446 MICROBIOLOGY 



Blue tongue. Spreull 25 describes the disease known in 

 South Africa among sheep as malarial catarrhal fever and 

 which is known among the natives as "blue tongue." It is 

 an inoculable disease of sheep characterized usually by fever 

 and by lesions in the mouth and feet. He showed that it 

 could be transmitted to cattle and to goats by inoculation. 

 Its cause has not been ascertained. 



This interesting disease of sheep known as blue tongue has 

 been shown by Robertson and Tyler to be due to a virus that 

 passes through a Berkefeld filter. It is destroyed, according 

 to Tyler, by drying but it resists advanced putrefaction of the 

 blood containing it. 



Infectious anemia of horses. Hempel, 26 after a careful 

 investigation of infectious anemia of horses, concludes that 

 its cause is an ultravisible virus, that animals which recover 

 have no immunity and that it is impossible to artificially 

 immunize horses against this disease. Mack 27 found intra- 

 cellular bodies in a small number of red corpuscles. 



African horse sickness. As early as 1900 M'Fadyean 28 

 showed that the cause of horse sickness in South Africa was 

 an ultravisible virus that would freely pass through a Berke- 

 feld filter and that was not entirely arrested by the close- 

 grained Chamberland F and B filters. He showed that the 

 virus remained infective when the plasma containing it was 

 heated to 75 C. and that it was highly resistant to the effect 

 of putrefaction occurring in the blood in which it was present. 



25 Spreull. Jour, of Comp. Path, and Therap., Vol. XVIII (1905) 

 p. 321. 



26 Hempel. Zeit. f. Infekt. * * * der Haustiere, Bd. V (1908) p. 

 381. 



27 Mack. Proceedings Am. Vet. Med. Asso., 1911. 



28 M'Fadyean. Jour. Comp. Path, and Therap., Vol. XIII (1900) 

 p. 1; also Vol. XIV (1901) p. 59. 



