BY DR. BURDON-SANDERSON. 289 



heart from the inferior cervical ganglion along the vagus, or 

 the recurrent, but most frequently by the cardiac branch 

 above described. For further details, see the explanation ot 

 fig. 242. 



Before entering on any experimental inquiry relating to the 

 accelerator nerves, it is absolutely necessary to make several 

 dissections. The mode of experiment is as follows: In a cu- 

 rarized rabbit in which artificial respiration is maintained in 

 the usual way, an incision is made in the middle line extending 

 from the upper third of the sternum to the upper end of the 

 trachea. The external jugular vein of one side is then brought 

 into view, tied in two places, and divided between the liga- 

 tures. The sterno-mastoid muscle is also divided between 

 ligatures : a strong, threaded aneurism needle is thrust under 

 the sterno-clavicular ligament and the upper fibres of the 

 pectoral muscles ; these, with the ligament, are divided be- 

 tween ligatures, and the cut ends drawn aside. By this pro- 

 ceeding, the carotid artery, the internal jugular vein, and the 

 subclavian vein, are brought into view. These veins and the 

 vena anonyma are tied and divided in the manner already in- 

 dicated, and any other vessels which come in the way are se- 

 cured. A simpler and more rapid mode of performing the 

 operation is the following: The superficial parts having been 

 exposed by two lines of incision, one of which is in the middle 

 line, while the other extends from it on either side in the di- 

 rection of the sterno-clavicular ligament, and the jugular vein 

 having been divided between ligatures, the next step is to find 

 the pneumogastric nerve at the upper part of the wound, and 

 free it from the surrounding tissues. This done, a blunt aneu- 

 rism needle is threaded and passed carefully, with its convexity 

 backwards, along the course of the nerve, between it and the 

 carotid artery. Its point is then made to penetrate the sheath 

 and fascia immediately above the long, cord-like, sterno-clavi- 

 cular ligament. The thread is then severed, and the ends 

 having been drawn out to a sufficient length, the two ligatures 

 are tightened, the one inside and the other outside of the 

 aneurism needle, after which the whole of the tissues which 

 arc tied off between the ligatures, including the great veins, 

 may be raised on the needle and divided. The needle, which 

 has been carefully kept in its place, is now again threaded, 

 and its point pushed downwards under the edge of the pectoral 

 muscles, as far as the upper surface of the first rib. The point 

 is then pushed outwards and forwards through the muscles, 

 the thread is again severed, and the muscles are divided be- 

 tween the two ligatures in the manner already described. By 

 this proceeding a deep hollow (see fig. 243) is exposed, in 

 which, among other important parts, the ganglion inferius 

 lies, covered by a layer of fascia. This hollow is bounded 

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