90 THE HUMAN BODY. 



besides, much more susceptible than grown persons to the 

 bad effects of these things. 



TOBACCO. 



6. Tobacco is a drug of very great power. A drop of 

 the oil extracted from it, placed on the tongue of a dog, 

 will kill him almost as quickly as prussic acid. It is 

 occasionally used as a medicine, but with caution, because 

 its effects are so severe. 



Its odor and taste are disagreeable. When taken for 

 the first time, it causes intense nausea and wretchedness. 

 By persisting in its use, the revolt of nature is commonly 

 overcome, and a liking for it is acquired. Its immediate 

 effect is then a feeling of tranquillity and comfort. Sol- 

 diers and sailors, and others who have to endure great 

 physical labors, find in it support and relief. Students 

 use it because it gives them a freer flow of ideas; men of 

 pleasure, because it causes agreeable sensations. In some 

 cases it seems to do no harm : in others, its bad effects are 

 easily seen. 



7. It diminishes the appetite for food. It sometimes 

 causes disease of the mouth and throat. It weakens the 

 stomach. It becomes an absolute necessity: brain and 

 stomach demand it. Often the amount used must be 

 increased until it is hardly ever out of the mouth. At 

 first soothing the nerves, it at last makes them irritable 

 and unsteady. 



8. Its effect on the heart is so marked, that the term 

 "smokers' heart" is well known to physicians as indicating 

 irregular and weak action. The student whose brain is 

 rendered more active by it, may find himself suffering at 

 length from head-troubles, and failure of nerve-strength; 



