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LABORATORY COURSE IN SERUM STUDY 



LESSON XX 

 WASSERMANN REACTIONS 



II 

 TECHNIQUE OF TESTS 



t 



I. PRELIMINARY COMPLEMENT TITRATION 



ON account of the complement variability of guinea pigs' 

 serum and of the desirability of using a uniform amount of com- 

 plement, a fresh titration of the complement is done on each 

 occasion when Wassermann tests are performed. In order to 

 allow a margin of safety, twice that amount of guinea pigs ' serum 

 is used in the tests which in the preliminary titration gives com- 

 plete laking with 2 units of amboceptor in 15 minutes. 



(The quantities of all the ingredients given here are known as 

 "half Wassermann" quantities; that is, for the sake of economy and 

 convenience half the amount of patients' serum, guinea pig serum, 

 sheep cells, etc., described in the original Wassermann test are used 

 and the total volume is made to 2.5 c.c. instead of 5 c.c. Some workers 

 carry economy farther and use " tenth Wassermann" quantities. 



There are also some workers who instead of redetermining the dose 

 of complement each time, keep the dose of complement constant 

 0.5 c.c. of 10 per cent serum for half Wassermanns and redetermine 

 the amboceptor unit. The net result is not very different, but since the 

 guinea pig is the variable factor it seems more reasonable to vary the 

 amount of guinea pigs' serum.) 



Into each of 7 tubes put 0.5 c.c. of 5 per cent sheep cells, two units 

 of amboceptor and 10 per cent complement (fresh guinea pig serum) in 

 the following amounts: 1 



Bring the volume of all the tubes up to 2.5 c.c. by addition of 



saline solution. 



1 The following is the preferable order of adding the reagents: 



First pipette the complement, second the amboceptor, third the saline solution 



and last the red cells, shaking thf tubes thoroughly while the cells uro being :idded. 



