• CATARRHAL INFLAMMATION OF THE LUNGS. 125 



DISEASES OP THE LUNGS. 



Catarrhal Inflamiuation of the Lungs ; Pneumonia. 

 (Catarrhal Pneumonia ; Lobular Pneumonia ; Broncho-pneumonia.) 



Etiology. Catarrhal inflammation of the kmgs generally 

 originates as a secondary disease following bronchitis, by an exten- 

 sion of the inflammation of the small bronchia into the alveola, 

 or from the obstruction of the bronchial tubes. The causes of 

 lobular pneumonia are from accumulations of mucus in the trachea, 

 which may be only imperfectly coughed up, or in very weak cases, 

 lying in the tubes, become decomposed and putrid, and act as an 

 irritant. These, on inspiration, are carried into the deep portions 

 of the lungs directly on the alveoli, and from a capillary bronchitis 

 it may become converted into a catarrhal pneumonia. In some 

 cases particles of food, medicines, especially thick mixtures, get into 

 the larynx, when the animal is unconscious or where there is partial 

 paralysis of the throat. These substances penetrate into the lung--, 

 and are very difficult to dislodge from the bronchia. This form 

 of the disease is generally termed traumatic or aspiring pneumonia. 



Pathological Anatomy. In a lung affected with catarrhal 

 pneumonia we always find all the characters of bronchitis, and 

 as the disease advances the groups of alveoli that belong to the 

 affected bronchia are rapidly filled with the catarrhal deposit, 

 preventing the air from penetrating into them. Soon we see an 

 intense hypersemia of the walls of the alveoli and the exudation 

 of a thin, non-curdling fluid and numerous white blood-cori^uscles 

 which soon become pus-corpuscles, and the commencement of a 

 fatty degeneration and detachment of the alveolar cells. The 

 alveoli and the small bronchia become entirely filled with pus- 

 corpuscles and a certain number of blood-corpuscles and broken- 

 down epithelial cells, and the inflamed portion of the lung can 

 easily be distinguished from its healthy surroundings. They form 

 hard, tough, roundish or lobuiated lumps which vary in size and 

 number, projecting s'ightly above the surface of the lung, and on 

 making a cross-section of the diseased portions in the earlier stages of 

 the disease they are seen to be dark bluish-red and later ou become 

 gray, while the surrounding tissue that is not diseased is normal, 

 or, what is more frequent, is slightly congested with blood. The 



