THE SPECIAL SENSES 35 



of the sensibilities. In insect life we find the sense of 

 touch, the sense of sight, the sense of taste, the sense of 

 smell, and the sense of hearing. 



The Study of the Special Senses. Our impressions of 

 the character of the world around ns are based upon 

 experiences gained through organs of special sense. We 

 are acquainted with only those things which influence 

 our senses, and so, in speaking of special senses, we are 

 wont to consider them from our own standpoint. There- 

 fore our study of the senses of those forms of life which 

 cannot communicate their impressions directly to us, 

 must be carried on by comparison with our own impres- 

 sions. In ourselves, we are aware of five senses, namely : 

 smell, touch, taste, hearing, and sight. In our classifi- 

 es lion of the senses of lower animals, we classify the 

 senses of these animals accordingly as the actions of 

 these senses compare with the physiological functions 

 of our own. It is possible that other forms of life have- 

 other senses, but it is somewhat difficult for us to com- 

 prehend clearly the character of a sense which we our- 

 selves lack. Dissections of special sense organs do not 

 always give conclusive evidence as to the significance 

 of the sense organs. For instance, it would be hard 

 to tell, by cutting to pieces, whether a certain organ was 

 used for tasting or smelling, or for either. Our conclu- 

 sions are frequently based upon observations made upon 

 the actions of certain special sense organs. Our present 

 knowledge, then, of special sense organs 1ms been gained 

 by experiments with living Wins, and by anatomical 

 investigations. 



