The Hemolytic Amboceptor 329 



that the essential difference between the normal serum and 

 the syphilitic serum can be reduced to precise calculation it 

 is imperative that, in all the tests, the same quantity of 

 added serum be employed. Experience has shown this 

 quantity to be 0.2 c.c., and this we regard as the unit of 

 serum to be tested. 



To titrate the antigen we require (i) a normal human 

 serum and (2) a known syphilitic serum, obtained from 

 blood drawn from the arm veins of cases known to be well 

 and cases known to be syphilitic respectively. These serums 

 should be kept on hand in the laboratory in consider- 

 able quantity, as they are constantly needed for making the 

 controls that must accompany each test, as well as for making 

 the preliminary titration of the antigen. 



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 c.c. of the 

 normal serum; each tube of the other group, 0.2 c.c. 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 follow- 

 ing tabulation: 



TABLE I. Series "with the Normal Serum, 

 Tubes. 



1. i unit of + i unit of -f- antigen o.oi u &^ S = Complete 

 complement normal serum --5.c ^ hemolysis. 



2. i unit of -|- i unit of + antigen 0.03 *ga 5 = Complete 

 complement normal serum 5^ * hemolysis. 



3. i unit of + i unit of + antigen 0.05 *1 J % = Complete 

 complement normal serum |-^-^ hemolysis. 



4. i unit of + i unit of + antigen 0.07 jg. i = Complete 

 complement normal serum t^ 1 o hemolysis. 



5. i unit of + i unit of + antigen 0.08 g ^~_ = Complete 

 complement normal serum -w'S.tnlJ hemolysis. 



6. i unit of + i unit of + antigen 0.09 "? 1-| = Complete 

 complement normal serum !~-3 jjj hemolysis. 



7. i unit of + i unit of + antigen o.i B*i * = Complete 

 complement normal serum t <u< o^rt hemolysis. 



8. i unit of + i unit of + antigen 0.12 J -3 03 ft Complete 

 complement normal serum 'g g-cTg^g hemolysis. 



9. i unit of + i unit of + antigen 0.15 M g g = Complete 

 complement normal serum |C ^ 1 2 , hemolysis. 



10. i unit of + i unit of + antigen 0.18 g.1 f f*l Complete 

 complement normal serum S^ hemolysis. 



i unit of -{- i unit of + antigen 0.2 bog.o^=No 

 complement normal serum jjj =3-5 hemolysis. 



ii 



