TUBERCULOSIS. 419 



its use the disease can be eradicated from the herd, a clean herd 

 established in a few years without very serious loss or hardship, and 

 the danger of its spread to man removed. Tuberculin may therefore 

 be considered a most beneficial discovery for the stock raiser. 

 Strange to say, many of these men have been incredulous, antago- 

 nistic, or prejudiced against the tuberculin test by misinterpreting 

 published statements, by incorrect, imsubstantiated, or exaggerated 

 reports, and by alleged injurious effects to healthy cattle. 

 Law has clearly stated the question when he says — 



Blany stock owners still entertain an ignorant and unwarranted dread of the 

 tuberculin test. It is true that when recklessly used by ignorant and careless 

 people it may be made a root of evil, yet as employed by the intelligent and 

 careful expert it is not only perfectly safe, but it is the only known means of 

 ascertaining approximately the actual number affected in a given herd. In 

 most infected herds living under what are in other respects good hygienic condi- 

 tions two-thirds or three-fourths are not to be detected without its aid, so that in 

 clearing a herd from tuberculosis and placing both herd and products above 

 suspicion the test becomes essential. * * * in skilled hands the tuberculin 

 test will show at least nine-tenths of all cases of tuberculosis when other 

 methods of diagnosis will not detect one-tenth. 



Objection to its use among those who are not acquainted with its 

 method of preparation or its properties is perfectly natural, but it 

 is difficult to explain the antagonism of farmers who are familiar 

 with the facts connected with the manufacture and use of tuberculin. 

 Probably the most popular objection to tuberculin is that it is too 

 searching, since it discovers cases in which the lesions are small and 

 obscure. While this fact is admitted, it should also be remembered 

 that such a small lesion to-day may break down and become widelj' 

 disseminated in a relatively short period. Therefore any cow 

 affected with tuberculosis, even to a slight degree, must be considered 

 as dangerous not only to the other animals in the herd but also to 

 the consumer of her products. 



In 1898, Bang, of Copenhagen, one of the highest European 

 authorities, in his paper presented to the Congress for the Study 

 of Human and Animal Tuberculosis, at Paris, said : 



Numerous tests made in almost every civilized country ha^'e demonstrated 

 that in the majority of cases tuberculin is an exceUent means for diagnosing 

 the existence or nonexistence of the disease, but .giving us no positive Infor- 

 mation as to the extent to which the disease has progressed. When tuberculin 

 produces a typical reaction we may be almost sure that there exists in the body 

 of the animal a tubercular process. The cases in which a careful examiner has 

 not succeeded in finding it are very rare, and I am led to believe that when, 

 notwithstanding all the pains taken, it has escaped discovery, the reason is 

 that it is located in a portion of the lx)dy that is particularly inaccessible. 

 Nevertheless, it is not to be denied that a fe^-er, entirely accidental and of 

 short duration, may in some rare cases have simulated a reaction. However 

 this may be, the error committed in wrongly condemning an occasional animal 

 for tuberculosis is of no practical consequence. 



