Symptoms. Diagnosis. 49 



for 1 to 3 days, stop eating and ruminating, and also develop symptoms 

 of colic or tympany, after which recovery takes place. After intravenous 

 injection of blackleg virus a similar mild infection sometimes appears. 



Very severe cases of infection occur sometimes in which the 

 animals suffer from general indisposition, tympany, and diarrhea and 

 succumb in 8 to 12 hours, without the appearance of a distinct swelling. 



The existence of a genuine parturient blackleg, according to the 

 latest investigations, seems doubtful (see page 37) and could at best 

 be ascertained by autopsy, and then only in cases where the muscles 

 in the neighborhood of the genital organs show the characteristic 

 necrotic changes (such a case was observed by Kosselmann). 



In sheep the disease has a sudden onset, and is indicated 

 by a stiff walk, weakness of the back, moderate tympany, 

 champing of foam, and high fever. On the surface of the 

 front portion of the body, particularly on the neck and lower 

 chest, the wool is raised at one place, and here a swelling may 

 be found the size of the palm of the hand (Scheibel). 



In swine blackleg mostly appears with a severe acute inflammation 

 of the throat and heavy phlegmonous swelling of the surrounding parts 

 (Marek, Born). The development of the tumor which may extend 

 backwards and to the shoulder is also accompanied with feverish symp- 

 toms, by vomiting and diarrhea, and the latter symptoms are also ob- 

 served when the crepitant swelling has developed on a posterior ex- 

 tremity (Battistini). 



Diagnosis. The rapid course and the development of a 

 crepitant, edematous swelling, in cases wdiere the latter appears 

 on the surface of the body, make the diagnosis fairly easy. If, 

 ho^vever, the swellings are in the interior of the body, the nature 

 of the acute feverish attack can only be surmised through other 

 factors, particularly by the fact that blackleg frequently ap- 

 pears in the particular region. The disease may be mistaken, 

 especially for malignant edema, in the course of which crepitant 

 s^vellings appear on the surface of the ^ body also. ^ The 

 appearance of the sw^ellings, which are restricted to certain re- 

 gions and to young animals, in those parts of the body with 

 abundant musculature is suggestive of blackleg. Besides, the 

 swelling is here more emphysematous, the contained fluid dark 

 red and foamy, and the muscles are black colored, while in 

 malignant edema the swelling is more edematous, the fluid 

 gray-red or colorless, and the muscles diffusely reddened or 

 only red-gray (Gutzeit). The development of an edematous 

 crepitant swelling in the neighborhood of the external genital 

 organs at the time of birth will in itself be an indication of the 

 presence of malignant edema. 



Blackleg is differentiated from anthrax more readily, for 

 in the latter edematous sw^elhngs are rare and, if present, al- 

 ways hot and painful without crepitation. In phlegmonous 

 inflammations of the subcutaneous tissue, from pyogenic wound 

 infection the local character of the disease is distinctly indicated 



