DIAGNOSTIC INOCULATION. 233 



provided the difference between the highest pre- and post- 

 injunction temperatures is at least 1° C. (1.8° F.) indicates 

 the existence of tuberculosis. 



The International Veterinary Congress of Budapest has 

 accepted the following interpretation of the results of a tuber- 

 culin test : 



1. A post-injection temperature exceeding 40° C. [104° 

 F.j, provided the temperature at the time of injection did not 

 exceed 39.5° C. (103.1° F.), is to be regarded as a positive 

 reaction. 



In post-injection temperatures of cattle between 39.5° C. 

 [103.1° F.] and 40° C. [104.0° F.] the results are to be re- 

 garded as doubtful and to be considered upon their own 

 merits. 



If the pre-injection temperatures of cattle exceed 39.5° C. 

 [103.1° F.], or if those of calves less than six months of age 

 exceed 40° C. [104.0° F.], the tuberculin test should be made 

 at a later date. 



Reliability. The tuberculin test cannot be regarded 

 as absolutely infallible. About 95% of the tuberculous ani- 

 mals give a positive reaction. Animals in advanced stage of 

 the disease frequently do not react. As a rule, however, a 

 physical examination of such animals reveals symptoms which, 

 when considered alone, would at least awaken suspicion as to 

 the existence of the disease. Only a small per cent, of the 

 reacting animals is found to be free from tuberculosis. Nev- 

 ertheless, tuberculin is the best diag- 

 nosticum in our possession. 



The Conjunctival or Ophthalmic Tuberculin Test. With a 

 camel's hair brush or by means of a pipette introduce one-half 

 cubic centimeter of common tuberculin, tuberculin A, or Bovo- 

 Tuberculol D, solutio I, into the conjunctival sac. To facilitate 

 the operation, secure the head of the animal, depress the lower 

 eyelid and drop the tuberculin into the pocket thus formed. 



Tuberculosis is indicated if a pronounced mucopurulent 

 conjunctivitis develops in a few hours. 



The technic is simple and may be carried out without se- 

 curing the "animals. 



