One season it may appear as a contagious catarrh, another season as an infectious sore throat, and at other times as a bronchitis or pneumonia, and, lastly, as a contagious gastritis or gastro-enteritis. Frequently all these forms may co-exist in a single outbreak, and often a single animal exhibits the whole of these manifestations. For the convenience of description of the symptoms of this multiform malady we divide it into five principal forms, as follow : 1. The Catarrhal, attacking chiefly the eyes and nostrils.

2. The Pharyngeal or Tonsillar, affecting the region of the throat.

3. The Pulmonary or Chest form.

4. The Abdominal or Gastro-enteric.

5. The Cachectic or Wasting.

The Catarrhal form of distemper is that which is generally seen in the cat, and is the least fatal of any. The first symptoms noticed are a watery discharge from one and sometimes both eyes, the lids of which may be partially or completely closed, so as to hide the front of the eye, and a frequent licking of the upper lip and nose as if they were parched and burning. After a day or so the inner lining of the eyelids may be very much reddened, swollen, and giving rise to a yellow-white or greenish-white thick discharge, which adheres to the lids and seals them together. There may also be shivering fits, a dull open coat, and a great desire for warmth (this being so intense in some cases that the animal frequently gets under the grate when a fire is in it). There is sneezing, followed by a snuffling kind of breathing ; the nostrils discharge a thick, ropy, whitish or greenish matter, which clings to their openings, and very often closes them up. When the pharynx or larynx is the seat of catarrh there are frequent fits of coughing. The appetite is diminished or absent, but thirst is, as a rule, great. There may also be seen at times vomiting, diarrhoea, or constipation.

Emaciation is gradual and slight, or rapid and great, varying according to the severity of the symptoms.

The breathing is not much altered in the majority of cases, but in a few instances it becomes frequent. The temperature rises a few degrees, but this is variable, and it is sometimes normal. The body and limbs feel cold to the touch, and sometimes give off an offensive odour. The tongue, lips, hard and soft palates, and gums (especially around the teeth) are occasionally ulcerated. Now and again the eyes become the seat of ulceration, which on rare occasions becomes perforated ; at other times they become affected with a severe inflammation, which extends to the whole eyeball and destroys this organ. There is at times dulness or drowsiness, and the animal seeks dark corners or gets under the furniture. Many cats from sheer nervousness, especially in strange places, avoid the fire and seek obscure or lofty positions. Recovery generally takes place within a fortnight or three weeks, but death may take place within twenty-four to forty-eight hours from the commencement of the attack.

The Pharyngeal, Tonsillar, or Throat form is the most deadly manifestation of distemper. The first symptom to attract attention is the drivelling of clear, ropy albuminous saliva from the corners of the mouth. The animal crouches upon all four of its limbs; there is a frequent gulping movement, and a sound is emitted from the throat as if there was an attempt to swallow the thick ropy saliva which clings about the mouth and pharynx ; the swallowing seems difficult or impossible ; food is refused, but thirst is constant, although the animal seems incapable of swallowing; there is a great dulness or depression, and the cat appears indifferent to its surroundings.

On examination of the outside of the throat it is found swollen and painful, the glands are enlarged, and there appears to be a gurgling noise at each inspiration and expiration. On inspection of the mouth and back of the throat, the tongue and pharynx are found to be covered with a thick, ropy, bubbling saliva, the mucous membrane is swollen and congested, and the soft palate is of a pinkish or even dark reddish arborescent appearance, due to the congested state of the small bloodvessels. Sometimes ulcers appear on the hard and soft palates. After a day or so the depression increases, there is a discharge from the eyes and nostrils, which appears at first as a clear viscid fluid, and afterwards becomes yellowish or dirty green in colour, and, if the animal lives long enough, ultimately bloody, in consequence of it irritating the mucous membranes and surrounding skin of the eyes and nose. There may also be a catarrhal or purulent foetid discharge from one or both ears, but this is quite exceptional, and is mostly seen in cases having a fatal termination.

If the prostration is very great, and there is rapid loss of weight and condition, and the discharge from the mouth, nostrils, and eyes becomes foetid, coupled with total loss of appetite, and no abatement of the other symptoms, a fatal termination is to be anticipated. Late in the complaint the pharyngeal mucus may become of a dirty colour or sanious ; purple spots appear on the tongue, gums, and lips, and there is a moan or cry emitted at each respiratory effort ; convulsive movements of the muscles of the temples, shoulders, and thighs set in, and death takes place from intoxication. The temperature rises at first, but when a fatal termination is to be anticipated it falls below the normal.

The Pulmonary or Chest form, although not so frequently seen in the cat as in the dog, may appear from the outset as a distinct localisation, or follow or intervene during an attack of the other forms as a complication. It major may not be ushered in by shivering fits ; the coat becomes dull and open, there is sneezing or coughing, or both ; tears run from the eyes, and mucus issues from the nostrils, and there is a great desire for warmth. The temperature is elevated, and varies from 102.50 to 1060, but rarely running a typical course. The cough, when present, is frequent and rattling or harsh, and sometimes dull. On listening to the chest wheezing, rattling, or blowing, or rubbing, or splashing sounds may be heard. Emaciation is either gradual or rapid, thirst is generally great, but the appetite is diminished or absent.

The breathing is either quickened or the inspiratory and expiratory efforts may be prolonged and accompanied or not with a moan or grunt, which is sometimes associated with fluid in the chest cavity, which is known by the pumping or lifting action of the flanks, this effusion in one or both of the pleural sacs being either of a clear greenish or amber-tinted or bloody or dirty yellowish appearance, and sometimes of a foetid odour. Besides pleurisy, which is only occasionally encountered, there may be pneumonia, bronchopneumonia, or bronchitis, according to the structure of lung involved in this form of distemper. (For a description of these localisations or complications, see under their respective headings.)