ANTIGEN PROPERTIES OF CEREBROSPINAL FLUID 



I 77 



c. Demonstration of meningococcus antigen in the spinal fluid of a patient 

 with a possible meningitis. 



The spinal fluid contains meningococcus antigen thus proving that the patient is 

 suffering from epidemic cerebrospinal meningitis. Neither the double amount, of 

 serum, a double amount of antigen, a mixture of normal spinal fluid with specific serum, 

 nor normal serum with the specific spinal fluid binds complement. Only a mixture of 

 meningococcus extract and specific serum gives complement fixation. 



The results obtained by complement fixation depend to a great extent 

 upon the quantitative relationship of the various ingredients. The affinity 

 toward the complement existing between the antigen and amboceptor on 

 the one hand, is balanced by that between the hemolysin + blood on the 

 other. By modifying their quantitative proportions different results may 

 be obtained. If for example the strength of the hemolysin is excessively 

 increased, it is possible that the previously bound complement is again de- 

 tached and hemolysis ensues. Originally the results were read after the 

 mixtures had remained two hours in the incubator and twenty-four hours 

 in the ice-box. At the present, most authorities agree to read the results 

 at a time when the control tubes are ready; that is when the complement 

 is bound or hemolysis has been completed in those tubes in which these 

 respective phenomena should occur. 



12 



