256 MEDICAL BACTERIOLOGY 



which persisted in the blood undiminished by treatment and for long periods 

 after cessation of treatment, after the disappearance of all signs and symptoms 

 of the disease, persons apparently in good health and looked upon as having 

 recovered. I have never discovered such a case; if they do occur they are very 

 few. Every patient I have seen who. persistently gave a positive Wassermann 

 in spite of active treatment has had active syphilis, usually of the central 

 nervous system, and with one exception all have died within 3 years after com- 

 ing under observation. 



COMPLEMENT FIXATION TESTS IN THE DIAGNOSIS OF INFECTIOUS DISEASES 



OTHER THAN SYPHILIS 



In most, if not all, infectious diseases amboceptors capable of fixing comple- 

 ment in the presence of the offending organism are present in the blood serum. 

 In most diseases other than syphilis the amboceptors are not so regularly or con- 

 stantly present in sufficient amount to be demonstrable by a technique less sen- 

 sitive than will elicit pseudopositive reactions, hence complement fixation tests 

 in most diseases are not so valuable as other tests in establishing the nature of 

 the infection. Probably future discoveries will greatly extend the field of use- 

 fulness of complement fixation tests. 



Complement fixation tests may also be employed to determine the identity 

 of an unknown antigen. No matter for what purpose this method of investi- 

 gation is used, the principle is the same, the inherent non-specific properties of 

 the substances entering into the test are the same, the danger of errors and the 

 methods of precluding them are the same and consequently the technique should 

 be the same. 



Next to syphilis the complement fixation test is most frequently used in the 

 diagnosis of gonococcus infections; not the acute suppurative infections of the 

 eye, urethra or vagina, but in those cases where the heart, the Fallopian tubes, 

 ovaries, testicles, seminal vesicles or the articulations are involved sometime 

 after the subsidence of disease at the atrium of infection. In 'the absence of 

 these complications or sequelae the test is also made at times to determine 

 whether or not the body is free of gonococci after the subsidence of gonorrhea 

 and the disappearance of gonococci. The test has a distinct value, a positive 

 reaction obtained 3 months after apparent recovery or during the course of an 

 arthritis or endocarditis practically always indicating persistent infection, but 

 it does not have 'so great a value as the Wassermann has in the diagnosis of 

 syphilis, because a much larger number of persons infected with the gonococcus 

 give a negative reaction. 



In making a complement fixation test for gonococcus infection the technique 

 is exactly the same as the Wassermann except, of course, gonococcus antigen 

 not syphilitic antigen is used and the gonococcus antigen must be titrated im- 

 mediately before each test. 



Antigen for gonococcus complement fixation tests is made by culturing the 

 gonococcus on Wertheim's or other appropriate media at 37C. for i or 2 days, 

 washing the growth off with normal salt solution, shaking the salt solution 



