The larynx is the organ of voice, placed at the upper part of the air passage. It performs a double function, one part of which is connected with the voice, the other with respiration. It is situated between the base of the tongue and the windpipe at the upper and fore part of the neck.

The general character of laryngitis varies according to the extent and severity of the inflammation. The disease may run a mild uncomplicated course or it may be accompanied with an exudation of lymph, a condition distinguished as croup.

Causation

Faulty kennel arrangements and consequent exposure to cold and wet. Extremes in temperature so often experienced by petted house dogs, which are by their habits, particularly predisposed to inflammations of the air passages. Mechanical irritations from prolonged barking and from foreign bodies not at once removed. Injuries to the neck, such as continued tugging at a chain may be sufficient to induce the disease. Inflammations of the adjacent parts, as is frequently the case in catarrh of the nasal mucous membranes, extend to the throat, involving the larynx.

Symptoms

A hoarse, barking cough, excited by external pressure over the windpipe, is one of the diagnostic characters of acute laryngitis. In the earlier stage the expectoration is scanty and of thick mucus, later it becomes abundant, and is more easily expelled.

Fever may be more or less intense, or it may be wanting. If the swelling of the membrane be not great, the breathing is not notably increased. With a greater amount of swelling, labored respiration and difficult breathing are added. Inspiration and expiration are both affected by the obstruction, but more especially the former. It is harsh or noisy.

There is frequently more or less difficulty in swallowing, and a light, bub-bling discharge from the nose. In cases where great obstruction exists the suffering is intense. The eyes are congested and expressive of the great distress the animal is experiencing. The suffering is at times rendered more violent by spasm, and the respiratory acts are less frequent than normal. With these symptoms, the disease in a large proportion of cases will end fatally, and the mode of dying be by suffocation.

Diagnosis

The diminished frequency of the respiratory acts, and the absence, on auscultation and percussion, of signs denoting pulmonary disease. The peculiar husky character of the cough. The suffering increased spasmodically, with intervals of comparative ease. The tenderness over the larynx, and the reddened swollen appearance of the mucous membrane of the throat. The presence of these symptoms excludes all other diseases which might be confounded, and render a diagnosis easy.

Prognosis

The prognosis depends essentially upon the severity of symptoms and efficiency and promptness of the treatment. When there is little or no infiltration of the sub-mucous tissues as inferred by the comparative ease in breathing, the chances are favorable. If the obstruction aside from that due to spasm, be sufficient to interfere greatly with respiration, a fatal result may be anticipated.

Treatment

The injurious influences of changes in the air, should be avoided by maintaining a uniform temperature in the room in which the animal is placed. A sponge should be wrung out in hot water, and applied to the neck, being frequently changed. Five grain doses of Dover's powder will greatly relieve the discomfort, and in the milder cases its use is admissible. Opiates, in the severer forms of the disease, should be given guardedly, and not carried so far as to blunt the perception of the want of breath. A full dose of castor oil should be given early in the affection, to draw the blood to the intestines. Spasms in breathing are often relieved by emetics, and twenty grains of ipecac can be wisely given during an attack. The oil of copaiba is admirable in its action, and when inflammation of the larynx first manifests itself, doses of fifteen drops may be given from three to six hours as the severity of the symptoms indicate. It will be well to emulsify it in this way; add a teaspoonful of the oil to a raw egg, and beat well with a fork; give one fourth of the quantity at each dose. The following mixture is also very efficacious in this disease. -

℞ Potass. Chloratis ℥ i.

Ammon. Mur. ℥ i.

Syr. Tolu. ℥ i.

Aquas ℥ ij.

Ft. Mist. Sig. Dose one teaspoonful in mild cases, every two hours. In very severe attacks, the same dose every fifteen minutes.

If the disease assumes a severity threatening suffocation, the dog should be made to inhale steam or medicated vapors. If the room be too large to moisten the entire atmosphere, a tent can be made by placing a sheet over two chairs, under that the dog be placed, and a hot iron or stone be thrown into a pan of water. To medicate the steam add a tablespoonful of the compound tincture of benzoin for every quart of water. When death from suffocation is imminent and all other means prove futile, tracheotomy is the only hope remaining.

It is important to remember that a symptom which is considered highly characteristic of rabies, and one which frequently appears early in the disease, is the peculiar alteration in the tone of the voice. The bark is described as a sound between a bark and a howl uttered in a rough, hoarse tone, which might be called croupy, and is attributed by some to a swollen condition of the pharynx and larynx.