12 BULLETIN 517, U. S. DEPAETMENT OF AGRICULTURE. 



COMPARISON OF RESULTS OF AGGLUTINATION AND INTRA- 

 DERMAL TESTS ON NATURALLY INFECTED BIRDS. 



Through the assistance of Eoy E. Jones, we located and purchased 



47 birds that had given positive or questionable agglutination tests, 

 applied by the Connecticut Agricultural Experiment Station. These, 

 together with nine controls, were injected for the intradermal test 

 on June 23, 1916, and readings were taken at 24 and 48 hours. 



Of the birds reported positive to the agglutination test applied by 

 the Connecticut station, there was total agreement in 28, or 70 per 

 cent, of the cases in that they also gave positive intradermal test as 

 determined 24 hours after injection and displayed unquestionable 

 lesions when eventually slaughtered. Of those reported positive to 

 the agglutination test, 30, or 75 per cent, revealed lesions at autopsy. 



Thirty-five birds gave positive reactions to the intradermal test. 

 Autopsy revealed that of these 29, or 83 per cent, possessed un- 

 doubted lesions, in 5 the lesions were questionable, and in 1 no lesions 

 occurred. Of those reported positive to the agglutination test, 3 

 birds, or 7 per cent, failed to react to the intradermal test, and 

 autopsy revealed no lesions. On the other hand, 2 birds, or 5 per 

 cent, that had given positive agglutination tests, gave negative in- 

 tradermal tests, and autopsy revealed lesions. Thus, the percentage 

 of absolute failures of each test as judged by the other test and by 

 the autopsy findings were very similar in amount. 



Seven birds had given questionable agglutination tests. Of these, 

 S were negative to the intradermal test and negative at autopsy. 

 One reported questionable gave a positive intradermal reaction and 

 autopsy revealed lesions. The intradermal test on the other 3 yielded 

 positive, negative, and questionable results, respectively, and autopsy 

 of all 3 furnished inconclusive information. 



Of the nine controls, one displayed a marked reaction at 24 hours, 

 consisting of a swelling of the wattle to three times its normal thick- 

 ness. Autopsy revealed undoubted lesions, and a pure culture of 

 Bacterium puUorum was isolated from the ovary. Four others dis- 

 played traces consisting of swelling of the lower border of the wattle 

 to about twice the normal thickness. On autopsy, one of these was 

 found to contain undoubted lesions and a pure culture of B. pulloruni 

 was obtained. 



The examination of the wattles at 48 hours revealed swellings vary- 

 ing from a trace to positive in only 22 birds, or 46 per cent, of those 

 tested. This result compared with the 28 birds regarded as positive 

 at 24 hours and verified by subsequent autopsy, again indicates that 



48 hours is too long to secure all the positive reactions. Among the 

 controls only 1 displayed any swelling whatsoever, and this case 

 proved on autopsy to be positive. 



