WASSERMANN AND OTHER COMPLEMENT FIXATION TESTS 239 



Take a test-tube rack built to carry 1 2 tubes in a row and place a tube in 

 each of the first 10 holes and one in the twelfth. 



Make a 10 per cent, solution of fresh guinea-pig serum in normal salt solu- 

 tion by mixing i cc. of serum with 9 cc. of salt solution. 



Put 0.3 cc. of the 10 per cent, solution of guinea-pig serum in the first tube. 



Put 0.4 cc. of the 10 per cent, solution of guinea-pig serum in the second tube. 



Put 0.5 cc. of the 10 per cent, solution of guinea-pig serum in the third tube. 



Put 0.6 cc. of the 10 per cent, solution of guinea-pig serum in the fourth tube. 



Put 0.7 cc. of the 10 per cent, solution of guinea-pig serum in the fifth tube. 



Put 0.8 cc. of the 10 per cent, solution of guinea-pig serum in the sixth tube. 



Put 0.9 cc. of the 10 per cent, solution of guinea-pig serum in the seventh 

 tube. 



Put i.o cc. of the 10 per cent, solution of guinea-pig serum in the eighth tube. 



Put i.i cc. of the 10 per cent, solution of guinea-pig serum in the ninth tube. 



Put 1.2 cc. of the 10 per cent, solution of guinea-pig serum in the tenth tube. 



Put i cc. of the 10 per cent, solution of guinea-pig serum in the last tube. 



Put one unit of amboceptor in every tube except the last. Do not put any 

 amboceptor in the last tube. 



Put i cc. of 5 per cent, suspension of red blood cells in every tube. 



Shake the tubes to mix their contents and place in incubator. 



At the end of an hour remove and inspect the tubes. 



The last tube contains guinea-pig serum and blood cells only; if any hemoly- 

 sis occurs in this tube it indicates that the guinea-pig serum is of itself destruc- 

 tive to blood cells and hence cannot be used in making complement fixation tests. 

 The last tube should show no hemolysis. 



Having learned from inspection of the last tube that the serum is accept- 

 able, provided it contains complement, the other tubes are then inspected to 

 detect the presence and quantity of complement. 



A unit of complement is the smallest amount that will cause complete 

 hemolysis of i cc. of a 5 per cent, suspension of red cells, together with one 

 unit amboceptor, when incubated at 37C. for i hour. 



THE WASSERMANN TEST 



Just as normal untreated rabbits have no amboceptors in their blood serum 

 which can act on red blood cells, normal humans who have not been infected 

 with syphilis have no amboceptors in their blood serum which can act on syphi- 

 litic antigen. 



Just as rabbits that have been injected with red cells do have amboceptors 

 in their serum which can act on red blood cells, humans who have been infected 

 with syphilis do have amboceptors in their serum which can act on syphilitic 

 antigen. 



The Wassermann test is a test to determine the presence or absence of syphi- 

 litic amboceptors in a given individual's serum. For this purpose five sub- 

 stances are necessary: 



