4 PROTOZOA N PARASITES. 



they classed these parasites with the Coccidia, a 

 group of Protozoa, included in the division Sporozoa, 

 that are parasitic in various parts of animals and birds. 



In the smaller white spots, evidently those above 

 referred to, the same investigators found numbers of 

 Flagellata ; these ' Infusoria/ or tailed Protozoa, 

 have been named Jlonocercomonas gallincehy Rivolta. 



Pfeiffer has also made observations reoardmo- these 

 flagellate forms, but he regards them as Tricomas, 

 minute flagellate forms with two whip-like flagella. 

 My own investigations clearly support the discoveries 

 of the above scientists, but the part played by the 

 Tricomas seen by Pfeiffer I could not in any way 

 follow. Fowls would easily take the disease from 

 the Coccidia when injected into a scratch in the 

 mucous membrane of the pharynx, but in no case 

 could I *' plant ' the disease by means of the flagellate 

 forms. 



The Forms of Parasites. 



Ivivolta states that these Coccidia develop in the 

 epithelial cells. In this stage the Protozoan is in a 

 thin shell, which contains a number of spores, lemon- 

 shaped in form, and known as ' pseudo-navicellse.' 

 These spores in due course turn into true amoeboid 

 forms, the so-called embryos of Coccidia ; and, accord- 

 ing to the above authority, these amcebuloe can 

 migrate between the epithelial cells. On reaching 

 the topmost layer of epithelium they take up their 

 abode in the youngest cells, where they become 



