42 FIRESIDE SCIENCE. 



stove and volatilized, in a church or theatre, will 

 produce distressing cough and asthma simultaneously 

 upon thousands of people. The one hundredth part 

 of a grain, pricked into the skin with a pin, will 

 produce giddiness, nausea, and fainting. This 

 poison exists in tobacco in the proportion of from 

 two to nine pounds in one hundred of the dried 

 leaves, the quantity varying in tobacco grown upon 

 different soils. 



A consideration of .these facts regarding nicotine is 

 well calculated to surprise and alarm every smoker. 

 There is no exaggeration in the statement ; but we 

 must remember that nicotine does not exist in to- 

 bacco in a free state. It is called by chemists an 

 alkaloidal principle, and found in tobacco in chem- 

 ical combination with an acid. The acid is identical 

 with the malic, found in fruits ; but in tobacco it is 

 called nicotic acid. The virulence of nicotine is 

 considerably modified not only by its association 

 with the acid which it holds, but probably by the 

 presence of the other substances. Modified, how- 

 ever, as it is, it confers upon tobacco poisonous 

 properties of a most extraordinary character. 



The third distinguishing chemical agent which 

 tobacco contains, is an empyreumatic oil, which is 

 obtained when the cured leaves are distilled in con- 

 nection with high-pressure-steam. Foxglove (Digi- 

 talis purpurea), another of the poisonous plants, 



