i48 



THE SPECIAL SENSES 



easily demonstrated by closing the nasal cavities and bandaging 

 the eyes when the sensation of taste iiroduced by certain foods 

 will often disappear entirely. This fact also accounts for loss 

 of taste in cases of colds in the head, the nasal passages being 

 clogged by mucus. Certain substances taste sweet when first 

 taken into the mouth and bitter when swallowed. This is due 

 to the fact that these substances are capable of stimulating both 

 sweet and bitter taste buds and also demonstrates that these 

 primary sensations are carried by different afferent nerve fibers. 



Olpaotoet Sensations. 



Distribution of fibers and end organs. — The nasal cavity 

 is located just above the hard palate. It commxinicates 



Fig. 210 — Section of nose showing outer waU of riglit nasal carity; u,, b, o, d, 

 interior of nose; ft, olfactory bulb giving off nerves to inside of nose. 



with the external air through the two nasal openings and 

 with the pharynx by a single posterior opening. The 



