36 CONTROL SERIES No. 63 



intervals. Dilutions ranging from 1:10 to 1:160 were employed. In order to 

 prevent the hens from injuring the squabs, the latter, at about 3 weeks of age, 

 were removed from the house with their parents and returned when able to fly. 

 The duration of the period away from the flock was approximately 3 weeks. 

 A few birds were temporarily removed for treatment of injuries. 



The 5 pigeons and their progeny hatched 30 squabs. Eight squabs (3 to 34 

 days of age) died during the course of the experiment. Two squabs were unfit 

 for examination and the remaining six were necropsied. 5. pidlortim was not 

 isolated. The duration of the experiment was approximately 15 months. All 

 birds remained negative to the agglutination test. 5. pvllorum was not isolated 

 from those killed and necropsied. Four pigeons (12, 13, 42, and 43) which had 

 been in contact with the infected chickens for 462, 376, 45, and 45 days respec- 

 tively, were not killed and are not included in the following table, which shows 

 the number of davs the birds were in contact with the infected chickens. 



Sparrow 



For this experiment, 66 sparrows {Passer domesticus) were caught in the vicin- 

 ity of the laboratory. They were confined in metal cages and given scratch 

 grain, grit, and water. All birds were tested by the tube agglutination test prior 

 to the period of exposure. In bleeding the birds, difficulty was encountered in 

 obtaining a sufficient amount of blood to test the sera in the lower dilutions. 

 Whenever possible, dilutions of 1 :25, 1 :50, and 1 :100 were employed. No reactors 

 or naturally infected birds were detected among these 66 sparrows. 



Six methods of exposure were employed. Forty-two birds were divided into 

 groups, according to the method of ex-posure, as follows: Group I, inoculated 

 intraperitoneally; Group II, inoculated subcutaneously ; Group III, fed with a 

 pipette; Group IV, instillation into the eye; Group V, contamination of feed; 

 and Group VI, contamination of litter. A saline suspension of 5. pullorum with 

 a turbidity equal to tube No. 3 of the McFarland nephelometer was prepared 

 from a 24-hour agar slant and used as the infective agent. The birds were tested 

 by the tube agglutination method in dilutions of 1:25, 1:50, and 1:100. In some 

 cases subsequent tests were made at frequent intervals and in a few instances 

 in higher dilutions. All birds in this experiment were necropsied. Birds in the 

 supply cages served as controls. 



Clinical manifestations were detected in birds among each group. Depression, 

 ruffled feathers, inappetence and dyspnoea were observed. Since the sparrows 

 were frightened very easily, it was difficult to obtain the complete clinical mani- 

 festations. Symptoms were observed for a period of 4 days in some cases. No 

 ovarian lesions were found. It is possible that due to the size of the organ, 

 gross lesions were not perceptible. Unfortunately the determination of agglutinin 

 production was not satisfactory because difficulty was experienced in collecting 

 the blood, and death frequently occurred within a short time after exposure. 



