28o BLACK LEG 



ization. In this countr}-, records are wanting of observations 

 on this point. 



Arloing has called attention to a mild form of this disease 

 in which the symptoms are slight debility, loss of appetite and 

 slight local swelling. 



§ 203. Morbid anatomy. After death the carcasses of 

 animals which have died of this disease soon become distended 

 with gas. This is due in part to the fermentation in the 

 digestive tract and in part to the formation of gas in the sub- 

 cutaneous tissues due to the presence of the specific bacillus. 

 The subcutaneous distension is especially marked in the region 

 of the swellings but it extends for a considerable distance from 

 these foci in the direction of least resistance. The tympanitic 

 condition often causes the two legs on the upper side of the 

 carcass to extend out straight without touching the ground. 

 A dark, blood-colored, frothy discharge flows from the nostrils 

 and anus. Decomposition takes place very rapidly except in 

 the affected muscles, which retain a sweetish-sour odor for a 

 considerable time after other parts of the carcass have become 

 putrid. 



The skin covering the swelling is often affected with dry 

 gangrene. The subcutaneous connective tissue is jellow, 

 gelatinous, infiltrated with blood and bubbles of gas which 

 escape if the tumor is incised. The muscles underneath the 

 tumors are of a dirty brown or of a blackish color. At other 

 places they are dark red or dark yellow and, when exposed for 

 some time to the air, they may have a golden lustre. They are 

 brittle, putrid and very rich in fluids. They crackle on palpa- 

 tion. When incisions are made into them, blood of a frothy, 

 greasy, tarry appearance and of a sickish, fetid odor issues 

 from them when they are squeezed. The fibres of the muscles 

 show extremely varied degenerative changes. The gases that 

 are present in the muscles are inflammable and burn with a 

 bluish flame on being ignited. They are said to have but 

 little odor, on which account it is assumed that the}' consist of 

 carburetted hydrogen. They are also said to contain carbonic 



