GROUP OF PYOGENIC COCCI. 51 



The infection may be caused by any one of a number The Me 

 of micro-organisms, the pneumococcus, the typhoid coccus 

 bacillus, the influenza bacillus, the tubercle bacillus, 

 the Streptococcus or Staphylococcus pyogenes. When 

 the meningitis results from infection with these 

 organisms it is generally secondary to an infection 

 elsewhere in the body, as, for example, during pneu- 

 monia, typhoid fever, pulmonary tuberculosis, or 

 septicemia. 



The primary form of meningitis, the form that 

 frequently occurs in epidemics and is more commonly 

 called spotted fever, is due to infection with the 

 meningococcus or the Micrococcus intracellularis 

 menmgitidis, and must not be confused with the forms 

 mentioned above, which are always secondary. 



The meningococcus was identified and described 

 by Professor Weichselbaum in 1887. The micro- 

 organism was found in the cerebrospinal fluid of 

 patients sick with the disease, and generally within the 

 bodies of the leucocytes. For this reason the term 

 intracellular is used in its description. The coccus 

 occurs in pairs, a diplococcus which in appearance is 

 not unlike the gonococcus. It can be cultivated on 

 the ordinary laboratory media. 



The presence of the disease is detected by finding 

 the meningococcus in the cerebrospinal fluid, which is 

 withdrawn by inserting an aspirating needle into the 

 cerebrospinal canal, at the level of the third or fourth 

 lumbar vertebra. This procedure is spoken of as 

 lumbar puncture, and may be performed by physi- 



Morphol- 

 ogy 



