506 



THE TECHNIC OF COMPLEMENT-FIXATION REACTIONS 



1 : 10 with the addition of 8 c.c. of normal salt solution, after which the 

 anticomplementary titration is made. 



In this method of preparing antigen the endotoxins constitute the 

 main antigenic principle. Kolmer and. Brown, after an experimental 

 study of the various antigens, found that a simple suspension of gono- 

 cocci in salt solution yielded slightly better results. The various 

 strains are grown for from forty-eight to seventy-two hours, and are 

 then washed off with sterile saline solution, observing particular care 

 not to include portions of the culture-medium. The suspension is 

 then shaken to break up clumps, and heated to 56 C. for an hour. A 

 small amount of preservative is now added, and the antigen stored in 

 1 c.c. ampules. Before using it is diluted 1 : 10 or 1 : 20, and titrated 

 for the anticomplementary dose. 



Alcoholic extracts of gonococci have very little practical value, as 

 alcohol is not satisfactory for extracting the antigenic principles of 

 bacteria. Warden 1 has reported good results with a new lipoid antigen. 



The anticomplementary dose of the antigen should be determined, 

 and one-half or one-quarter this amount should be used in conducting 

 the main test. An antigenic titration may also be conducted with an 

 antigonococcus serum, to determine the antigenic value of the antigen, 

 but in practice it is sufficient to use one-half the anticomplementary 

 dose. This titration should be conducted and the antigen standardized 

 before the main tests are adjusted. 



In the following table the results of an anticomplementary titration 

 of a gonococcus antigen are given, the approximate dose having been 

 ascertained in previous titrations (Fig. 120). 



TABLE 17. ANTICOMPLEMENTARY TITRATION OF A GONOCOCCUS 



ANTIGEN 



1 Jour. Amer. Med. Assoc., 1915, Ixv, 2080; Jour. Lab. and Clin. Med., 1916, i, 333: 



