In _gangrene of the lung_ the part may be in the dried condition of an eschar; it may indicate gangrene only by its altered color, its flaccidity, its fetid smell and the altered appearance of all its microscopic elements; it may be denoted by a putrid softening, the tissue easily breaking down into a stinking pulp of mixed fibrous and granular materials; or lastly there may be merely a cavity with traces of putrid contents, the dead mass having been detached, disintegrated and expectorated. _Modifications of the Blood and Distant Organs._ A marked feature of pneumonia is the destruction of red blood globules. This is early indicated in the staining of the visible mucosæ by the liberated hæmoglobin and by actual count they may be reduced in the horse from 7,500,000 to 6,000,000 per cubic millimeter (Trasbot). There is an increase of white globules, an absolute increase, not only in ratio to the red. The hæmatoblasts are enormously increased especially during defervescence. The fibrine (fibrine formers) is materially increased; in the horse from 3.5 to 6.7 or 7.5 per 1,000 (Grehaut). Albumen is diminished. Soda salts are increased. The bronchial lymphatic glands are always congested, swollen and reddened with some serous effusion. They may become the seat of inflammatory cell growth (embryonic tissue) or even of suppuration. The abscess may open into the bronchia or pleura. These are especially to be dreaded from their tendency to implicate the inferior laryngeal nerve and induce roaring. Pleurisy is inevitable when the inflammation reaches the surface of the lung, hence hydrothorax is often present. Pericarditis and hydropericardium are similarly met with. Endocarditis is occasionally present and may be traced to strain of the valves of the laboring heart, or to direct infection with the pneumonia microbe. Dilatation of the right ventricle is common as a result of the obstructed pulmonary circulation. Fatty degeneration of the heart and congestions of the intestinal mucosa, liver, kidneys, and spleen are further complications. Finally laminitis and rheumatoid affections occur as complications.