COURSE AND TERMIXATIOX. 503 



tissue, but this has been succeeded by softening and purulent 

 infiltration ere resolution has been established. 



For the first few days of the earlier stages of the disease, 

 during the continuance of the conditions of arterial irritation 

 and vascular engorgement, the symptoms of febrile disturb- 

 ance are great and sometimes alarming ; immediately succeed- 

 ing the defervescence of the pyrexia, which may be within the 

 first week, the respirations become more embarrassed or 

 quicker, although both temperature and pulse may have fallen. 

 Should return to health not show itself by the gradual develop- 

 ment of functional activity in the pulmonary vesicular struc- 

 ture, followed by the resumption of the respiratory murmur, 

 the condition of lung-consolidation may continue to advance, 

 and death result from deficiency of aerating pulmonary surface. 

 (Jr even when partial resolution is established we may have, 

 by the softening and rapid disintegration of tissue and its 

 absorption, a condition of blood-contamination, and a renewal 

 of fever and inflammatory action. In primary pneumonia of 

 a severe type, particularly when associated with bronchitis, 

 there is occasionally exhibited a tendency to the occurrence of 

 metastatic action; in the horse this is apt to assume the 

 character of inflammation of the vascular structures of the 

 feet. 



When occurring as a secondary affection, or in conjunction 

 with other diseased conditions, particularly where epizootic 

 influences and surroundings of an evil and debilitating 

 character are in operation, pneumonia is more apt to assume 

 a less certain and determinate course, and is more likely to 

 terminate in destructive changes than in resolution. The 

 inflammatory action is here probably more truly of the patchy 

 or catarrhal type ; there is little or no fibrinous exudation as 

 compared with the pure croupous variety, the chief changes 

 being a filling of the alveoli with cell proliferations, which, in 

 the milder cases, undergo liquefaction and removal, and in those 

 which do not thus terminate forming collections of indurated 

 cheesy material, which may take on further changes of a more 

 stable or fugitive character. These local patches of inflamed 

 and altered lobules may be distributed throughout a consider- 

 able extent of lung-tissue, which otherwise gives evidence of 

 previous bronchial inflammation. Often they seem to the eye, 



