Contagious Pneumonia in the Horse. 105 



were large areas of infarction, necrosis, with encystment, casea- 

 tion, and lobular and perilobular exuadation and hepatization. 



Liver, enlarged, tense in its capsule, but soft and friable on its 

 cut surface, with areas of softening and necrosis. Both kidneys 

 congested, with pale zones of necrosis ; right enlarged. Beside 

 the substernal exudate, there was extensive hsemorrhagic exudate 

 between the serratus magnus and ribs. The blood, very dark, 

 brightened on exposure to air. 



Diagnosis : This may be based mainly on the prevalence of 

 the disease in the district, or the fact that the victim has come 

 from a long railway journey with risks of exposure, or has stood 

 by a horse just arrived ; on the prompt loss of appetite and sud- 

 den and extreme rise of temperature, without notable lung 

 lesions ; on the deep brownish yellow discoloration of the visible 

 mucosae, especially that of the eye, and on the yellow discharge 

 from the nose, the tardiness with which successive cases follow 

 each other comparatively to influenza, and the absence in large 

 measure of the early extreme prostration of that affection. (See 

 table under influenza). 



Prognosis varies with the progress of an epizootic, and the 

 youth and susceptibility of the animal together with the favorable 

 or unfavorable conditions of life. The death rate is usually high 

 at the outset when the more susceptible animals are attacked, and 

 for the same reason, in the young that have not been previously 

 exposed. Old and debilitated animals with broken down con- 

 stitutions suffer severely, and bad hygiene contributes much to 

 the mortality. The deaths vary from one to twenty per cent. 

 But short of death, permanent injury follows in a number of 

 cases. Encysted sequestra remain in the lungs for months and 

 when liquefied and absorbed, leave fibroid masses in place of 

 healthy lung tissue. The fibrous organization of peribronchial 

 exudates, impairs respiration, and the same is true of the fibrous 

 development of false membrane. Thus the horse is left perma- 

 nently broken-winded or short-winded, or from interference with 

 the recurrent laryngeal nerve, laryngeal hemiplegia (roaring) 

 ensues. In still other cases permanent adhesions of the peri- 

 cardium, or insufficiency of the cardiac valves, or disease and 

 distortion of joints or tendons, or nervous, hepatic or renal de- 

 generations destroy or seriously impair the value. 



