EXPERIMENT STATION REPORTS. 191 



tion ill cattle and swine, there are certain phases of the technic of the 

 test which need improving. 



From tliese studies during tlie past year has evolved a paper. "The 

 anti-complementary jji'operty of fresh bovine serum," which has been 

 snbmitted to and accepted for pnblication in the Journal of Infectious 

 Diseases. 



Additional studies are reported here as follows: 



A Serological Study of Several Strains of Bact. ahnrtits (Bang). 



AVlien a certain microbe is found to be tlie etiological factor in a dis- 

 ease process, it is necessary that a detailed study be made of a number 

 of strains of tlie microbe in cpiestion in order to determine if there exist 

 ditfei'ent antigenic grou])s or sub-groups, and their possible relation to 

 eacli other. Tlie detection of antigenic difference in dift'erent strains of 

 an organism serves a two-fold jturpose: namely, further to aid in the 

 diagnosis of the disease and the selection of strains for immunological 

 purposes. 



In grou]tiiig Buct. nicUtrnfiiii Fusier and Meyer (1) included several 

 strains of Barf, (thortux in the study. Their data show that Bact. 

 (ihnrtufi falls into one grou}), namely Group I of the melitensis classi- 

 fication. 



This paper represents an attempt to detect possible serological dif- 

 ferences of several strains of Bact. abortus and to place them in groups 

 or sub-groups accordingly. 



Method of ^tudy. 



A number of cultures of Bac\t. abortus which were collected from 

 different parts of this country and Europe should serve as a fair repre- 

 sentative of all strains now in existence. From these strains antigens 

 were prepared for the agglutination test and employed against blood 

 sera from aborting animals located in dift'erent parts of this country. 

 By proceeding with the study in this manner instead of employing the 

 usual scheme for determining serological ditterences in strains of an 

 organism, it seems reasoiuible to believe that the particular group of 

 organism infecting animals in dift'erent parts of the country might also 

 be found. 



The histories of the various strains of Bact. abortus used in this study 

 ap})ear in Taible 1. They are practically the same strains as were used 

 in the pathogenic studies (2). The groups of Bact. inelitensis were in- 

 cluded for the ])urpose of determining their serological relationship to 

 infectious aliortion. 



The source and origin of the various samples of blood sera are as 

 follows : 



Number 1. Collected froin three-year-old cow in Experiment Station 

 herd. No history of abortion infection. 



Nuni;ber 2. Collected by I'rofessor I). H. Jones, Ontario Agricultural 

 College, Gueli>h, Ontario; four-year-old cow, aborted first and second 

 calves from natural infection. 



Number :>. Collected by Dr. Beach, University of California, abortion 

 histoiy not given. 



