ERADICATION OF PULLORUM DISEASE 1931-32 21 



placed in the house and given access to Plot I for 6 weeks. During this time Plot 

 II received the weekly applications of feces in quantities of one-third bushel. 

 The plots were used alternatel}^ every 6 weeks, the idle plot receiving weekly 

 applications of feces. Group II (12 hens) was added to the flock 6 weeks after 

 Group I was housed. Group I was ex-posed to the contaminated soil for 24 weeks 

 and Group II for 18 weeks. 



The hens in Groups I and II were tested by the tube agglutination test (in 

 dilutions of 1:10 and higher) at weekly intervals for the first 18 weeks and at 

 biweekly intervals for the remaining 6 weeks. The antigen used was identical 

 with that used for investigation No. 3, (Non-infected females may contract 

 pullorum disease through eating fresh eggs laid by infected hens). 



In the second experiment, pullorum disease-free birds were ex-posed to litter 

 contaminated with feces from positive-reacting hens. Two groups of birds 

 were used. Group I contained 15 pullets, 3 hens, and 1 cockerel. Ten of the 

 fifteen pullets and the one cockerel were purchased as day-old chicks from a 

 breeder whose flock had been free from pullorum disease, as determined by the 

 tube agglutination test, for 1 year. They were tested first when 4 weeks of age 

 and at 2-week intervals thereafter. They were 7Y2 months old at the beginning 

 of the experiment. The remainder of Group I (5 pullets and 3 hens) were origi- 

 nally obtained from three breeders whose flocks have been negative to the tube 

 agglutination test for 1 or more years. They had been previously used on an 

 ex-periment unrelated to pullorum disease and had always been negative to the 

 tube agglutination test. Group II (11 hens) was purchased from a breeder whose 

 flock had been negative to the tube agglutination test for 7 years. 



An 8 X 12 foot house with a wire sun porch of the same dimensions was used. 

 Clean shavings were used as litter. Hard grain was fed morning and afternoon 

 in the fitter. The soiled litter was replaced completely four times with clean 

 shavings. The feces were obtained from the same group of positive reacting 

 hens which was the source of supply in the soil contamination ex-periment. 

 The duration of the ex-periment was from December 21, 1931, to April 25, 1932. 

 On six dates the feces were frozen to the dropping boards when collected. The 

 mean average temperatures for the months of December to April, inclusive, 

 were as follows: 



Month Mean Average Temperature 



December 31.6° F. 



January 33.5° 



February 26.3° 



March 31.9° 



April 44.4° 



The coldest month was February, when the minimum morning temperature 

 reached during the month was + 3 ° F. and the maximum morning temperature 

 was 34° F. 



After the birds in Group I were placed in the house, approximately one-quar- 

 ter bushel of feces from the positive-reacting birds was added to the litter. Then 

 feces were added at weekly intervals for 12 weeks. At the end of the twelfth 

 week, Group II was added and the feces were applied to the litter daily, in quan- 

 tities of one to two quarts for 5 weeks. Then the experiment was terminated, 

 due to an outbreak of laryngotracheitis in these birds. 



The birds were tested by the tube agglutination test (in dilutions of 1:10 and 

 higher) at biweekly intervals. The antigen was identical to that used in the 

 s oil contamination experiment. 



