THE WHOLE BLOOD TEST FOR PULLORUM DISEASE 11 



Table 4. -influence of blood-antigen dilution 

 on degree of agglutination.* 



*Refer to legend of Table 3. 



tested two weeks previously, and the results are listed in Table 3. It may be 

 seen that the reactions obtained at both trials agree very closely. 



EXPERIMENTAL TESTING IN COMMERCIAL FLOCKS 



In determining the true value of the whole blood test as a diagnostic means of 

 detecting "carriers" of pullorum infection, it was deemed expedient to select 

 infected flocks of a desirable size which could be tested with the whole blood 

 test at frequent intervals until negative. After no more reactors could be detected 

 with the whole blood test, the flock was to be check-tested with the standard tube 

 method. All birds that showed reactions of interest from a diagnostic point of 

 view were either retained in quarantine on the premises or taken to the laboratory 

 for further observation. 



The scope of this investigation also included a determination of the com- 

 parative efficiency of the whole blood and standard tube methods, by using both 

 methods simultaneously in eliminating pullorum-disease "carriers" from an 

 infected flock through repeated testing. Likewise in this phase of the investiga- 

 tion, birds which gave reactions of diagnostic interest were subjected to further 

 study. 



Results 



Two known infected flocks (A and B) were selected and tested with the whole 

 blood test to determine its efficiency as a diagnostic means of detecting pullorum- 

 disease-reacting birds. The original plan was to test the flocks at approximately 

 monthly intervals until no reactors appeared and then to check test them with 

 the standard tube test. Unfortunately this plan could not be followed, due to the 

 fact that reactors continued to appear on retest, which threatened to delay the 

 hatching season; hence the flock owners requested that the whole blood test be 

 supplemented with the standard tube test in order to hasten eradication of the 

 infected birds in the flock. At the completion of the test all reactors were check- 



