LUMBAR PUNCTURE. 133 
teriologists think the two organisms are in reality 
identical. 
The vavey 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 examinationn—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sinks slowly to the bottom, and is withdrawn after some hours, 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 method, but Mr. Leedham-Green 
informs him that it is of considerable value. 
