CITRON'S MODIFICATION OF WASSERMANN REACTION 185 



c. Tube i shows complete absence of hemolysis and 



2 shows complete hemolysis: +-f- 



d. Tube i shows partial hemolysis and 



2 shows complete hemolysis: + 



e. Tube i shows doubtful binding and 



Weakly 

 positive. 



2 shows complete hemolysis: ' 

 /. Tubes i and 2 show complete hemolysis: ., Negative. 

 When a series of tests is to be performed, it is advisable to include in the 

 reaction three sera previously tested, one strongly positive, another weakly 

 positive and a third, negative, so that the new results can be more readily 

 compared. In this way absolutely reliable and constant values will be 

 obtained. 



Every new antigen should be tested for four weeks before its practical value can be 

 assured. During this month, all the tests should be done with both the old and new ex- 

 tract and only if their results are identical should the new extract be employed. The 

 author is in the habit of mixing the new antigen with the old one after the former has 

 proved itself efficient. Occasionally the new antigen varies in strength from the old 

 one. In such a case, if stronger, it must be used in a smaller dose (0.18 and 0.9) or if 

 weaker, must be used in larger dose (0.22 and o.n). Shaking the antigen should be 

 strictly guarded against. 



In order to control the effect of normal liver substances contained in 

 the antigen an extract is prepared from normal fetal liver (normal antigen). 

 When sera from cases of clinically evident lues are to be examined, it is 

 unnecessary to have control tests with the normal fetal extract as antigen. 

 On the other hand, such control tests are absolutely necessary in impor- 

 tant differential diagnosis as between lues and carcinoma, and in all 

 diseases of the nervous system. Here a positive reaction can only then 

 be taken as evidence of syphilis if the complement fixation test is positive 

 with the syphilitic antigen and negative with the normal liver antigen. 

 If on the other hand it be positive with both extracts, it does not speak for 

 a luetic infection. 



A strongly positive Wassermann reaction indicates the presence of a 

 luetic infection. A weakly positive result can be similarly interpreted 

 if the serum control tube (Tube No. 3) is completely hemolyzed. If, 

 however, the latter still shows some non-hemolyzed red blood cells, the + 

 reaction must be considered as =*= or a reaction of indefinite nature. 

 Only exceptionally are such doubtful reactions found in perfectly healthy 

 individuals, although they are more often encountered in different in- 

 fectious diseases (typhoid, measles, scarlet fever) and tumors. A positive 

 diagnosis of lues should never be made upon a =*= reaction. On the 

 other hand if there is a history of lues, or clinical evidences of its existence, 

 a =1= reaction is to be interpreted as + and should warrant further specific 

 therapy. As an end result of specific therapy a =*= reaction is not sufficient. 



