96 THE COW IN HEALTH AND DISEASE 



made in the fold of skin reaching from the 

 tail to the anus. An enlargement or thicken- 

 ing of this fold of skin indicates that the animal 

 is tubercular. The latter method can be more 

 easily applied and we believe just as positive 

 in its reactions. It requires a greater expe- 

 rience to enable the veterinarian to use the 

 intra-dermal or the skin test. 



Many cow owners are of the opinion that 

 the tuberculin test is harmful to their cows, 

 but nothing could be farther from the truth as 

 there can not possibly be a live germ in the 

 tuberculin after it is prepared and ready for use 

 In the preparation of tuberculin it is boiled 

 several times and also filtered through the 

 finest porcelain filters which are capable of 

 holding up any germs that can be seen by the 

 aid of a microscope. So it is well to keep in 

 mind that tuberculin can not possibly do your 

 cows any harm and that it is the only reliable 

 method that we have of determining the pres- 

 ence of tuberculosis in the cow. 



The Control of Tuberculosis. 



After we have learned that a cow has tuber- 

 culosis or that a herd of cows have tubercular 

 ones among them, the question of the best way 

 to dispose of them, comes to our attention. 

 There are many things that govern this, among 

 them being the value of the animal, the ex- 

 tent of the disease, the value of the animal for 

 breeding purpose, etc. 



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