THE SPECIAL SENSES 285 



sense organs each designed to perceive its special kind of sen- 

 sation and is incapable of reporting any other. 



246. The Special Senses. Several of the organs of special 

 sense do not have to come in contact with what they report 

 upon to be affected by them. By the sense of sight, the eye 

 perceives, often at considerable distances, sizes, colors, shapes 

 and motions and by the sense of hearing, the ear detects vibra- 

 tions in other bodies. The sense of smell enables the nose to 

 judge of the odors of substances at a distance, though in this 

 case particles of the substance in a finely divided condition or 

 in the gaseous form must enter the nose and come in contact 

 with the sense organs. By the sense of taste, the tongue judges 

 of the flavors of -different substances, though this sense is not 

 as comprehensive as we often imagine it to be, for much of 

 what passes for taste is really due to sensations sent to the 

 brain by the nose. To be tasted, substances have to be dis- 

 solved. The sense of touch is the most widely distributed of 

 all the special senses, being located throughout the skin and in 

 many parts of the mucous membrane as well. It is probably 

 the sense from which all the others have been derived. The 

 five special senses are commonly supposed to be all that the 

 body possesses, but it can be easily shown that there is a tem- 

 perature sense in the skin by means of which we are able to 

 ascertain whether a thing is hotter or colder than the skin 

 itself, and an equilibrium, sense in the ear which keeps the body 

 informed of its position in space. 



246. The End Organs of Special Sense. The end organs of 

 special sense, each responding to its appropriate stimuli, are 

 necessarily modified for the duties they have to perform. 

 Those which are concerned with touch and temperature are 

 found in papillae very much like the other papillae of the 

 dermis. Those which receive sensations of touch are some- 

 what unevenly distributed, being most numerous on the tip of 

 the tongue, the lips, finger tips and forehead, and farthest 



