CHAPTER XLII 

 THE EFFECT OF DRUGS ON THE BODY 



248. Drugs. Although plants, or substances derived from 

 plants, make up the bulk of our food, there are, nevertheless, 

 many plants in the world which react in a harmful way with the 

 protoplasm of the body. Even mustard, which is used in 

 small quantities with the food as a condiment, when applied 

 in larger amounts to the skin will form blisters. Contact 

 with poison ivy or poison sumach may also cause the skin to 

 blister, accompanied by an intolerable itching. The common 

 nettle, if lightly touched, will sting the hand with almost the 

 intensity of a bee sting. Fortunately there are very few plants 

 in the United States that act as contact poisons, but there are 

 a great many of even our common plants that will cause death 

 if eaten. Most of these plants are harmful because of an 

 alkaloid they contain, but the fact that the alkaloids strongly 

 affect different parts of the body may be taken advantage of 

 in medicine. In the hands of a skilful physician even the 

 most deadly may be used in the cure of disease. The plants 

 and plant products used in medicine are called drugs. In 

 the case of most drugs, however, it is not the drugs themselves 

 which cause the cure but rather the nervous system which is 

 stimulated by the drugs to cause a greater activity in the cells. 

 It is sometimes a question whether drugs are really of use in 

 illness, and the physician is coming more and more to rely upon 

 rest, a proper diet, and careful nursing for the recovery of his 

 patient. 



249. Use of Drugs. Although the physician may prescribe 

 drugs to be taken during illness, when we recover our health, 

 we are in no need of drugs. Nevertheless, in almost every 

 land, man has shown a disposition to make use of certain sub- 

 stances of this kind. Those he most favors are such as give 



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