324 



INFECTION AND IMMUNITY 



The method of Noguchi is still used by a few investigators, but is 

 not at present in common use, though we have no doubt that if sys- 

 tematically followed it would develop as quite satisfactory. 



The tests are done in our own laboratory with the original sheep 

 cell antisheep serum hemolytic system. They are done in half 

 quantities, titrations being made with 0.5 c.c. of a 5 per cent emulsion 

 of washed sheep cells. Each day the complement (fresh guinea-pig 

 diluted 1:10) is titrated with cells sensitized with 2 units of stock 

 amboceptor. Fresh amboceptors are titrated from time to time so 

 that a reasonable constancy is obtained. The hemolytic system is kept 

 as constant as possible from day to day. The unit (minimal hemolytic 

 amount) of a new specimen of amboceptor is determined by titrating 



SCHEME FOR WASSERMANN TEST. 



ADAPTED TO ORIGINAL WASSERMANN SYSTEM AFTER SCHEME OF NOGUCHI. 



O =test tube. 



Place in water bath at 40 C. for one hour, then add to all tubes red blood cells 

 and amboceptor. These are previously mixed so that 2 c.c. contains the equivalents 

 of 1 c.c. of a 5 per cent emulsion of sheep corpuscles and 2 units of amboceptor. 

 Again expose to 40 C. If the serum tested is positive, tubes 1 and 3 should show 

 no hemolysis, all the other tubes showing complete hemolysis in one hour. 



