46 SEPTICAEMIA IN CHICKENS 



four daj's to a week results in an acute exudative nephritis. 

 The swollen or degenerated epithelium of the tubes surrounds 

 irregular masses of coagulated exudate and white blood cor- 

 puscles, among which are numerous short chains of strepto- 

 cocci. In very acute cases with sudden death the liver shows 

 extreme h\'peraemia. The cells have a slightly granular ap- 

 pearance in addition to the fatty infiltration usually seen in the 

 liver of well kept fowls. When death does not occur until 

 after twenty-four hours the liver cells also show parenchyma- 

 tous or fatty degeneration ; their outlines become indistinct, 

 the body very granular, and the nucleus takes the stain but 

 faintly. Interlobular and intralobular collections of round cells 

 and leucocytes appear, and in more chronic cases centers of 

 coagulation necrosis may be seen. The lungs become hepat- 

 ized. The walls of the bronchioles are thickened and the 

 streptococcus maj' be seen in the minute capillaries. The air 

 cells are filled with plasma, red blood corpuscles, and epi- 

 thelium, among which the microorganism is easily detected." 



§ 41. Differential diagnosis. This affection must be 

 differentiated from infectious leukaemia and chicken cholera. 

 The positive diagnosis of each must rest with the etiological 

 factor. A number of diseases of fowls have been described 

 from various places in Europe and Africa but none of them 

 seem to be caused by a streptococcus. 



§ 42. Prevention. The separation of the well from the 

 diseased fowls and placing them in uninfected houses or yards 

 is of the first importance. Norgaard and Mohler found that 

 immunity' may be produced in susceptible animals by the fil- 

 trate of bouillon cultures, bj' sterilized bouillon cultures of the 

 specific streptococcus, and with the serum of artificially im- 

 munized animals. 



REFERENCES. 



N6rg.\ard and. Mohler, Apoplectiform septicaemia in chickens. 

 Bulletiv No. j6, U. S. Bureau of Animal Industry, 1902. 



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