INTEA CELL ULAEIS MENINGITIDIS. 521 



there are very few diplococci present in the spinal fluid, 

 so that a failure to find them in a 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 fluid 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 cm. 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 vertebrae. 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 cm. in children and 

 7 or 8 cm. 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 should be withdrawn.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. 



