1919.] rUBLIC DOCUMENT — No. 31. 55a 



who had stock tested in 1917 or 1918 are experiencing but 

 little trouble in securing sufficient eggs from healthy birds to 

 meet their requirements for hatching the present season. 



With the return of either Dr. Gage or Dr. Lentz to the 

 department, it is expected that the fowl testing will be resumed. 



Bacterium Pullorum Studies. 

 In an earlier report the following studies relative to B. 

 puUorum by Dr. Gage were outlined: — 



1. Bacterium pullorum infection. 



2. A comparison of the antibodies of B. pullorum with those of the 

 B. coli-B. iyphi-B. dysentera' group of agglutinins. 



3. The toxicity of B. pulloruvi products. 



These several studies were incomplete in February, 1918, 

 when Dr. Gage left the department for service in the army. 

 The data have been preserved, and the work will be completed 

 and details published upon his return. It is to be hoped that 

 the completed projects may throw some light upon the manner 

 in which bacillary white diarrhea is spread among chicks and 

 adult birds, and possibly give us a simpler and shorter method 

 for making the blood test without a sacrifice of the accuracy 

 which is characteristic of the present complicated method. 



Hog Cholera Investigations. 



The studies now being made by the writer relative to the 

 prevention of hog cholera by the use of anti-hog cholera 

 serum, and the endurance of the acquired immunity to the 

 disease possessed by pigs born of mothers that are either 

 naturally immune or have been made so b}^ the simultaneous 

 treatment with serum and virus, have been continued through- 

 out the year, use having been made of a herd of from 75 to 

 150 pigs that are fed largely upon raw garbage for purposes 

 of experimentation. 



In carrying on these investigations several difficulties have 

 been encountered that have interfered with the work to a 

 greater or less extent. The most important of these has been 

 the securing of a suitable supply of serum and virus for the 



