360 



ELEMENTARY PHYSIOLOGY 



glossopharyngeal, the other the gustatory, which 

 is a branch of the fifth nerve (see Lesson XI.). The 

 latter chiefly supplies the front of the tongue, the former 

 its back and the adjacent part of the palate ; and there 

 is reason to believe that difl'erent taste sensations are 

 supplied by the two nerves. 



The peculiar cells in the taste-buds are the sense- 

 organules of taste, and, with the delicate terminations of 

 the glossopharyngeal and gustiitory nerve which may be 

 traced to them, constitute the essetdial parts of the organ 



Pio. 114. — Diagram of a Circumvallatk Papilla, and of Taste-Buds. 



A, A circumvallate papilla cut across ; e, epidermis ; d, dermis ; t, 

 taste-buds ; n, nerve fibres. 



B, Two taste buds ; e, epidermis ; d, dermis ; c, the outer or cover 

 cells shown in the lower bud; n, four inner cells with processes; m, 

 processes projecting at mouth of buds. 



of taste. The tongue itself, which by its movements 

 brings the sapid sulistances into immediate contact with 

 these modified epithelium cells, may be regarded as the 

 accessory part. 



The great majority of the sensations we call taste, how- 

 ever, are in reality complex sensations, into which smell, 

 and even touch, and the temperature sense, as in the 

 sensation of cold produced by peppermint, largely enter. 

 When the sense of smell is interfered with, as when the 



