80 THE ANIMAL PARASITES OF MAN 



path. An , 1860, xviii., p. 523), in which a thick-walled tumour, measuring 

 9 ii mm., was found in the liver of an elderly woman. Long oval forma- 

 tions surrounded by two membranes, measuring 0-056 mm. in diameter, 

 and containing a number of small roundish bodies were found in the 

 tumour. Virchow is of opinion that these foreign bodies were develop- 

 mental forms of the ova of pentastomes l rather than coccidia. 



The coccidia which Podwyssotzki states that he found in the hepratic 

 cells and in their nuclei are also problematical (Podwyssotzki., " Ueb. d. 

 Bedeut. d. Coccid." in d. Path. d. Leber d. Mcnschen, C. f. B. u P., 

 1889, vi., p. 41). The parasite is termed Caryophagus hominis. 



An observation by Thomas, of the presence of " Coccidium ovi forme " in 

 a cerebral tumour the size of a pea, and surrounded by' a bony substance, 

 occurring in a woman, aged 40, must admit of another explanation. 

 (Thomas, J., "Case of Bone Formation in the Human Brain due to the 

 Presence of Cocc. ovif." Journ. Boston Soc. Med. Sc., 1899, in., p. 167 ; 

 C. /. B., P. u. J., 1900, p. xxviii., 1882). 



2. Coccidium hominis (Rivolta, 1878). 

 Syn. : Cystospermium hominis, Riv., 1878 ; Coccidium perforans, R. Lckt., ] 879. 



Remak was the first observer to confirm the fact that this 

 species inhabits the intestinal epithelial cells of rabbits, giving 

 rise to severe diarrhoea, which usually causes death. A few later 

 authors consider that the parasite is identical with Coccidium 

 cuniculi, but there are differences between the two forms which 

 justify the formation of a separate species. 



Apart from its habitat, the difference consists in the smaller 

 size of the oocysts (0-024 0-026 0-035 mm - m length, and 

 0-0128 0-014 0-002 mm. in breadth), in its more rounded 

 form, and in the residual body that is always present after sporu- 

 lation and absent in Coccidium cuniculi. Moreover, the time 

 employed for the segmentation of the globular cystic contents 

 into sporoblasts differs in the two species ; in Coccidium hominis 

 the time taken is three or four days, in Coccidium cuniculi three 

 or four weeks. In other particulars the two species agree. 



As Railliet and Lucet have demonstrated, infection is brought 

 about by the ingestion of mature spores. In consequence of the 

 schizogony such a severe auto-infection follows within a few days 

 that the entire small intestine is affected. Even with the naked 

 eye whitish spots may be observed in the mucous membrane 

 caused by the wholesale colonisation of schizonts and sporonts in 

 the cellular epithelium as well as in Lieberkuhn's glands. The 



1 Compare trematodes of man. 



