LUMBAR PUNCTURE 183 



(e) Miscellaneous 



Secondary to typhoid fever. 



Typhoid bacillus (rare). 

 Secondary to influenza. 



Influenza bacillus (rarej. 

 Secondary to anthrax, etc. 



Anthrax bacillus, etc. (rare). 



Of these, the organisms which are most likely to occur are : 



The tubercle bacillus'! 



Meningococcus /accounting for about 90 per cent, of cases. 



The pneumococcus. 



Streptococci and staphylococci in secondary cases due to spread from 

 ear, etc. 



And this shows roughly the order of frequency. 



Preparation of Films. If the fluid is thick and purulent, 

 films should be prepared, dried, and fixed in the ordinary way. 

 If the fluid is thin and watery, it should be centrifugalized or 

 allowed to stand for some hours. A certain amount of coagu- 

 lation will take place, and the sediment which collects will 

 contain the bulk of micro-organisms. The clear fluid should 

 be poured off and used for testing chemically, and the sedi- 

 ment used for the preparation of films, of which several will 

 be required. The subsequent examination will depend to 

 some extent upon the nature of the organism which is prob- 

 ably present; for general purposes stain one or more films 

 with LofHer's methylene blue (two minutes), wash, dry, mount, 

 and examine. 



Streptococci and staphylococci will be readily recognized by 

 their morphological characters. If diplococci are present 

 they may be pneumococci, Weichselbaum's diplococci, or 

 gonococci. Stain a film by Gram's method and counterstain 

 with neutral red in the metliod described for the gonococcus. 

 Pneumococci will retain the violet stain, while Weichselbaum's 

 organism and gonococci will be coloured red. 



The Rarer Causes of Meningitis. The bacilli of typhoid 

 fever, a'nthrax, influenza, etc., may also be recognized in the 

 methylene blue specimen, and should be identified (if possible) 

 by a careful study of their morphological appearances and 

 reaction to Gram's stain. 



If no organisms are found in the methylene blue specimens 

 after a careful search, and if the characters of the fluid are 



