152 
Coccidia parasitic in man 
Institute at Berlin. The findings are recorded by Virchow (I860), who says 
that the parasites were found in the villi of the small intestine. Virchow adds 
that the “psorosperms” in this case ‘’agree completely with those which 
I have seen in the dog.” He describes the latter as “ faired psorosperms” — 
“relatively small bodies, regularly arranged together in two’s, provided with 
a strong double-contoured membrane.” There can thus be little doubt that 
he had in mind the canine form of the coccidian parasite now generally known 
as Isospora bigemina. This supposition is strengthened by the fact that he 
further compares Kjellberg’s “psorosperms" with similar bodies which he 
himself had found in the kidney of a bat, and of which he gives some figures. 
So far as I am aware, this parasite has never been studied or describee] since; 
but from Virchow’s account, it seems probable that it was also a species of 
Isospora (= Diplospora). 
It therefore seems probable that Kjellberg discovered, in the small intestine 
of man, a coccidian belonging to the genus Isospora, and closely resembling 
that of the dog (I. bigemina). 
Virchow's case. Virchow (1860) further described and figured some bodies 
which he had himself discovered in the liver of a woman. They were somewhat 
large oval structures—some 75 microns i n length 1 —with a thick shell surrounded 
by a gelatinous envelope, and with protoplasmic contents strongly suggesting 
helminth ova undergoing segmentation. Virchow regarded these bodies as 
“worm eggs,” and suggested that they probably belonged to a pentastomid. 
He failed, however, to find any “worms” associated with them. Some later 
writers have pronounced Virchow’s case to have been one of hepatic cocci- 
diosis, believing the “eggs” to have been the oocysts of a coccidium. Railliet 
(1895), for example, says that Virchow’s parasite was “quite clearly a 
coccidian” (p. 133); but 1 cannot find the slightest justification for such a 
statement. In my opinion the bodies found by Virchow were almost certainly 
not the oocysts of a coccidium, but were probably, as he believed, ova of a 
metazoan parasite. In any case, they seem to have been very different from 
the hepatic coccidia of Gubler, and cannot possibly have been the oocysts of 
Eimeria stiedae. 
Eimer s cases. In his well-known work on coccidia, Eimer (1870) records 
the finding of “psorosperms” in two human bodies in the Pathological 
Institute in Berlin. The histories of the cases were almost unknown. "The 
alimentary canal was filled, and its epithelium completely infiltrated" with 
the parasites. Beyond noting that “the form of the ‘psorosperms’ was here 
the same as in the aforesaid animals” he gives no description of them. "The 
aforesaid animals,” it may be noted, included mice and others, and the coccidia 
infesting them probably belonged to several different genera. In my opinion 
it is now quite impossible to identify Eimer’s “psorosperms" with certainty. 
1 Virchow (1860) states that the length of the structures was 0-003 of a Paris inch, ^lanchard 
(1889) and nearly all subsequent commentators give their length as 56 /a. 
