Tuberculosis ix Cattle. 21 



always tends to a temporary lowering of temperature but in the 

 presence of tuberculosis it soon rises again. 



loth. Change of food is liable to produce a slight indigestio7i and 

 rise of temper-ature . This should be avoided as far as possible, 

 and when a herd is taken up from pasture for the test it should 

 have grass, ensilage or other succulent food. 



These are examples of the sources of fallacy which attend on 

 the reckless and unintelligent use of tuberculin. They only show 

 that skill and training are necessary to its successful use, and 

 that in the absence of these the apparent results are not to be too 

 unhesitatingly accepted. In all cases, in the absence of the re- 

 quisite education and experience it is desirable that the animals 

 which have shown a rise of temperature should be separated 

 from the herd and tested anew after the lapse of three or four 

 weeks. In this wa}' such errors may be almost entirely excluded. 



nth. An ayiimal with adva?iced tuberculosis sometimes fails to 

 react. The subject is, however, usually emaciated and bloodless, 

 breathes hard and has rapid pulse on exertion and shows une- 

 quivocal symptoms of tuberculosis to the skilled examiner. Such 

 cases can, therefore, rarely escape a physical examination. They 

 are noticed mainly to guard against the mistake of making the 

 rise of temperature or its absence the sole test of tuberculosis. 



.i2th. It is objected to tuberculin that it detects even the 

 slightest and most latent cases of tuberculosis, some of which 

 would recover and many would remain useful for years. This 

 objection would be valid if our object were to obtain the greatest 

 possible money return from the individual tuberculous cow at the 

 expense of any risk to the sound herd. But tuberculin is, and 

 should be used for the purpose of a complete eradication of the 

 tubercle bacillus from the herd and the preservation of a sound 

 stock which with its products will be above suspicion. If this is 

 not aimed at ; if the latent cases are to be retained in the herd 

 and the advanced cases only removed then truly tuberculin should 

 have no place in your system. Physical examination should be 

 all sufficient for 3^our purpose. But you could not place the herd 

 at once above suspicion, you could not sell its members with a 

 guarantee of soundness, and you could not assure the consumers 

 that the uncooked dairy products were safe. 



