CHAPTER VI. 

 THE TUBERCULIN TEST OF CATTLE FOR TUBERCULOSIS. 



I. THE DIAGNOSIS OF TUBERCULOSIS. II. THE ORIGIN OF THE TUBERCU- 

 LIN TEST. III. THE NATURE AND APPLICATION OF TUBERCULIN. 



IV. THE VALUE AND RELIABILITY OF THE TUBERCULIN TEST. 



V. THE HARMLESSNESS OF TUBERCULIN. VI. CONCLUSIONS REGARD- 



ING THE TUBERCULIN TEST. VII. SUMMARY OF DIRECTIONS FOR MAK- 

 ING THE TUBERCULIN TEST. 



I. The Diagnosis of Tuberculosis. 



The symptoms of tuberculosis in cattle are not sufficiently prominent, 

 except in advanced stages or when superficially located, to enable one to 



A COW AFFECTED WITH ADVANCED TUBERCULOSIS. 



The disease is partly located in the lymph glands of the throat, as shown 

 by the position of the head. The glands are so much enlarged that, through 

 pressure on the larynx, they greatly narrow the orifice through which air 

 reaches the lung; and yet the visible bodily condition of the cow has re- 

 mained very good, and is better than that of most dairy cows. 



diagnose this disease by the ordinary methods of physical examination. 

 And the cattle may, without showing any clinical symptoms, be in such 

 a stage of tuberculosis as to render them capable of spreading disease. 

 Indeed, an animal may be fat and sleek, eat and milk well, have a bright, 

 glossy coat, and be apparently in the pink of condition, and still be 



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