CHAPTER XXIII 

 THE CARE OF THE SENSE ORGANS 



Means of protection. The sense organs because of 

 their delicacy have been given careful protection by 

 nature whenever possible. This protection is usually 

 afforded by their location, as in the case of the organs 

 of smell, of taste and of hearing. In the case of the eyes, 

 however, the range of vision is so important that they 

 must be located on the surface of the body. They there- 

 fore have a special covering, the lids, which act as shut- 

 ters, to be opened for vision and closed for protection. 



Care of the ear. The ear would seem to be ade- 

 quately guarded by its location in a very deep bone of 

 the skull, where it can be reached only through a long 

 and crooked canal. This canal, however, must be kept 

 open so that sound waves may pass through it, and thus 

 it is the ear's weak point. Through the canal insects 

 may pass and objects may be thrust 1 in spite of the 

 protection afforded it by the growth of hairs. Insects 

 are easily removed by a drop of oil or water. The en- 

 trance of objects we ourselves can control. The drum 

 is so delicate that, were it not for the sake of cleanli- 

 ness, we might lay down the rule that we should permit 

 nothing whatever to be introduced into its canal. 



1 Recent investigations have shown that many prairie animals, 

 as wolves and coyotes, are deaf because of injury to the ear by the 

 entrance through the canal of the heads of certain grasses. These 

 have actually penetrated the drum and caused an inflammation 

 which has destroyed the inner ear. 



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