THE TECHNIQUE OF SERUM REACTIONS 323 



Modifications of the Wassennann Test. Since the original for- 

 mulation of the Wassermann reaction a great many modifications have 

 been suggested by various workers, some of them being radical changes 

 involving the altering of the hemolytic system ; others, however, merely 

 adding precautions here and there to increase the delicacy of the 

 reaction. The literature on this subject is too voluminous to be com- 

 pletely covered. We indicate, therefore, some of the most important 

 changes from the original that have been found valuable, and give in 

 greater detail the methods as at present in use in our own laboratory. 



Bauer has called attention that human serum contains a certain amount of 

 natural hemolysin for sheep corpuscles. In his original modification, there- 

 fore, he does not use hemolytic rabbit serum as amboceptor. His modification 

 as a whole cannot be accepted for general use because human sera do not 

 contain a uniform amount of hemolysin for sheep cells, and some contain 

 none whatever. However, the presence of natural amboceptor, so-called, in 

 human sera is taken account of by many workers, and it is important to 

 recognize this, since naturally it adds to the amboceptor added with sensitized 

 cells and leads to a lack of uniformity in the dosage of amboceptor in 

 individual tubes if included. 



Noguchi has worked out a test in which the difficulties presented by the 

 presence of normal sheep amboceptor are eliminated, in that he uses an 

 antihuman hemolytic serum and human cells as the hemolytic system. It 

 enables him also to use the cells of the patient or of any other human being, 

 thus eliminating the necessity of getting fresh sheep cells. His tes'ts are 

 set up as follows: 



Tube 1. 1 drop patient's serum -{- complement (0.1 c.c. of 40 per cent guinea-pig 



serum) -|- antigen. 



Tube 2. 1 drop patient's serum -|- complement. (No antigen.) 



Tube 3. 1 drop known syphilitic serum -|- complement -|- antigen. 



Tube 4. 1 drop known syphilitic serum -|- complement. (No antigen.) 



Tube 5. 1 drop known normal serum -(- complement -f- antigen. 



Tube 6. 1 drop known normal serum -j- complement. (No antigen.) 



Tube 7. Complement alone (for hemolytic system control). 



To each tube then add 1.0 c.c. of the one per cent emulsion of human 

 corpuscles. Shake mixtures thoroughly and incubate or place in water bath 

 at 38-40 C. for one hour. Then add to each tube 2 units of antihuman 

 amboceptor (serum of rabbit immunized with human cells) and replace in 

 water bath for one hour. At the end of this time in a positive test there 

 will be no hemolysis in Tubes 1 and 3 while all the other tubes will show 

 hemolys'is. 



