586 Tuberculosis. 



to the results obtained by Koch's subeutaneous test. Cattle free from tuberculosis 

 but affected with other diseases (Metritis, Cancer, etc.) did n6t react to the test.. 

 The results of tests by Vallee were equally satisfactory, 494 cattle in 521 tests 

 giving the same result for each method (12 cattle with positive thermal reactions 

 gave no cutaneous reaction). Foth succeeded in detecting about one-half of the 

 tuberculous individuals among the Danish quarantine cattle by this method. By 

 the method of Eoemer and Joseph (0.1 ce. of 50% tuberculin) Joseph records 

 only one error in 126 cattle as shown by subsequent post-mortem examination, 

 viz., one animal out of 79 tested, while no reactions occurred in 27 healthy animals 

 tested. Zschokke found in his experiments with 300 cattle, which were for the 

 most part slaughtered afterwards, that neck and tail inoculations were of about 

 equal value and that both were subject to about 15% error, only 85% of known 

 tuberculous cattle giving positive reactions. 



The intracutaneous method is applicable also for swine, the tuber- 

 culin being injected into the skin at the base of the ear near the median 

 border on the dorsal surface. If the animal is tuberculous a flat swell- 

 ing with central reddened zone will develop after twenty-four hours. 

 In some cases there may be a hemorrhage, the size of a silver doUar, 

 in the center of the swelling, which may lead to necrosis of the overljdng 

 skin. 



This method, recommended by Moussu and Mantoux, was tried by Zschokke 

 on 266 pigs with thef result that 90% of the tuberculous animals gave positive 

 reactions. 



(d) Local Subcutaneous! Reaction. According to Vallee and 

 Fernandez dead bacilli with their* fat contents removed, mixed with four 

 parts of finely pulverized glass and injected in amounts of 1 mg. into 

 the subeutis of the ear produce, in tuberculous cattle, in addition to 

 the edematous swelling which occurs simultaneously with the thermic 

 reaction in the subeutaneous method, a very painful, edematous swelling 

 which is valuable for diagnostic purposes. This condition results from 

 the slow absorption of the injected mass at this point. This method has 

 not yet been used in actual practice. 



Comparative value of the various tuberculin tests. Accord- 

 m^ to collected experiences the best results are obtained by 

 ElScli's subcutaneous method. In this test a positive reaction 

 is a certain indication of tuberculosis while a negative reaction 

 indicates with the greatest probability the absence of the disease. 

 A great advantage offered by this method consists in the 

 possibility of recognizing the presence or absence of a febrile 

 reaction by the maximum temperature recorded after injection 

 of the tuberculin. The intradermal or intracutaneous test is nest 

 in value to the subcutaneous method. This produces with the 

 use of 50% tuberculin good and clear results in both positive 

 and* negative cases. The ophthalmic test is of less diagnostic 

 importance, errors being much more frequent than in the fore- 

 going methods, especially in that even tuberculous animals not 

 infrequently give no reactions whatever. The cutaneous test 

 has the least practical value, errors occurring much more fre- 

 quently than in any of the others ; this is due, in part, to the 

 fact that the positive reaction is frequently impossible of differ- 

 entiation from a simple traumatic reaction. 



Under these circumstances it is advisable, in all cases where 

 an accurate diagnosis is the first consideration, to use the siib- 



