WASSERMANN REACTION J33 



1. We add to a small test-tube 



(a) '05 c.c. of serum from the suspected case, heated for half 

 an hour at 55 C. to destroy the human complement, and '5 c.c. 

 of '8 per cent, salt solution ; 



(6) 'I c.c. of an alcoholic extract of guinea- pig's or ox's liver 

 (this can be prepared by extracting finely minced liver with four 

 volumes of alcohol for 3 to 4 days and then filtering) ; 



(c) A certain amount of guinea-pig's serum, usually ! c.c., to 

 act as complement. 



As controls we use (a) a tube containing complement and 

 serum in salt solution and (b) another tube containing comple- 

 ment and extract in salt solution. 



The mixtures are then placed in the incubator for one and a 

 half hours, to allow fixation of complement to occur. 



2. We then add to each of the tubes 1 c.c. of a 5 per cent, 

 suspension of sensitised corpuscles (usually sheep's or ox's), i.e., 

 corpuscles to which there has been added a sufficient quantity of 

 immune serum to produce lysis on the addition of complement. 



The mixtures are then placed in the incubator for another hour. 

 If lysis of the corpuscles does not occur in the first tube, but 

 occurs in the controls, the complement has been fixed in the 

 first stage by the mixture of serum and liver extract. This is 

 a positive result, and indicates the presence of syphilis. If the 

 corpuscles undergo lysis, all the complement has not been 

 fixed the result is negative. When the amount of serum to be 

 tested is small, the amounts given may all be proportionately 

 reduced. 



Quantitative Methods. Such is the test as usually performed, 

 and in this form it usually gives satisfactory results. It is to be 

 noted however, on the one hand, that the liver extract alone may 

 fit a certain amount of complement, rarely more than three doses, 

 and, on the other hand, that the heemolytic value of fresh serum 

 varies, i.e., the amount of complement is not always indicated 

 by the volume of serum. It is accordingly better, and in a 

 laboratory this can be readily done, to estimate the hsemolytic 

 dose of the guinea-pig's serum, and to prepare a series of tubes, 

 each containing the same amounts of serum and of liver extract, 

 but with a different number of doses of complement in each tube. 

 In this way we can find the number of doses of complement 

 deviated in each case. As controls, the effect of the extract 

 alone and of the serum alone can be tested at the same time. 

 With the amounts of extract and serum mentioned, a positive 

 result indicating the presence of syphilis may be accepted when 

 five or more doses of complement are deviated in addition to the 



