The Hygiene of Tobacco 297 



than if it were the most prized drug in the physician's 

 dispensary. 



The opportunity may be taken here to explain the 

 physical constitution of tobacco. The green leaf con- 

 tains a large percentage of complex organic bodies, 

 which retard combustion and emit a most offensive 

 smell in burning. The curing and manufacture of 

 the green leaf into smokable tobacco get rid of or 

 modify these bodies. Excessive fermentation, how- 

 ever, blackens the leaves and produces ammonia 

 compounds. 



Tobacco consists largely of mineral constituents. 

 These burn into ash, which should be white or grayish- 

 white in colour. In good dry leaf the ash is not 

 excessive in quantity, forming from 12 to 20 per cent, 

 of the leaf. Reddish ash denotes the presence of 

 iron, and black ash is due to excess of carbon result- 

 ing in imperfect combustion. 



Nicotine (QoHN), the essential characteristic alka- 

 loid of tobacco, found in no other plant, is colourless 

 and liquid at the ordinary temperature. It. is a 

 virulent narcotic poison. Nicotine, it may be noted, 

 is an antidote to strychnine and strychnine to nico- 

 tine. Nicotine is not present in large quantities in 

 tobacco, forming from i to 9 per cent. French and 

 German tobaccos contain the most, 9 per cent, Vir- 

 ginia and Kentucky 4 or 5 per cent, and Havana 

 and Manila only 2 to 3 per cent. 



Small as is the percentage of nicotine, it is largely 

 consumed and destroyed in the smoke, the ratio 

 depending on the freeness of combustion. The greater 

 bulk of nicotine is therefore not inhaled. 



