178 THE NERVOUS SYSTEM 



visceral efferent fibers of the cranial nerves. These are small myelinated fibers, 

 which end in sympathetic ganglia, where they arborize about sympathetic 

 cells, the axons of which terminate in smooth or cardiac muscle or in glandular 

 tissue. The neurons of this series are, therefore, characterized by the fact that 

 the impulses which they transmit must be relayed by neurons of a second order 

 before reaching the innervated tissue (Fig. 119). This group of nuclei is indi- 

 cated by black in Fig. 120 and by fine stipple in Figs. 121 and 122. 



The dorsal motor nucleus of the vagus (nucleus vagi dorsalis medialis) has 

 been noted in the transverse sections through the medulla oblongata (Figs. 99, 

 103). It lies along the dorsolateral side of the hypoglossal nucleus, subjacent 

 to the ala cinerea of the rhomboid fossa, and along the side of the central canal 

 in the closed part of the medulla oblongata. The general visceral efferent fibers, 

 which arise from the cells in this nucleus, leave the medulla oblongata through 

 the roots of the vagus and accessory nerves; but those entering the accessory 

 nerve leave that nerve by its internal ramus and join the vagus (Fig. 120). 

 Hence all of the fibers from this nucleus are distributed through the branches of 

 the vagus to the vagal sympathetic plexuses of the thorax and abdomen for the 

 innervation of the involuntary musculature of the heart, respiratory passages, 

 esophagus, stomach, and small intestines (Van Gehuchten and Molhant, 1912), 

 and for the innervation of the pancreas, liver, and other glands. 



There are relatively few sensory collaterals reaching the dorsal motor nucleus, 

 and these come in large part from sensory fibers of the second order, arising in 

 the receptive nuclei of the trigeminal, glossopharyngeal, and vagus nerves. 



The nucleus salivatorius is located in the reticular formation, some distance 

 from the floor of the fourth ventricle at the junction of the pons and medulla 

 oblongata near the caudal end of the facial nucleus and the rostral end of the 

 nucleus ambiguus (Figs. 121, 122). The more caudal portion, or nucleus sal- 

 ivatorius inferior, sends general visceral efferent fibers by way of the glosso- 

 pharyngeal nerve to the otic ganglion for the innervation of the parotid gland. 

 The rostral part, or nucleus salivatorius superior, lies dorsal to the large motor 

 nucleus of the facial nerve, to which nerve it sends general visceral efferent 

 fibers. These run from the facial nerve through the chorda tympani to the sub- 

 maxillary ganglion for the innervation of the submaxillary and sublingual sal- 

 ivary glands (Kohnstamm, 1902, 1903, 1907; Yagita, 1909; Feiling, 1913). 



The Edinger-Westphal nucleus is a group of small nerve-cells located in 

 the rostral part of the nucleus of the oculomotor nerve. Here it is placed 

 dorsolateral to the median unpaired portion of that nucleus (Figs. 121-123). 



