CHAPTER XIV. 



THE TECHNIQUE or COMPLEMENT FIXATION. 



Original method of Bordet-Gengou. Wassermann-Bruck's modification. Technique 

 of serum diagnosis for syphilis. Echinococcus disease. Serum diagnosis of other dis- 

 eases, epidemic meningitis, tuberculosis, gonococcus infections, typhoid fever. Differen- 

 tiation of proteids according to Neisser -Sachs. 



I. The Original Method of Bordet-Gengou. 



a. The antigen consists of bacteria grown upon agar for twenty-four 

 hours and then suspended in physiological salt solution to make a rather 

 concentrated emulsion. 



For typhoid bacteria Bordet and Gengou take 5 c.cm. of salt solution to each cul- 

 ture of bacteria. 



For tubercle bacilli 80 mg. of the bacteria are suspended in i c.cm. of salt solution. 



b. The serum containing the antibody is heated for one-half hour at 

 56 C. to destroy the complement. 



c. As complement, the fresh serum of a normal animal or human being 

 is used. - r 



d. The hemolysin consists of the inactivated serum of a rabbit that 

 has been immunized against sheep's or goat's erythrocytes, or the serum 

 of a guinea-pig injected with rabbit's red blood cells. 



e. The respective red blood corpuscles are washed, to free them of 

 their complement containing serum. 



A definite amount of bacterial suspension is mixed with varying amounts of in- 

 activated immune serum and a proportional amount of complement is added. These 

 three ingredients are mixed and allowed to remain at room temperature for four to 

 five hours. During this time the complement is fixed if the antigen and antibody are 

 of a homologous nature. In order to see whether this union has taken place or not, 

 hemolysin and erythrocytes are added in a mixture thus prepared: 2 c.cm. of inactivated 

 hemolysin + twenty drops of washed blood cells are mixed and allowed to remain to- 

 gether for about fifteen minutes so that the erythrocytes are sensitized, i.e., united with 

 the hemolytic amboceptor. Of this mixture each tube receives o.i to 0.2 c.cm. If 

 the complement has not become fixed, hemolysis occurs in several minutes. If the 

 complement has become fixed, hemolysis does not occur; since, however, the hemolysin 

 also contains hemagglutinin, the erythrocytes are agglutinated and sink to the bottom 

 of the tubes; 



As control tests, Bordet and Gengou considered the following very necessary: 

 i. Bacterial suspension + inactivated normal serum (instead of immune serum) 



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