8 MASS. EXPERIMENT STATION BULLETIN 148. 



From Table 4, it can be seen that of the 619 eggs tested Bacterium 

 pullorw7i was detected in eggs laid by hen No. 10, once during July, egg 

 laid 7-30-13; by hen No. 18, once during July, egg laid 7-26-13; by hen 

 No. 6, three times during the month, eggs laid 7-16-13, 7-17-13 and 

 7-19-13; by hen No. 5, once during month, egg laid 7-30-13; by hen No. 

 2, twice during month, eggs laid 7-26-13 and 7-30-13; by hen No. 52, 

 twice during month, eggs laid 7-21-13 and 7-23-13; by hen No. 13, twice, 

 eggs laid 7-22-13 and 7-26-13; by hen No. 792, three times, eggs laid 

 7-23-13, 7-25-13 and 7-30-13; by hen No. 714, once during month, egg 

 laid 7-27-13. During August from hen No. 8 Bad. pulloruni was isolated 

 from one egg laid 8-18-13; by hen No. 1, once during month, egg laid 

 8-15-13; by hen No. 10, twice, eggs laid 8-12-13 and 8-15-13; by hen No. 

 2096, once during month, egg laid 8-12-13; by hen No. 5, twice, eggs laid 

 8-2-13 and 8-4-13; by hen No. 7, twice, eggs laid 8-4-13 and 8-13-13; 

 by hen No. 13, once, egg laid 8-25-13; by hen No. 792, once, egg laid 8-12- 

 13; by hen No. 714, once, egg laid 8-13-13. During September the or- 

 ganism was isolated from egg of hen No. 48, once, egg laid 9-6-13; by 

 hen No. 714, once, egg laid 9-21-13; by hen No. 464, twice, eggs laid 

 9-13-13 and 9-16-13. 



Of the 16 cultures of Bacterium pullorum isolated from eggs in Jul}'' the 

 yolk material of 13 in sterile bouillon had been retained in bacteriological 

 incubator for more than seventy-two hours. Of the 12 isolated in August, 

 all yolk material in bouillon had been retained in bacteriological incubator 

 more than seventy-two hours. From the 4 isolated in September, the 

 egg material had been in incubator but forty-eight hours. After August 1 

 it was planned to put all eggs in bacteriological incubator prior to testing, 

 and this brought forth egg material which yielded cultures of Bacterium 

 pullorum which had not been detected in July, namely, the infection was 

 detected in hen No. 8, hen No. 1, hen No. 2096 and hen No. 7. By the 

 previous incubation of eggs, for one to three daj^s, the organism had mul- 

 tiplied to such an extent that it was possible to detect the organisms in 

 7 individuals in whom it had not been detected in Jul5^ From egg material 

 incubated in bacteriological incubator at 38° to 39° C. for seventy-two 

 hours or longer it was much easier to detect the organism. Usually it 

 was present in large numbers, and the organism on the agar-slant usually 

 became visible within the first twentj^-four hours' incubation. In general 

 it may be stated that egg testing of these hens' eggs yielded better results 

 after this preliminary incubation of the eggs in bacteriological incubator, 

 and it was found always advisable to wait seventj'^-two hours before con- 

 sidering a sample negative as regards colonies on subsequent agar streaks. 



From what has been determined here, and from the work of Rettger and 

 Jones, it can be clearly seen that diagnosis by egg testing is impractical. 

 In some cases, however, the egg testing has given results with the exami- 

 nation of the first few eggs. According to the work in tliis laboratory, it 

 has been found that if a bird is badly infected persistence in egg testing 

 will usually yield a positive result. Of the 619 eggs tested from hens in 



