20 MASS. EXPERIMENT STATION BULLETIN 148. 



irregular and very often covers a long period of time before the organism 

 is detected; therefore it is impractical for rapid diagnosis. 



2. Preliminary incubation of the eggs in a bacteriological incubator 

 at 38° to 39° C. prior to testing aids in the determination of the organism. 



3. The macroscopic agglutination test as carried out in this laboratory, 

 has proven a good laboratory method for the detection of adult hens har- 

 boring, or which have harbored, Bacterium pnllorum. 



4. Our work substantiates that of Jones, in that it is possible to cause a 

 local infection of the ovarian tissue by intravenous injections of pure 

 cultures of Bacterium pullorum. 



5. The agglutinin is very stable, withstanding temperatures of 60° C. 

 and over for one-half hour. If properly preserved, it will yield results 

 after two weeks. Agglutinins have been found from infected hens which 

 reacted positively in dilutions from 1-100 to 1-5,000. 



6. Polyvalent test fluids yield more uniform results than monovalent 

 fluids, although in birds of marked infection monovalent test fluids gave 

 very good results. Test fluids if properly preserved on ice will keep in a 

 verj' active state for more than two months. 



7. Rabbits react to injections with pure cultures of Bacterium pullorum, 

 but by careful immunization yield very active agglutinins and also bacte- 

 riolytic sera. Agglutinins produced by immunizing rabbits are much more 

 stable than those from hens harboring the organism. 



8. A striking pathological condition found in the ovaries of all birds 

 was the exhibition of lobulated and retention cysts which varied greatly 

 in size. From these, it was usually easy to isolate B. pullorum. 



Acknowledgment. — Thanks are due my sister, Ethel G. Gage, for 

 careful work in connection with calculation and rearrangement of the 

 scientific data from our card-indexing system. 



