164 Coccidia parasitic in man 
Brought forward 5 cases 
In the intestine, by 
Kjellberg [recorded by Virchow (I860)] ... ... ... 1 case 
Eimer (]870) ... ... ... ... ... ... ... 2 cases 
In the faeces, by 
Railliet and Lucet (1890) ... ... ... ... ... 2 „ 
Total ... 10 cases 
From this it may be concluded that human coccidiosis is not a common 
affection: especially when it is remembered that several of the above cases are, 
to say the least, by no means well authenticated 1 . 
(3) As regards the parasites present in these cases, we find the information 
necessary for their identification either wholly lacking or exceedingly deficient. 
The coccidium inhabiting the liver appears to resemble Eimeria stiedae of the 
rabbit. There is no evidence, however, to prove that it is of this species; and 
there is some—namely, its size—to indicate that it is not. The coccidia found 
in the small intestine and in the faeces were, so far as there are anv indications, 
of a species belonging to the genus Isospora, and resembling /. bigemina of 
cats and dogs. In short, there is evidence that man mav harbour an Eimeria 
in his liver and an Isospora in his gut ; but beyond this it would be hazardous 
to draw any inferences. 
The foregoing conclusions may be fairly drawn, I think, from the cases 
analysed in the present section. At the same time, however, it must be pointed 
out that the cases considered—or at least some of them—appear less uncertain 
when viewed in the light of more recent work. The conclusions are here 
tentative, not final. They constitute merely a “vindemiatio prima,” in the 
Baconian manner, before we proceed to study further instances. But it is well 
to state them clearly at this point, since they give us a basis of fact from which 
to judge the value of the opinions which have been expressed at various times 
by writers on human coccidiosis. The most important of these opinions I shall 
now chronicle as briefly as possible. 
B. Opinions concerning the Coccidial Parasites of Man, as expressed 
by the Chief Compilers and Commentators. 
Various writers have, on various occasions, held widely different views 
regarding the coccidia parasitic in man. These differences—so far as concerns 
us at present—are chiefly regarding (1) their systematic position; (2) their 
specific identity or diversity in respect to similar parasites occurring in other 
hosts; and, consequently, (3) their nomenclature. Even the most casual con- 
1 For my own part, I am quite prepared to believe that the cases of Gubler, Dressier, Silcock, 
and Kjellberg, are the only real cases of human coccidiosis recorded. But such a view is, perhaps, 
hypercritical. 
