Infection, in traumas, meningitis, encephalitis, strangles, etc. Symptoms: evidence of trauma, chill, hyperæsthesia irritability, drowsiness, giddiness, stupor, spasms, paresis, coma, dilated pupils, congested mucosæ, vomiting. Location indicated by muscular groups involved. Treatment: As in meningitis: trephining in hopeful cases. The formation of abscess in the cranial cavity has been referred to in connection with injuries to the cranium and meningo-encephalitis. It may here be said in general terms that this abscess is a product of infection. In the horse the most common cause is strangles, and especially such cases as run a tardy or irregular course with imperfect softening and limited suppuration in the submaxillary or pharyngeal region. It is to be looked on as an extension of the purulent infection so as to cause a secondary abscess. The same may occur in case of ordinary abscess in any distant organ. In the brain as elsewhere suppuration may result from direct local injury as in the case of blows by clubs, or yokes, running against walls or posts, falls, the effects of butting, injuries by bullets and otherwise. In these cases, as noticed under concussion, there may be two points of injury (and two abscesses) one, in the seat of the injury, and one in a deeper part of the brain, at the opposite wall of the cranium. Again abscess may result in the brain from extension from a similar process going on in the vicinity. Thus otitis extends through the middle and internal ear to the brain, and its starting point may have been more distant, namely, in the Eustachian tube, or pouch, or in the pharynx. The _symptoms_ vary according to the size of the abscess, the rapidity of its formation and the amount of attendant congestion. In the common cases resulting from strangles, I have usually found the animal down, unable to rise, blind, amaurotic, with dilated pupils, congested mucous membranes, and occasional spasmodic movements of the limbs, neck and head. The symptoms may, however, vary through hyperæsthesia, irritability, drowsiness, giddiness, stupor, local or general paralysis with occasional spasms or convulsions. There may be an initial shivering, and a rise of temperature, yet as pressure on the brain increases it may become normal or subnormal. In circumscribed abscess the symptoms may be much less severe, not perhaps exceeding irritability, drowsiness, and some paresis or local paralysis.