SMELL 



251 



upper part of the cavity of the nose, one half being on 

 each side. It is made up of elongated cells, among 

 which are the pointed olfactory cells, containing the 



Skull bones 



Olfactory bulb 

 Olfactory nerve 

 Olfactory nerve branches 



Nerve ganglion 



Nerve supplying nose 



palate and pharynx 

 Eustachian tube 



Hard palate 

 Soft palate 



FIG. 135. Diagram showing distribution of olfactory nerve on outer side of nasal 

 cavity. 



ends of the olfactory nerves. When stimulated by 

 volatile particles of substances, the olfactory cells start 

 the nervous impulses which pass up the olfactory nerves 

 to the higher centres in the cortex, thereby producing 

 sensations of odors. 



Influence upon taste. How much the sense of smell 

 has to do with the flavor of food is readily appre- 

 ciated when the nose is closed by pinching the nostrils 

 or by a head cold. Even such a highly flavored food 

 as an onion cannot be distinguished under these circum- 

 stances from a turnip; and other foods, except those 



