The control of tuberculosis is largely in the hands of the breeder and dairyman. This is a disease that requires the cooperation of stockmen and sanitary officers in the application of control measures. If there are several open cases of tuberculosis in a herd of cattle, the application of the tuberculin test, removal of the reacting animals and disinfection of the premises are not sufficient to eradicate the disease. It is necessary to repeat the tuberculin test within six months, and later at twelve-months intervals, until none of the animals that remain in the herd react. The most practical method of disposing of dairy cows that react to the tuberculin test is to slaughter them. Unless a large percentage of the herd is tubercular, it is not advisable to practise segregation and quarantine. This may be advisable if the reactor is a valuable breeding animal, unless visible symptoms are shown. The milk from reacting cows may be used if it is boiled or sterilized. Whenever a calf is born of a reactor, it should be separated from the mother and fed milk from a healthy cow. The separation of the tubercular from the healthy cows must be complete. Separate buildings, yards and pastures that do not join the quarters where the healthy animals are kept should be provided. The person attending the reactors should not attend the healthy animals, and separate forks, shovels, pails and other utensils should be provided for the two herds. The best method of controlling tuberculosis in hogs is to slaughter all reactors, disinfect yards and houses and move the herd. If the old quarters are free from filth and carefully disinfected, the hogs may be returned without danger of infection after six months. A retest of the herd should be made before returning them to the permanent quarters and the reactors slaughtered. QUESTIONS 1. Give the history of the early experimental work in tuberculosis; give the common methods of spreading the disease. 2. What are the symptoms and post-mortem lesions in tuberculosis? 3. Give the method of controlling tuberculosis. CHAPTER XXVIII INFECTIOUS DISEASES COMMON TO THE DIFFERENT SPECIES OF DOMESTIC ANIMALS SEPTICAEMIA AND PYAEMIA.--The term commonly used in speaking of simple septicaemia and pyaemia is blood poisoning. These infectious diseases are _caused_ by several different species of bacteria that gain entrance to the tissues by way of wounds. The bacteria that cause pyaemia are transferred by the blood stream to different organs and produce multiple abscesses. In septicaemia, the bacteria may occur in immense numbers in the blood and produce a general infection of the tissues, causing a parboiled appearance of the liver, heart, voluntary muscles and kidneys, and enlargement of the spleen. The two forms of infection are often present at the same time. [Illustration: FIG. 97.--_Staphylococcus pyogenes_.] [Illustration: FIG. 98.--_Streptococcus pyogenes_.]