230 MARKET DAIRYING 
ture in infected animals, while in those unaffected the 
temperature remains the same. It must be added, how- 
ever, that in the last stages of the disease, tuberculin fails 
as a diagnostic agent, but this is of little consequence 
since the disease is readily recognized in these stages by 
a physical examination. 
The tuberculin test should not be applied to cows in 
heat or shortly before and after calving; neither may 
reliable results be expected with cows suffering from 
garget or other diseases. A period of at least 60 days 
should elapse before a retest is made for tuberculosis. 
In regard to the reliability of the test, there is plenty 
of evidence to show that when the testing is done by 
competent persons the test is almost infallible. In Cali- 
fornia, for instance, 817 out of 9,618 head tested reacted 
and 817 upon post-mortem examination showed tuber- 
culosis. The accuracy of the test in this case was 100%. 
In Massachusetts 86,223 were tested, and of the 10,760 
that reacted, 99.34% showed tuberculosis. In Wiscon- 
sin, out of 408,000 tested, 24,784 were killed and 98.39% 
of these showed tuberculosis. We might go on this way 
indefinitely showing figures bearing upon the accuracy 
of the tuberculin test, and it is such figures that milk 
producers should be thoroughly acquainted with before 
being asked to submit their cows to the test. 
Regarding the efficiency with which the tuberculin 
testing is done, it cannot be denied that there is often 
cecasion for criticism. The testing should be done by 
experienced men who have shown proficiency in this 
always prima facie evidence that the work is being con- 
linc. The fact that the tester is a veterinarian is not 
ducted satisfactorily. We have many men that. style 
themselves veterinarians who are nothing more nor less 
