86 TECHNICAL BULLETIN 5. 



The results presented in this table need no comment. It can readily be 

 seen that, with the exception of one culture obtained from flock Xo. 15, 

 all cultures obtained from dead chicks which had been hatched from 

 positive-reacting birds were maltose-dextrine-dulcite negative, and pro- 

 duced gas in dextrose. This is significant in that these flocks were widely 

 distributed, and the only exception to this rule was the one noted above. 

 This culture was maltose-dextrine-dulcite negative and was anaerogenic. 

 At any rate, it gave none of the reactions for Bad. mnguinarium. On 

 this experiment were 5,619 breeding hens and 924 were positive reactors, 

 giving a positive agglutination up to dilutions of 1,000 and over. It is 

 reasonable to believe that these results would be substantiated by a 

 repetition of the experiment. While there are, as already noted, certain 

 factors which have influenced the test and which may suggest need of 

 modifications, — • such as the validitj^ of the agglutination tests, based on 

 interagglutinability of Bad. pullorum, Bad. sanguinarivm and other 

 antigens in both Bad. puUorum and Bad. sangtmiarium serum, — yet the 

 fact remains that in the twenty flocks mentioned the agglutination test 

 definitely located infection in 924 birds in a total number of 5,619. The 

 differential characteristics of the cultures isolated from dead chicks which 

 had been hatched from the eggs laid by these positive-reacting birds proved 

 to be typical Bad. pullorum, conforming morphologically and biochemically 

 to the standard set as a result of fermentative, serological and morpho- 

 logical studies completed. 



After all is said about chances of error with the test, data are constantly 

 being accumulated which indicate that the agglutination when carefully 

 controlled through epidemiological work is at present the best method we 

 have of locating Bad. ptdlorum infection and furnishing poultrjmien a 

 starting point for its elimination. 



Summary. 



From the foregoing data the following conclusions appear justified con- 

 cerning the diagnosis of Bad. pullorum infection in the domestic fowl: — 



1. From the fermentation studies conducted over a period of three 

 years, it was found that Bad. pullorum is maltose-dextrine-dulcite negative 

 and aerogenic, while all cultures of Bad. sanguinarium studied have been 

 maltose-dextrine-dulcite positive and anaerogenic. These characteristics 

 are constant. Whenever there has been question as to cultural and 

 morphological differentiations, these investigations have shown that the 

 biochemical tests have aided in making a final decision. Variations in 

 morphology of the pullorum strains are frequent; therefore doubtful 

 cultures should be submitted to the maltose-dextrine-dulcite test and 

 checked by gas production in dextrose. Experience has shown that this 

 procedure should be followed as a routine in all laboratories ha\ing to do 

 with the pullorum problem. 



2. From the examination of 600 avian specimens for the anaerogenic, 

 non-motile, maltose-dextrine-dulcite positive form which produced en- 



