The presence of biliary coloring matter in sufficient quantity to give a yellow color to the skin, constitutes the diseased condition known as icterus or jaundice. Strictly it is never an individual affection, it being a symptom, and incidental to various disorders.

Jaundice often appears when its cause cannot be clearly determined; again, it is an important morbid condition, convenience in considering which demands special recognition and classification. In considering it as an individual disease, cases are to be excluded in which it occurs with an affection, the existence of which is clearly determined.

In acute and chronic hepatitis and certain constitutional diseases it is to be regarded merely as a symptom.

Causation

In a great majority of cases jaundice depends on obstruction of the passage of the bile to the intestine.

From obvious facts it is reasoned that more commonly the bile is reabsorbed after the secretion of it has taken place. Defective secretion however, either with or without obstruction doubtless occurs, and the constituents of the bile accumulate in the blood if not thrown out by some unusual channel.

It is conjectured that more or less of those indefinite symptoms which are commonly included under the name "biliousness," are due to a deficient elimination of the bile or at least one of its elements.

The more apparent exciting causes are over fatigue, the indiscriminate use of powerful emetics and cathartics, indigestion, obstinate constipation, traumatic injuries, and sudden chills.

When the functions of the skin are arrested by cold there are two ways in which disease is supposed to be produced. One relates to the circulation; the blood being driven from the surface accumulates in the internal organs inducing congestion.

The other method of action relates to the increased activity demanded of certain organs, to compensate for the deficient elimination of the skin. It is to be remembered that the skin is an important medium, through which matters proper to be evacuated from the body are expelled. Again any material change in the condition of the skin affects the perspiration, the office of which is principally to regulate the temperature of the body.

Thus it will be seen that disease may not infrequently originate from the action of cold applied to the surface of the body, as in sudden immersions in water and too rapid cooling after a hard run; the radical and rapid changes of temperature being the most active.

Some authors include fighting and prolonged sport among the causes of jaundice. While the direct action of these influences is unexplained, it can however be appreciated, that in a variety of ways irritation and excitement can induce changes in the system, sufficient to give rise to the disease under consideration.

Symptoms

Pie signs in the earlier stage are vague and confusing. The manner of the animal changes, he becoming dull, languid, and averse to exertion. The reabsorbed bile appears to exert a narcotic influence on the nervous system, producing dulness, a disposition to sleep, a fall in the poise, and a torpid condition in the functions of the body generally. The nose, month, and breath are hot and dry; the abdomen hard, and back arched. The coat loses its glossy look and becomes dry and staring.

As the bile exerts its influence on circulation, the respirations become less frequent. In some cases a disposition to constantly scratch is noted. The appetite disappears, thirst becomes excessive, and vomiting frequent; the matter expelled being greenish and at times in extreme cases bloody. Pain is at times evident and colicky in character.

When tenderness and pain both exist in the region of the stomach, it is evidence of a low type of inflammation of the mucous membrane lining the stomach and upper part of the intestine.

Generally the bowels are constipated, but not always as diarrhoea sometimes occurs. The appearance of the discharges affords evidence as to whether the obstruction is complete or partial.

In the former the passages are day-colored or ashy, while in the latter they are nearer the color in health. A peculiar fetid odor is noted in discharges devoid of bile. The appearance of the yellow tint dispels all doubts as to diagnosis if the other symptoms have proved insufficient. The mucous membranes first show the coloring; the skin then is rapidly affected. The urine in jaundice is loaded with bile, and when voided leaves a decided stain.

Nutrition for a time may be but a little affected; then emaciation is rapid. When the disease progresses to a fatal termination the pulse falls, the extremities grow cold, the skin clammy, and death ensues.

Diagnosis

The appearance of the yellowish tint renders the diagnosis positive. To determine the cause in individual cases is far from easy. The symptoms in the early stage of the attack, viz., loss of appetite, vomiting, and tenderness, indicate a possible inflammation of the mucous membrane of the stomach and upper part of the intestine. Sometimes gall-stones form in the gall-bladder, and in passing down into the intestine become lodged and obstruct the canal; pain of the severest character is the evidence of this accident.

Worms sometimes cause obstruction, but they with certain other causes can only be determined at the autopsy.

Prognosis

The gravity as well as the symptoms depend on the morbid conditions which give rise to the affection. The discharging duct or canal leading from the gall-bladder enters into the intestine near the stomach; in sab-acute inflammation of the mucous membrane lining these parts, the irritation is liable to extend into the duct and cause its lining to become swollen, the passage closing and becoming obstructed, it being too small to admit of much swelling and remain open. The prognosis in such cases is favorable. If a gall stone becomes lodged, recovery will depend entirely upon its passage into the intestine or backward up into the gall-bladder.

When death occurs in jaundice from the retention of bile, the liver is the seat of serious disease. When permanent obstruction exists without serious structural changes elsewhere, life may be prolonged and nutrition sustained for a long time; sooner or later however, the vital powers fail, the body wastes, exhaustion follows, and death results. In severe cases terminating fatally the disease runs a rapid course, the duration generally being from three to five days.

Treatment

It is to be remembered that in the majority of cases jaundice is due to a sub-acute inflammation of the stomach and adjoining portion of the intestine, and the natural tendency of the disease is to recovery. In diet and medication all influences calculated to add to, or prolong the irritation must be studiously withheld. Unless the urgency of symptoms demands a more vigorous treatment, a bland and digestible diet with gentle laxatives will suffice.

Calcined magnesia should be given in teaspoonful doses in milk two or three times dally to keep the bowels active. All fatty food should be withheld, and milk and gruels largely be depended upon. If pain exists opiates should be employed.

The attacks which occasionally occur resembling colic, are at times due to the formation of gas; by the absence of bile the contents of the intestines are no longer influenced by its antiseptic property, decompose and gas is generated.

In severe attacks of jaundice in which the constitutional symptoms indicate gravity, the need is urgent and the treatment must be energetic and immediately applied. The animal should be placed in a warm room, it being remembered the skin must be protected from cold, lest its elimi-native functions be destroyed, and one avenue through which the bile can be thrown out of the system be closed. Calomel is the agent most to be depended upon, and should be given in doses of one half a grain each, four times a day. Bather than combine the calomel with laxatives it is wiser to give them separately and only as the need is apparent. Hot baths if needed will increase the activity of the skin, and sweet spirits of nitre in one half teaspoonful doses, given in water every two or three hours, stimulates the kidneys. Food should be milk, eggs, scraped beef, and broths.