MEASURES AGAINST BOVINE TUBERCULOSIS. 69 



ance. Under the circumstances, emaciation as a symptom of 

 tuberculosis cannot be given very heavy consideration. Aus- 

 cultation and percussion of the lungs do not yield the results 

 that might be expected, and the same may be said of palpa- 

 tion of the superficial lymph glands. Neither the lungs nor 

 accessible lymph glands are necessarily involved in advanced 

 cases. 



Emphasis has been laid upon the value of detecting the 

 tubercular udder, as if it were a very important factor in the 

 contamination of milk. As a matter of fact, the development 

 of tuberculosis in the udder to a degree that would attract 

 attention is very rare. Smith (49) believes that roughly speak- 

 ing the udder becomes tuberculous through metastasis in per- 

 haps 1% of tubercular cows. Miiller (27)' states that 1.62% 

 of all cows slaughtered in Germany show tuberculosis of the 

 udder. Mammitis, associated with steptococci, is very com- 

 mon and causes indurated areas in the udder that raise insur- 

 mountable difficulties in the differential diagnosis by physical 

 signs. The bacteriological examination of samples of milk 

 from the suspected udder is the only reliable means for identi- 

 fying tuberculosis of the udder. 



In the discussion of the tuberculosis problem the idea is 

 sometimes implied that the detection and removal of the worst 

 animals from a herd will effect some measure of improvement in 

 diminishing the disease. Such a procedure does not appreci- 

 ably diminish the opportunity for the further spread of infection 

 and certainly does not benefit the large number already slightly 

 affected. Physical examination and removal of the con- 

 demned animals anticipates by a considerable period the nat- 

 ural breaking down from the disease and results in the removal 

 of some others less seriously diseased but which happen to be 

 easily detected. It results in no permanent improvement along 

 the line of extinguishing the infection. 



The writer's personal experience in physical examination of 

 dairy herds for tuberculosis has been most unsatisfactory. 

 About 300 cows supplying a town with milk were examined 

 once in each of two successive years. Cows showing definite 

 unmistakable physical signs of tuberculosis, warranting slaugh- 



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