APPLICATION OF THE TUBERCULIN TEST. 



81 



shows ear-tags as described. The characters borne by the tag 

 are stamped on at the factory and consequently may not be 

 readily imitated for fraudulent purposes. Furthermore, dupli- 

 cation of numbers will not occur. The ear-tags should be 

 affixed after a test to all animals whether they have reacted 

 or not. It is of no particular value to tag only non-reactors, 

 since after subsequent exposure of the animal to infection the 

 tag gives no guarantee of freedom from tuberculosis. In one 

 case where such a practice was in vogue, it was observed that 

 dairymen would willingly purchase a tagged cow without fur- 

 ther guarantee of health. Furthermore, owners have pointed 

 out the death from tuberculosis of a tagged animal as an evi- 

 dence of the unreliability of the test. It is not well to encour- 

 age the idea that an ear-tag is a fetish against tubercular infec- 

 tion. It is quite possible that ear-tags may be lost and also 

 that ear-tags may be transferred to other animals for fraudulent 

 purposes. An absolutely safe identification, then, requires fur- 

 ther safeguards. For this purpose the writer devised a 3 by 

 5-inch card printed with the outline of a cow and blanks for 

 important data (53). 



Label No.'/i:-'/.. ^xf:eAliviMCLiL. Ovmex.Z-i^-l-lJ.iil~- 



Fig. IJ. Card employed by the writer for the identification of cows. 



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