450 VETEEINAEY HYGIENE 



the Bacillarij pyroplasma, but for which the name P- parmun 

 would be more suitable. 



In this extremely interesting class of blood parasites, the 

 method of infection is most important. In the case of the 

 malarial parasite of man the life cycle is completed in the 

 body of the mosquito, while in the genus pyroplasma the 

 tick of each species of animal is the infecting agent; in 

 some cases it is also the elaborating agent ; for example, 

 the East Coast fever of cattle cannot be produced by direct 

 inoculation, but only by feeding ticks on the affected cases, 

 and subsequently placing their successive stages of nymphs 

 and adults on healthy animals (see Ticks, p. 417). By an- 

 alogy with the before-mentioned parasites, we conclude that 

 the schizogenic stage of this organism occurs in the blood, 

 while the sporogenic stage occurs in the body of the tick. 



In the muscles of certain animals Sporozoa are found, 

 and are here known as Sarcosporidia. The Sarco-cystis 

 Miescheriana is found in the muscles of the pig ; S. Bertrami 

 in those of the horse ; S. tenella in the Bhee^^ ; S. Blanchardi 

 in the ox, more especially in the heart muscle. Sporozoa 

 also cause disease in fish, both the barbel and carp being 

 known to suffer. 



Ciliata. — Ciliated infusoria are met with in the digestive 

 canal of all domesticated animals, and are non-pathogenic. 

 They are possibly concerned in certain physiological pro- 

 cesses connected with digestion. 



Bacteria. ^ — These represent a group of very low vegetable 

 organisms, closely allied to the lowest algae. They are 

 classified into the following groups : 



Coccacece : so called from their spherical shape. 

 Bacteriacece : so called from their rod shape. 

 Spirillacece : so called from their screw shape. 



According to their method of reproduction the bacteria 

 are further grouped : 



' Strep)tococcus : Cells grouped in a chain. 

 Sarcina : Cells grouped in a cube. 

 Micrococcus or^ 

 , Staphylococcus . 



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Coccacea 



, [ Cells grouped irregularly. 



