362 SENSITIVE SYSTEM. 



#*# I take this opportunity of acknowledging- the services afforded me 

 in the dissection of the nerves by Mr. Bean, V.S., who, I believe, is in 

 practice at Durham. Unwearied assiduity and unusual zeal had qualified 

 him in an especial manner for such an undertaking; and I hope that he is 

 now enjoying that support which his professional acquirements will always 

 render him deserving of. 



Section X. 

 SENSITIVE SYSTEM. 



INCLUDING THE NOSR; THE EYE; AND THE EAR. 



OF THE NOSE. 



THE nose comprehends the apparatus of the organ of smell ; 

 a sense so acute and cognoscent in the horse-species, as greatly 

 to make up for the deficiency of that of tniicli. 



Division. — The component parts of the nose are divisible into 

 such as are hard in their nature, and such as are soft. 



THE HARD PARTS comprise the bones and the cartilages. 



THE SOFT PARTS are comprehended in the membrane 

 lining the various nasal cavities and passages. 



Cavities. — The cavities of the nose consist of the nasal fossce 

 and the different sinuses of the head. 



Nasal Fossa. 



The nasal fossse are the two chambers or lateral cavities, 

 whose external openings are the nostrils. Their avails or external 

 parietes are almost entirely osseous; and to the osseous sys- 

 tem (page 45) the reader must turn for a description of the 

 manner in which the fossiE are formed, and of the bones entering 

 into their formation. But, in addition to bone, they are carti- 

 laginous in their constitution. 



THE CARTILAGES OF THE NOSE are fve in num- 

 ber: — of which one (the septum nasi) is situated internallj/ ; the 

 other four (entering into the composition of the nostrils) exter- 

 nally. 



THE SEPTUM NASI is the vertical cartilaginous partition 

 interposed between the nasal fossoe. It exhibits four borders. 

 The inferior one is received into the groove of the vomer; while 

 the superior presents a lengthened channel between two elevated 

 edges, into which is admitted the internal crest formed by the 

 union of the nasal bones. Its posterior border is affixed to the 

 ethmoidal plate : its anterior serves to sustain the cartilages 

 forming the nostrils. Both its sides are completely covered by 

 the Schneiderian membrane. 



