TASTE AND SMELL 



99 



tory lobe. These deeper cells send axis cylinder processes 

 up and along the olfactory tract to different centers in 

 the gray matter of the cerebrum. 

 These centers lie in the temporal 

 lobe, back of the eye (Fig. 58). 



The olfactory nerves have a 

 path exceptionally direct from 

 their external or peripheral end 

 to the brain center in which 

 they rise. Just what is the 

 connection between this fact 

 and the other often observed 

 fact that stronger mental asso- 

 ciations cling about sensations 

 of smell than about almost any 

 other external impressions, it is 

 not easy to say. 



Strong reflex nervous action 

 often results from excessive stimulation of the olfactory 

 nerves, as when a person faints in consequence of inhal- 

 ing certain odors. 



130. Effects of Alcohol upon Taste and Smell. The ha- 

 bitual use of drinks containing alcohol, of tobacco, and of 

 very strongly flavored foods is found to dull the sense of 

 taste, and by alcohol, at least, the olfactories are rendered 

 less acute. 



Fig. 58. Diagram of the path 

 of an olfactory impulse. 



The impulse passes from the 

 olfactory cells of the nose to the 

 olfactory bulb (01. B} , and thence 

 to the olfactory center (01. G) on 

 the inner side of the temporal 

 lobe of the cerebrum. 



DEMONSTRATIONS AND EXPERIMENTS 



42. The Tongue. By the aid of a hand mirror the pupil can 

 easily distinguish the filiform and fungiform papillae, on his own 

 tongue. The circumvallate papillae lie so far back that it will be 

 found more convenient to demonstrate them on the tongue of one of 

 the domestic animals (dead). 



