Cattle Ticks and Texas Fever 



223 



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they were given the generic name Pyrososma and because they were 



usually found two in a corpuscle, the specific name, bigeminum. It 



is now generally accepted that 

 the parasite is the same which 

 Babes had observed the year 

 before in Roumanian cattle 

 suffering from hsemoglobinuria, 

 and should be known as Babesia 

 bovis (Babes). 



By a series of perfectly con- 

 clusive experiments carried on 

 IBS. Babesia bovis in blood corpuscles. near Washington, D. C. , Smith 



and Kilbourne showed that 



this organism was carried from Southern cattle to non-immune ani- 

 mals by the so-called Southern cattle 



tick, Boophilus annulatus (= Mar- 



garopus annulatus) (fig. 139). 



Of fourteen head of native cattle 



placed in a field with tick-infested 



Northern cattle all but two contracted 



the disease. This experiment was 



repeated with similar results. Four 



head of native cattle kept in a plot 



with three North Carolina cattle 



which had been carefully freed from 



ticks remained healthy. A second 



experiment the same year gave similar 



results. 



Still more conclusive was the ex- 

 periment showing that fields which 



had not been entered by Southern 



cattle but which had been infected by 



mature ticks taken from such animals 



would produce Texas fever in native 



cattle. On September 13, 1889, sev- 

 eral thousand ticks collected from 



cattle in North Carolina three and 



four days before, were scattered in a 



small field near Washington. Three i 39 . The cattle tick (B 



out of four native animals placed in comsto?k! e; 



hilus annulatus). 

 ) male. After 



