28 ELEMENTARY PHYSIOLOGY. [l. 



fusiform enlargement, the ganglion of the 

 trunk. 



12. Note the hypoglossal, a large nerve running 

 across the pneumogastric a little centrally of its 

 ganglion. Trace it forwards to the muscles of 

 the tongue. 



13. Follow up the sympathetic nerve, it has, at about 

 the level of the ganglion of the pneumogastric, a 

 considerable enlargement, the superior cervi- 

 cal ganglion; observe the fibres which run 

 from this along the carotid artery and its 

 branches. 



14. In the dog the sympathetic and pneumogastric 

 nerves which run in a common sheath in the 

 neck (cf. C., 28 (y)) separate from one another 

 a little distance from their respective ganglia. 



15. Partly saw through the symphysis menti, then 

 use a lever and force the rami asunder, and in 

 the following dissection cut through or remove 

 any muscles necessary. 



16. Trace the lingual backwards. It will be found 

 to join the inferior dental (a large nerve 

 entering into the lower jaw), to constitute, with 

 other branches, the inferior maxillary nerve. 

 Trace this back to the front edge of the tympa- 

 nic bulla. 



17. Note in the dog the small nerve, chorda tyin- 

 pani, which joins the lingual soon after the 

 latter branches off from the inferior dental; 

 trace the chorda tympani centrally, it will be 

 found to make its exit from the tympanic bulla 



