18 MASS. EXPERIMENT STATION BULLETIN 148. 



infected individuals were used. For this reason, in the work carried out 

 here, the lowest diagnostic dilution was 1-100. If reaction resulted with 

 Bacterium pullonmi in this dilution it was considered positive, and the in- 

 dividual rated as a reactor. 



Since Bacterium 'pullorxmi has been placed in the B. coli-typhi-dysenterce 

 group of bacteria it was considered of interest to determine if Bacterium 

 pullorum agglutinative sera were specific for Bacterium pullorum. For 

 these tests the best known members of the B. coli-typhi group of bacteria 

 were used. The sera from two hens harboring the organism was drawn 

 and diluted with carbolated salt solution 1-20. Test fluids of uniform 

 turbidity were prepared, as previously for Bacterium pullorum, of the fol- 

 lowing organisms: B. coli communis, B. coli communior, B. icteroides, 

 B. enteritidis, B. paratyphi A., B. paratyplii B., B. typhi abdominalis, B. 

 Fowl cholera, B. cloacce, B. lactis acrogenes, and lastly a test fluid of Bacte- 

 ruim pullorum. Complete sets of test tubes were made for each, and 

 to each was added the amount of Bacterium pullorum agglutinative sera 

 to give the required dilution. The dilutions in all sets were from 1-100 to 

 1-5,000, the principal dilutions between these ranges were in the following 

 order: 1-100, 1-200, 1-300, 1-400, 1-500, 1-800, 1-1,000, 1-1,200, 1-1,500, 

 1-1,800, 1-2,000, 1-2,500, 1-3,000, 1-4,000 and 1-5,000. 



By observation of Table 10 it can be seen that the Bacterium pullorum 

 agglutinative sera caused agglutination only when put in contact M'ith 

 Bacterium pullorum. Not the slightest agglutination occurred in any 

 of the tubes containing test fluid other than Bacterium pullorum. From 

 this data it would seem that the Bacterium pullorum agglutinin is highly 

 specific, and therefore is of great diagnostic value in all work in which 

 the organism must be determined. 



Agglutinins obtained by the Immunization of Rabbits against 

 Bacterium Pullorum. 

 Rabbits are easily infected with Bacterium pullorum, or at least show 

 a marked reaction when injected with pure cultures of this organism; but 

 by a careful procedure of immunization they yield verj^ active agglutinins 

 and also bacteriolytic sera. From 100 tests made in this laboratory it 

 has been found that these agglutinins elaborated in this way are much 

 more stable than those from individuals harboring the organism. Rabbits 

 retained in this laboratory at the present time furnish sera which were 

 active in dilutions up to 1-5,000. Agglutinins in such sera have aided 

 greatly in the diagnosis or differentiation of cultures of Bacterium pullorum. 



Summary. 



From the work carried out at this laboratory during the summer of 1913, 

 the following conclusions appear to be justifiable: — 



1. Although the egg test for the determination of Bacterium pidlorum 

 may yield positive results showing ovarian infection, the elimination is 



