NOSE. 



723 



nicate with the par vagum, to divide into two 

 branches, one of which is distributed to the 

 tongue and the other to the oesophagus. M tiller 

 states, that in the rattlesnake he has found this 

 nerve escaping from the cranium by a special 

 opening behind that for the eighth pair, with 

 which it communicates, as also with the first 

 cervical.* 



In Fishes, the last cerebral nerve is described 

 by Weber as arising by three roots, the poste- 

 rior having a ganglion, and passing out of the 

 cranium by a special foramen in the occipital 

 bone, and being distributed to the pectoral fin. 



From these circumstances Miiller conceived 

 that an analogy exists between the hypoglossal, 

 or ninth nerve, and the spinal nerves, and says, 

 " If we now take into consideration that the 

 first spinal nerve in the human subject has 

 sometimes only an anterior root, and that the 

 hypoglossal in man has only an anterior root, 

 but that in some mammalia (according to the 

 hypothesis of Mayer) it has a posterior root 

 also, it will be evident that the hypoglossal 

 nerve belongs to the class of spinal nerves, and 

 is as it were the first spinal nerve, which, how- 

 ever, generally passes out through a foramen in 

 the cranium ; this consideration renders the 

 analogy between the last cerebral nerve in 

 fishes and the hypoglossal nerve still greater.''f 



Physiology. That the ninth pair is the 

 nerve which influences the motions of the 

 tongue is generally admitted, and that it de- 

 serves the name given to it of motor Ihigug 

 has been proved by the experiments of Mayo, 

 Majendie, and Miiller. 



When in the living animal this nerve is ex- 

 posed and excited by pinching or galvanism, 

 violent spasms of the entire tongue are pro- 

 duced, and its division is followed by paralysis 

 of that organ. 



On this subject Mayo performed the follow- 

 ing experiment. " I divided the ninth nerve 

 on one side of the tongue in a dog; the ani- 

 mal did not seem much incommoded, but 

 lapped up milk readily. I then divided the 

 nerve on the opposite side ; the animal ap- 

 peared distressed, and did not again lap up the 

 milk offered to it, though it smelt to it; and 

 finally, when mustard was smeared on its nos- 

 trils, it made no use of its tongue to remove 

 it, though evidently suffering from it."} Further, 

 Mayo found that when the nerve was divided 

 on both sides in a rabbit, and the tongue drawn 

 out of the mouth, the animal had not the 

 power of again retracting it. 



A very interesting case is related by Montault 

 and quoted by Miiller, where a tumour pressing 

 on the ninth nerve of the left side at its exit 

 from the cranium produced an atrophy of this 

 nerve; the symptoms were paralysis of the left 

 side of the tongue with gradual wasting of the 

 organ on that side ; but the sense of taste was 

 not in the least affected, being as perfect on 

 the paralysed side as on the other. 



We are warranted from these facts in consi- 



* Elements of Physiology. 



* See Elements of Physiology. 



$ See Mayo, Commentaries, partii. p. 11. 



dering the ninth nerve as that which influences 

 the motions of the tongue in articulation and 

 deglutition ; but, besides directing the motions 

 of the tongue, the ninth nerve influences the mo- 

 tions produced upon the os hyoides by the sterno- 

 hyoid, sterno-thyroid, and thyro-hyoid muscles, 

 which muscles receive branches, as before de- 

 scribed, from the ninth and cervical plexus. 

 The importance of this connection in action of 

 these muscles with the tongue, in the perform- 

 ance of the functions of articulation and deglu- 

 tition, is obvious; and in the turkey Miiller 

 has found a long branch going from this nerve 

 to supply the muscles which in that bird 

 shorten the trachea. 



It is asserted that the ninth nerve, in addition 

 to its motor influence, is also endowed with a 

 certain degree of sensibility, and that, if the 

 nerve be stretched or pinched in a living ani- 

 mal, there is evidence of the animal suf- 

 fering pain ; this has been tried on dogs and 

 cats. Now if in these animals this nerve has 

 a double origin, this would be easy to under- 

 stand ; but Mayer himself could not detach a 

 posterior root in the cat; so that if this nerve, 

 either in man or other animals, has any of the 

 properties of a nerve of sensation, it is owing 

 to the filaments which it receives from the cer- 

 vical plexus. But the degree of sensibility 

 communicated to the tongue through the in- 

 fluence of this nerve in this way must be very 

 trifling; and it is now as well proved that the 

 tactile sensibility of the tongue is owing princi- 

 pally to the influence of the gustatory branch 

 of the fifth, as that the motions of that organ 

 are directed by the influence of the ninth pair. 



( G. Stokes.) 



NOSE. (Human Anatomy.) (Gr.pin; Lat. 

 Nasus; German, Nuse ; French, Nez; Italian, 

 Naso ; Dutch, Neiis.) The nose is the organ 

 of the sense of smell, and a part of the appara- 

 tus of respiration and voice, and in accordance 

 with the variety of its offices is complex both in 

 form and in structure, many different tissues en- 

 tering into its composition. The most simple 

 method of describing its anatomy in man is 

 the synthetical; I shall therefore give an ac- 

 count, first, of its skeleton, composed of bones 

 and cartilages ; and then, in succession, of each 

 of the parts placed on the skeleton, and subser- 

 vient to its several functions. 



The bones of the nose are chiefly concerned in 

 the formation of the internal deeply-seated part 

 of the organ, that part which is called the nasal 

 fosstG, (cav& nares, or nures internee,) or the ca- 

 vities of the nose. These cavities are open 

 widely anteriorly to the atmosphere, and poste- 

 riorly to the pharynx. The anterior aperture 

 is, in the osseous skeleton, heartshaped, broader 

 below than above, bounded below and on each 

 side by the palatine and ascending processes of 

 the superior maxillary bones, and above by the 

 nasal bones. Its borders are, in the lower half, 

 smoothly rounded ; in the upper half, sharp 

 and uneven. Below and in the middle line 

 the anterior nasal spine projects forwards and 

 upwards; and above it is the osseous septum, 

 which divides the fossae into two equal cr 



3 A 2 



