APPLICATION OF COMPLEMENT FIXATION 205 



cases of active tuberculosis in which the diagnosis on clinical and 

 bacteriological grounds is reasonably certain. 



"Acid-Fast Fixation." Of great interest is the fact as shown by 

 Cooke and others that the complement-fixation test affirms the close 

 biological relationship of the acid-fast bacilli. From rabbits immunized 

 with various acid-fast bacilli Cooke obtained sera which reacted inter- 

 changeably with each member of the group employed in the experiment. 

 In certain instances the immune sera reacted somewhat more strongly 

 with their own antigenic organism than with others of the group. Cooke 

 also found that the sera of tuberculous patients react not only with 

 the tubercle bacillus but also with other acid-fast bacteria. Sera from 

 cases of leprosy also contain complement-binding substances which 

 react with antigens made from several members of the acid-fast group, 

 the cases of nodular leprosy giving more striking fixation than those 

 of anesthetic type. According to Cooke, the Wassermann test gives 

 crossed reactions in tuberculosis which are too frequent to be ex- 

 plained by the coincidence of syphilis. 



COMPLEMENT FIXATION IN GONOCOCCUS INFECTIONS 



As with other immune reactions of the animal body, time plays an 

 important part in the production of complement-fixing bodies in gono- 

 coccal infections. Acute gonorrhea is usually diagnosed with ease 

 by bacteriological methods, but it is not until the disease has persisted 

 several weeks that complement-fixing bodies are likely to be demon- 

 strated. The value of complement fixation appears in those cases where 

 simpler bacteriological methods are not adaptable, such as gonorrheal 

 rheumatism and endocarditis, as well as infections of deeper parts of 

 the genital tract, such as the Fallopian tube, Cowper's glands and 

 prostate. The test is also useful in determining the cure of the disease. 



Miiller and Oppenheim in 1906 reported favorable results with the 

 gonococcus complement-fixation test. Bruck and subsequently 

 Meakins had a similar experience, but more recent study indicates 

 that the older methods possess little specificity. The work of Teague 

 and Torrey, Wollstein, Watabiki and Schwartz and McNeil demon- 

 strated the occurrence of numerous immunologically distinct forms of 

 gonococcus and the necessity for using several strains in the antigen. 

 It now appears that from ten to fourteen strains are desirable. 



The production of antigen has been extensively studied. Salt 

 solution extracts appear to be satisfactory. Alcohol extracts have no 

 value, and Wilson believes that a lipoid-free antigen presents an im- 

 provement in titer, stability and freedom from anti-complementary 

 activity. Warden claims good results with an antigen composed of 

 salts of the fats of the gonococci. Thomson, working under the direc- 

 tion of Col. L. W. Harrison, reports excellent results by dissolving 

 the organisms in decinormal sodium hydrate solution and restoring 

 to the neutral point by decinormal hydrochloric acid. In the hands of 

 most workers the sheep-rabbit hemolytic system appears to be satis- 



