TECHNIQUE OF WASSERMANN REACTION 173 



6. Killed tubercle bacilli -f- guinea-pig immune serum + guinea-pig complement + 

 rabbit's hemolysiu + goat's blood or sheep's blood. 



7. Whooping cough bacilli + patient's serum + guinea-pig's complement -f rabbit 

 hemolysin -f goat's or sheep's blood. 



8. Meningococci -+- human convalescent's serum + human complement + guinea- 

 pig's hemolysin + rabbit's blood (Cohen). 



Foix and Mallein examined twelve cases of scarlet fever and obtained a 

 positive result in ten cases when the streptococcus grown from a scarlet 

 angina was used as antigen. Antibodies were found on the fourth day. 

 These results were confirmed by Schleissner. 



II. Wassermann-Bruck's Modification. 



a. Antigen. Instead of entire bacteria, only bacterial extracts are 

 employed. These are made in the same manner as the artificial aggressins. 



For typhoid bacteria Leuchs advises that the bacterial suspension should first be 

 killed for twenty-four hours at 60 C. and then shaken for two days. In tuberculosis 

 good results are obtained by using Koch's preparation of old and new tuberculin. 



The bacterial extracts when very fresh contain a great .deal of precipi- 

 tinogen which diminishes in several days and finally disappears. Its 

 presence does not disturb complement fixation. The bacterial extracts 

 must be well protected from light and kept in the cold. 



After the extract has stood for some time a sediment forms; under no circumstance 

 should this be disturbed or shaken. The required amount of antigen should be care- 

 fully poured off, and not pipetted off. Just as soon as the required amount is obtained, 

 the extract should be returned to the ice-box. 



b. The antiserum is inactivated by heating, even if the serum is old and 

 contains very little or no complement. 



Old, non-heated serum is often antihemolytic. Temperatures over 60 C. should 

 be strictly guarded against as the amboceptors may be destroyed. Heating for a 

 period, longer than one-half hour may make a serum anticomplementary, i.e., bind 

 complement. Sera containing bile at times prevent hemolysis. Chylous sera obtained 

 during the period of digestion and milky sera seen in nursing women usually do not 

 'interfere with the complement fixation reaction. 



Exudates, transudates, and spinal fluids are treated like sera. Exu- 

 dates very rich in albumin frequently coagulate during mactivation. 

 In order to avoid this, it is advisable to dilute such fluids with physio- 

 logical salt solution. Occasionally exudates tend to fix complements 

 spontaneously. 



