Mild _catarrhal symptoms of the nose and throat_ are usually present, the discharge being at first serous and later muco-purulent. As a rule this is complicated with more or less bronchitis, but this does not indicate anything serious. Acceleration of the breathing, sneezing, and cough are present. Cough may be at first nervous, husky and paroxysmal, but later as the discharge is established it assumes a looser, mucous character. It is liable to be roused by excitement, by drinking cold water, by inhalation of dust, or by giving medicine. In connection with these symptoms there are some indications that the digestive organs are involved. The pharyngeal and submaxillary glands may be swollen and tender. If the subject has been seized just after a full meal, there may be slight tympany, and in any case, the fæces are passed in small balls, a few at a time, hard and with a baked or glistening surface. These may have an unusually strong or heavy odor, and laxatives are liable to act with dangerous energy. The urine is scanty and high colored, sometimes icteric. In such mild attacks, which constitute the majority, improvement may be noted as early as the fourth day, and a prompt recovery follows. With extensive _thoracic lesions_, the symptoms are much more severe and the danger greatly enhanced. These may occur in any patient, but there appears to be a special predisposition in the young and still very susceptible animals, in those crowded together in close, badly aired buildings, in the overworked, poorly fed or in any way debilitated subject, and in horses that have been especially excited and exposed, as by railway travel. In exceptional cases _congestion of the lungs_ may be so acute as to lead to speedy death, and the objective symptoms do not differ greatly from those of ordinary cases of this condition, if we except the very high temperature in influenza, associated as it is with the fact of the epizoötic prevalence of the disease. In _pneumonic_ cases the lesions are usually double and have a tendency to develop toward the lower borders of the lungs, just behind the elbow or farther back, and less frequently in the centre of the organ. It may be impossible to detect crepitation, but sounds of distant organs (heart beats, bronchial blowing, intestinal rumbling) are heard with unwonted clearness over the consolidated parts. A mucous râle can usually be detected behind the shoulder blade, along the line of the larger bronchia. Percussion sounds may be indefinite, as the area of consolidated lung is usually small in ratio with the hyperthermia. The area of flatness in ordinary fibrinous pneumonia is usually much greater with a high fever, and if the lesions are on one side only, right or left, it is still more suggestive. The crepitation too in pneumonia is significant. When the pulmonary lesions are extensive by reason of œdema, a marked infiltration may often be noted on the lower surface of the trunk or in the limbs as well.