CLASS SECOND.
OF NARCOTIC POISONS GENERALLY.
The term narcotism has been used by different writers with different
significations, but is now generally understood to denote the effects of
such poisons as bring on a state of the system like that caused by
apoplexy, epilepsy, tetanus, and other disorders commonly called
nervous. Narcotic poisons, therefore, are such as produce chiefly or
solely symptoms of a disorder of the nervous system.
The mode in which most narcotic poisons act has been well ascertained:
they act on the brain or spine or both by entering the blood-vessels.
Hence they are most active when most directly introduced into the blood,
that is, when injected into the veins; and when they are applied to an
entire membranous surface, their energy is in the ratio of its absorbing
power. Thus, when injected into the chest, they act more rapidly than
when swallowed. According to the generally received opinion, they are
conveyed with the blood to the brain and spine on which they act. But,
according to the views of Messrs. Morgan and Addison, they produce on
the inner coats of the blood-vessels a peculiar impression, which is
conveyed to the centre of the nervous system along the nerves.
The usual symptoms in man and the higher order of animals are giddiness,
headache, obscurity or deprivation of the sight, stupor or perfect
insensibility, palsy of the voluntary muscles or convulsions of various
kinds, and towards the close complete coma. The symptoms of each poison
are pretty uniform, when the dose is the same. But each has its own
peculiarities, either in the individual symptoms, or in the mode in
which they are combined together.
The morbid appearances they leave in the dead body are commonly
insignificant. In the brain, where chiefly the physician is led from the
symptoms to expect unnatural appearances, the organs are in general
quite healthy. Sometimes, however, the veins are gorged with blood, and
the ventricles and membranes contain serosity. The blood appears to be
sometimes altered in nature; but the alteration is by no means
invariable, and sometimes none is remarked at all. Many of the
statements to be found in authors on the morbid appearances caused by
narcotics are far from being accurate.
Before proceeding to notice the genera of this class in their order,
some remarks must be premised on the principal diseases which resemble
them in the symptoms and morbid appearances. Of these the only diseases
of much consequence are _apoplexy, epilepsy, inflammation of the brain,
hypertrophy of the brain, inflammation of the spinal cord, and syncopal
asphyxia_.
_Of the Distinction between Apoplexy and Narcotic Poisoning._
_Of the Symptoms._—The symptoms of apoplexy are almost exactly the same
as those of the narcotic poisons, namely, more or less complete
abolition of sense and the power of motion, frequently combined with
convulsions. This disease commonly arises from congestion or effusion of
blood within the skull; but one variety of it, the nervous apoplexy of
older authors, or simple apoplexy of the moderns, is believed to be an
affection of the brain, unaccompanied by any recognizable derangement of
structure.
Apoplexy and narcotic poisoning may be often distinguished by the
following criterions: