CHAPTER LIX. 

 THE INTRA-CORPUSCULAR tt/EMATOZOA (continued). 



Section III. The genus Piroplasma, 1 p. 786. 

 Introduction. 



1. Piroplasma bigeminum, p. 787. 



Morphology and method of multiplication, p. 787. Methods of examina- 

 tion, p. 790. Immunity, p. 791. 



2. Piroplasma ovis, p. 791. 3. Piroplasma canis, p. 791. 4. Piroplasma equi, 

 p. 792. 5. Piroplasma pithed, p. 793. 



Section IV. The genus Theileria, p. 793. 

 Theileria parva, p. 793. 



BLOOD parasites of the genus Piroplasma (Patton and Laveran) are the 

 cause of disease in cattle, sheep, horses, dogs, monkeys and possibly other 

 animals. 



The life history of the Piroplasmata is still only imperfectly understood. 

 These parasites have been investigated by Koch and Klein, Nuttall and 

 Graham-Smith, Kinositha, Miyajima and others, but there is a want of 

 agreement in the conclusions which these observers draw from their observa- 

 tions. There is, however, no doubt but that reproduction takes place both 

 by schizogony and by sporogony. The schizonts, which may either be intra- 

 corpuscular or free in the plasma, are amoeboid and rounded or annular and 

 by a process of budding give rise to rounded merozoiites. The sporonts are 

 intra-corpuscular and pyriform ; they contain a nucleus and a blepharoplast 

 and multiply asexually by longitudinal division in the blood ; the forms 

 resulting from division may remain attached by their pointed ends and 

 undergoing further division give rise to star-shaped forms or rosettes 

 (cf. p. 788). 



Sporogony occurs in the alimentary canal of ticks (and perhaps also of 

 some biting flies and mosquitos). According to Koch and Klein the sporonts 

 which are set at liberty in the stomach of the insect can be differentiated into 

 spherical macrogametes and cuneiform microgametes. The fertilized macro- 

 gamete (zygote) assumes a vermicular form, is motile and becomes club- 

 shaped (ooJcinete). 



Schaudinn, having noticed forms resembling Trypanosomes in animals 

 infected with piroplasmata, put forward the hypothesis that the Piroplasmata 

 should be grouped with the Trypanosomata. Miyajima observed large 

 flagellated parasites similar to Trypanosomes in broth cultures sown with 

 the blood of Japanese oxen affected with piroplasmosis (P. parvum [ Theileria 



1 Synonyms : Hcematococcus, Babes ; Babesia, Starcovici ; Pyrosoma, Smith and Kil- 

 bourne ; Ixodioplasma, Schmidt. 



