Haughwout : Human Coccidiosis 
477 
the parasites in Cragg’s two cases that went to autopsy was 
not realized. 
I am strongly of the belief that the symptoms exhibited by 
my patient were due to his coccidiosis. Beyond an infection 
with Blastocystis he carried no parasites except the Isospora, 
and much of the time his diet was under strict regulation. 
Noe’s patient complained of pain in the right iliac region, and 
he exhibited hepatic enlargement and persistent diarrhoea. 
Noc reports the presence of no other intestinal parasite, 
although the high eosinophile count (6.5 per cent) looks 
suspicious. 
The gross and microscopical lesions accompanying infections 
with Isospora hominis must remain a matter for speculation 
until some case goes to auptopsy. Porter (13) says the epithe- 
lium of the ileum is often most heavily infected and that the 
jejunum is also invaded. This postpones the settlement of the 
whole question of pathogenicity. Cases so far reported have 
been in adults and the symptoms — when there have been any — 
seem not to have been grave. We have yet to see how it will 
affect young children and enfeebled persons. The best ac- 
count of the microscopical lesions accompanying coccidiosis 
that is available to me is that of Tyzzer,(l5) who studied 
coccidiosis in the bile ducts of the rabbit. He says (pp. 249 to 
251) : 
The parasites attack only epithelial cells. The young form inhabits 
the protopasm of the cell, which becomes more and more distended as the 
parasite develops. The nucleus, at first slightly indented, later becomes 
crescent-shaped. The structure of the chromatin cannot be made out, and 
the nucleus is stained darkly. Thus at the termination of this process, the 
epithelial cell is reduced to a saci containing a parasite, having on one side 
a darkly stained crescent, representing the degenerated nucleus * * *. 
Ruptured cells are found from which the parasites have been set free. 
Degeneration and destruction of epithelial cells thus follow their invasion 
by parasites. Numerous mitoses are seen in the epithelium and, where the 
infection is not overwhelming, proliferation is in evidence. The epithelium 
is markedly thickened and its cells are crowded. Accompanying the de- 
struction of single cells, exudative phenomena are absent. With the de- 
struction of small areas of epithelium, there is exudation of fibrin and leuco- 
cytes * * *. The latter occurs, however, only occasionally, and is the 
exception rather than the rule. When bacteria are present, the exudative 
phenomena are increased. The surrounding connective tissue is rich in cells. 
There are large numbers of lymphoid and plasma cells. Epithelioid and 
lymphoid cells occur between the cells of the epithelium. The epithelium 
oftentimes lacks a definite basement membrane, and young connective 
tissue and epithelium is so mingled that the resulting relations are 
