THE SPECIAL SESNES. 51 



have generally a strong and peculiar smell, although 

 this is by no means always the case. 



THE SENSE OF TASTE. 



The special nerves of taste have their 

 The Tongue, loop-like endings chiefly in the tongue, 



which is, consequently, usually spoken 

 of as the organ of taste. But these papillae, or end 

 expansions of the nerve of taste are also distributed 

 over the walls of the back part of the mouth. On 

 account of the numerous little folds of nerve endings 

 on the tongue, this organ has quite a velvety appear- 

 ance. Besides serving as the chief organ of the 

 sense of taste, the tongue also aids in the chewing 

 of the food and in producing the sounds of speech. 



When substances which have a taste come 

 HOW We . . 



Perceive in contact with the papillae or nerve loops 



Taste. Q ^ e tongue, the impression is at once 

 carried to the brain and mind. In order that 

 such an impression can be made the substance 

 to be tasted must be in a dissolved state. 

 No dry or solid substance can be tasted. So 

 -the mouth is" kept moist, and, as we shall learn 

 later, during the process of eating, a large quantity 

 of saliva is thrown into the mouth. This dis- 

 solves at least a portion of the food or substance 

 which is in the mouth, so that its taste is well per- 

 ceived. When the mouth is dry from disease, or 

 from great thirst, food has but little taste and is 

 very unpalatable. So when the nerves of the tongue 



