ACTION OF TOBACCO AST) NICOTINE 425 



Respiration. — The 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 bron- 

 chial mucus are at first increased and then diminished by 

 the action of nicotine in stimulating and then depressing 

 the ganglia in the course of the secretory nerves. 



Eye. — Nicotine affects the pupil variously. It is trans-, 

 iently dilated in the dog and cat ; constricted in the rabbit ; 

 and, in man, contraction is follovi^ed by dilation. These 

 differences appear to depend upon whether the drug stimu- 

 lates more the sympathetic (dilation) or the oculomotor 

 (contraction) ganglia. 



Elimination. — jSTicotine is in part destroyed by the liver. 

 . 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 acting poisons. When swallowed, it causes, in ani- 

 mals, 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 volun- 

 tary motion and quietude. There are vomiting (in the case 

 of some animals), purging and micturition. The respira- 

 tion 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 ; respira- 

 tory and heart stimulants, as strychnine, atropine, and alco- 

 hol; together with external heat and artificial respiration. 

 The minimum lethal dose is about one drachm 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 



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