313 VEGETABLE DRUGS 



SECTION III.— DRUGS ACTING CHIEFLY ON THE 

 MOTOR NERVES. 



Class 1. — Depressing the Motor Nerves. 



Tabacum. Tobacco. 

 (Non-official.) 



Synonym.— Tahaci folia, B. P., Fr. ; Tabak, G. 



The commercial dried leaves of -Nicotlana Tabacum Linne (nat. ord. 

 solanaceae). 



Habitat. — Tropical America. Cultivated in various temperate and tropical 

 parts of the earth. 



Description. — The leaves are up to 50 cm. long, oval, or ovatelanceolate, acute, 

 entire, brown, friable glandular-hairy of a heavy, peculiar odor and- a nauseous, 

 bitter and acrid taste. 



Constituents.— Chiefly nicotine, C^ Hu N^ (0.7-5.-11. 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 little of it, but in its stead, pyridine, C5H5N, and various 

 aUied alkaloids, viz., picoUne, C„H,N; lutidine, C,H„N; rubidine, CuH„N; cori- 

 dine, Ci„H„N; parvoline, CoH^N; and collidine, CsHuN; together with small 

 amounts of sulphur, creosote, acetic and hydrocyanic acids and carbon compounds. 

 Pyridine resembles nicotine in depressing the central nervous system and motor 

 nerves and in paralyzing respiration, and is said to be formed more in pipe 

 smoke, while, in the smoke of cigars, the less harmful collodine is produced by 

 dry distillation. Furfurol is another harmful constituent of tobacco smoke— one 

 of the constituents of fusel alcohol in new whiskey and distilled liquors producing 

 headache. There is as much furfurol in some cigarettes as in 2 ounces of whiskey. 

 Nicotine and furfurol exist to very slight degree in Turkish tobacco. 



Do«e.— Nicotine, H. & C, gr. 1/60-1/20, (.001-.003). 



Action of Tobacco and Nicotine. 



Action External. — Tobacco is a local anodyne^ antiseptic and para- 

 siticide. 



Action Internal. — Digestive Tract. — The physiological effect of 

 tobacco is due to nicotine. Nicotine increases peristaltic action and, in 

 large doses, causes tetanic spasm of the intestines, even when it is injected 

 into the blood. This happens through paralysis of the inhibitory or 

 splanchnic ganglia, and stimulation of the motor ganglia (Auerbach's) in 

 the bowel walls. In toxic quantities nicotine is a powerful gastro-intes- 

 tinal irritant, and produces the usual symptoms of pain, vomiting (in ani- 

 mals capable of the act), purging and collapse. 



Circulation. — The action of nicotine on the circulation is complicated. 

 The chief effect is due to primary stimulation of the vagus centre and 

 heart muscle with more forcible contractions and slowing of the heart, 

 followed shortly by depression of the cardiac vagus ganglia and heart 

 muscle, with feeble and rapid pulse — after large toxic doses. In the 

 same manner there is a transient stimulation followed by depression of 

 the vasoconstrictor centres and ganglia, with consequent primary rise 

 and subsequent fall in blood tension. 



Nervous System and M-uscles. — Nicotine acts first to stimulate the 

 reflex excitability of the spinal cord, medulla and hind brain in large 



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