Acute Fibrinous Pneumonia. Pneumonitis in the Horse. 263 



febrile and other symptoms subside and the exudations in the 

 effused lung undergo a process of liquefaction and absorption 

 until neither auscultation, nor percussion nor even the examina- 

 tion of the lung after death will show the slightest trace of the 

 pre-existent disease. This is the most common termination in 

 single pneumonia in the horse. 



Splenisation is that condition of lung already described under 

 the head of pulmonary congestion, and if affecting both lungs 

 throughout, necessarily destroys life by arresting the aeration of 

 the blood. 



Abscess. Diffuse suppuration is very common in the stage of 

 gray hepatization. In this the affected lung becomes more or less 

 extensively infiltrated with pus, limited by no distinct membrane 

 like the pus of an abscess, but exuding freely from the cut sur- 

 face of the lung or escaping from its interstices when it is pressed. 

 It is preceded and in its early stages associated with the formation 

 of granular masses and corpuscles. Its existence cannot be cer- 

 tainly ascertained though it may be surmised when after hepatiza- 

 tion of a portion of lung a mucous rAle, a sort of gurgling, is heard 

 in the adjacent bronchium and an abundant muco-purulent dis- 

 charge takes place from the nose. It threatens extensive de- 

 struction of lung tissue. 



Circumscribed suppuration or abscess is infrequent though occa- 

 sionally met with in the horse and ox. In this case the excessive 

 exudation at one point liquefies, and the surrounding lymph be- 

 coming organized into a vascular membrane, an abscess is formed. 

 This may burst into the bronchial tubes and be discharged by the 

 nose. In less favorable cases it makes its way toward the pleu- 

 ral surface and opens into the cavity of the chest. It is impossi- 

 ble to detect the existence of a pulmonary abscess, though after 

 it has burst into a bronchial tube the existence of the cavity may 

 be ascertained by the amphoric sound heard on auscultation. 



Animals may recover from such pulmonary suppurations, or if 

 they are too extensive, the consequent depletion may induce hec- 

 tic and death. 



Gangrene of the Inng is happily rare and has appeared to be 

 connected with close, foul stables, previous ill-health, and work, 

 after the onset of pneumonia. It is characterized by high tem- 

 perature (ro6° to 108° F.) by great dullness and prostration, due 



