FIXATION OF COMPLEMENT 



121 



where complement after being incubated for one hour 

 alone is added to the amboceptor and sheep's cor- 

 puscles. In a second series of tubes prepared in this 

 way the results would be : 



Result 



Partial haemolysis 

 Almost complete hsemolysis 

 Coiri'plete hceinolysis 

 Complete haemolysis 

 Complete haemolysis 



By this means we arrive at the exact amount of 

 guinea-pig serum that represents one unit of comple- 

 ment. This will be of practical value later as seen in 

 quantitative tests. 



Patient's Serum. — The serimi of the patient's 

 blood will usually separate spontaneously from the 

 clot and can be drawn off with a capillary pipette. If 

 not, the clot can be broken up well with a platinum 

 loop and the serum separated by centrifuging the 

 tube. The clear serum can then be readily drawn off. 

 The patient's serum is heated in a water-bath at 5^"" C. 

 for half an hour to destroy the natural complement 

 present (inactivation) . This can be carried out while 

 the complement is being titrated. At the same time a 

 known syphilitic and a known non-syphilitic ^erum 

 should be inactivated to be used in the test as controls. 



