The term “parotiditis” indicates an inflammatory condition of the parotid gland. Of this disease several forms exist. The disease is termed simple when due to accidental causes or infections, specific when resulting from some special disease germ like the ray fungus. Anatomically, these diseases consist in inflammation of the glandular parenchyma and connective tissue stroma which surrounds the acini. ACUTE PAROTIDITIS. =Causation.= The causes of acute parotiditis are varied. Mechanical violence or contusions (due to collisions with fixed bodies, horn thrusts, or blows from the ox-goad) may produce it, the glandular parenchyma and connective tissue separating the acini or the peri-glandular tissue being torn, crushed, lacerated, and often also directly infected in consequence of the injury. Ascending infection through the medium of the salivary ducts represents a second possible cause of the disease. Finally, parotiditis may, in some cases, constitute only a localisation of a general disease. It seems a fact that in rare circumstances parotiditis may assume an epizootic character, and attack a large number of animals in a particular stable or in neighbouring stables; and if, under these circumstances, we are unable to blame the food (which has not been done), we are forced to admit the influence of infection and contagion. =Symptoms.= Whatever the cause, the symptoms are generally well marked. In many cases the first indication of the disease is apparent or real want of appetite, always complicated with difficulty in swallowing, and often accompanied by trifling fever. Salivation, resulting from irritation of the gland and inability to swallow, becomes abundant, and at once draws attention to the buccal cavity and adjacent parts. Inspection of the patient then reveals the existence in the parotid region of a diffuse swelling, which on palpation is found to be hot and painful, and to occupy the whole of the parotid region between the lower jaw and the upper extremity of the neck. The lesion is usually unilateral, but occasionally bilateral. Parotiditis may terminate in resolution, suppuration, or necrosis. The suppuration may either be simply subcutaneous and extra-glandular, or may involve a portion of the salivary gland and of the parotid lymphatic gland in addition. Necrosis is exceptional, though Moussu saw double and total gangrene of both parotids, complicated with septicæmia, in the animal, of which a sketch is given herewith. [Illustration: $1]