2. To what conditions are the injurious effects of keeping animals in a
poorly ventilated stable due?
3. State the purpose of ventilation. How can the need of ventilation be
determined in a stable?
4. State the causes of "cold" in the head; give the treatment.
5. State the cause of bronchitis; give the treatment.
6. What are the causes of pneumonia? Describe the symptoms and treatment.
7. What symptoms are characteristic of pleurisy? Give the treatment for pleurisy.
8. Give the causes and treatment of "heaves."
CHAPTER IX
DISEASES OF THE CIRCULATORY ORGANS
GENERAL DISCUSSION.—The circulatory organs are the heart, arteries, veins and lymphatics. The heart is the central organ of the circulatory system (Fig. 23). Its function is to force the blood through the blood-vessels. It is situated in the thoracic cavity between the lungs, and enclosed by a special fold of the pleura, the pericardial sack. There are two kinds of blood-vessels, arteries and veins. The arteries leave the heart and carry the blood to the many different organs of the body. The veins return to the heart and carry the blood from the body tissues. The capillaries are small blood-vessels, microscopic in size, that connect the arteries with the veins. The arteries carry the pure blood. The opposite is true, however, of the lesser or pulmonary system. The pulmonary artery carries the impure blood to the lungs, and the pulmonary veins carry the pure blood back from the lungs. The lymphatic vessels carry a transparent or slightly colored fluid and chyle from the tissues and alimentary canal. This system of vessels empties into the venous system.