THE NERVOUS SYSTEM 137 



The True Function of Stimulants. One whose heart 

 has nearly given out because of exposure to severe weather 

 may be temporarily revived by alcohol. It will not be wise 

 to do so unless it is certain that a warm fire and protection 

 will be reached before the reaction comes. Much less would 

 be necessary to revive an abstainer than a drunkard. Ha- 

 bitually disturbing the body with stimulants makes them 

 ineffective in a time of emergency. A cup of coffee will 

 not keep a watcher awake if he is used to coffee. 



Definitions : Stimulant, Narcotic, Poison. A stimulant 

 is anything that excites the body to activity, but is of no help 

 or of insignificant help, in replacing the strength used up. 



A narcotic is anything that deadens or dulls the nervous 

 system. It comes from a word meaning " to benumb." 



Poisons are active substances, which, taken in quantities, 

 as man takes food, destroy life ; in smaller quantities they 

 injure the body and may destroy life. Alcohol is a poison. 

 Wine, beer, whisky, contain varying quantities of it. 



The Narcotic and Stimulant Effects of Poisons. Ex- 

 amples of poisons are alcohol, nicotin, opium, arsenic, 

 strychnin. Poisons excite the body when taken in small 

 doses, while in large doses they produce paralysis and 

 death. The irritating or stimulating effect is due to de- 

 rangement of the functions or to the efforts of the cells to 

 free the body of the destructive substance. The narcotic 

 effect is due to the poison having so benumbed the nerves 

 and injured the cells that their activities cease, or become 

 less for a time. You readily see how the same poison can 

 be both a stimulant and a narcotic : the stimulating effect 

 always comes first, followed by the stupefying effect. If the 

 dose is very small, the stimulating effect will last longer ; 

 if it is large, the narcotic effect is greater and felt more 

 quickly. A habit of using stimulants is an invariable sign 



