CHAPTER XXIII 



THE TECHNIC OF COMPLEMENT-FIXATION REACTIONS 

 THE WASSERMANN REACTION IN SYPHILIS 



Historic. Following Bordet's important discovery of complement 

 fixation no practical applications were made for several years until 

 Neisser and Sachs continued Gengou's studies on protein antigens 

 and amboceptors, and advocated complement fixation as a fine and 

 delicate method of control on the precipitin test in the detection and 

 differentiation of minute traces of proteins, as in the recognition and 

 diagnosis of blood-stains. 



Encouraged by these results, Wassermann used the method in an 

 attempt to discover in the blood-serum, during the course of an infection, 

 the bacterial proteins derived from a microorganism. Practical appli- 

 cation proved, however, that enough of these proteins did not exist free 

 in the blood to give definite complement fixation. 



In 1905 Wassermann and Bruck found that bacterial extracts may 

 be substituted for emulsions of bacteria as antigen in performing the 

 Bordet-Gengou test, and that extracts of diseased organs containing 

 large numbers of bacteria or their products may be employed. Accord- 

 ingly, these observers prepared aqueous extracts of tuberculous lungs 

 and glands and used them as antigens in the study of complement fixa- 

 tion in tuberculosis. Positive reactions were secured with an anti- 

 tuberculous serum and with the serums of persons who had received 

 injections of tuberculin. 



At this time Schaudinn and Hofmann discovered the spirochete of 

 syphilis, a finding that served to focus the attention of the medical world 

 upon this disease. In cooperation with Neisser, who was conducting 

 extensive researches on experimental syphilis in monkeys, Wassermann 

 and Bruck applied the complement-fixation method to the study of 

 these experimental infections, and published a report of their work on 

 May 10, 1906. 



At first monkeys were immunized with aqueous extracts of human 

 chancre, condylomata, syphilitic placenta, etc., and their serums, 

 mixed in vitro with these extracts, were found to give the complement- 

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