CHLOROFORM INJECTION INTO VERTEBRAL ARTERY 



197 



rapidly and artificial respiration must be started at once. 

 Close off the jugulars immediately and tie the ligatures 

 firmly. Be sure the lungs are well inflated but do not burst 

 them. Remove the ether quickly as no further anesthetic 

 is needed. If your first injection does not succeed well, 

 make a second one into the left carotid artery. Luckhardt 



-Cenfaqrade 

 thermometer 



Fig. 188. Arrangement of apparatus for keeping the systematic blood-pressure at a 

 constant level during the action of drugs which produce marked changes in the caliber 

 of the arterioles. The cannulas in the femoral arteries are connected with a siphon tube 

 which dips in a beaker containing warmed salt solution (or whipped or hirudinized 

 blood). Hirudin is injected intravenously to prevent clotting of the blood. The alti- 

 tude of the beaker above the animal regulates the pressure which can be maintained 

 in the blood vessels. This is read off from the mercury manometer. If the vessels 

 contract blood is forced over into the beaker but the arterial pressure does not rise. 

 When the vessels (arterioles) dilate the blood siphons back into the femoral arteries. 



has succeeded well by making- injections into the carotid 

 artery alone. (Some workers have obtained good results 

 by injecting a three per cent suspension of starch gran- 

 ules into the carotid artery.) This is easier than inject- 

 ing the vertebral on account of the dissection, but the me- 

 dulla may not be well reached through the carotid. In a 



