TUBERCULOSIS. 415 



and diarrhea, alternating with constipation. The animal generally 

 dies from exhaustion after a period of sickness which may last 

 months or even years. 



Tuberculosis in the abdominal organs is often signalized by abor- 

 tion and by abnormal sexual manifestations. When the brain is in- 

 volved, the disease may cause convulsions, unconsciousness, i^aralysis, 

 as well as peculiar movements in a circle, oblique position of the head, 

 etc. Lydtin quotes the following description of the disease as taken 

 from a Swiss sanitary order : 



A dry, short, interrupted, hoarse cough, which tlie sicli animals manifest, 

 especially in the morning at feeding time, still more after somewhat violent 

 exertion. At first these animals may be full blooded and lay on a considerable 

 amount of fat when well fed. As the disease progresses they grow thin and 

 show more and more those appearances which indicate diseased nutrition, such 

 as a staring, lusterless, disheveled coat ; dirty, tense skin, which appears very 

 pale in those regions free from hair. The temperature of the skin is below 

 normal. The loss of fat causes sinking of the eyes in their sockets. They 

 appear swimming in water, and their expression is weak. The cough is more 

 frequent, but never or very rarely accompanied with discharge. The body con- 

 tinues to emaciate, even with plenty of food and a good appetite, so that the 

 quantity of milk is small. At times in the early stages of the disease, still 

 more in the later stages, the diseased animals manifest considerable tenderness 

 when pressure is applied to the front or the sides of the chest by coughing, 

 moaning, etc. Often symptoms are wanting in spite of the existence of the 

 disease. 



Lydtin also quotes at length a description of the abnormal sexual 

 desire occasionally observed among cows when affected with this 

 disease. 



Diagnosis. — A disease so varied in its attack upon the different 

 organs of the body and in the extent of the disease process must nec- 

 essarily lead to mistakes when diagnosis is attempted by ordinary 

 means of examination. It has been confounded with the later stages 

 of pleuropneumonia, with parasitic diseases of the brain, the lungs, 

 the intestines, and with actinomycosis. A careful examination of the 

 lungs by ausculation and percussion enables the expert to locate large 

 tuberculous masses, owing to dullness, loss of respiratory murmur, and 

 abnormal sounds, such as blowing, whistling, and creaking. The 

 majority of cases of tuberculosis in cattle, however, including many 

 in which the lungs are quite seriously involved, can not be detected 

 in this manner. 



THE TUBERCULIN TEST. 



The tuberculin test, which is marvelously accurate in its indica- 

 tions, has been almost universally adopted for the detection of tuber- 

 culosis. Tuberculin is a drug prepared by sterilizing, filtering, and 

 concentrating the liquids in which the tubercle bacillus has been 

 allowed to vegetate. It contains the cooked products of the growth 



