19** ANSWERS TO PRACTICAL QUESTIONS 



of the tongue, and perceives especially sweet and sour 

 substances, ramifies over the face, and hence an acid will 

 "pucker" the features ; while the gth pair, at the base of 

 the tongue, which is sensitive to salt and bitter tastes, is 

 distributed also to the throat, and is in sympathy with the 

 internal organs, since it seems to be " a common nerve of 

 feeling for the mucous membrane generally." 



36. Is there any danger of looking "cross-eyed" for 

 fun? 



The muscles used thus in sport may become perma- 

 nently distorted. 



37. Should school-room desks face a window ? 



No. The light should be admitted so as to fall over 

 the shoulder upon the book. Many school-rooms are 

 arranged to accommodate the teacher only, while a blind- 

 ing flood of light pours directly into the faces of the 

 pupils. 



38. Why do we look at a person to whom we are listening 

 attentively ? 



One sense instinctively aids another. 



39. Do we really feel with our fingers ? 

 No. All sensation is in the mind. 



40. Is the eye a perfect sphere ? 



No. The front projects somewhat, while, at the back, 

 ihe optic nerve is attached like the stem to a fruit. 



