DISEASES OF HORSES 63 



ability of its existence in Indiana and several Western States. The 

 disease is also present in the Philippine Islands, Hawaiian Islands, 

 and Porto Rico. 



The period of incubation varies greatly, extending from three 

 weeks to four months, or even longer. In artificial inoculations 

 with pus through wounds in the skin, inflammation and swelling of 

 the lymph vessels may be noticed in twenty to sixty days, and these 

 vessels show in their course a development of hard nodules, from 

 which abscesses form. The natural infection is without doubt caused 

 through superficial wounds, such as galls, barbed-wire cuts, or 

 through various stable utensils, harness, bandages, insects, etc. 



Symptoms. The inflammation of the lymph vessels is usually 

 first observed on the extremities, especially on one or both hind legs; 

 it may also appear on the forelegs, shoulder, or neck, and more 

 rarely on the rump, udder, and scrotum. The lesions, as a rule, 

 develop in the tissue adjacent to the place of inoculation. In the 

 early stages of the disease the lymph vessels appear very hard and 

 thickened, and along their course hard nodules develop, ranging 

 in size from a pea to a hen's egg. Later these nodules soften, burst 

 spontaneously, and discharge a thick, yellowish pus. The surface 

 of the resulting ulcers or abscess cavities soon fills up with exuberant 

 granulation which protrudes beyond the surface of the skin, giving 

 a fungoid appearance. The affected extremities are considerably 

 enlarged, similar to cases of simple lymphangitis. In rare cases the 

 mucous membrane of the nostrils may also become affected, showing 

 yellowish flat elevations and ulcerations, and these may extend by 

 metastasis to internal organs. In cases where the mucous mem- 

 brane is affected, the submaxillary lymph gland may also become 

 enlarged and suppurate. The constitutional symptoms accompany- 

 ing this disease are not very marked or may be altogether absent. 

 There is usually only a very slight fever, which seldom runs over 

 102 F. The appetite is not impaired except in the advanced cases. 



Lesions. The anatomical changes are most marked in the skin 

 and the subcutaneous tissues. They may become 2 to 3 inches thick 

 and indurated as the result of fibrous-tissue formation, due to the 

 inflammation present. On the baconlike cut surface suppurative 

 areas and granulating sores may be noticed of various sizes, also en- 

 larged lymph vessels filled with clotted lymph mixed with pus. 



Diagnosis. The diagnosis is based on the characteristic ap- 

 pearance of the ulcerations, which show exuberant granulation of a 

 bright red color, inverted edges, and a thick, creamy, glutinous dis- 

 charge. These manifestations differentiate the disease from glan- 

 ders, in which the ulcers are craterlike, do contain exuberant granu- 

 lations, and the discharge is of a viscous, oily character. The sub- 

 maxillary and other nodes as well as the corded lymphatics in glan- 

 ders are more firmly attached to the adjacent tissues, and are there- 

 fore less movable. In some chronic cases of mycotic lymphangitis, 

 however, the lesions may closely resemble those of farcy, and in 

 these cases the microscopical examination of the pus will disclose 

 the nature of the affection. In the pus the saccharomyces can be 



