u 



EXERCISE 'VII 



Obs. 28. 

 Distal end of 

 n. splanchnicus 

 on art. pressure. 



ii. Return to the carotid. Insert arterial cannula and connect with 

 manometer. 



iii. While the kymograph is running, faradize with the hand-electrodes 

 the central stump of the splanchnic nerve, lifting it by its thread and taking 

 care that the electrodes are applied isolatedly to the nerve. Maintain the 

 stimulation for 5"-10". Observe effect on art. pressure (text-fig. 21). Stop 

 kymograph.] 



VI. If the preceding § V, which may be omitted at first performance of 

 the exercise, has been made, stimulate similarly, but using weaker induction 

 shocks, the distal end of the cut splanchnic nerve, lifting it by its thread and 

 ensuring isolated faradism as before, and record with the kymograph the effect 

 on the carotid pressure. But if § V has been omitted, proceed as follows : 



Text-fig. 21. Arterial pressure and distal end of splanchnic nerve ; decapitate 

 preparation (W. S. Penfield and E. Woods), a. p., carotid-pressure record by Hg 

 manometer ; z, zero-line of arterial pressure ; s, signal-line showing time of faradization 

 of distal trunk of severed splanchnic nerve ; t, time in 2" intervals. Note acceleration 

 of heart coincident with the second rise of arterial pressure. 



While your co-worker holds aside with flat retractors the viscera without 

 damage to them, pass, by means of a bent needle in handle, a thread round 

 the right splanchnic as far proximal in its course as possible (PI. Ill, fig. 5). 

 Tie this and cut the nerve proximal to the ligature ; free the peripheral stump 

 of the cut nerve and see that you have at least 2 cm. of it free for being lifted 

 by the ligature when later the electrodes are applied. Leave the thread and 

 nerve easily accessible for stimulation. Bring the edges of the wound 



