THE EAR, HEARING, TASTE AND SMELL 241 



taste which reach the tongue by way of the trigeminal nerve spring 

 from the medulla as part of the sensory branch of the facial. 



On the tongue most of the sensory nerves run to papillae; the 

 circumvallate have the richest supply, and on these are peculiar 

 end organs (Fig. 77) known as taste-buds; they are oval and em- 

 bedded in the epidermis covering the side of the papilla. Each 

 consists, externally, of a number of flat, fusiform, nucleated cells 

 and, internally, of six or eight so-called taste-cells. The latter are 

 much like the olfactory cells of the nose, and are probably con- 

 nected with nerve-fibers at their deeper ends. The capsule formed 

 by the enveloping cells has a small opening on the surface; each 

 taste-cell terminates in a very fine thread which there protrudes. 

 Taste-buds are also found on some of the fungiform papillae, and 



FIG. 77. Taste-buds. 



it is possible that simpler structures, not yet recognized, and con- 

 sisting of single taste-cells are widely spread over the tongue, 

 since the sense of taste exists where no taste-buds can be found. 

 The filiform papillae are probably tactile. 



In order for substances to be tasted they must be in solution: 

 wipe the tongue dry and put a crystal of sugar on it; no taste will 

 be felt until exuding moisture has dissolved some of the crystal. 

 Excluding the feelings aroused by acid substances, tastes proper 

 may be divided into sweet, bitter, acid, and saline. Although con- 

 tributing much to the pleasures of life, they are intellectually of 

 small value; the perceptions we attain through them as to quali- 

 ties of external objects being of little use, except as aiding in the 

 selection of food, and for that purpose they are not safe guides at 

 all times. 



Many so-called tastes (flavors) are really smells; odoriferous 



