CONTAGIOUS DISEASES. 827 



beast. No tissue of the body is exempt from its ravages, the lungs and 

 thoracic lymphatic glands being most often affected. The first appearance of 

 this disease is in the form of miliary tubercles, which may become fenced 

 in as described above, or by ulceration the germs are liberated and invade 

 surrounding tissues, sometimes forming malignant tumors and sometimes 

 leading on to complete destruction of the organ attacked. Miliary tuber- 

 cles are about the size of a small pea, and are usually seen in the great- 

 est number on the peritoneum and pleura lining the chest. In all severe 

 cases the disease overcomes nature's efforts to confine it and becomes gen- 

 eralized, causing cachexia, when the flesh and milk are unlit for food. 

 Inasmuch as it is difficult to determine when it is becoming generalized, 

 and as it is decidedly dangerous for people to eat meat and drink milk 

 that contain bacilli tuberculosis, it is proper to condemn all carcasses 

 that show more than slight localized infection, and those to be passed 

 should show the diseased parts well advanced in the calcareous stage. 

 It is no longer considered hereditary, but due in all cases to infection, 

 usually, we think, by inhaling the germs that are flying in dust, or by 

 eating or drinking them with the food and water. 



How to know it. — It is impossible to recognize it till it is far advanced 

 and cachexia is developing, the earliest symptoms being a general unthrifty 

 condition, the milk becoming poor in quality, thin and watery, although not 

 much less in quantity. The appetite is capricious; the hair looks dull, and 

 where it is white, there is a yellow skin; a dry, dull cough will be noticed; 

 the animal no longer licks itself; if the cow is with calf, she is apt to abort. 

 Emaciation ushers in the second stage, and progresses rapidly; the cough 

 gets worse; indigestion, tympanitis and diarrhoea follow, and soon reduce 

 the sufferer to skin and bones. Auscultation, and percussion of the lungs 

 may or may not detect a fullness and muffled breathing and other signs of 

 disease, but nearly always some pain will be evinced when the sides are 

 struck, or the fingers pushed forcibly in between the ribs. The tubercles 

 increase, sometimes breaking out on the surface of the body; the blood gets 

 thin and watery, wanting in red corpuscles; and, often, fatal diarrhoea sets in. 



To test an animal or herd suspected of tuberculosis, tuberculin is used. 

 It can be got from the Bureau of Animal Industry at Washington, D. C, 

 or from the State Experimental Stations. The animal's temperature is 

 taken morning, noon, and night, before the injection, to get the average 

 temperature, then inject the tuberculin about 11 o'clock at night, and be- 

 gin taking the temperature next morning at 6 o'clock, and take it every 

 two hours till 6 at night. If the injection causes a rise of temperature to 

 104° Fahrenheit at any time during the day the animal should be condemned 

 and slaughtered, subject to veterinary inspection. If an animal reacts or shows 

 a rise of temperature between 103° and 103.9°, he should be tested again 

 after a week. This test is very delicate and remarkably certain, there be- 



