SPECIAL SENSES 369 



epidermal tissue of the skin (fig. 183). It is believed that 

 those end organs that give the sense of pain lie nearer the 

 surface, while those for the sense of warmth lie more deeply 

 in the skin. 



The pressure spots are very dose together at the tips of 

 the fingers and on the tongue, a condition which makes these 

 places very sensitive to touch. Most parts of the body are 

 covered with fine hairs. Physiologists have shown that 

 pressure points lie over the hair follicles, and that the pressure 

 nerve fibrils end in a ring surrounding the hair follicle. Any 

 movement of the hair, therefore, stimulates the nerve fibril. 



Fig. 183. Papillae of skin in palm of hand (epidermis removed). E, 

 end organ of nerve; N, nerve; B, blood-vessels; V, capillaries. (After 

 Sappey.). 



Sense of taste. — The sense of taste is carried to the 

 brain through nerve fibers that have their end organs in 

 the mouth-cavity, particularly on the tip, the borders and the 

 back of the tongue. 



The circumvallate papilla shown in fig. 184 are the 

 largest taste papillae, but are few in number. In all of the 

 taste papillae there are found certain minute organs formed 

 of a mass of delicate cells each ending in a microscopic hair 

 which projects at the surface of the organ. These organs 

 are called taste buds and are the true sense cells, the hair- 

 like process being the part that is stimulated by substances 



