TOBACCO 399 



readily to opium, coal tar products, etc. As a mydriatic, 

 gelsemine is not to be compared with atropine for general 

 purposes, but its action is more transient. A solution (gr.8- 

 3 i.) is instilled (in man) in drop doses every fifteen minutes 

 for one hour, and then every thirty minutes for two hours, 

 to secure wide dilatation of the pupil ; or discs, containing 

 gr.g^ of gelsemine (with gelatine) are used for application 

 to the eye. 



SECTION III.— DEUGS ACTING ON THE SPINAL 

 COED AND MOTOE NEEVES. 



Class 1. — Depressing the Inferior Cornua 

 and Motor Nerves. 



Tabacum. Tobacco, 



Synonym. — T abaci folia, B. P. 



The commercial dried leaves of Nicotiana Tabacum 

 Linne (nat. ord. solanacese). 



Habitat. — Tropical America. Cultivated in various tem- 

 perate and tropical parts of the earth. 



Description. — The leaves are up to .50 Cm. long, oval or 

 ovate-lanceolate, acute, entire, brown, friable, glandular- 

 hairy, of a heavy, peculiar odor and a nauseous, bitter and 

 acrid taste. 



Constituents. — Chiefly nicotine, Cjo H^^ Nj (0.7-5.-10 per 

 cent.). A colorless, volatile, oily alkaloid, resembling tobacco 

 in odor and taste. Freely soluble in alcohol and ether; 

 less so in water. Nicotine is decomposed by heat and 

 therefore tobacco smoke contains none of it, but in its stead, 

 pyridine Cg Hg N, and various allied alkaloids, viz.: picoline, 

 Cg H^ N ; lutidine, C, Hg N ; rubidine, C^ Hj, N ; coridine, 

 Cio His N ; parvoline, Cg H^a N ; and collidine, C^ H^ N ; 

 together with small amounts of sulphur, creosote, acetic 

 and hydrocyanic acids and carbon compounds. Pyridine 

 resembles nicotine in depressing the spinal motor tract and 



