LECTURE XXXI. 

 SYMPTOMATIC ANTHKAX. 



This disease is also known as black leg, black quarter, etc. 



Definition. — A fatal infectious and enzootic disease of thrifty 

 young cattle. It is apt to appear year after year on certain pas- 

 tures or along certain valleys. Cattle over two years of age are 

 not usually affected. 



Cause. — A short spore-forming bacillus (Bacillus Chauvoci). 

 This germ is very resistant, being able to remain virulent for 

 years — under favorable conditions. Infection is usually made by 

 inoculation, either through the skin or mucous membranes, more 

 commonly through the former. 



Symptoms. — Local and general. 



Local symptoms. — There is usually a pronounced swelling in- 

 volving either the front or hind quarter. This swelling is char- 

 acterized by crepitation as one passes the hand over it, due to an 

 accumulation of gas in the loose subcutaneous tissues. The 

 swelling does not extend below the hock or knee. An incision 

 into the swelling reveals the presence of dark, froth)' blood, with 

 foul odor. This swelling is not invariable. Some cases, espe- 

 cially those which appear at the beginning of the outbreak and 

 die very suddenly, mav not show the characteristic swelling. 



Constitutional symptoms. — The constitutional symptoms are 

 usually acute and develop rapidly. The animal is dull, without 

 appetite. It shows high fever and marked debility. The consti- 

 tutional symptoms may last from one to three days, and the case- 

 usually terminates fatally. The fever may reach 106 or even 

 107. There is lameness in those cases which show 7 local swellings 

 of the front or hind quarters. 



Examination postmortem. — This reveals a tumor filled with 

 dark, frothy blood with fetid odor, and more or less filled with 

 gas. The spleen is normal and blood from the general circulation 

 is also apparently normal, clotting readily on exposure to air. 



Digitized by Microsoft® 



