat later Roche (1917) found fifteen Isos for a infections 
among 893 patients suffering from dysentery and diarrhoea at Salonika. 
Wenyon and O’Connor (1917) record a case found in Egypt, and note that 
“it seems probable that the infection came from Gallipoli.’* Savage and 
Young (1917) found six cases, out of 1088 men examined, among troops who 
had mostly served in Egypt, Gallipoli. Mesopotamia, and Salonika. Another 
case is recorded in Egypt by Martin, Kellaway, and Williams (1918), w r ho 
examined 422 patients suffering from diarrhoea and dysentery. Cragg (1917) 
found four cases of infection among 63 3 patients—invalided for “dysentery 
and allied complaints’ 1 from Mesopotamia—whom he examined in Bombay: 
and Boney, Grossman, and Boulenger (1918) have quite recently stated that 
among 890 British patients with dysentery and other intestinal disorders, 
1 The two patients passing “coccidian cysts” recorded from Manchester by Williamson 
( Journ. Roy. Army Med. Corps , 1917, xxviii, p. 451), and the four patients in Liverpool infected 
with “Coccidia (apparently Isospora type)” mentioned by Fantham ( Lancet , 10 June, 1916), 
probably belong to the same category. The patients were men from Gallipoli, but their infections 
were not accurately diagnosed. Cf. Dobell (1917). 
