JOURNAL OF AGRiaram RESEARCH 
DEPARTMENT OF AGRICULTURE 
You. V Washington, D. C., February 7, 1916 No. 19 
AGGLUTINATION TEST AS A MEANS OF STUDYING THE 
PRESENCE OF BACTERIUM ABORTUS IN MILK 
By X,. H. CooeEdge, 
Research Assistant in Bacteriology, Michigan Agricultural Experiment Station 
INTRODUCTION 
In the investigation of the effect on milk of the diseases of the cow, 
with special reference to infectious abortion, it was found desirable to 
examine a large number of samples to determine whether or not Bacte¬ 
rium abortus Bang was being passed with the milk. The cultural and 
animal-inoculation methods were the only ones found available for 
this work. 
The cultural method devised by Nowak 1 takes advantage of the fact 
that newly isolated cultures require an atmosphere partially depleted of 
oxygen. This atmospheric condition is obtained by growing the agar 
streaks from suspected material in a closed jar with Bacillus subtilis , 
having 1 sq. cm. of culture surface to each 15 c. c. of jar capacity. While 
the author has isolated BacL abortus from milk sediment by this 
method, it is too tedious a process to apply to any number of samples. 
Plates are likely to be overgrown with colonies of fast-growing organisms, 
and the method has the further disadvantage of requiring several weeks 
to isolate and identify the cultures. 
Evans 3 succeeded in isolating Bact. abortus from milk by plating on 
ordinary lactose agar to which 10 per cent of sterile blood serum was 
added just before plating. After incubating for four days, the colonies 
which developed were transferred to nutrient broth containing 1 per cent 
glycerin and to tubes of whole milk containing litmus. 
The other method of study, the inoculation of guinea pigs with the 
milk, while more reliable, is far from satisfactory, owing to the fact that it 
takes 8 to 10 weeks for the lesions to develop, and it is probable that the 
organism must be present in large numbers to cause the characteristic 
lesions with the 5 c. c. of milk used for inoculation. 
1 Nowak, Jules. I*e ba&lle de Bang et sa biologie. In Ann. Inst. Pasteur, t. 22, no. 6, p. 541-556, pi. 5-7. 
1908. 
2 Evans, Alice C. Bacillus abortus in market milk. In Jour. Wash. Acad. Sci., v. 5, no. 4, p. 122-125. 
1915- 
Journal of Agricultural Research, 
Dept, of Agriculture, Washington, D. C. 
(871) 
Vol. V. No. 19 
Feb. 7,1916 
Midi.—3 
