TUBERCULOSIS 195 



and eyes bright, and yet be extensively diseased, and die in a 

 short time. 



Diagnosis.— The only reliable test, practical on a large scale 

 in routine work, is tuberculin, which is very accurate but not 

 infallible. 



There are three recognized tuberculin tests (see Lecture 

 XL), all of which are useful. 



Medical treatment. — Medical treatment is not practical. It 

 is advisable to destroy or isolate diseased animals at once. Very 



Fig. 68. — Bovine Tuberculosis. (M. B. B.) 

 Tubercles on the great mesentery. 



valuable animals may be kept in isolation and used for breed- 

 ing purposes with good results when considerable added expense 

 and work are justified. 



Prevention. — Stockmen should breed and manage with a view 

 to increasing physical vigor. Bear in mind that an animal 

 may have a fine physical appearance and yet be easily sus- 

 ceptible to disease, if not actually diseased and a spreader. 



The practice of keeping cattle almost continuously in the 

 stable does not harmonize with plain teachings of physiology, 

 and the results must sooner or later be disastrous. The great 

 law of animal life, that use begets strength and idleness begets 



