MODIFICATIONS OF THE WASSERMANN REACTION 453 



hemolyzed contains one amboceptor unit, and in performing the test double 

 this amount is used. (See Fig. 115.) 



This titration should always be conducted before the actual tests 

 are set up, as is the rule in conducting the Wassermann reaction. When 

 the titer of the paper is known, it may not be necessary to set up all the 

 tubes of the foregoing series, as a few only are necessary to determine 

 if the same amount of paper as was used in the previous tests will suffice 

 with the new complement and corpuscle suspension at hand. 



All titrations and the main tests may be conducted in a water-bath 

 (37 C.)- With the aid of a good thermometer a satisfactory bath is 

 easily improvised. In fact, I believe that better results are secured 

 in the water-bath than in the incubator. It is possible, therefore, to 

 conduct these reactions in a perfectly satisfactory manner without the 

 aid of an expensive incubator. 



4. Antigen. Acetone-insoluble lipoids (Noguchi) are to be used 

 exclusively if the tests are conducted with active serums. When heated 

 serums are used, any extract may be employed, as in making the Wasser- 

 mann reaction, but the same antigen gives excellent results, and I use it 

 exclusively in conducting the Noguchi reaction with both active and 

 inactivated serums. 



The antigen must be titrated as usual, and its anticomplemen- 

 tary hemolytic and .antigenic properties determined. According 

 to Noguchi, an extract is satisfactory if it is antigenic in 0.02 c.c. 

 of a 1 : 10 dilution, and not anticomplementary or hemolytic in 

 amounts under 0.4 c.c. (1 : 10). In conducting the tests five times 

 the antigenic unit, or 0.1 c.c., is employed; this dose is at least four 

 times smaller than the anticomplementary unit, and is therefore safe 

 and satisfactory. 



The antigen is best preserved in methyl alcohol, as described on 

 p. 422. Dried on paper and properly preserved in sealed tubes in a cold 

 place it will retain its activity for several months, but as a general rule 

 it is best to use fresh emulsions of the alcoholic solution. 



Titration of Antigen. The anticomplementary, hemolytic, and 

 antigenic doses of an extract are determined in the same general manner 

 as was described under the Wassermann reaction. 



1. Anticomplementary Titration. A portion of the stock alcoholic 

 solution of acetone-insoluble lipoids is diluted with 9 parts of saline 

 solution. This is the emulsion that is employed in conducting the 

 Noguchi reaction, and contains 0.3 per cent, of the original lipoidal 

 substances. 



