290 Wassermann Reaction for Diagnosis of Syphilis 



The " set-up" for the titration of antigen is fairly simple. A 

 series of tubes is prepared and divided into two groups. Into each 

 tube in each group is placed i unit of complement. Each tube of 

 one group receives the addition of 0.2 cc. of the normal serum; each 

 tube of the other group, 0.2 cc. of the known syphilitic serum. All 

 the tubes now receive additions of antigen, so that one tube of each 

 group contains the same quantity. The quantity of antigen not 

 being known, it is only through the experience of others that we can 

 guess where to start. An idea can be formed through study of the 

 tabulation on page 289. 



From this we find that the unit of antigen is 0.09 cc., the 

 largest quantity of the antigen that can be added without prevent- 

 ing hemolysis when the normal serum is used is probably 0.18 cc. 

 At the same time 0.09 cc. is the smallest quantity that can be added, 

 when the syphilitic serum is used, to prevent it. In this case the 

 dose exactly fulfils Kaplan's requirement that "The unit dose of 

 antigen must completely inhibit hemolysis . . . of a known luetic 

 serum, provided double the dose does not interfere with the 

 complete hemolysis of cells using a known normal serum and 

 complement." 



We have now accomplished the titration of all five of the factors 

 involved in making the Wassermann reaction, but we have done 

 more, we have really done the test, and have seen positive and 

 negative results, for in titrating the antigen we have developed the 

 reaction by which we can confirm the diagnosis of syphilis in the 

 case from whom the syphilitic serum was obtained, and have failed 

 to develop it with the known normal serum. 



However, in order that those who perform the test may be able 

 to escape the numerous errors into which one may fall, it will be 

 necessary to point out the controls by which they can be avoided. 



A Wassermann reaction at the present time comprises not only 

 the test of the patient's serum, but simultaneously includes a long 

 series of other tests by which the validity of every part of the test 

 and the correct titer of all the reagents employed can be simultane- 

 ously ascertained. Every one who makes the test should practice 

 some such systematic method as is suggested by the following scheme 

 for the " set-up." Nine tubes are employed for the usual test. 

 These are stood in a rack in the same order for every test, and in the 

 course of time it becomes a matter of habit to know the tubes by 

 number, and to recall for what each stands. 



If many tests are to be made at one time, it is, of course, un- 

 necessary to make more than one series of controls. 



Of the complementary serum we add i cc. to 9 cc. of 0.85 per 

 cent, (physiologic) salt solution, making each cubic centimeter of 

 the dilution of the fluid equal o.i cc. This quantity, carefully 

 measured- by the same volumetric pipette, is dropped into each 

 tube, and this pipette laid aside. 



