LUMBAR PUNCTURE 199 



is sown into broth by drawing some sterile broth into the syringe and expelling 

 it again into the culture-tube. 



The india-rubber connexion is absolutely necessary : it allows the needle 

 to follow the movement of the spleen and so avoids any risk of tearing the 

 organ. 



Splenic puncture is not often performed and is not altogether unaccom- 

 panied by danger. 



Splenectomy in animals. 



The functions of the spleen in the resistance of the body to certain infectious 

 diseases can be studied by observation of the results following the removal 

 of the organ. Dogs and rats are the best animals for the experiment, but 

 the operation can be performed on many other species. 



The spleen is situated in the left flank beneath the lower false ribs and 

 near the left curvature of the stomach. 



1. Fix the animal on its right flank and anaesthetize it. 



2. Shave and asepticize the skin of the left flank. Sterilize all instruments 

 and asepticize the hands carefully. 



3. Make an incision a few centimetres long through the skin and sub- 

 cutaneous tissues immediately below the margin of the last rib, commencing 

 at the angle and continuing parallel to the bone. 



4. Cut through the aponeurosis of the external oblique and then of the 

 internal oblique on a director. 



5. Separate the fibres of the transversalis with the blunt end of a director. 



6. Incise the peritoneum for the whole length of the incision. 



7. The spleen will then be exposed or can readily be found by passing the 

 finger along the greater curvature of the stomach : draw it out of the wound, 

 being very careful not to lacerate it. 



8. Tear through the gastro-splenic omentum and put a firm silk ligature 

 around the vessel of the hilum. Cut through the pedicle on the distal side 

 of the ligature. 



9. Suture the muscles, close the skin wound with a few stitches and cover 

 the incision with collodion. 



12. Lumbar puncture. 



Man. 



By means of lumbar puncture, an operation devised by Essex Wynter, 

 a needle can be passed into the cerebro-spinal canal and the fluid withdrawn. 

 Bacteriological investigation of the cerebro- 

 spinal fluid is of great interest and importance 

 in cases of meningitis. 



Anatomical data. In the adult the spinal 

 cord only reaches to the lower border of the first 

 or upper border of the second lumbar vertebra, 

 but in children twelve months old it reaches to 

 the level of the third. The spinal cord cannot, 

 then, be injured by passing a fine trocar into 

 the spinal canal through the third, fourth or 

 fifth lumbar spaces. In these situations the 

 nerves comprising the cauda equina are sus- 

 pended in the cerebro-spinal fluid and are 

 collected into two lateral fasciculi separated by 



an interval of 5 mm. The lower down the FlG . 150 .-Landmark3 for 

 puncture is made the smaller the chance the operation of lumbar puncture 



