286 



INFECTIOUS DISEASES 



liver and other organs, may be full of tubercles without causing 

 noticeable symptoms of disease (Fig. 89), 



Tuberculosis may attack any organ of the body, and in the 

 different cases of the disease the symptoms may vary. Enlarge- 

 ment of the glands in the region of the throat, and noisy, difficult 

 breathing are sometimes present. The udder frequently shows 

 hard lumps scattered through the gland. Bloating may occur 

 if a diseased gland in the chest cavity presses on the oesophagus 



Fig. 89. — Cows affected with tuberculosis. Many cows having generalized tuberculosis are 

 not found out until tuberculin tested. 



and prevents the usual passage of gas from the paunch. Chronic 

 diarrhd'a may occur. If the disease involves the digestive tract, 

 the animal is unthrifty and loses flesh rapidly. Coughing is not 

 a characteristic symptom, and we should not place too much 

 emphasis on it. If the lungs become tubercular the animal 

 usually has a slight, harsh cough. The cough is first noticed when 

 the cattle get up after lying down, when the stable is first 

 opened in the morning and when the animals are driven. If 

 the chest walls arc thin, soreness from pressure on the ribs may 



