_Incubation_ appears to be longer than in equine influenza, varying in different cases from 3 to 10 days. _Symptoms._ These vary greatly in different cases, _mild_ and _severe_. Some, in the same stable with the severe cases, simply refuse food, are a little sluggish in work, cough, have hyperthermia (104° to 106° F.), respirations 20–25, pulse 60, with conjunctiva only moderately yellow, a slightly yellowish discharge from the nose, and no observable lung consolidation. The temperature descends to normal in three to five days, the symptoms generally abate, and the animal may be convalescent in eight or ten days. In the more _severe cases_ there may be seen a shivering fit, or it may pass unobserved. Then the first morbid phenomenon is usually a rapid and extreme elevation of temperature which may reach 104° or 106° F. in a few hours. With this there is great impairment or complete loss of appetite, and a loss of life and energy. In some cases the depression, stupor and muscular weakness suggest influenza but this is not the rule. Still more rare is infiltration of the eyelids and free watering of the eyes, yet in the absence of this, drooping of the upper eyelids is not uncommon. The respiration may be accelerated and short, from 20 to 30 per minute, and the pulse, which is usually small and weak in spite of the fever, may rise to 50 or 70 per minute. The breathing may be trembling or distinctly interrupted in the course of inhalation or exhalation, short and with no interval between inspiration and expiration. Cough may or may not be a marked feature, heard at long intervals only in some cases and frequent and painful in others. It is liable to be dry and husky rather than hard, loose or gurgling. The eye and to a less extent the nasal and buccal mucosa tend to show a yellowish shade, and this may even at an early stage show a distinct brownish orange, or even a dark mahogany hue. Yet dropsy of the lids or even epiphora are uncommon. A yellowish discharge from the nose is an almost constant feature and this may dry up into a yellow crust on the floor of the anterior nares and adjacent skin. The percussion and auscultatory indications of lung consolidation are rarely obtainable before the end of the second or third day and when at all extensive can usually be detected on both sides. Trasbot considers the double pneumonia as almost pathognomonic of contagious pneumonia. When confined mainly to the lower parts of the lungs and occurring in isolated areas, with lung tissue still pervious to air in the intervals, it comes more nearly to being so. Crepitation round the border of consolidated areas, is a more marked feature than in equal consolidations in influenza. It often becomes inaudible again as the disease advances. Blowing murmurs, coarse mucous râles, heart and intestinal sounds can often be heard with unusual clearness, in unusual situations, when an area of consolidated lung is immediately beneath. A transient dry friction sound of