TOBACCO AND NICOTINE 313 



doses — but this action is quickly followed by depression and paralysis of 

 the whole central nervous system and motor nerves. The muscles and 

 sensory/ nerves escape its influence. The most characteristic specific 

 action of nicotine consists in a transient stimulation^ followed by complete 

 loss of function^ of the peripheral sympathetic ganglia, as seen in the 

 effect of the drug upon digestion, the heart, secretions, and pupil. 



Respiration. — rThe respiratory centres are primarily stimulated but 

 later depressed and paralyzed by fatal doses of nicotine and death occurs 

 through respiratory failure. 



Secretions.-^-The secretions of sweat, saliva and bronchial mucus are 

 at first increased and then diminished by the action of nicotine in stimu- 

 lating and then depressing the ganglia in the course of the secretory 

 nerves. 



Eye. — Nicotine affects the pupil variously. It is transiently dilated ' 

 in the dog and cat; constricted in the rabbit; and, in man, contraction is 

 followed by dilation. These differences appear to depend upon whether 

 the drug stimulates more the sympathetic (dilation) or the oculomotor 

 (contraction) ganglia. 



Elimination. — Nicotine is in part destroyed by the liver and adrenal 

 secretion. It is also eliminated chiefly by the kidneys but also is found 

 in the saliva and sweat. 



Toxicology. — Nicotine is one of the most powerful and rapidly act- 

 ing poisons. When swallowed, it causes, in animals, local irritation and 

 pain in the throat and stomach; muscular tremors and weakness, on 

 account of which the animal falls. These symptoms are followed, first, 

 by severe tonic and clonic convulsions, and then by abolition of voluntary 

 motion and quietude. There are vomiting (in the case of some animals), 

 purging and micturition. The respiration is at first shallow and rapid, 

 but becomes weaker and slower, and death occurs from respiratory failure 

 and general collapse. The pulse is primarily slow and intermittent, but 

 later becomes rapid. The treatment of poisoning consists in evacuation 

 of the stomach; the use of tannic acid; respiratory and heart stimulants, 

 as strychnine, atropine, caffeine, and alcohol; together with external heat 

 and artificial respiration. The minimum lethal dose is about one dram 

 of tobacco, or one minim of nicotine, for small dogs. For horses, five to 

 ten drops of nicotine or one-half pound of tobacco. 



Uses. — Tobacco is not a particularly valuable medicinal agent. Its 

 internal action is often violent, and causes great nausea. Absorption and 

 poisoning may follow its external application in the smaller animals. The 

 drug may be employed for four purposes, as follows : 



1. As a local sedative. 



2. As a parasiticide. 



3. As a motor depressant. 



4. As a cathartic. 



External. — 1. Tobacco is an efficient sedative in decoction (1-40), 

 for relieving pruritus ani and vulvae. It must be remembered that absorp- 



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