PRACTICAL APPLICATIONS OF METHOD 



207 



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. 



Since many human sera normally contain small amounts of antisheep 

 sensitizer, it is the habit of many workers to add the sheep corpuscles, without 

 the sensitizer or amboceptor, and incubate for a half -hour. If, at the end of this 

 time, no hemolysis has occurred either in the front or the back ^ row, then 

 amboceptor may be added. This technique avoids the possible error introduced 

 by an excess of amboceptor, a condition which easily occurs when any large 

 amount is normally present in the serum and in addition to this 2 units are 

 added as in the test described above. 



The above represents the typical "Wassermann 7 ' as at present 

 carried out in most laboratories. It may be carried out just as well 

 and with greater economy of material by using one-half the amounts 

 throughout. It is evident that the performance of the reaction calls 

 for experience of serum technique, and knowledge of such reactions, 

 so that fortuitous irregularities may be intelligently controlled. It is 

 our opinion that the performance of routine Wassermann tests by 

 workers without a thorough knowledge of the fundamental facts of 



