WASSERMANN-BRUCK'S MODIFICATION. 157 



5. Typhoid bacilli + human convalescent serum + human complement + guinea-pig 

 hemolysin+ rabbit's blood. 



6. Killed tubercle bacilli 4- guinea-pig immune serum + guinea-pig complement + 

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



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

 hemolysin + goat's or sheep's blood. 



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

 hemolysin + rabbit's blood (Cohen). 



In addition Widal and Lesourd on examination of sixty-one typhoid 

 cases found fifty-eight with a positive reaction. Foix and Mallein examined 

 twelve cases of scarlet 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-B ruck'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 precipitino- 

 gen 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 carefully 

 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 comple- 

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

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

 the normal. 



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



c. Complement is obtained by killing a guinea-pig and using its serum 

 while fresh. The serum preserved in "Frigo" is, according to Sterns, not 

 reliable. 



d. Hemolysin is represented by the inactivated serum of a rabbit that 

 has been immunized against sheep's red blood cells. 



e. The twice washed sheep's red blood cells are used as erythrocytes. 



