COMPLEMENT FIXATION IN GONOCOCCUS INFECTIONS 509 



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 two units. Each day, before 

 the main tests are undertaken, the anticomplementary dose of antigen 

 is determined by placing increasing doses of diluted antigen with com- 

 plement and salt solution in a series of tubes, incubating for an hour, 

 adding two units of amboceptor and the corpuscles, followed by in- 

 cubation for another hour. One-half or one-quarter of the anticom- 

 plementary 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 



