140 



COMMON DISEASES. 



phatic glands in various portions of the body ; also involving the 

 pleurae, pericardium, and surface of various internal organs as 

 in the usual type of the disease. 



A peculiar fact which appears in connection with these men- 

 ingeal type cases is that the animals which are apparently most 

 seriously sick early in their histories are often the cases which 

 live longest, whereas the apparently milder cases die very quickly 

 and very unexpectedly. 



FIG. 55. HAEMORRHAGIC SEPTICAEMIA. (M. 11. R.) 



Meningeal type. Cow stupid. Early stage. 



DIFFERENTIAL DIAGNOSIS. 



It is very important to distinguish between black leg and 

 haemorrhagic septicaemia, because so far as our present knowl- 

 edge extends, we are helpless in the presence of haemorrhagic 

 septicaemia. We have no vaccine either preventive or curative, 

 and no medical treatment ; whereas black leg can be easily and 

 cheaply prevented by vaccination. 



fn both diseases, death is liable to occur very suddenly, but 

 black leg commonly affects only cattle under two years of age, 

 whereas haemorrhagic septicaemia affects all ages indiscriminately. 

 High temperatures are characteristic of black leg, especially earlv 



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