CONTAMINATED AIR 163 



some consideration. Speaking for these, David Starr Jordan 

 said, " We ask for a free passage through the world, with 

 pure air all the way." 



194. Nicotine. The tobacco of commerce is made of the leaf and 

 stalks of the tobacco plant (Nicotiana tabacum, a member of the 

 potato family). The tissues of this plant contain a violent poison 

 known as nicotine. Nicotine is a poison, either when taken internally, 

 that is, into the food pipe, or when injected into the body through 

 the skin. The people who are interested in tobacco, however, do not 

 " take " it that way ; they either smoke it, chew it, or snuff it. The 

 practical question is, What is the effect of nicotine when administered 

 in these ways ? 



195. Is smoking injurious? With very few exceptions the 

 first smoke nauseates the stomach, irritates the lining of the 

 windpipes and lungs, and irritates the eyes. Most people can, 

 with a few trials, get used to tobacco, so that further indul- 

 gence does not produce these acute effects. Finally, after one 

 has become used to it, tobacco has a soothing effect on the 

 nerves, so much so that the habitual user seriously misses his 

 supply if it is withheld for any length of time. 



The effects of tobacco-using on people vary according to 

 their sensitiveness to nicotine, their general health, and the 

 kind of work they do. Although cases may be found in which 

 no apparent harm has been produced by the use of tobacco, a 

 study of the effects of smoking on large numbers of people 

 has shown definite results, as (i) impairment of digestion, 

 (2) chronic irritation of the linings of the nose, larynx, wind- 

 pipes, and lungs, (3) effects on nerves and disturbance of 

 heart action, (4) retardation of growth, and (5) sometimes a 

 disturbance of the eyes. 



These effects of smoking need not all appear in one smoker ; 

 and it is quite possible that these effects are not all due to the 

 nicotine, of which only a small portion enters the system at 

 the worst. The smoke contains some of the products of 



