The treatment consists in good care, well ventilated quarters and careful nursing, the same as recommended in the treatment of pneumonia. At the very beginning, the pain may be relieved by the administration of small doses of morphine. If the conditions in the stable permit, a hot blanket that has been dipped in hot water and wrung out as dry as possible, may be applied to the chest wall and covered with a rubber blanket. This treatment should be continued during the first few days of the inflammation. These applications may be reinforced by occasionally applying mustard paste to the sides of the chest.

The animal should be allowed to drink but a limited amount of water. The feed must be highly nutritious. Milk and eggs should be given if necessary. A laxative dose of oil should be given. Calomel, aloes, and digitalis are recommended when the effusion period approaches in order to increase the elimination of fluid, and lessen its entrance into the body cavity. If the amount of effusion is large, puncture of the thoracic cavity with a trocar and cannula may be practised. This operation should be performed carefully, and all possible precautions used against infection of the wound. During the later period of the disease iodide of potassium, iron and bitter tonics should be given.

BROKEN-WIND, HEAVES.—The terms broken-wind and heaves are used in a way to include a number of different diseases of the respiratory organs of the horse. The term heaves is applied almost wholly to an emphysematous condition of the lungs. Broken-wind may include the following diseased conditions: obstruction of the nasal passages by bony enlargements and tumors; tumors in the pharynx; enlarged neck glands; collection of pus in the guttural pouches and paralysis of the left, or both recurrent nerves (roaring).

The common causes of heaves are pre-existing diseases of the respiratory organs, severe exercise when the animal is not in condition and wrong methods of feeding. Heaves is more common in horses that are fed heavily on dusty timothy and clover hay and allowed to drink large quantities of water after feeding, than in horses that are fed green feeds, graze on pastures or receive prairie hay for roughage. Chronic indigestion seems to aggravate the disease. Over-distention of the stomach and intestines due to feeding too much roughage and grain interferes with respiration. Severe exercise when in this condition may result in over-distention, dilation and rupture of the air cells. This is the most common structural change met with in the lungs of horses affected with heaves. It is termed emphysema.

The common symptoms noted are the double contraction of the muscles of the flank with each expiration, a short, dry cough and the dilated nostrils. The frequent passage of gas is a prominent symptom in well-established cases of heaves. Chronic indigestion is commonly present in heavy horses that are not well cared for, or are given hard work. This condition aggravates the distressed breathing.

Heaves is a permanent disorder, but it may be relieved by climatic changes and careful attention to the animal's diet.

The following preventive treatment is recommended: Dusty hay should not be fed to horses. Clover hay is not a safe feed for horses that are worked hard. When starting on a drive after feeding, the horse should not be driven fast, but allowed to go slowly for a few miles.

The symptoms can be greatly relieved by careful attention to the diet. A limited quantity of roughage should be fed, and this should be good in quality and fed in the evening. During the warm weather, the animal should be watered frequently. After quitting work in the evening the animal may be allowed to drink as much water as it wants. Plenty of grain, soft feed and roots may be fed. A small handful of flaxseed meal given with the feed helps in keeping down constipation. Fowler's solution of arsenic may be given twice daily with the feed, in half-ounce doses for a period of ten days or two weeks. Chronic indigestion should be combated by digestive tonics.

QUESTIONS

1. Name the organs that form the anterior and posterior air passages.