128 THE BREEDING OF ANIMALS 



In cases of typhoid fever, the so-called agglutination 

 test was found to be a fairly reliable agent for the diagnosis 

 of this disease. In 1907-8, Ginstead in Denmark applied 

 this test successfully to cows suffering from contagious 

 abortion. Later MacFadyean and Stockman l published 

 the results of a limited number of investigations, report- 

 ing unfavorably upon this method. Later Holth and 

 Wall, 2 after an extensive series of investigations involving 

 hundreds of cows, concluded that the agglutination test 

 was a reliable diagnostic agent but probably subject to 

 larger error than the complement fixation test. 



121. The complement fixation test. 3 Neither the 

 abortin nor the agglutination test has proven entirely 

 satisfactory under all circumstances. The most reliable 

 test now available is the complement fixation test. 4 

 Connaway of the Missouri Experiment Station says, 

 " This test has been found very reliable as a diagnostic 

 method in contagious abortion. The result of the test 

 on some infected herds shows that in old infected herds 

 the per cent of re-acting animals runs from 60 to 90 per 

 cent." This is- a highly complicated and difficult test 

 to make, but will with practical certainty cause a reaction 

 in cows that have been infected. Cows that have aborted 

 may develop an immunity to this disease, and when this 

 has occurred the complement fixation test cannot be 

 used to distinguish between those cows which will abort 



1 MacFadyean and Stockman, "Report of the Departmental 

 Committee to inquire into Epizootic Abortion," Pt. I, and 

 Appendix, London, 1909. 



2 "Berl. Tierartzt Woch.," Bd., pp. 686-688, 1909. 



3 See Surface, Kentucky Exp. Sta. Bui. No. 166; MacNeal 

 and Mumford, Illinois Exp. Sta. Bui. No. 152 ; Russell, Science, 

 N. S., vol. 34, p. 494, 1911 ; Wisconsin Research, Bui. No. 24, 

 1912. 



4 Missouri Experiment Station, Bui. 131, p. 486. 



