XVIII 



THE SPECIAL SENSES AND SENSATIONS 



255 



get sensations of rough and smooth, wet and dry, soft 

 and hard, and hot and cold. In the muscles, joints, and 

 tendons, similar " touch bodies " are found which give 

 us sensations that make muscular contractions accu- 

 rate, and balancing, 

 standing, and walk- 

 ing possible. 



The sense of ^p am JT B 



A '* ' *W 



touch may be 

 highly developed 

 by regular exercise. 

 The blind read by 

 passing the fingers 

 over slightly raised 

 letters or points. 

 They distinguish 

 their friends and 

 all objects about 

 them by the touch. 

 The quality of paper, silks, and other fabrics is deter- 

 mined by expert buyers very largely through the sense 

 of touch. 



1. Blindfold a member of the class and touch different parts of 

 his body. Ask him to locate accurately the part touched. 



2. Touch the palm of the hand with a colored pencil and have 

 him find the exact point with another pencil. Measure the distance 

 between the two points. Repeat this several times on the same part 

 of the body. 



3. Try different parts of the body in the same way. 



4. With the points of a pair of scissors slightly separated touch 

 the tip of the index finger. How far apart can you feel the points 

 as two when placed on the skin at the same time ? 



FIG. 134. Different kinds of touch bodies. 

 A, from the cornea of the eye ; B, from the 

 tongue of the duck ; and C, D, E, from the 

 skin of the fingers. (Drawn by Zinns.) 



