418 DISEASES OF CATTLE. 



those that are not tuberculous, but which show an elevation of tem- 

 perature as a result of (a) advanced pregnancy, (h) the excite- 

 ment of oestrum, (c) concurrent diseases, as inflammation of the 

 lungs, intestines, uterus, udder, or other parts, abortion, retention 

 of afterbirth, indigestion, etc., (d) inclosure in a hot, stuffy stable, 

 especially in summer, or exposure to cold drafts or rains, (e) any 

 change in the method of feeding, watering, or stabling of the animal 

 during the test. Notwithstanding all these possibilities of error, 

 the results of thousands of tests show that in less than 3 per cent 

 of the cases tested do these failures actually occur. In the first class 

 the chances of error are decidedly reduced by the skilled veterinarian 

 by making careful physical examination and diagnosing clinically 

 these advanced cases, and by the injection of double or triple doses 

 into all recently tested cattle, with the taking of the after temper- 

 ature, beginning twQ hours following the injection and continuing 

 hourly for 20 hours. 



It is therefore apparent that tuberculin should be applied only 

 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 exami- 

 nation. The latter observation is extremely important and should 

 always be made on every animal tested. 



In the second class errors are avoided by eliminating from the 

 test those cases that are nearing parturition or are in heat or show 

 evidence of the previously mentioned diseases or exhibit tempera- 

 tures 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 reac- 

 tion 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 percentage 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 beeen adopted tuberculosis is gradually 

 being eradicated, while it is spreading rapidly and becoming widely 

 disseminated in those districts in which the tuberculin test has not 

 been used. Without its use the disease can not be controlled and 

 the owner is confronted with serious and continuous losses; with 



