VASOMOTOR SUPPLY OF THE ORGANS. 635 



glionic fibers. In one interesting instance the constrictor fibers 

 for the head were supposed to take a somewhat different course. 

 It was shown by SchifT, long ago, that in the rabbit the ear receives 

 vasomotor fibers from the auricularis magnus nerve, a branch of the 

 third cervical nerve. Later investigations indicate (Meltzer) that 

 the ear, in fact, receives most of its vasoconstrictor fibers by this 

 route. Fletcher, however, has shown that these fibers do not emerge 

 from the brain in the roots of the third cervical, but rather in the 

 general outflow from the thoracic region. After reaching the sym- 

 pathetic chain these particular fibers pass to the third cervical by 

 the gray rami from the first thoracic ganglion, which communicate 

 with a number of the cervical nerves. On the other hand, the 

 vasodilator fibers for the head are supplied in part by way of the 

 cervical sympathetic, following the same general path as the con- 

 strictors, and in part by way of the cranial nerves (seventh, ninth) 

 and the sympathetic ganglia with which they connect. According 

 to Langley, the outflow of the seventh nerve passes to the spheno- 

 palatine ganglion, whence as postganglionic fibers they accompany 

 the branches of the superior maxillary nerve and cause vasodila- 

 tation in the membrane of the nose, soft palate, tonsils, uvula, roof 

 of mouth, upper lips, gums, and pharynx. The well-known dilators 

 of the submaxillary and sublingual glands are contained in the 

 chorda tympani branch of the seventh nerve; the preganglionic 

 fibers terminate probably in the small peripheral ganglia connected 

 with these glands. The fibers that emerge in the ninth pass in 

 part directly to the tongue and in part terminate first in the otic 

 ganglion, whence they are distributed with the branches of the 

 inferior maxillary to the lower lips, cheeks, gums, and parotid and 

 orbital glands. Dastre and Morat describe the vasodilators in the 

 cervical sympathetic as reaching the fifth cranial nerve by com- 

 municating branches from the superior cervical ganglion and state 

 that they cause dilatation of the bucco-facial region, that is, 

 the lips, the gums, cheeks, palate, nasal mucous membrane, and 

 the corresponding skin areas. 



The Trunk and the Limbs. The vasoconstrictor fibers for 

 these regions are distributed, so far as is known, chiefly to the skin. 

 They are all derived immediately from the sympathetic chain and 

 ultimately from the outflow in the anterior roots of the thoracic 

 and lumbar spinal nerves. Those for the upper limbs arise from 

 the midthoracic region chiefly (fourth to ninth thoracic nerves), 

 those for the lower limbs arise in the nerves of the lower thoracic 

 and upper lumbar region (eleventh, twelfth, thirteenth thoracic 

 [dog] and first and second lumbar). The vasodilator fibers in the 

 nerves of the limbs have been demonstrated frequently, as already 

 explained. Whether or not these fibers also pass through the 



