332 THE NERVOUS SYSTEM 



instances that even the manhood which seems strongest 

 may be overcome, and so refuse to take the fearful risk of 

 placing himself within the power of so insidious a foe ? 

 Does not the truest courage lead a man to avoid ventur- 

 ing needlessly and recklessly into the presence of so terri- 

 ble a danger? And should not a man of really noble 

 character deliberately choose to make his influence help- 

 ful, rather than harmful, to those weaker than himself ? 



481. Other Narcotics in Common Use. Narcotics are very 

 widely used by the human family for the relief which 

 they give from pain or fatigue, or for the direct pleasur- 

 able sensations which they impart. All are deadly poisons 

 when taken in sufficient quantities. Those most common 

 (after alcohol) are tobacco and opium. 



It has already been shown that tobacco may affect 

 unfavorably many parts of the system, and is especially 

 injurious to the young. It stimulates in small quantities 

 and narcotizes in larger ones, working its effects directly 

 upon the nervous system. Nicotine is a powerful poison 

 found in tobacco. It affects the nerve cells, injures the 

 brain, and leads especially to weakness of the heart by 

 interfering with its supply of nervous force. Many 

 cases of cancer of mouth and throat are believed to 

 have resulted from tobacco smoking. 



Opium, for its benumbing influence upon the nerves, is 

 used by large numbers of persons, especially in Oriental 

 lands. Its continued use deranges all the digestive proc- 

 esses, disorders the brain, and weakens and degrades the 

 character. Like alcohol, it produces an intolerable crav- 

 ing for itself, and the strongest minds are not proof 

 against the deadly appetite. 



482. Self-control versus Appetite. Man is a bundle of 

 appetites. Every organ, every cell even, craves its appro- 



