. . '. ! ^ •. ; ' • .;, 



CHRONIC INFECTIOUS :T)IgE"A6'I5S; -.lOl 



sider a reaction positive if the highest temperature 

 after injection exceeds the pre-injection temperature 

 by 2-7° F. 



(2) Ophthalmic Ti(,herciiUn Test.— For this test con- 

 centrated bovine tuberculin is used. A few drops of 

 the tuberculin are dropped into the conjunctival sac, 

 the eye is then closed and slightly massaged for about 

 one minute. The result of the test is determined 

 between the twelfth to the twenty-fourth hour after 

 application of the tuberculin. The untreated eye 

 serves as a control. Particular attention should be 

 paid to the character of the exudate and to the appear- 

 ance of the membrana nictitans. In positive reactions 

 the latter is intensely reddened and its normally 

 sharp border is thickened and swollen, there is lacry- 

 mation of the eye, and about the twelfth to eighteenth 

 hour there is a production of a purulent secretion 

 which accumulates under the nasal canthus of the eye. 

 In healthy animals a catarrhal inflammation of the 

 eye may be produced. This test is very useful where 

 there is a suspicion of a previous subcutaneous injection 

 of tuberculin having been given, as this has no effect on 

 the conjunctival reaction, whereas in the subcutaneous 

 test a previous injection may obscure the reaction. 



(3) Intradermal Test,— Yon Pirquet (1907) has shown 

 that the injection of minimal quantities of tuber- 

 culin into the upper layers of the cutis of tuberculous 

 patients produced local reddening and swelling at the 

 point of injection. Yallee applied this diagnostic 

 method in horses and cattle with the same satisfactory 



