1. What is the specific cause of distemper? Give the symptoms and treatment. 2. What are the different methods of spreading influenza? Give the symptoms and treatment. 3. Give the cause and methods of controlling glanders. 4. Give the cause and treatment of contagious pleuropneumonia. CHAPTER XXX INFECTIOUS DISEASES OF CATTLE [Illustration: FIG. 117.--A case of "lumpy jaw."] ACTINOMYCOSIS, "LUMPY JAW."--This is an infectious disease that is characterized by the formation of tumors and abscesses (Fig. 117), and the destruction of the infected tissues. The disease is common in cattle and usually affects the bones and soft parts of the head. In the United States, where the disease is known as "lumpy jaw" the jawbone is commonly affected. In European countries the disease frequently involves the tongue, and the term "wooden tongue" is applied to it. The disease may affect regions of the body other than the head. Actinomycosis of the lungs sometimes occurs. Swine and horses may be affected by this disease. _The specific cause_ of actinomycosis is commonly known as the ray fungus (Fig. 118). This fungus grows on certain plants, and the animal usually contracts the disease by eating plants or roughage that have the fungus on them. Grasses having awns that are capable of wounding the mucous membrane of the mouth and penetrating the gums are most apt to produce the disease. Young cattle that are replacing and erupting their teeth are most prone to "lumpy jaw." Conditions that favor bruising of the jaw and external wounds favor the development of actinomycosis. The fungus grows in the tissues, causing an inflammatory reaction and destruction of the tissue. The ray fungus can be seen in the diseased tissue or the pus as yellowish, spherical bodies about the size of a grain of sand. Each of these bodies is formed by a large number of club-like bodies arranged about a central mass of filaments. [Illustration: FIG. 118.--The ray fungus.] _The local symptoms_ are characteristic (Fig. 117). The tumor may involve the soft tissues of the head. If the jawbone is affected the tumor feels hard and cannot be moved about. Sometimes it is soft and filled with pus. Tumors of long standing may possess uneven, nodular surfaces and fistulous openings. When the tongue is affected, it is swollen and painful, and prehension and mastication of the food may be impossible. When the pharynx is the seat of disease, breathing and swallowing are difficult and painful. Actinomycosis of the lungs may present the appearance of a chronic pulmonary affection. If the disease involves the head and lungs, the animal may become unthrifty and emaciated. In doubtful cases a microscopic examination of a piece of the tumor, or some of the pus, may be necessary. _The treatment is surgical and medicinal_. Small, external tumors may be removed by an operation. Sometimes an incision is made into the diseased tissue and a caustic preparation introduced.