356 THE BACILLUS OF TUBERCULOSIS 



4. Any rise in temperature between 39.5 C. (103 F.) and 40 C. 

 (104 F.) must be regarded as of doubtful significance; animals 

 exhibiting such require special study. 



The question of how soon an animal reacting positively will again 

 react has been studied experimentally by a number of investigators. 

 According to Nocard's experiments on 24 cows reacting positively 

 upon the first test, 33 per cent, reacted positively to another test made 

 twenty-four to forty- eight hours after the termination of the first 

 test; 50 per cent, positively after eight days; 60 per cent, positively 

 after two weeks, and 100 per cent, after one month. According to 

 the experience in the Prussian Sea Quarantine Station, 100 per cent, 

 react positively in a second test made almost immediately after the 

 first has completely disappeared, but five times the amount of the 

 first test dose must be used. According to Valle the double dose of 

 the first test dose will give a positive result when used thirty-six to 

 forty-eight hours after the termination of the first reaction. The 

 maximum temperature, however, is reached much earlier in the 

 second test and the fall in temperature is more rapid than in the 

 first test. 



The accuracy of the conclusions drawn from the test varies accord- 

 ing to the good judgment of those who make the test. According to 

 Bang, under satisfactory conditions the positive diagnosis upon the 

 basis of the test is found correct in 96 per cent. According to Jensen's 

 statistics 90.8 per cent, of tubercular animals out of a total of 468 

 gave a positive result. Ever's statistics of 563 cases later examined 

 by postmortem examinations showed a correct interpretation of a 

 positive test in 86.9 per cent. The recent experience in the United 

 States with the tuberculin test of cattle has been even more favorable 

 than the earlier observations in Europe. Melvin reported that of 

 24,784 head of cattle tuberculin-tested in 1907-08 with a positive 

 reaction, 24,387, or 98.39 per cent., upon being slaughtered were 

 found to be tubercular. Nocard and Hutyra and Marek state that 

 animals affected with echinococcus or actinomycosis never react 

 positively to the tuberculin test. 



Ophthalmo-tuberculin Reaction. Wolf-Eisner and Calmette almost 

 simultaneously and independently introduced another form of 

 tuberculin reaction into medical practice. It consists in the instil- 

 lation of one or two drops of a tuberculin solution prepared in a 

 special manner from the watery solution of an alcoholic precipitate of 

 a killed tubercle bacilli culture into the conjunctival sac near the 

 inner canthus of the eye. The test has been found quite accurate 

 in man, and several observers have tried it on cattle. Bailliart, 

 reporting to the Sixth International Tuberculosis Congress in Wash- 

 ington, stated with reference to the ophthalmo-tuberculin test in 

 cattle: "The ophthalmo-reaction is a diagnostic procedure which 

 is usually without danger if it is applied only to eyes free from 

 tubercular lesions of any kind. It is sometimes followed by mild and 



