34 CONTROL SERIES No. 63 



The birds were placed on experiment in three different groups. Group I 

 consisted of 6 birds which were exposed to infection by three different methods, 

 as shown in Table 11. Birds 1 and 2 received daUy doses, 3 cc, 6 days a week 

 for 8 weeks. At the end of the ninth week, they were placed together. Two 

 squabs, hatched during the fifteenth week, died at 9 days of age. 5. pullorum 

 was not isolated at necropsy. Agglutinins were first observed 4 weeks after the 

 initial exposure. At no time were agglutination reactions observed to be typical 

 or complete in any dilution. 



Table ii — Data Concerning Exposures, Agglutination Titers, and 

 Necropsies for Pigeons in Group I 



Agglutination not complete in any dilution. 



The adult pigeons were killed and necropsied 17 weeks after the first exposure. 

 At this time both birds were negative to the agglutination test and S. pullorum 

 was not isolated. Birds 3 and 4 were inoculated intraperitoneally with 3 daily 

 doses (0.5 cc.) of the suspension. After 1 week, the inoculations were repeated. 

 No agglutinins were detected 4 days after the first exposure, while on the seventh 

 day agglutinins were present. During the second week, clinical manifestations 

 (depression, weakness, ruffled feathers, and inappetance) were observed. At 

 this time the agglutination titer attained its maximum, which was followed by 

 a rapid decline. The birds were placed together in one cage after 9 weeks. At 

 17 weeks, they were killed and necropsy revealed no gross lesions. 5. pullorum 

 was not isolated. Birds 5 and 6 were exposed by instilling 1 drop (0.04 cc.) of the 

 suspension into the left eye. Six daily doses per week were administered for 7 

 weeks. A very slight trace of agglutination was observed in the lower dilutions. 

 The birds were placed together during the sixth week. At 14 weeks, they were 

 killed and necropsied. No gross lesions were observed, and 5. pullorum was not 

 isolated. 



Group II consisted of 12 pigeons, of which 10 were exposed by the same 

 methods employed for Group I, and 2 were held as controls. Two birds were 

 placed in each cage. The same strain as used for the guinea fowl was employed. 

 A suspension of this strain, with a turbidity equal to tube No. 3 of the McFarland 

 nephe lometer, was found pathogenic for 3 pullets. At the end of the exposure 

 periorf, the strain was tested again for its pathogenicity. A loss in pathogenicity 

 was sJightly perceptible. 



Table 12 shows that 4 pigeons (3, 7, 20, and 26) were exposed to the suspen- 

 sion by the oral route, 4 (8, 12, 16, and 31) by intraperitoneal inoculation, and 

 2 (10 and 28 1 by ocular instillation. 



