HYGIENE OF THE NERVOUS SYSTEM 319 



466 How to induce Sleep. Insomnia has become so com- 

 mon of late that special attention should be paid to ways 

 of promoting sleep. A great variety of drugs are used 

 for the purpose, but some of them are extremely danger- 

 ous, and none of them should ever be taken except by the 

 advice of a competent physician. Any activity of cells, any 

 production of energy, nervous energy as well as other 

 forms, gives rise to certain substances harmful to the 

 body. By natural provision the presence of this waste 

 matter in the blood causes a feeling of fatigue which in- 

 clines to a lessening of activity and gives opportunity for 

 recuperation. To promote sleep, we cat off so far as possi- 

 ble the various sources of stimulus to the nerves. We 

 recline at full length that the trunk muscles may be relieved 

 from the effort to preserve the equilibrium. We remove all 

 burdensome or uncomfortable clothing which might con- 

 stantly excite the nerves of the skin. A warm bath just 

 before retiring tends to allay external irritation and helps 

 to withdraw the blood from the head. We darken the 

 room and close the door against noise. For some hours 

 before retiring our occupations should be free from excite- 

 ment. One who is inclined to sleeplessness should do no 

 evening brain work. A serene frame of mind conduces 

 to repose. Although late and heavy meals are not to be 

 recommended, it has been found that to eat moderately of 

 easily digested food at bedtime will sometimes withdraw 

 the blood from the brain and dispose to sound sleep. 

 Active physical exercise during the day, sufficient to cause 

 fatigue of the muscles, is usually followed by restful sleep. 

 For brain workers a short period of active exercise before 

 retiring a quick walk or practice with dumb-bells or 

 Indian clubs may promote sleep. So may a hot foot- 

 bath, or vigorous rubbing of the feet and legs, or other 



