66 CONTROL SERIES No. (33 



Flock III had not been tested previously and revealed 6.45 per cent reactors 

 as detennined by the agglutination test. The reactors were distributed through- 

 out the entire flock. 



On February 8 the entire flock was tested by both methods. A total of 276 

 birds was tested in approximately 6 hours. The birds were confined in a number 

 of small pens which necessitated frequent moving of the testing equipment. 

 The atmospheric temperature was a few degrees below freezing. The technique 

 of the whole blood test was identical to that employed on February 5 in Flock 

 II. The results of the tests were as follows: 



Wlwle Blood Tube 



Test Test 



Number of birds positive 14 14 



Number of birds doubtful 4 4 



Number of birds negative 258 258 



D 



Retested with W.B.T. 

 only, Feb. 15 



Number 



Group Classification of Birds N 



I Positive to both tests 14 



II Negative to both tests 256 



III Negative to W.B.T. and doubtful to tube test 2 



IV Doubtful to W.B.T. and negative to tube test 2 : 



V Doubtful to both tests 2 



* One bird was killed by owner. 

 ** One bird died. 



1* 



2 



1** 



The surviving reactors in Groups III and V were submitted to the laboratory 

 for necropsy. Birds in Group IV were retained in the flock. The results of the 

 necropsies were as follows: 



On March 11, Flock III was tested for the second time by both methods. 

 A total of 227 birds was tested in approximately 4 hours. The technique for 

 the whole blood test was identical with that employed on February 8. No 

 reactors were detected by either method. 



Discussion 



Among 260 tests for Group I, made with both methods, there was a dis- 

 agreement of 17.31 per cent. The disagreements between the results of the two 

 methods were observed throughout the testing period, most of them occurring 

 when the serum titer of the bird was low. However, in some birds with high 

 serum titers, the two tests did not always agree. Among the birds necropsied 

 S. pullorum was isolated from 1 that reacted negatively to the whole blood test 

 and positively to the tube test. This bird was at no time regarded as positive 

 to the whole blood test. However, the titer at necropsy was less than 80. The 

 disagreements between the tests of the two methods were not as numerous in 



