THE CRANIAL NERVES 



651 



with nasal respiration, its division leads to a loss of movement of the 

 nostrils. Phonation is impaired. 



This nerve also contains secretomotor and vasomotor fibers for 

 the submaxillary and sublingual glands which reach their destination 

 by way of the chorda tympani. It also embraces secretomotor fibers 

 for the lacrimal glands which pass through the ganglion sphenopala- 

 tinum and reach the second branch of the trigeminus and subsequently 

 the nervus zygomaticus and nervus lacrimalis. Its sensory fibers 

 convey taste impressions from the front part of the tongue. They 

 form the nervus intermedius and are affixed to the chorda tympani 

 and lingual nerves. 



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FIG. 323. THE ORIGIN OF THE SIXTH AND OF THE MOTOR PART OF THE SEVENTH NERVE. 

 VI., Sixth nerve; VII., seventh nerve; a.VII., ascending part of the root of seventh 

 shown cut across near the floor of the fourth ventricle; g, genu of seventh nerve-root; 

 n.VI., chief nucleus of the sixth nerve; n.'VI., accessory nucleus of sixth; n.VII., nucleus 

 of seventh; d.V., descending root of fifth; pyr., pyramid-bundles; VIII.v., vestibular 

 root of eighth nerve. (Schafer.) 



8. The auditory nerve consists of two groups of fibers possessing a 

 certain anatomical and functional independency. One of them is con- 

 cerned with hearing and forms its cochlear branch, and the other with 

 the sense of equilibrium and forms its vestibular branch. In the horse 

 and sheep these fibers are in fact absolutely separated from one another 

 throughout their course. 



The auditory nerve enters the bulb in two parts, an external and 

 an internal. The fibers of the former are derived chiefly from the 

 cochlea, and those of the latter from the semicircular canals and the 

 vestibule of the internal ear. The first connect with the spiral gan- 

 glion of the cochlea and the latter with the vestibular ganglion of the 

 semicircular canals. These peripheral stations are comparable to 

 the spinal ganglia, because the cells composing them send out processes 

 which soon divide into two branches. One of these connects with the 



