J 94 ANSWERS TO PRACTICAL QUESTIONS 



act of " sniffing," which is a mixed respiratory and nasal 

 muscular effort, is used to bring odorous substances more 

 surely and extensively into contact with the upper and 

 proper olfactory region of the nose, besides causing a 

 larger amount of them to pass over the mucous surface in 

 a given time. -MARSHALL. 



20. Why do red-hot iron and frozen mercury (40) 

 produce the same sensation ? 



The sensation in both cases is that of pain, not that of 

 touch. 



21. Why can an elderly person drink tea which to a child 

 would be unbearably hot ? 



The sensation of touch has become impaired, and is 

 much less delicate. 



22. Why does an old man hold his paper so far from his 

 eyes? 



" Far sight " is common among elderly people, and is 

 remedied by convex glasses. In old age the power of 

 adjusting the crystalline lens is lost. 



23. Would you rather be punished on the tips of your 

 fingers than on the palm of your hand ? 



The sense of touch is much keener in the tips of the 

 fingers than in the palm of the hand. 



24. What is the object of the eyebrows ? Are the hairs 

 straight ? 



They serve to prevent the perspiration of the forehead 

 from running down into the eye. They act, in a measure, 

 with the eyelashes, also to screen the eye from the dust 



