PIROPLASMOSIS. 27 



liver substance but in the bile. These prurigerous masses on 

 microscopic examination are found to contain numbers of coc- 

 cidia. It may possibly be taken for tuberculosis unless carefully 

 examined. The walls of the intestine may be invaded as well 

 as the liver. 



HiEMOSPOBIDIA. 



These protozoa have an alternation of generations correspond- 

 ing with an alternation of hosts : the non-sexual stage is passed 

 in the blood of a vertebrate, the sexual sporogonous stage in 

 the gut of an invertebrate. They are all parasites of the blood 

 of animals and man, and have risen into great prominence from 

 the fact that they are the cause of malarial fevers in man and 

 the devastating cattle diseases, such as East Coast fever, red- 

 water or Texas fever, and the fatal malignant jaundice of canines. 



The malarial fevers are carried by several species of mos- 

 quitoes belonging to the Anophelinae, the cattle and canine 

 fevers by Ticks. 



Only two genera of Haemosporidia need be mentioned here — 

 namely, Plasmodium, which contains the malarial species, and 

 Piroplasma, which contains the animal fever parasites. 



PlEOPLASMOSIS. 



This latter genus contains several species parasitic in the 

 blood of mammals (fig. 6). These species are so closely related 

 that they can scarcely be distinguished from one another, save 

 for the fact tliat they occur in different hosts. The diseases 

 these blood parasites produce are spoken of as piroplasmoses. 

 In acute form the chief symptom is haemoglobinuria, caused 

 by the destruction of the red blood corpuscles. 



Redwater. — This is one of the best-known diseases caused by 

 Piroplasmce. It is also spoken of as Texas or Southern fever in 

 America. This is caused by the parasite Piroplasma higemina 

 (Smith and Kilborne). The species producing European Eed- 

 water is the same. The parasites occur during one period as 



