50 CONTROL SERIES No. 63 



The birds in Lot A were given 2 series of 6 consecutive daily doses. These 

 2 series of doses were separated by 1 day. Table 20 shows that no agglutinins 

 were observed 4 days after the first exposure. On the seventh day, agglutinins 

 were present in both birds and persisted until the time the birds were necropsied. 

 One bird manifested a marked inflammatory reaction of the structures within the 

 periorbita of the infected eye. Bird No.- 1 was killed and necropsied at the end 

 of 8 weeks. Peritonitis and ovarian lesions were observed. 5. pullorum was 

 isolated. Bird No. 2 appeared listless and anemic 10 weeks after the first inocu- 

 lation. At this time an inspissated egg was expelled. Death occurred on April 

 17. Necropsy revealed an enlarged, friable, and mottled liver with a rupture of 

 the right lobe. Pericarditis and peritonitis were also observed and 5. pullorum- 

 was isolated. 



Birds in Lot B were given two series of 3 consecutive daily doses a week 

 apart. Table 20 shows that agglutinins were observed at the same time as in 

 Lot A, but in a lesser amount. Bird No. 3 manifested an inflammatory reaction 

 in the periorbital structures with an extensive involvement of the inferior palpe- 

 bra. Bird No. 3 was killed and necropsied on March 25. Necropsy findings re- 

 vealed an enlarged, hemorrhagic liver, and two ovules, one being hemorrhagic 

 and the other misshapen. Bird No. 4 was killed and necropsied May 14. Ex- 

 tensive peritonitis and misshapen, inspissated ova were observed. S. pullorum 

 was isolated from both birds. 



Group II consisted of 16 pullorum disease-free Rhode Island Red cockerels 

 (approximately 2J^ months of age), divided into four lots. Factors such as size 

 and general condition of the birds were considered in selecting the birds for the 

 different lots. AU birds were placed in individual cages. The infective agent 

 employed consisted of a saline suspension prepared from a 24-hour agar growth 

 and adjusted to a turbidity ranging between 1.5 and 1.75 on the McFarland 

 nephelometer scale. The organism used was a strain recently isolated from a 

 chick (2Y2 months of age). Birds in Lots A, C, and D were exposed to infection 

 through the ocular route. Birds in Lot B received the infective material per orem. 

 The first dose for all lots was given on August 10. The size of the daily dose was 

 practically the same for all birds (0.03 cc). All birds were tested by the tube 

 agglutination method at approximately weekly intervals in dilutions of 1:10 and 

 higher, sufficient to determine the titer. The birds were killed and necropsied 

 approximately 10 weeks after the first exposure. The following tissues were 

 placed on culture medium: pericardial fluid, liver, and spleen from all birds 

 and testicles, heart, and kidney from some birds. The S. pullorum strains isolated 

 were tested for colonial, tinctorial, biochemical, and agglutinable characteristics. 



Lot A consisted of 5 birds which received 6 consecutive daily doses. Clinical 

 manifestations, such as increased lacrimation and infiltration of the structures 

 in the periorbita, were observed approximately 2 weeks after the first ex-posure. 

 These gross pathological changes disappeared after 4 weeks. Table 21 shows 

 that agglutinins were present 7 days after the first ex-posure. All birds developed 

 a serum titer of 1:640 or higher during the period of observation. Two birds 

 (Nos. 194 and 225) revealed lesions. In bird 194 a pericarditis, abscesses in the 

 heart muscle, enlarged spleen, and peritonitis were observed. In bird 225 the 

 changes were confined to the heart and pericardial sac. 5. pullorum was isolated 

 from birds 194 and 224. 



Lot B consisted of 5 birds which received 6 consecutive daily doses. Each 

 of the individual doses was diluted with 1 cc. of sterile saline in order to facilitate 

 the administration per orem. The suspension was administered by inserting a 

 1 cc. pipette into the esophagus. No clinical manifestations were observed in 

 these birds. Table 21 shows that agglutinins were detected in bird 188, 10 days 

 after the first exposure. Bird 216 possessed agglutinins 17 days after the first 



