IN HYGIENIC PHYSIOLOGY. 189 



Jf). What is the cause of one's foot being " asleep " ? 



(See Physiology, p. 225, note.) 



20. When an injury to the nose has been remedied by 

 transplanting sltin from the forehead, why is a touch to 

 the former felt in the latter ? 



The mind refers the sensation to the place where the nerve 

 naturally had its origin i.e., the part over which its tiny fibers 

 were originally distributed. 



21. Are closely -curtained windoivs healthful ? 



No. They keep out the sun and the fresh air. 



22. W r hy, in falling from a height, do the limbs in- 

 stinctively take a position to defend the important organs ? 



The reflex action of the spinal cord moves the limbs, into a 

 position of defense, the brain having no time to act. 



23. What causes the pylorus to open and close at the 

 right time ? 



The reflex action of the nerves which preside over that 

 organ. In a similar way, a tickling in the throat excites 

 coughing. 



24. VTliy is pleasant exercise most beneficial ? 



A chief condition of keeping the brain healthy is to keep 

 the unconscious nervous functions in full vigor, and in natural 

 alternations of activity and repose. Thus it is that (besides its 

 effect in increasing the breathing and the general vigor of the 

 vital processes) muscular exercise has so manifest a beneficial 

 influence on a depressed or irritable state of mind. The bodily 

 movement, by affording an outlet to the activity of the spinal 

 cord, withdraws a source of irritation from the brain ; or it 

 may relieve excitement of that organ by carrying off its energy 

 into a safe channel. HINTON. 



25. Why does grief cause one to lose his appetite ? 



Through the action of the sympathetic system. 



26. W'Tiy should we never study directly after dinner ? 



