THE WASSERMANN REACTION 



617 



read off the minimal hsemolytic dose i.e. the first tube which 

 is absolutely clear. If the m.h.d. does not fall between 0-0001- 

 0-0009 c.c. the test can be repeated, using the stronger dilution of 

 amboceptor (tube 3a). It is better, however, to use an amboceptor 

 which does fall between these limits. 



IV. DAILY KOUTINE. (1) Wash, or complete the washing, of 

 the sheep's blood corpuscles. 



(2) Kill, or bleed, the guinea-pig and prepare the serum for 

 complement. 



(3) Make up fresh saline solution. 



(4) Standardise the complement (A) and antigen control (B). 

 (All subsequent measurements under 1 c.c. are made with the 

 1 c.c. pipette ; up to 10 c.c. with the 10 c.c. pipette ; above 10 c.c. 

 with a 50 c.c. measure.) Materials : (a) Four tubes in the rack, 

 front row, for A ; four tubes in the rack, back row, for B. (b) Com- 

 plement diluted 1 in 24 (0-1 c.c. complement -j- 2-3 c.c. saline), 

 (c) Complement 2 times stronger (0-2 c.c. complement +1-7 c.c. 

 saline) for antigen control, (d) 5 per cent, corpuscle suspen- 

 sion containing amboceptor. This is made up as follows : The 

 quantity required is 0-5 c.c. for every tube in the test -f 10 c.c. 

 Every specimen requires two tubes, and if 30 bloods are to be 

 tested, 30 + 10 = 40 c.c. are required. The quantities will be as 

 follows : (3) corpuscles (centrifuged deposit), 2-0 c.c. ; (2) ambo- 

 ceptor, 4 m.h.d. per tube i.e. if m.h.d. = 0-0005, 0-002 per 

 tube x 80 =0-16 c.c.; (1) saline 37-84 c.c. Every half c.c. 

 of this mixture will contain 0-002 of amboceptor, the correct 

 quantity per tube. Make up in the order of the numbers and 

 shake after each addition, (e) Diluted antigen, made up as 

 follows : Rinse out and clean a 1 c.c. pipette with spirit. Take 

 0-3 c.c. of heart extract and 0-2 c.c. of cholesterin and place in 

 a dry test-tube. Run in 7 c.c. of saline and shake. 



