13 



to a significant degree and showed no signs of disappearing. •*! I 

 therefore do not venture to draw from these observations the con- 

 clusion that those animals which fail to react one year after a typical 

 reaction are to be regarded as cured. In many cases this conclusion 

 would perhaps be justifiable, but as it cannot always be the case I 

 consider it advisable to look upon the animals which have once 

 shown the typical reaction as suspicious, and to leave them in the 

 reacting division. At the repetition of the test in the spring of 1894, 

 the reaction failed again in about 20 per cent of the cases. For the most 

 part these were the animals which had not reacted in the previous 

 year. Individuals among them showed slight reaction. Several 

 which had reacted twice before did not do so this time. The result 

 of the spring test in 1895 was still more significant. Of 69 suspected 

 animals 21 did not react and nine did so only doubtfully. In the 

 case of 15 of these animals the reaction had previously failed either 

 in one or in both of the previous years. These observations are 

 certainly very peculiar and will with continued observation perhaps 

 yield an interesting explanation of the course of bovine tuberculosis. 



Though I have advised the veterinarians not to test again the 

 isolated reacting animals because I feared that the eventual failure 

 of the reaction might prove confusing, still reports of such repetition 

 have been returned to me. Of 144 tuberculous animals, retested 

 after one year, eleven (7.6 per cent) did not react the second time- 

 Such cases are therefore not so frequent elsewhere as they were at 

 Thurebylille. 



The fact that the repetition of the tuberculin test, especially after 

 a short time, yields a result different from the first has a certain 

 practical significance. When cattle owners who possess healthy 

 herds must purchase new animals, they should be advised to test 

 the cattle with tuberculin before admitting them to the stable, or to 

 purchase them on a guarantee that such test has been made. In 

 spite of all foresight there is still the danger that tuberculous ani- 



a calcified bunch of nut size and a pair of smaller similiar ones in a mediastinal 

 gland. 



b. (12-years old) May 1S9-2 temperature rose to 40.8°, May 1893 to 39.8°, July to 38.9°. 

 The dissection in Aug. 1893 showed in the lungs tliree ulcerated deposits of the 

 consistency of soft cheese, lying apparently in enlarged bronchia. 



c- (3 1-2 years old) May 1893 the temperature rose to 40.6°; May 1893 to 39.4°; July 

 to .38.8°. The dissection in Aug. 1893 showed a cement like mass of pea size in one 

 bronchia, alto an equally large calcified buncli in one bronchial gland. 



41. (Four and a half years old cow) May 1893 the temperature rose to 40.8°; May 

 1893 to 38.9°; July to 38.9°." A dissection. May 1893, showed a small lime bunch in a 

 mediastinal gland and a similar one in a bronchial gland. In the lung an almond 

 sized cheese like bunch and a pea sized bunch of cement character, partly consist- 

 ing of young whitish gray tissue; also single pearl bunches on the corresponding 

 part of the pleura. 



