496 THE SEXSE OF SMELL. 



are peculiar, more resembling those of the sympathetic nerve 

 than the filaments of the other cerebral nerves do, containing 



Fw. 176. 



Nerves of the septum nasi, seen from the right side (from Sappey after Hirschfeld 

 and Leveille). %. I, the olfactory bulb; 1, the olfactory nerves passing through 

 the foramina of the cribriform plate, and descending to be distributed on the septum ; 

 2, the internal or septal twig of the nasal branch of the ophthalmic nerve ; 3, naso- 

 palatine nerves. 



no outer white substance, and being finely granular and nu- 

 cleated. The branches are distributed principally in close 

 plexuses ; but the mode of termination of the filaments is not 

 yet satisfactorily determined. 



The sense of smell is derived exclusively through those parts 

 of the nasal cavities in which the olfactory nerves are dis- 

 tributed ; the accessory cavities or sinuses communicating with 

 the nostrils seem to have no relation to it. Air impregnated 

 with the vapor of camphor was injected by Deschamps into 

 the frontal sinus through a fistulous opening, and Richerand 

 injected odorous substances into the antrum of Highmore; 

 but in neither case was any odor perceived by the patient. 

 The purposes of these sinuses appear to be, that the bones, 

 necessarily large for the action of the muscles and other 

 parts connected with them, may be as light as possible, and 

 that there may be more room for the resonance of the air in 

 vocalizing. The former purpose, which is in other bones ob- 

 tained by filling their cavities with fat, is here attained, as it 

 is in many bones of birds, by their being filled with air. 



All parts of the nasal cavities, whether or not they can be 

 the seats of the sense of smell, are endowed with common sen- 

 sibility by the nasal branches of the first and second divisions 



