No. 4.] CATTLE COMMISSIONERS. 475 



infection takes place through the skin ; in fact, deeper- 

 seated muscles, such as the diaphragm or tenderloin, are 

 very rarely attected. He says : " It is doubtful if infection 

 ever takes place through ingestion. In any case it has 

 proved exceedingly difficult to produce the disease, even by 

 feeding enormous doses of highly virulent material to sus- 

 ceptible animals." 



The name of the disease, blackleg, is a popular one, 

 based upon its symptoms and lesions. It has been known 

 as quarter-evil as well as blackleg, because it usually attacks 

 one quarter of the animal, causing a swelling, with for- 

 mation of gas under the skin, which causes it to crackle on 

 pressure ; the surrounding tissues are infiltrated with blood 

 or bloody serum, and the adjacent muscles are dark brown 

 or black, and easily torn. Comparing these appearances 

 with most of those described as occurring among the young 

 cattle of Worcester County, it would seem that, if the 

 disease there was blackleg, it was certainly a peculiar form. 

 In the majority of cases where post-mortem examinations 

 were made the lesions were chiefly in the throat, in the 

 walls of the pharynx, the roof of the tongue, the glottis 

 and surrounding tissues. These lesions were quite con- 

 stant in tlie animals that died within a day or two of being 

 taken sick ; in animals that lived several days the lesions 

 were then found in other parts of the alimentary canal, and 

 the patients presented symptoms of generally sick animals, 

 having a high temperature and loss of appetite, but no 

 swellings upon the surface of the body or legs, as described 

 as being among the symptoms of blackleg. 



The one inoculation experiment upon a heifer did not 

 produce the results that might be expected from the hypo- 

 dermic injection of a large quantity of the bacillus of black- 

 leg, but a single experiment of this kind is not conclusive. 



The disease is spoken of as blackleg in this report be- 

 cause the bacillus found by I)rs. Smith and Coolidge re- 

 sembles so closely the blackleg bacillus; but, if it is the 

 same, it seems to ])e a modified form, having an affinity for 

 the digestive tract instead of a tendency to produce its 

 lesions in the muscles near the surface of the body and the 

 subcutaneous connective tissue. 



