4 MASS. EXPERIMENT STATION BULLETIN 148. 



seventy-two hours. In many cases when there was doubt concerning 

 organism, all materials were plated out and colony again streaked from 

 such plates. 



In view of the fact that many inquiries had been received here at this 

 laboratory concerning the egg test for the determination of this organism, 

 it was decided worth while to test all eggs laid by these suspected hens, 

 and also to record what effect the retention of egg prior to testing, and 

 length of time egg material remained in the bacteriological incubator at 

 38° to 39° C, had in facilitating isolation of the organism. 



In tables 1, 2 and 3 are exhibited the data obtained from the egg tests 

 tabulated to show when egg was laid, by which hen laid, and whether the 

 organism was isolated from the hen, a fact designated by a plus sign. It 

 also shows to how long a period of incubation the egg material in bouillon 

 was submitted before being streaked on the agar slants. 



During the period of making the first egg tests all eggs were retained 

 at room temperature until tested, or they were tested on the same day, 

 soon after laying. Later, however, it was found advisable to retain at the 

 temperature of the bacteriological incubator, about 39° C, before insert- 

 ing in sterile bouillon, to afford perhaps a preliminary proliferation of 

 the organism. 



