AND PHYSIOLOGY. 



401 



skin, in which are found the loop of a nerve, and a blood- 

 vessel with some cellular tissue. The main use of them seems 

 to be to place the nerve in such a position, that it will be most 

 easily impressed with whatever external substances it may be 

 brought into contact. 



FUNCTIONS. 



736. The Superficial Parts of the Body most 

 abundantly Supplied with Nerves.— The parts of the 

 body lying deep beneath the skin, are but sparingly supplied 

 with nerves of sensation, which is a great comfort to those un- 

 fortunate persons who are subjected to surgical operations, 

 since the most painful part is in cutting through the skin, 

 which is the quickest part of the operation. This, however, 

 is the case only when the deep parts are in health (including 

 the bones) ; for if any of these parts, and especially the bones 

 and ligaments, are diseased, they constitute a source of the 

 greatest pain. The necessity of this arrangement is obvious 

 from the protection which the surface of the body requires 

 from violence and heat. Were it not for these body-guards, 

 we by our other senses should seldom know when friction or 

 heat was consuming the skin, nor when cold was destroying 

 its vitality. 



737. Value of this Sense to the Blind.— To those de- 

 prived of the sense of vision, this sense is of great value, since 

 it is by this only that they are enabled to pursue any labor, 

 or instruct and please themselves by raised alphabets, or 

 play upon musical instruments. And it is interesting, not to 

 say wonderful, to see what accuracy is acquired by the blind 

 in detecting true from spurious coins, or in distinguishing the 

 quality of cloth by feeling alone. It is said on good author- 



Wbat is the function of the papillae? 736. Why are the superficial parts of the body 

 the most abundantly supplied with sensitive nerves ? Why does the skin need sensibil- 

 ity ? 737. What is said of the value of this sense to the blind ? What example* *re 

 mentioned as illustrating its extreme acuteness in the blind ? 



