TOBACCO 423, 



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- ^/aoo of gelsemine (with gelatine) are used for application 

 to the eye. 



SECTION" III.— DETJGS ACTING CHIEFLY 01^ THE 

 MOTOK NERVES. 



Glass I, — Depressing the Motor Nerves. 



Tabacum. Tobacco. 



Synonym. — Tabaci folia, B. P. 



The commercial dried leaves of ISTicotiana Tabacum 

 Linne (nat. ord. solanacese). 



Habitat. — Tropical America. Cultivated in various 

 temperate 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, Cio Hj^ Ng (0.7-5.-10 

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

 tobacco in odor and taste. Ereely soluble in alcohol and 

 ether ; less so in water. jSTicotine is decomposed by heat and 

 therefore tobacco smoke contains little of it, but in its stead, 

 pyridine C5 Hg JST, and various allied alkaloids, viz. : picoline, 

 Cg H7 N"; lutidine, C7 H9 IST; rubidine, Cji H^^ IST; coridine, 

 CjoHislSr; parvoline, CgHigJST; and collidine, CgHuN; 



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