570 PIROPLASMOSIS 



by the tick rhipicephalus evertsii. In this disease Theiler made the 

 interesting observation that when the blood of a donkey which had 

 recovered from the disease was injected into a horse the latter suffered a 

 slight illness only, although the organisms were present in the blood 

 injected. Such a fact is of importance, as attenuation of virulence in 

 pathogenic protozoa seems, so far as our present knowledge goes, a not 

 very common event. (4) Piroplasma canis. This causes a piroplasmosis 

 occurring in dogs. 



With regard to the pathology of infection by piroplasmata we know 

 nothing. The diseases are often extremely fatal, carrying off nearly 

 every individual attacked, but we do not know the nature of the 

 changes originated. 



