INTRACELLULARIS MENINGITIDIS. 521 
there are very few diplococci present in the spinal fluid, 
so that a failure to find them ina microscopical examina- 
tion should not be taken to prove that the disease was 
not due to this organism. For cultures a considerable 
amount of fluid must be used, for we have found, as 
described by Councilman and others, that there may 
be very few living diplococci even in 1 c.c. of fluid. 
To obtain the fiuid the patient should lie on the right 
side with the knees drawn up and the left shoulder de- 
pressed. The skin of the patient’s back, the hands of 
the operator, and the large antitoxin syringe should be 
sterile. The needle should be 4 em. in length, with a 
diameter of 1 mm. for children, and longer for adults. 
The puncture is generally made between the third 
and fourth lumbar vertebre. The thumb of the left 
hand is pressed between the spinous processes, and the 
point of the needle is entered about 1 cm. to the right 
of the median line and on a level with the thumb-nail, 
and directed slightly upward and inward toward the 
median line. At a depth of 3 or 4 em. in children and 
7 or 8 em. in adults the needle enters the subarachnoid 
space, and the fluid flows out in drops or in a stream. 
If the needle meets a bony obstruction withdraw and 
thrust again rather than make lateral movements. 
Any blood obscures the microscopical examination. 
The fluid is allowed to drop into absolutely sterile test- 
tubes or vials with sterile stoppers. From 5 to 15 c.c. 
should be withdrawn. No ill effects have been ob- 
served from the operations, 
