284 POISONS : THEIR EFFECTS AND DETECTION. [§§ 34 I- 343 . 
muscular irritability is unaffected. The convulsions are not influenced 
by artificial respiration, and are therefore to be considered as due to 
the direct influence of the alkaloid on the nervous system. Nicotine 
has a striking influence on the respiration, first quickening, then 
slowing, and lastly arresting the respiratory movements : section of 
the vagus is without influence on this action. Death is evidently due 
to the rapid benumbing and paralysis of the respiratory centre. Death 
never follows from heart-paralysis, although nicotine powerfully influ¬ 
ences the heart’s action, small doses exciting the terminations of the 
vagus in the heart, and causing a slowing of the beats. Large doses 
paralyse both the controlling and exciting nerve-centres of the heart ; 
the heart then beats fast, irregularly, and weakly. The blood-vessels 
are first narrowed, then dilated, and, as a consequence, the blood- 
pressure first rises, then falls. Nicotine has a special action on the 
intestines. As 0. Nasse 1 has shown, there is a strong contraction of 
the whole tract, especially of the small intestine, the lumen of which 
may be, through a continuous tetanus, rendered very small. This is 
ascribed to the peripheral excitation of the intestinal nerves and the 
ganglia. The uterus is also excited to strong contraction by nicotine ; 
the secretions of the bile and saliva are increased. 
§ 341. Fatal Dose. —The fatal dose for dogs is from J to 2 drops ; 
for rabbits, a quarter of a drop ; for an adult not accustomed to tobacco 
the lethal dose is probably 6 mgrms. 
§ 342. Post-mortem Appearances. —There seem to be no appearances 
so distinctive as to be justly ascribed to nicotine or tobacco poisoning 
and no other. 
A more or less fluid condition of the blood, and, generally, the signs 
of death by the lungs, are those most frequently found. In tobacco¬ 
poisoning, when the leaves themselves have been swallowed, there may 
be some inflammatory redness of the stomach and intestine. 
§ 343. Separation of Nicotine from Organic Matters, etc. —The 
process for the isolation of nicotine is precisely that used for coniine 
(see p. 273). It appears that it is unaltered by putrefaction, and may 
be separated and recognised by appropriate means a long time after 
death. Orfila detected it in an animal two or three months after death ; 
Melsens discovered the alkaloid unmistakably in the tongues of two 
dogs, which had been buried in a vessel filled with earth for seven 
years ; and it has been found, by several experiments, in animals buried 
for shorter periods. Nicotine should always be looked for in the 
tongue and mucous membrane of the mouth, as well as in the usual 
viscera. The case may be much complicated if the person supposed 
to be poisoned should have been a smoker ; for the defence would 
naturally be that there had been either excessive smoking or chewing, 
1 Beitrdge zur Phynologie der Varmbewequny, Leipsic, 1866, 
