424 VEGETABLE DEUGS 



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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 coUidine is produced by dry dis- 

 tillation. Nicotine exists to a very slight degree in Turkish 

 tobacco. 



Dose.— Nicotine, H. & C, gr. V60-V20 (.001-.003). 



ACTIOK" OF TOBACCO AND NICOTINE. 



Action External. — Tobacco is a local anodyne, antiseptic 

 and parasiticide. 



Action Internal. — Digestive Tract. — The physiological 

 effect of tobacco is due to nicotine. ISTicotine increases peri- 

 staltic action and, in large doses, causes tetanic spasm of the 

 intestines, even when it is injected into the blood. In toxic 

 quantities nicotine is a powerful gastro-intestinal 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 stimula- 

 tion of the vagus centre, with slowing of the pulse, followed 

 shortly by depression of this centre and heart muscle with 

 feeble and rapid pulse — after large toxic doses. In the same 

 manner there is a transient stimulation followed by depres- 

 sion of the vasoconstrictor centres with consequent primary 

 rise and subsequent fall in blood tension. 



Nervous Syste-m and Muscles. — Nicotine acts first to 

 stimulate the reflex excitability of the spinal cord, medulla 

 and hind brain in large doses — but this action is quickly 

 followed by depression and paralj'sis of the whole central 

 nervous system and motor nerves. The muscles and sensory 

 nerves escape its influence. All sympathetic ganglia are 

 first stimulated and then depressed by nicotine. 



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