LUMBAR PUNCTURE. 133 



teriologists think the two organisms are in reality 

 identical. 



The rarer causes of meningitis. The bacilli of typhoid 

 fever, anthrax, influenza, &c., may also be recognised 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 such as indicate that meningitis is 

 present, the presumption is that the case is one of 

 tubercular meningitis. Films should be stained in 

 the method already described (p. 72) and carefully 

 searched ; the bacilli are present in very scanty num- 

 bers, and many films may have to be examined before 

 one is found. * 



Cultural examination. The tubes which have been 

 inoculated by allowing the fluid to drop directly on to 

 the surface of the medium are to be incubated for 

 twenty-four hours at the body temperature. Strepto- 

 cocci, staphylococci, pneumococci, and the rarer organ- 

 isms will probably have developed by this time, and 

 will have formed colonies such as have been previously 

 described. Weichselbaum's diplococcus forms (on blood 

 serum) " round, whitish, shining, viscid looking colonies 

 with smooth, sharply defined outlines which attain a 

 diameter of one to one and a half millimetres in twenty- 

 four hours." The colonies on agar are similar but 

 slightly larger, and the growth may become confluent. 



* Lenharz adds a shred of clean cotton-wool to the fluid. This 

 sinks slowly to the bottom, and is withdrawn after some hours, 

 spread on a slide, dried and stained for tubercle bacilli. The author 

 has had no experience of this ir.ethod, but Mr. Leedham-Green 

 informs him that it is of considerable value. 



