326 



GENERAL MICROBIOLOGY 



TITRATION OF COMPLEMENT 



Incubate all tubes in water bath at 37 C. for one-half hour and read. 



A. 0.9% salt solution. 



B. 1% dilution of inactivated immune rabbit serum in salt solu- 

 tion. 



C. 1% suspension of washed sheep-blood cells in salt solution. 



D. 20% solution of fresh guinea pig serum in salt solution (0.4 

 c.c. complement made up to 2 c.c. with salt solution). 



E. * A variation of reaction according to strength of complement, 

 -f = complete hemolysis. 



=no hemolysis. 



The inactivation is accomplished by heating to a tem- 

 perature of 56 C. for one-half hour to destroy the com- 

 plement. If not used for several days it is not necessary 

 to heat, > as complement is destroyed on standing. If it 

 is to be kept for some time, preserve by adding 5% 

 phenol sufficient to make a 0.5% solution. It is then 

 titrated to determine the smallest quantity which will bring 

 about a complete solution of the same quantity of washed 

 sheep blood cells used in the titration of the complement, 

 when in the presence of a proper quantity of complement. 



3. Antigen. Antigen is an extract of the specific bacteria 

 made by growing the bacteria on agar and washing off with a 

 few cubic centimeters of salt solution, and is preserved with 

 phenol sufficient to make 0.5% and glycerin sufficient to 

 make 1%. The suspension is placed in a shaking machine 

 for three hours a day for three consecutive days to obtain 

 homogeneity. 



