mPLOOOCCUS INTRACELLULARIS MENINGITIDIS. 303 



the operator to thrust the needle directly forward rather 

 than from side to side. An antitoxin needle, 4 cm. in 

 length, with a diameter of 1 mm., is well adapted for 

 infants and young children. A longer needle is neces- 

 sary for adults and children over ten years of age. 



"Aspiration of the fluid is not necessary, but some 

 operators prefer to attach a hypodermic syringe to the 

 needle, to afford a better grasp for the hand. In this 

 case the syringe would have to be detached to allow 

 the fluid to flow. The additional manipulation, and 

 possibly the defective sterilization of tlie syringe, 

 might impair the subsequent bacteriological examina- 

 tion. 



" The puncture is generally made between the third 

 and the fourth lumbar vertebrse, sometimes between the 

 second and third. 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. Care must be exercised to prevent the 

 point of the needle from passing to the left of the 

 median line and striking the bone. 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 usually 

 by drops. If the point of the needle meets with a bony 

 obstruction, it is advisable to withdraw the needle some- 

 what, and to thrust again, directing the point of the 

 needle toward the median line, rather than to make 

 lateral movements, with the danger of breaking the 

 needle or causing a hemorrhage. The smallest quantity 

 of blood obscures the macroscopic appearance of the 

 fluid by rendering it cloudy. The fluid is allowed to 

 drop into an absolutely clean test-tube, which previously 

 has been sterilized by dry heat to 150° C. and stop- 



