80 



EXPERIMENTAL PHYSIOLOGY. 



carotid artery. With an aneurysm needle or a blunt-pointed curved 

 seeker, free the carotid from its sheath for about an inch and place 

 two ligatures under it. Tie the peripheral ligature (the one farthest 



FIG. 23. Stand, manometer, pressure bottle, etc., for recording blood pressure. 



from the heart). Place a bull-dog forceps on the artery central 

 to the central ligature. 



Separate the vagus nerve from the carotid sheath on both sides 

 of the neck, and place ligatures, without tying them, around both 



