188 ANSWJKRS TO PRACTICAL QUESTIONS 



12. Is a seldom-opened parlor likely to be a healthy 

 room ? 



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

 niture, 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 ? 



(See Physiology, p. 204, note.) 



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



14. In amputating a limb, what party ivhen divided , 

 ivill cause the keenest pain ? 



When a surgical operation is performed, the most painful 

 part of it is the incision through the skin ; the muscles, carti- 

 lage, and bone being comparatively without sensation. Hence, 

 if we could benumb the surface, certain of the lesser operations 

 might be undergone without great inconvenience. This is, in 

 fact, very successfully accomplished by means of the cold pro- 

 duced by throwing a spray of ether, or of some other rapidly 

 evaporating liquid, upon the part to be cut. 



15. 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, deranged nutri- 

 tion, and hence a disturbance, of the entire economy. 



16. Is there any truth in the proverb that "he who 

 sleeps f dines" ? 



The proverb expresses the fact that the nourishment of the 

 brain and other parts goes on actively during sleep, they being 

 controlled by the sympathetic nerves. 



17. What does a high, wide forehead indicate? 



It suggests a large brain and a high intellectual power. 



18. How does indigestion frequently cause a headache? 



Through the action of the sympathetic system. 





