118 INFECTIOUS DISEASES DUE TO PROTOZOA 



In experimental cases in dogs the total number of leucocytes 

 increased suddenly on the appearance of symptoms, reaching 

 15,000-19,000, then falling somewhat on the day of death. The 

 percentage of polymorphs exceeded 90% from the time of the 

 appearance of symptoms to death. In experimental cases in 

 rabbits and guinea pigs there was a polynuclear leucocytosis 

 from the time symptoms appeared and an increase in the number 

 of leucocytes in some of the cases. In some there was no increase 

 in the number of leucocytes, in a few there was a leucopenia. 



TEXAS FEVER 



The protozoon causing this disease was first observed by Babes 

 (1888) in Roumania in the blood of cattle affected with hemo- 

 globinuria. In 1889, Smith found the organism in the blood of 

 cattle suffering from Texas fever and named it Pyrosoma bige- 

 minum. The generic name has been changed to Babesia. 



In the acute form of the disease the parasites may be found in 

 the circulating blood during the febrile period. When the fever 

 subsides and the number of red corpuscles has been found greatly 

 reduced, the parasites disappear rapidly from the peripheral 

 blood, the reduction of temperature usually coinciding with the 

 more or less rapid disappearance of the parasites. An occasional 

 parasite may be found for some clays or even a week after recovery 

 has set in (Smith and Kilbourne). Kossel and Weber report that 

 the parasites are abundant during the time hemoglobinuria is 

 present. When hemoglobinuria disappears the parasites disappear 

 or are very scarce in the circulating blood. In one case Kossel 

 and Weber found individual large typical pyriform parasites in 

 the blood seven days after the disappearance of hemoglobinuria. 



In acute cases the parasites appear in fresh blood as two pale, 

 pear-shaped bodies situated within red corpuscles. The broader 

 end of the parasite is rounded, the other end long and tapering. 

 The tapering ends are directed toward each other and are ordinarily 

 close together. Sometimes a thin film of protoplasm may be made 

 out connecting the (wo tapering ends. The broad ends may 

 occupy various positions as regards each other; sometimes they 

 are rather close together so the pyriform bodies lie nearly parallel, 

 then they may point away from each other, the pyriform bodies 



