36 Veterinary Medicine. 



patient, it becomes a task of great difficulty to diagnose at once 

 the particular outbreak that is met with in the field. In some out- 

 breaks, however, the differential features are clear enough to 

 allow the veterinarian to pronounce at once on the true nature 

 of the disease. In others he must withhold his diagnosis until 

 he can put it to the test of microscopic examination, bacteriological 

 culture, the Widal test, or inoculation. 



Hog Cholera may be decided upon, when upon wholesome food, 

 in healthy environment, without any change of food, and in six 

 to fourteen days after the introduction of pigs from outside, or 

 the arrival of strange pigs in the near vicinity, or higher up on 

 the watershed, sickness appears tardil} 7 , taking one or two daily, 

 with or without a sudden hyperthermia, petechias on nose, eyes, 

 belly, axilla, or groin, a general soreness of the skin and abdo- 

 men, stiffness or weakness, hiding much under the litter, enlarge- 

 ment of the lymph glands, costiveness with dark red rectum and 

 glazed dung, followed by a profuse, watery, foetid, bloody, black 

 or yellow diarrhoea, and death mostly after one or two weeks or 

 more. The absence of cough, and the presence of ulcers bearing 

 necrotic sloughs on the lips, mouth or skin, and above all the 

 presence of the button-like necrotic ulcers on the mucosae of the 

 caecum, colon or ileum may be accepted as conclusive evidence on 

 this point. So also its prompt fatality to rodents, but not to 

 pigeons. 



Swine erysipelas has a much 'shorter incubation, more rapid 

 and violent onset, deeper, darker congestion of visible mucosae, 

 more extensive petechias of skin, mucosae, serosae, and tissues gen- 

 erally, a comparative absence of inflammatory and necrotic lesions 

 of bowels, a very early and high mortality in swine, rabbits and 

 pigeons, and a harmlessness toward the inoculated Guinea pig. 



Swine plague also shows a shorter incubation, a speedy eleva- 

 tion of temperature, more mucous congestion, less indication of 

 abdominal tenderness or of diarrhoea, more cough, dyspnoea, 

 wheezing and objective symptoms of pulmonary consolidation, 

 less congestion or engorgement of the spleen, or ulceration of 

 the bowels, and finally is very much more fatal to pigeons, and 

 spares neither rabbits nor Guinea pigs. 



Widal test. The cessation of movements and the agglutination of 

 the bacilli of hog cholera, noted by Dawson, is a valuable test, 



