184. ANSWERS TO I'RACTICAL QUESTIONS 



1 1. When one's finger is burned, where is the ache ? 



All pain is in the brain. It is located, however, by the 

 mind, at the place of the injury. 



12. Is a parlor generaHy a healthy room ? 



No. It is generally ill-ventilated, and, to preserve the 

 furniture, kept dark, and hence damp. 



13. Why can an idle scholar read his lesson and at the 

 same time count the marbles in his pocket ? 



The duality of the brain may, perhaps, account for this. 



(See Physiology, page 162, note.) 



14. In amputating a limb, what part, when divided, will 

 cause the keenest pain ? 



When a surgical operation is performed, the most pain- 

 ful part of it is the incision through the skin ; the muscles, 

 cartilage, and bone being comparatively without sensa- 

 tion. Hence, if we could benumb the surface, certain of 

 the lesser operations might be undergone without great 

 inconvenience. This is, in fact, very successfully accom- 

 plished by means of the cold produced by throwing a 

 spray of ether, or of some other rapidly evaporating liquid, 

 upon the part to be cut. 



1 5. What is the effect of bad air on nervous people ? 



The nerves connect all the organs of the body. They 

 are therefore especially sensitive to a derangement in the 

 function of any organ. Bad air causes impure blood, de- 

 ranged nutrition, and hence a disturbance of the entire 

 economy. 



