410 DISEASES OF CATTLE. 



It is therefore apparent that tuberculin should only be applied by 

 or under the direction of a competent veterinarian, capable not only 

 of injecting the tuberculin but also of interpreting the results, and 

 particularly of picking out all clinical cases by physical examination. 

 The latter observation is extremely important and should always be 

 made on every animal tested. 



In the second class errors are avoided by eliminating those cases from 

 the test that are nearing parturition or are in heat or show evidence of 

 the previously mentioned diseases or exhibit temperatures sufficiently 

 high to make them unreliable for use as normal. Then, in reading 

 after temperatures it is advisable not to recognize as a reaction an 

 elevation of temperature less than 2° F. and which at the same 

 time must go above 103.8° F., and the temperature reaction must 

 likewise have the characteristic rainbow curve. (Those cases which 

 approximate but do not reach this standard should be considered 

 as suspicious and held for a retest six weeks later.) In addition, 

 a satisfactory tuberculin must be used, also an accurate thermometer 

 and a reliable syringe, in order that a sufficient dose of tuberculin may 

 be given. Finally, the number of apparent errors of the tuberculin 

 test will be greatly diminished if a careful post-mortem examination 

 is made, giving especial attention to the lymph glands. This low per- 

 centage of failures being the case, cattle owners should welcome the 

 tuberculin test, not only for their own interest but for the welfare of 

 the public as well. Where this method of diagnosing the disease has 

 been adopted tuberculosis is gradually being eradicated, while it is 

 spreading rapidly and becoming widely disseminated in those districts 

 where the tuberculin test has not been employed. Without its use 

 the disease can not be controlled and the cattle owner is confronted 

 with serious and continuous losses; with 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 bene- 

 ficial discovery for the stock raiser. Strange to say, many of these 

 men have been incredulous, antagonistic, or prejudiced against the 

 tuberculin test by misinterpreting published statements, by incor- 

 rect, unsubstantiated, or exaggerated reports, and by alleged injurious 

 effects to healthy cattle. 



Law has clearly stated the question when he says — 



Many 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 conditions 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 



