The purpose of a needle for the puncture of the spinal canal is threefold: (1) to measure the pressure of the spinal fluid; (2) to withdraw fluid through it for examination, and (3) to inject substances into the spinal canal.
The needles devised for this purpose, heretofore, have depended on the use of the three-way cock. Such mechanism is very apt to get out of order, and requires an undue amount of attention on the part of the operator in order that the flow of fluid may take its proper course.
For the past two months I have used a needle which I think overcomes these difficulties. It is efficient and at the same time easy to take care of. The needle possesses a stylet which is made so as to fit the barrel accurately, and is likewise so fashioned that it cannot be withdrawn during the use of the