126 BACTERIOLOGICAL DIAGNOSIS. 
LUMBAR PUNCTURE. 
Fluid may be removed from the spinal meninges for 
a bacteriological or other examination by means of 
Quincke’s lumbar puncture. The information furnished 
by this means is often of very great value; in fact Osler 
says that ‘during the past ten years no single measure 
of greater value in diagnosis has been introduced.” 
The process is simple, easy, and entirely devoid of 
danger, and can be carried out without an anesthetic. 
Requisites.-1. A suitable needle. In children the 
spinal meninges will be reached at a depth of 3-4 centi- 
metres (roughly 1-14 inches) while in adults the depth 
may be twice as great. The needle should not be less 
than 23 inches long for an infant and 4 inches for an 
adult, and should be sharp and strong. An antitoxin 
needle will answer every purpose. Aspiration is un- 
necessary, and no syringe is required. 
2. Materials for disinfection of the patient’s skin and 
(if cultures are to be taken) the hands of the operator. 
Hot water, soap, alcohol, ether, perchloride lotion (1 in 
1000). 
3. Apparatus for boiling the needle in a dilute solu- 
tion of washing soda.* 
4. Spray for local anesthesia. (If used). 
5. A test-tube sterilised by dry heat and plugged 
with dry cotton-wool. 
6. If cultures are to be taken the tubes of medium 
should be inoculated at the time of the operation if 
* If possible the needle should be sterilised by dry heat previous 
to the operation and kept in a tube plugged at both ends with 
cotton-wool as in the method recommended for the collecticn of 
blood for bacteriological examination. 
