(c) Doubtful Cases.
To these belong Virchow’s case[185] where, in the liver of an elderly woman, a thick walled tumour measuring 9 to 11 mm. was found. Among the contents of this tumour there were oval formations 56 µ long, surrounded by two membranes and enclosing a number of round substances. Virchow considered these foreign bodies to be eggs of pentastomes in various stages of development, others consider them to be Coccidia.
The Coccidia which Podwyssotzki claims to have seen in the liver of a man, not only in the liver cells, but also in the nuclei, are also problematic.[186] The parasite was called Caryophagus hominis.
Again, other explanations can be given to an observation by Thomas, on the occurrence of Coccidium oviforme in a cerebral tumour of a woman aged 40. The growth was as large as a pea and surrounded by a bony substance.[187]
Genus. Isospora, Aimé Schneider, 1881.
Syn.: Diplospora, Labbé, 1893.
Belonging to the section Disporea, that is, forming only two spores, each with four sporozoites.
Isospora bigemina, Stiles, 1891.
Syn.: “Cytospermium villorum intestinalium canis et felis,” Rivolta, 1874; “Coccidium Rivolta,” Grassi, 1882; Coccidium bigeminum, Stiles, 1891.
This parasite lives in the intestinal villi of dogs, cats, and the polecat (Mustela putorius, L.). According to Stiles,[188] the oöcyst divides into two equal ellipsoidal portions or sporoblasts which become spores and then each forms four sporozoites. The oöcysts of this species vary from 22 µ to 40 µ in length and from 19 µ to 28 µ in breadth. Each spore is 10 µ to 18 µ long and contains four sporozoites. The parasites live and multiply, not only in the gut epithelium, but also in the connective tissue of the intestinal submucosa. Wasielewski has seen merozoites in the gut of the cat.