22 N. H. Age. Experiment Station- [Bulletin 256 



losses as high as 60 per cent of all chicks hatched. This had dropped 

 to around eight per cent in a year or two after testing was underway. 

 In the last three years the infection in the thousands of birds tested 

 lias fallen from approximately three per cent to less than one-half of 

 one per cent. 



In the past season 150,416 birds in 164 flocks were tested. What was 

 thought to be the "peak" in this work was reached in the years from 

 1923 to 1925 when 40,000 birds were tested annually. The statement 

 was made at the time that it seemed probable ''that from now on ap- 

 proximately 25,000 to 30.000 birds will be tested annually. " 



The prophecy was entirely wrong. Seventy thousand birds were 

 tested in 1927, practically 80,000 the next year, virtually 125,000 in 

 1929, and 150,000 in 1930*.- Four thousand birds were tested when the 

 work began in 1918. 



Over 72.000 birds comprising 62 flocks are now on the accredited 

 list. The figures in 1928 were 54 flocks and 36,330 birds. The flocks 

 then averaged 675 birds apiece; now the average is approximately 

 1,175. 



During the past season only 18 per cent of the flocks were found in- 

 fected as compared to 27 per cent the previous season. The majority 

 of these were flocks tested for the first time. One hundred per cent of 

 the birds in 143 flocks were tested and 119 of these passed one or more 

 clean tests. No reactors were found in 15 flocks in which only part of 

 each flock was tested. Eight new flocks were added to the accredited 

 list after having passed the second 100-per-cent clean test. {Miscel- 

 him ous Income) 



Rapid Eradication of Pullorum Disease. The most rapid way to 

 eradicate pullorum disease from a poultry flock is to save only the birds 

 which test absolutely negative to the "rapid serum" method of agglu- 

 tination testing, according to investigations made by C. A. Bottorff. 

 "While this method may reduce the size of a flock 25 to 30 per cent, 

 one would still have enough breeding stock to build the flock to its 

 original size the following season. 



In this work a flock of 769 birds with 13 original reactors was tested 

 at monthly intervals until two clean tests were obtained the third and 

 fourth months. To prove the success of the method a retest was made 

 at the end of 10 months and another at the end of 16 months, the flock 

 ranking 100 per cent clean each time. 



In none of the tests were birds saved that showed the slightest trace 

 of an agglutination. 



The flock was reduced to 592 birds following the first retest, with 

 seven of those removed showing a strong reaction. The second retest 

 cut the flock to 561 birds. Only two definite reactors were included 

 among the birds removed and no birds following the third and fourth 

 retests which were both negative. All tests were checked by the stand- 

 ard-tube method. {Miscellaneous Income) 



How- Pullorum Disease May Spread. Pullorum disease was shown 

 in an experiment conducted by C. A. Bottorff to have spread rapidly 

 from a group of infected birds to clean birds that ranged with them. 



After the two groups had been together for one month the infection 

 had spread to one pei- cent of the clean group; by two and one-half 



