Ophthalmic Tuberculm Test. 583 



The first conjunctival tests .that were made on cattle did not give very 

 nniform results, probably because they were made with weak solutions of tuberculin. 

 While Yallee, Lignieres, Guerin and Delattre reported very satisfactory results, 

 Arloing, Vanderheyden, Gratz and Eeinecke would not admit any practical value 

 whatever for this test. Subsequently, however, Garth, Kranich and Gruenert showed 

 tliat although dilute solutions of tuberculin gave unreliable results, concentrated 

 material produced distinct and specific reactions. By using 50% tuberculol they 

 succeeded in demonstrating the presence of the disease in 96.1% of reactors at 

 the time of slaughter. 



Since then nearly all eye tests have been conducted with concentrated bovine 

 tuberculin with results correspondingly more favorable. Thus Sekyra reports 15.9% 

 of errors in the diagnosis of 82 cattle, Eichter 14.7% of doubtful results and 

 16% of positive errors in 75 cattle, Opalka and Duering had 10% of negative 

 reactions in 60 tuberculous cattle, while on the other hand Klimmer and Kiessig 

 found 83.3% of reactors tuberculous at post-mortem examination after slaughter, 

 and of 14 non-reactors all were found to be free from the disease at slaughter; 

 of 121 cattle that were tested by both the conjunctival and the subcutaneous methods 

 87.6% gave the same results for both tests, while 12.4% gave different or opposite 

 results. Similarly favorable results are reported by Marineseu for 820 cattle, 

 Meyer for 150 and Bellini for 200 test cattle. Basing his conclusions on 487 

 conjunctival tests of 412 Danish quarantine cattle and 66 tests of that number 

 of inland cattle Foth found that the test gave pronounced and positive results 

 in about 505 of such cattle as had ceased to react to the subcutaneous test on 

 accoimt of previous applications of tuberculin. 



Technic of the Ophthalmic Test. With the head of the animal secured by 

 an assistant a few drops of tuberculin are dropped into the conjunctival sac by 

 means of a pipette, or the tuberculin may be applied with a camels' hair brush 

 on the lateral portion of the bulbus, whereupon the closed eyes are slightly massaged 

 for one-half to one minute. 



The material used should be 50% of concentrated bovine tuberculin. In 

 Germany bovotuberculol D Sol. I and 50% tuberculin A Dohna has been found 

 effective. Foth however obtained good results also with a 5% solution of dry 

 tuberculin. It. seems that tuberculins containing ground or pulverized bacilli 

 (endotoxins) are better adapted for local tests. 



The result of the test is determined between the 12th to 24th hour after 

 application of the tuberculin. The untreated eye serves as a check or control. 

 Particular attention should be paid to the character of the exudate and to the 

 appearance of the membrana nictitans. In positive reactions the latter is intensely 

 reddened and its normally "sharp border is swollen or thickened. In exceptional 

 cases the reaction may persist for three or four days. 



Other mucous membranes besides the conjunctiva have been found to be 

 hypersensitive to applications of tuberlin in tuberculous animals, Eichter calls 

 attention to the special adaptability of the vaginal mucous membrane for this 

 purpose. After application of the bovotuberculin to the accessible portion of 

 the mucous membrane of the vagina, the reaction, if positive, will manifest itself 

 in redness, swelling, and the production of a glairy, whitish mucous or sometimes 

 purulent exudate. Although the results are equally as accurate as those of the 

 conjunctival test (20% errors) this method is hardly to be considered as practical 

 on account of the possibility of secondary infection which might interfere with the 

 diagnosis. 



3. Tuberculin- Cutaneous Tests (Dermo-reaction, intra- 

 dermal reaction). Since Pirquet (1907) has shown that the 

 inoculation of minimal quantities of tuberculin into the upper 

 layers of the cutis of tuberculous persons produced local red- 

 dening and swelling at the point of inoculation, Vallee applied 

 this new diagnostic method in horses and cattle with the same 

 satisfactory and positive results. The scarified area, into which 

 tuberculin had been rubbed, usually showed a distinct reaction 

 in tuberculous animals while healthy animals showed slight 

 inflammatory reddening at the border of the area only in ex- 

 ceptional cases. Since then other investigators have verified 

 these results and thus proved the specific value of the cutaneous 

 reaction. The technic of the method has been variously modified 



