FITZGERALD AND FRASER 821 



been made in dealing with certain phases of the subject. We wish to give a brief 

 sketch of additional results or uses of this reaction. No attempt has been made to 

 review the voluminous literature bearing upon this phase of agglutination, even were 

 that possible. We have, rather, chosen illustrations for the purpose of showing some 

 of the many and multifarious ways in which the reaction has forwarded the study of 

 bacteriology. 



There is no laboratory method of gauging the therapeutic value of antimeningo- 

 coccus serum comparable in its practical application to the assay of diphtheria or 

 tetanus antitoxin. It has been established that sera having a high agglutination titre 

 against the meningococcus are therapeutically more effective than those with a low 

 titre. In addition, since certain^ types or representative strains from groups I, II, and 

 III are used for the immunization of horses, it is important to determine the degree 

 of polyvalency. A polyvalent antimeningococcus serum is therefore tested to de- 

 termine its agglutination titre against the standard group strains. A polyvalent 

 standard control serum is used for comparison. In a similar manner, polyvalent 

 (mannite fermenters and non-fermenters) antidysentery serum is tested as to its 

 agglutinative titre in addition to its neutralizing value for toxic filtrate from a 

 Shiga strain. 



The antigenic power of typhoid vaccine^ is tested by the agglutination method by 

 estimating the antibody response of rabbits when injected with the vaccine. The 

 standardization of monotypical sera for diagnostic purposes is also gauged by agglu- 

 tination. 



Mention has been made of the value and use of the agglutination test as an aid to 

 the diagnosis of enteric fevers. It is of definite assistance also in the detection of 

 typhoid carriers. The reaction is positive in from two-thirds to three-quarters of 

 those in whom typhoid bacilli persist, and more frequently in recovered than healthy 

 carriers.^ In tularemia,"* in suspected cases of Malta fever and B. abortus infection, an 

 agglutination test is of diagnostic value; similarly, as evidence of infection with 

 Leptospira ictcrohaemorrhagiae.'^ The Weil-Felix^ reaction in suspected typhus fever 

 may be carried out. 



In veterinary medicine the agglutination reaction is widely used for B. abortus 

 infection of cattle. Fitch,' Gwatkin,^ and Schroeder and Cotton' report that all 

 proved carriers of B. abortus show a postive reaction in higher dilution than i/ioo. 

 In bacillary white diarrhea of chicks and pullorum infection, Gwatkin" considers any 



' Wadsworth, A. B.: /. Exper. Med., 33, 107. 1921. 



^ Russell, F. F., Nichols, H. T., and Stimmel, C. O.: Mil. Surgeon, 47, 359. 1920. 



■5 Gay, F. P.: Typhoid Fever, p. 130. Macmillan, 1918. 



'' Francis, E., el al.: Bull. Hyg. Lab., No. 130. 1922. 



5 Wadsworth, A. B., ei. al.: J. A.M. A., 78, 1120. 1922. 



^Weil, E., and Felix, A.: Wien. kUn. Wc/inschr., 29, ^S- 1916. 



7 Fitch, C. P., el al.: J. Am. Vet. M.A., 54, 6S1. 1919. 



sGwatkin, R.: Rep. Out. Vet. Coll. 1923. 



9 Schroeder, E. C, and Cotton, W. E.: /. Am. Vet. M. A., 64, 479. 1924. 



"Gwatkin, R.: op. oil. 1926. 



