454 



THE TECHNIC OF COMPLEMENT-FIXATION REACTIONS 



indicates that the serum was not anticomplementary. This control test 

 should never be omitted. 



3. A corpuscle control, including 1 c.c. of the corpuscles in salt solu- 

 tion. This tube should show no hemolysis. 



The following table gives the results of a titration with an alcoholic 

 extract of syphilitic liver diluted 1:10 (see Fig. Ill): 



TABLE is. ANTICOMPLEMENTARY TITRATION OF AN ORGANIC 



EXTRACT 



In this titration tube No. 6, containing 1.2 c.c. of the antigen emulsion 

 showed beginning inhibition of hemolysis and was recorded as the anti- 

 complementary dose. 



2. Hemolytic Titration. As previously mentioned, organic extracts 

 are capable in themselves of hemolyzing red cells; this is due to the 

 hemotoxic action of lipoids and alcohol. Extracts of organs that have 

 undergone advanced autolysis and decomposition are very likely to be 

 hemolytic. 



Serum exerts an inhibiting influence on the lytic action of an organic 

 extract. Hence the hemolytic dose of an extract depends largely on 

 whether or not complement serum is used in the titration. 



When an organic extract is titrated in the presence of complement, 

 the hemolytic dose is higher than the anticomplementary dose. In the 

 foregoing titration 3 c.c. of the extract emulsion showed beginning 

 hemolysis, and when 4 c.c. was used, hemolysis was complete. These 

 large amounts of emulsion give the tube contents quite a milky appear- 

 ance, but close inspection shows that all the cells are broken up. 



