TOBACCO AND NICOTINE 639 



produced from oxidation of the nicotine. Tobacco slowly 

 burned, as when smoked, is decomposed, and the smoke 

 contains volatile fatty acids and ethers, traces of hydro- 

 cyanic acid and ammonia, while the nicotine in great part 

 is converted into alkaloids of the benzine series pyridine 

 (C 5 H 5 N), collidine ((CH 3 )C 5 H 2 N), picoline (CH 3 C 5 H 4 N), and 

 lutidine ((CH 3 )C 5 H 3 N). 



ACTIONS AND USES. Tobacco and nicotine are in-contact 

 irritants. They stimulate and then paralyse the spinal 

 cord, the motor nerves of muscles, and the nerve-cells 

 controlling involuntary muscles, and secreting glands. 

 They enfeeble circulation, cause trembling, staggering gait, 

 convulsions, and death from respiratory failure. Tobacco 

 is rarely prescribed internally, but is used externally as an 

 antiparasitic. Nicotine and Nicotianin are antiseptic. 



GENERAL ACTIONS. Strong solutions of tobacco are in- 

 contact irritants of mucous and denuded skin surfaces. 

 Partly from this topical irritant action and partly from 

 stimulating motor nerves they cause vomiting in carnivora. 

 Large doses in all animals induce gastro-enteritis with 

 collapse. The active principle is quickly taken up from 

 absorbing surfaces. Dogs dressed with concentrated decoc- 

 tions frequently suffer from salivation, nausea, and vomiting, 

 while human patients have been poisoned by enemata. 



Nicotine is somewhat similar in action to conine and lobel- 

 ine, producing a preliminary stimulation of certain nerve- 

 cells (especially cells of sympathetic ganglia), and of the 

 central nervous system, followed by depression and paralysis 

 of them. Thus by the stimulation and subsequent depres- 

 sion of vagus ganglion cells, the heart is first slower and 

 even intermittent, then quicker. Similarly, blood-pressure 

 is briefly raised, and then lowered by stimulation and 

 depression of the ganglion cells on the course of the vaso- 

 constrictor nerves. In the same manner the secretion of 

 saliva, sweat, and bronchial mucus is first increased and 

 then lessened. Peristalsis is at first (and briefly) inhibited 

 by stimulation of the peripheral splanchnic ganglion cells, 

 and then is greatly increased and exaggerated by their 

 paralysis. By a combination of local and central action 

 respiration is at first quickened and shallow, later becoming 



