215 



■SYMPTOMS OR SIGNS OF TUBERCULOSIS AS OBSERVED IN LIYING 



CATTLE. 



Tuberculosis may be acute or chronic; the former is rare; 

 "the latter is comraou and lasts for months or years. The 

 physical signs or symptoms in the living animal are ex- 

 tremely variable — depending upon the location, extent and 

 severity of the disease. 



If the lungs and air passages are involved there may be, in 

 the early stages, a harsh, dry, rough cough. Violent exer- 

 tion, excitement, eating dry food or drinking cold water may 

 cause the animal to cough. Sometimes the animal coughs 

 at the beginning of exercise or upon rising after having lain 

 down for some time. Striking the animal over the ribs a 

 sharp rap with the knuckles may arouse the cough. Strik- 

 ing the chest with the knuckles may reveal regions or spots 

 where the sound is muffled or dull instead of being resonant 

 as in health. If the ear be applied to the chest, it may de- 

 tect a weak, highly pitched whistling sound, made by the 

 air rushing through some partially obstructed bronchial 

 tube. Or, the ear may hear a sound that resembles bubbles 

 of air passing through a thick liquid ; this would indicate 

 the presence of a liquid in the bronchial tubes. These last 

 two tests are difficult and the trained expert is often mis- 

 taken ; because there is such a limited area on the sides of 

 the chest that can be thus inspected and because, in many 

 instances, the area of lung tissue involved may be very 

 small and deeply seated. A physical examination of 

 the lungs in the living animal is satisfactory only in the ad- 

 vanced stages of the disease where the tuberculous animal 

 is poor and the diseased part of the lung is very large. As 

 the disease advances the cough may become more and more 

 aggravated ; a discharge from the nose may appear ; the 

 hair becomes rough and dry, and is not shed regularly ; the 

 skin becomes scurfy and clings closely to underlying tissues. 

 In aggravated cases the animal ma}^ become greatly ema- 

 ciated ; yet, in some cases, the animal will remain in good 

 :flesh when the lungs are extensively tuberculous. 



