Pneumonia is distinguished from broncho-pneumonia by the existence of dulness at the period of crisis, whilst in the case of broncho-pneumonia this period is only marked by partial dulness, which is even then sometimes slight. Moreover, broncho-pneumonia usually develops much more slowly. The disease, then, is distinguished from peripneumonia by the following points:— (_a_) By the character of the temperature curve, which is regular in pneumonia, only attaining its highest point at the period of crisis, whilst in peripneumonia it ascends suddenly, and presents sudden oscillations. (_b_) The appetite remains, although diminished. (_c_) Sensitiveness in the region of the ribs is but feebly marked, or is entirely absent, simple pneumonia not being accompanied by pleurisy. (_d_) The dewlap never shows œdema, a symptom which usually accompanies the period of crisis in peripneumonia, when the jugular veins and the anterior vena cava are compressed. (_e_) These signs alone are almost sufficient on which to base the =diagnosis=, but they are often supplemented by two others, of some what less importance (for in exceptional cases they may also be observed in simple pneumonia), viz.—the absence in most instances of a membranous sound, and of a well-marked souffle. =Prognosis.= Two-thirds of the cases recover. This proportion might be increased if the veterinary surgeon were called in at the beginning. =Lesions.= Post-mortem examination reveals neither pleural exudate nor pleural lesions. The lung is large and of increased weight, hepatised along its lower borders, and congested in its upper part. The sero-hæmorrhagic infiltration of the interlobular spaces varies, according to the region examined: the upper regions are engorged and black, owing to capillary hæmorrhages and blood clots, which completely surround the pulmonary lobule, the latter being violet or brownish-red in colour. In the hepatised portions the lobules are of a washed-out reddish tint, and the interspaces of a whitish colour. The bronchi are filled with frothy, whitish mucus; the small bronchi sometimes contain fibrous concretions and the mucous membrane is injected, and may be destroyed in places. The bronchial lymphatic glands are enlarged, congested, and contain small hæmorrhages.