0. Dobell 19:> 
of it may therefore be left to some future investigator who is fortunate enough 
to find it once more 1 . 
SUMMARY AND GENERAL CONCLUSIONS. 
From a study of the organisms themselves, so far as this has been possible, 
and from an analysis of all accessible records relating to them, I conclude that 
there are four distinct species of coccidia which may parasitize man. These 
are: (1) Isospora hominis Rivolta, 1878 (emend.), discovered by Kjellberg in 
1860, and recently investigated by Wenyon; (2) Eimeria wenyoni n.sp., a form 
discovered in 1915 by Wenyon; (3) Eimeria oxyspora n.sp., another new form, 
here described for the first time; (4) an undetermined species of Eimeria (?) 
which was discovered by Glubler in 1858. This last inhabits the human liver, 
whilst the three others probably live in the small intestine. Probably some 
seventy cases of infection with the Isospora have now been seen, mostly in 
persons who have been in the Near East; but the other parasites appear to 
be extremely rare, and little is known concerning their probable geographical 
distribution. 
All these parasites are probably peculiar to man. There is no evidence that 
any of them is or can be parasitic in any other host. The prevailing belief that 
the coccidia of man are identical with those of rabbits, cats, or dogs, is there¬ 
fore unfounded. Furthermore, there is as vet no good evidence to show that 
man may harbour any species of coccidia other than the four just enumerated. 
All these forms, however, require fuller investigation. They are here briefly 
and incompletely described from the data at present available. 
There is at present no proof that the coccidia of man—with the probable 
exception of the species occurring in the liver—can produce a clinically recog¬ 
nizable pathological condition of “coccidiosis”: and as yet no method of 
treatment which will eradicate an infection with any species has been dis¬ 
covered. 
London, August 1918. 
1 As it seemed possible that specimens or preparations from the case studied by the late 
Dr Silcock might still be in existence at St Mary’s Hospital, my friend Capt. S. R. Douglas, l.M.S. 
(ret.), very kindly instituted inquiries on my behalf, and searched through the records and material 
in the Pathological Department. His efforts unfortunately were unavailing, but I take this 
opportunity of thanking him again for his help in the matter. Up to the present, therefore, 1 have 
had no opportunity of studying the parasites themselves from any case of human hepatic cocci- 
diosis. 
13—2 
