APPENDIX 201 



In using lecithin, 0.3 gms. lecithin are dissolved in 

 50 cc. absolute alcohol, shaken with 50 cc. physio- 

 logical salt solution and filtered. The filtrate must 

 be clear. 



4. Suspension of human blood corpuscles. One 

 drop of blood from a normal individual is mixed 

 with 4 cc. physiological salt solution. 



5. Serum to be tested. About 10 or 15 drops of 

 blood are collected in a small tube and allowed to 

 clot. The clear serum is used for the tests. 



Method. Take six clean test tubes, size 10 cm. 

 by i cm. Into the first two of these place one drop 

 from a capillary pipette of the patient's serum to be 

 tested. Into each of the second two tubes (which 

 serve as controls) put one drop of serum of a syphi- 

 litic case known to give a positive reaction. Into 

 each of the third pair of tubes put one drop of 

 serum of a normal person. Now to each of the six 

 tubes add i cc. of the suspension of human blood 

 corpuscles and 0.04 cc. fresh guinea-pig serum as 

 complement. Lastly, into one tube of each pair 

 put one drop of the " antigen " solution from a 

 capillary pipette. The second tube of each pair 

 receives no antigen. 



After being well mixed by shaking, the six tubes 

 are incubated at 3 7 C. for one hour, after which each 

 tube receives two units * of antihuman amboceptor. 

 The tubes are returned to the incubator for two 



* The term "amboceptor unit" is used to designate the amount of 

 ambcceptor which, on the addition of the optimum amount of comple- 

 ment, just suffices to produce complete haemolysis. 



