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Full text of "Medical Jurisprudence And Toxicology"

CHAPTER XXXH

CARDIAC POISONS

NICOTIANA TABACUM   (TOBACCO,  TAMBAKU)  *>

This belongs to N.O. Solanacese, and is originally a native plant of
America, but is now cultivated largely all over India.

The dried leaves of tobacco are used in India as articles of luxury by
almost all classes of people, who use them either in the form of smoke or
snuff, or chew them with lime alone or with lime and pan. The leaves are
manufactured as cigars (cheroots) in Trichinopoly and Burma,

The leaves yield two active principles, nicotine and nicotianine.

Nicotine, Ci0Hi4N2.—This exists in all parts of the tobacco plant, but
notably in the leaves, which contain from 0.6 to 6 per cent in combination
with malic and citric acids. It is a colourless, volatile, oily liquid, turning
brown and resinous on exposure to air. It has a burning acrid taste, and
a penetrating, disagreeable odour. It is soluble in water, alcohol and ether,
the solution being, alkaline in reaction. It first stimulates and then depresses
the vagal and vasomotor ganglia. Similarly, it first stimulates and then
paralyses the cerebral and spinal centres. In smaller doses it contracts the
pupils but when toxic symptoms develop, it dilates them.

Nicotianine.—This is also known as tobacco camphor, and is a volatile,
crystalline substance, unimportant from a medico-legal point of view.

Duboisia Hopwoodii, belonging to N.O. Solanaceae, and growing in
Australia, contains piturine, a volatile liquid alkaloid, acting exactly like
nicotine.

Symptoms.—These are burning, acrid sensations in the mouth and
throat, which spread down the oesophagus to the stomach, and are followed
by salivation, nausea, vomiting, sometimes diarrhoea, giddiness, faintness,
numbness, muscular weakness, tremors, cold, clammy skin, and partial or
complete unconsciousness. Hearing and vision may be affected, the pupils
are at first contracted, but later on become dilated. The pulse is generally
slow at first, and then becomes very rapid, and cardiac arrhythmias may
occur. After very large doses, the pulse may be first accelerated and then
slow and feeble. The respirations are at first rapid and laboured, and after-
wards slow and sighing. Death occurs from respiratory failure caused by
paralysis of the muscles of respiration, the heart continuing, to beat for some
time afterwards. Sometimes, there may be delirium and convulsions. In
some instances death may occur very rapidly, the symptoms being those of
sudden paralysis of the central nervous system.

Chronic Poisoning.—This occurs from over-indulgence in tobacco for a
long time. It may also occur amongst workmen employed in tobacco
factories.

Symptoms.—These are cough from irritation of the throat and bronchial
tubes, wheezing and dyspnoea, loss of appetite, vomiting, diarrhoea, anaemia,
faiixtness, cardiac irritability and weakness, quick, irregular pulse, tremors
and impaired memory. Eye-sight may be affected, leading to amblyopia in
the central field, particularly for coloured objects.

Fatal Dose.—Three to four drops of pure nicotine taken into the stomach
would probably prove fatal to an adult. Recovery has, however, followed 4
grammes of pure nicotine, as most of it had been eliminated by the vomiting