INFECTIOUS DISEASES 337 



aggravated, and the animals become weak and thin and have a rough 

 coat. 



Tuberculosis of the brain, or meninges, is not common and the 

 symptoms evidenced will depend upon the location of the lesion. 



Osseous tuberculosis is associated with interference of locomotion 

 and tumefaction of the affected bone. 



The length of the course of tuberculosis is variable. In young pigs 

 it may produce fatal termination in from two to three months after 

 the onset. Older swine rarely die of tuberculosis, as the disease as- 

 sumes a chronic form in them and they are usually marketed before 

 the disease has manifested itself clinically. 



Diagnosis. — The clinical diagnosis of this disease is practically im- 

 possible without the use of the tuberculin test. The lesions may be 

 identified and the disease can therefore be recognized at autojasy. 



The intradermal tuberculin test is most applicable to swine. This 

 test is made by the injection into the dermis at the base of the ear 

 of from three to five minims of ordinary tuberculin.* The reaction 

 consists of a dense swelling at the point of injection and becomes most 

 prominent on the second or third day after injection. 



The subcutaneous tuberculin test may be used, but it is not as ap- 

 plicable to swine as it is to cattle. The ophthalmic test may also be 

 employed in swine. 



Microscopic examination may be made of the various discharges 

 for the purpose of identifying the tubercle bacilli. In making this 

 test it must be remembered that there are other acid-fast bacteria 

 and further that the absence of tubercle bacilli in the preparations 

 examined is not positive proof of the absence of the disease. 



Animal inoculations may be resorted to, particularly in cases in 

 which no tuberculin test has been made and there is a dispute as to 

 the nature of the lesions found. 



Treatment. — Curative treatment is of no value in porcine tuber- 

 culosis. The only rational method is to sell the affected swine subject 

 to the post-morten inspection findings. In this way some value will 

 be obtained by the original owner, there will be no loss to the packer 

 and no danger to the consumer. 



Tuberculosis is a preventable disease and the losses from it could 

 be avoided, or at least materially diminished, by proper control of 

 tuberculosis in cattle. With our present farm methods the eradication 

 of porcine tuberculosis cannot be accomplished until the disease is 

 eradicated in cattle. The judicious use of skimmed milk, including 



