THE WASSERMANN REACTION 503 







This is prepared by extracting 1 grm. of heart-muscle with 10 c.c 

 of absolute alcohol for three or four days. To 4 parts of this 

 extract add 5 parts of a 1 per cent, alcoholic solution of 

 cholesterin. 



The solution of antigen must be tested as regards its possible com- 

 plement fixing properties alone and in the presence of a known 

 positive syphilitic serum. This is done by taking a series of dilutions, 

 e.g. from 1 in 2 to 1 in 64, adding to each of these hsemolytic system 

 and complement, and observing (after incubation) the least dilution 

 of antigen which ceases to fix. This having been ascertained, this 

 particular dilution of antigen is now tested with a good known 

 positive syphilitic serum to see that it does fix complement under 

 these conditions. If the antigen does not fulfil these requirements 

 it must be rejected and a fresh one prepared. 



(b) Hcemolytic system. This may be serum haemolytic for ox, 

 sheep, or human red-blood corpuscles, with the homologous cor- 

 puscles (see p. 183). 



The hcemolytic serum or hcemolytic amboceptor is usually prepared 

 in the laboratory by injecting a rabbit with washed red-blood 

 corpuscles (see p. 184), but the horse is occasionally employed. 

 The haemolytic serum should be of high titre and may conveniently 

 be stored in quill-tubing or in small ampoules, which after sealing 

 are heated in a water-bath to 57 C. for an hour on three or four 

 successive days and kept in a dark cool place. This sterilises and 

 destroys the complement, leaving only the haemolytic amboceptor. 



The blood corpuscles. If blood is obtained from the slaughter- 

 house it should be defibrinated at the time of bleeding. If human 

 blood is used (Noguchi's method), the blood from a prick is allowed 

 to drip into citrated saline solution. In either case, the corpuscles 

 are washed twice with 0-85 saline solution and a sufficiency is used 

 to make a 5 per cent, suspension by volume in the saline solution. 

 This is preferably used fresh, but will keep for a day or two in the 

 ice-safe. 



(c) Complement. Fresh guinea-pig serum diluted to 1 in 10 with 

 0-85 per cent, saline is usually employed, though in some methods 

 the complement present in the serum to be tested is made use of. 

 In the method here described the amount of complement present 

 in the fresh guinea-pig's serum is ascertained, the serum being then 

 diluted to double the minimum amount required to produce complete 

 haemolysis. 



Every fresh lot of the hsemolytic amboceptor should be tested 

 both as to its haemolytic activity and also as to the amount of 

 complement necessary to produce complete haemolysis with varying 



