C. Dobell 
191 
This species is added here chiefly for the purpose of directing attention to 
our ignorance of it. Hitherto it has been wrongly regarded as identical with 
the species which occurs in the liver of the rabbit ( Eimeria stiedae). 
Altogether there are but five recorded cases of infection with this organism; 
namely, the cases of Gubler 1 (1858), Dressier (Leuckart, 1863, 1879), Peris and 
Sattler (Leuckart, 1879), Peris and von Sommerring 2 (Leuckart, 1879), and 
Silcock (1890). These were recorded respectively in Paris, Prague, Vienna, 
Giessen, and London. Gubler and Silcock have given some account of their 
patients: of the others practically nothing is known. Gubler has described the 
parasites—in the language of his day, and in ignorance of their nature— and 
Davaine (1860), Silcock. and Leuckart have noted their resemblance to E. 
stiedae. Dressier’s rude sketches of the oocysts which he found have been 
reproduced by Leuckart (1863, 1879). Beyond these fragments nothing of any 
value can be gleaned concerning the coccidia themselves. 
That the hepatic coccidium of man displays a general resemblance to 
E. stiedae seems probable from the testimony of Gubler, Davaine, Leuckart, 
and Silcock. We learn from the first that the oocvst is ovoid. This is confirmed 
by Dressler’s drawings and Silcock’s description, and is implicit in Leuckart’s 
account. Gubler further noted the presence of a micropjde at one end of the 
oocyst. Nobody, however, has recorded the size of the latter; but from Dress¬ 
ler’s drawings—the magnification of which is given by Leuckart— it is evident 
that its length is about 20 fi. It thus appears that the oocysts of the human 
hepatic coccidium are much smaller than those of Eimeria stiedae ; and this 
is confirmed by Davaine (1860), who expressly states that they resemble the 
smaller forms found in the rabbit’s liver 3 . Silcock alone seems to have seen 
the formation of spores within the oocyst. The other observers saw only the 
oocysts with unsegmented contents. But Silcock gives no description of the 
sporulation, and does not state how many spores and sporozoites were formed. 
He appears, however, to have believed that the human coccidium is similar, 
in these respects, to Eimeria. stiedae as described and figured by Leuckart. 
Perhaps it may be concluded from this that the human parasite is also an 
Eimeria. Beyond this it would be rash to draw any conclusions as to its 
systematic status. 
Dressler’s drawings, as reproduced by Leuckart, apparently show four 
oocysts seen under a low magnification (330 diameters), in which little can 
be made out; and two larger (magnified 1000 diameters) which are apparently 
1 Gubler was the original discoverer of the organism. 
2 This case, as already noted, is very doubtful; nor is there much to support the one preceding 
it. They are cited here on the authority of Leuckart—not a very convincing authority where the 
Protozoa are concerned. 
3 The oocysts of E. stiedae are commonly 35^-37 /x in length. 1 have never seen any measuring 
less than 30 /x. It is noteworthy that Leuckart himself gives figures of E. stiedae, magnified 550 
diameters (1870, fig. 106, p. 256), which arc approximately equal in size to those which he gives 
of the human parasite (Dressler’s figure, Fig. 114, h and c, p. 281) stated fo be enlarged 1060 
diameters. 
Parasitology xi 13 
