THE TASTE, TOUCH, AND VOICE. 65 



constitutes a part of the face. The nostrils are two in 

 number. In the Mammals the outer walls of the nose are 

 made of cartilage, but internally the nostrils communicate 

 with bony cavities, and these cavities are lined with what 

 is called the pituitary membrane, on which are expanded 

 the olfactory nerves or nerves of smell. 



Odors are particles of extreme fineness which escape from different 

 bodies and spread through the air like vapors. These are received 

 through the nose and excite the nerves of smell, and the nerves of 

 smell send the impressions which they receive to the brain. 



The taste is the sense by which animals perceive the 

 flavor of bodies, and by which they are mainly guided in 

 the choice of their food; though smell also aids them in 

 this matter. The nerves of the taste terminate in the tongue, 



O " 



and in little bodies called papillae which cover its surface. 

 In some kinds of Mammals these are very harsh, as in the 

 cat tribe, and in the ox ; in others, as in Man and in the 

 dog, they are very soft and delicate. 



The sense of touch in the Mammals is spread over the 

 whole body, since the nerves of sensation expand over the 

 whole surface of the body ; but the sense of touch in its 

 greatest perfection is limited to certain parts of the body. 

 In Man the sense of touch in its true power resides in the 

 hand in the fingers, which are especially adapted for the 

 exercise of this faculty. No other mammal, probably, ex- 

 hibits this sense in so great perfection as he ; though the 

 trunk of the Elephant possesses the same in a remarkable 

 degree. 



With the exception of the Birds and a few reptiles, the 

 Mammals are the only animals that are furnished with .vocal 

 organs. So that if the Mammals, Birds, and Reptiles were 

 removed from the earth, no vocal sounds would be heard ; 

 for we must bear in mind here, that the buzzing of bees, 



