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Cordelia parasitic in man 
C. The Coccidia described from Man in 19J 5 and later. 
The year 1915 marks a definite advance in our knowledge of the coccidia 
of man, for towards its close two species were carefully studied and described 
for the first time by Wenyon. His observations will now be briefly reviewed. 
Wenyon's cases. The organisms originally studied by Wenyon (1915, 
1915 a) were found in soldiers invalided to England, suffering from dysentery 
and enteritis, from the Gallipoli campaign of 1915. In the faeces of some of 
these patients Wenyon discovered structures which were apparently the 
oocysts of a coccidium. These had previously been found in similar cases by 
Woodcock (1915) and Low (vide Wenyon, 1915), who, however, did not 
succeed in identifying them with certainty 1 . But Wenyon was able to observe 
all the stages of speculation, and to demonstrate that the species is one which 
possesses an oocyst containing two tetrazoic spores. He therefore referred the 
parasite to the genus Isospora, though he did not give it any specific designation. 
This coccidium has an oocyst resembling that of Isospora bigemina, but 
usually smaller, more pellucid and slender, and more delicate in appearance. 
It is a well-marked species, on the whole, and has since been found and 
recognized by a number of other observers (Woodcock and Penfold (1916), 
Roche (1917), Cragg (1917), etc.). A fuller description of the parasite will be 
given later, in the systematic part of this paper. For the moment it will 
suffice to note here that none of the later observers has been able to add any¬ 
thing of importance to Wenyon's description of the organism; and none of 
them has proposed a specific name for it 2 or assigned it to its proper systematic 
position. Although it is highly probable, from analogy, that the organism 
inhabits the epithelium lining the small intestine, this has not yet been actually 
demonstrated. Up to the present, although over sixty cases of infection have 
been recorded, the parasite is known only from the stages (oocysts) passed in 
the faeces. These are, nevertheless, sufficient to establish its systematic status 
with certainty. 
In a later publication, Wenyon (1915 b) was able to record the discovery 
of a second coccidial parasite, found in the faeces of a single patient in the 
same series of cases. This organism was an Eimeria, with small spherical 
oocysts (about 20 g in diameter), containing four oval dizoic spores and re¬ 
sembling E . falciformis of the mouse. As in the case of his Isospora, Wenyon 
was able to observe the characters most important for the systematic deter¬ 
mination of the parasite, though he gave it no specific name. 
1 Woodcock (1915) found only the unsegmented, or partly segmented, oocysts: ‘‘for some 
reason or other no further development has ever been observed.’ He correctly concluded, how¬ 
ever, though on very slender evidence, that “the coccidian is apparently of the Isospora type 
rather than the Coccidium type.” 
2 The name Coccidium isospora employed by Savage and Young (1917) I take to be a misprint 
or lapsus calami. The organism is an Isospora and not a Coccidium ( = Eimeria), and cannot be 
named in this fashion. If the authors’ intention was to call the species isospora . then its name— 
for them—would be Isospora isospora. 
