Tuberculosis 



127 



recorded 24, 48 and 72 hours after the injection. A positive 

 reaction is indicated in a typical case by a large swelHng 



Fig. 18. 



Head of chicken showing positive tuberculin reaction of comb 

 and right wattle. (After Van Es and Schalk.) 



about the point of injection. In the wattle this organ often 

 becomes two to three times its original thickness. 



Agglutination and complement fixation tests have also 

 been used to diagnose this disease.^ The tests so far re- 



' Himmelberger, L. G., loc. cit. 



