217 



Bones and articulations are at first swollen and hard. 

 Bones may later become soft, and if close to the skin, may 

 be opened for an abscess. 



When the brain, the spinal cord and their coverings are 

 tuberculous the animal shows more or less signs of paraly- 

 sis or mental derangement. In a brief time general stupid- 

 ity, paralysis or convulsions may occur. 



DIAGNOSIS. 



How to Recognize Tuberculosis. 



The physical signs or symptoms peviously mentioned may 

 enable the veterinarian to recognize tuberculosis in well 

 marked cases, but there are many dangerous and badly in- 

 fected cases that can not be recognized by the veterinarian 

 if he bases his diagnosis upon physical signs alone. The 

 United States Veterinary Medical Association at their last 

 meeting declared that tuberculosis in cattle could not, in 

 many cases, be determined by physical examination alone. 

 Besides the symptoms given we have the following aids to 

 assist in making a more accurate diagnosis : 



(1). Microscopical examination of the nasal discharge, of 

 the saliva, of the milk and of the tubercles that erupt on 

 the surface or that may be surgically removed from the skin 

 or superficial tissues of the body. 



(2). Inoculating susceptible auima,ls with any of the 

 liquids or materials mentioned in (1). 



(3). The Tuberculin Test. 



The first two of these methods are very tedious and diffi- 

 cult, and in many instances entirely without definite results. 



The tubercle bacilli are rarelv found in the milk in suffi- 

 cient numbers to admit of their detection by the use of the 

 microscope. It is only in very severe cases that the tubercle 

 bacilli can readily be detected in the milk. Some claim that 

 the udder or milk glands must be tuberculous before bacilli 

 are in quantities sufficient for easy and accurate microscopic 

 detection. Inoculating susceptible animals (guinea pigs, 



