482 THE TECHNIC OF COMPLEMENT-FIXATION REACTIONS 



desirable than the preceding one, as the results are more difficult to 

 read. 



Complement serum is diluted 1 : 10 and used in dose of 0.1 c.c.; 

 corpuscles are made up in a 10 per cent, suspension and used in dose of 

 0.1 c.c., the amboceptor is titrated with these amounts of complement 

 and corpuscles, and used in dose equal to one and one-half units. Each 

 day, before the main tests are undertaken, the anticomplementary dose 

 of antigen is determined by placing increasing doses of diluted antigen 

 with complement and salt solution in a series of tubes, incubating for an 

 hour, adding one and one-half units of amboceptor and the corpuscles, 

 followed by incubation for another hour. One-half or one-quarter of 

 the anticomplementary dose is used in making the main test. The 

 serums are inactivated and used in three ascending doses, 0.005, 0.01, 

 and 0.02 c.c., equivalent respectively to 0.5, 1, and 2 c.c. of a 1 : 100 

 dilution (0.1 c.c. serum, 9.9 c.c. salt solution). The fourth tube of each 

 series contains the maximum dose of serum without antigen, and is the 

 serum control. The other controls, general technic, and readings of the 

 reaction are the same as those previously described. 



SPECIFICITY OF THE GONOCOCCUS COMPLEMENT-FIXATION TEST 

 Viewed from a practical standpoint, the reaction is highly specific. 

 While complement-fixation experiments with antigens of gonococci and 

 meningococci and their respective immune serums have demonstrated a 

 biologic relationship between these microorganisms, yet practically with 

 human serums an antigen of pure cultures of gonococci will fix com- 

 plement only with the gonococcus antibody (amboceptor). In this 

 technic a specific antigen is employed, and it is, therefore, a true applica- 

 tion of the Bordet-Gengou reaction of complement fixation by specific 

 antigen and specific antibody (amboceptor). Obtained under proper 

 technical conditions, a positive reaction is invariably reliable, and indi- 

 cates the presence of a focus of living gonococci. 



PRACTICAL VALUE OF THE GONOCOCCUS COMPLEMENT-FIXATION TEST 

 From our present knowledge of this reaction, it may be stated : 



1. That the difficulty of isolating and preserving a sufficient number 

 of cultures of true gonococci in order to prepare a satisfactory poly- 

 valent antigen constitutes a weighty drawback to the practical use of 

 the test. 



2. Because the gonococcus antibody, unless complicated by wide- 

 spread gonococcal metastases, is produced in small amount in the 



