Narceine

The most contradictory observations have been published on the action of this principle. By Bernard, Béhier, and Eulenburg it is held to possess remarkable hypnotic power, and to be free from stimulating and convulsant action; by Fronmüller, Harley, Da Costa, Mitchell, and others, it is considered feeble, if not inert. The physiological actions of narceine, therefore, remain subjudice. Until further researches are made with chemically pure narceine, and by competent observers, it will be safer to give no opinion on the subject of its actions and uses.

The other alkaloids of opium are curiosities of chemical and physiological research, and may be dismissed in a few words.

Cryptopine is in a much greater degree than narceine an hypnotic and anodyne.

Thebaine has a strong convulsant action in animals.

Various circumstances modify the action of opium. These are chiefly age, sex, idiosyncrasy, habitual use, and certain states of the system, as the presence of pain, uraemia, etc.

The extremes of life are relatively more susceptible to the action of opium, and especially is the susceptibility to its action great in early life. Fatal opium narcosis has ensued in a nursing infant whose mother had taken a medicinal dose. A single drop of laudanum has produced lethal effects in a child under six months of age. Women are more easily affected by opium than men, and they are more apt to be thrown into a condition of hysterical excitement than put to sleep. Nausea, vomiting, headache, and depression much more frequently occur in women than in men. As a rule, therefore—but to this rule there are, of course, numerous exceptions— women are less favorable subjects for the administration of opium than men.

More than age or sex is the action of opium influenced by idiosyncrasy. There are persons so easily affected by it that the minutest quantity will cause uncontrollable vomiting, faintness, vertigo, and alarming prostration. It is never safe to administer morphine hypodermatically to such subjects, unless in an extremely small dose.

The habitual use of opium diminishes in a remarkable degree the susceptibility to its action. Numerous instances are on record in which a pint or more of laudanum has been taken daily, or several hundred grains of opium, or a scruple of morphine. The author has met with a patient who took a scruple of morphine a day subcutaneously. When opium is given by the stomach, for the relief of a chronic painful disease, to maintain a constant effect increasing doses are necessary. The power of the stomach to absorb opium is doubtless impaired by frequent repetition of the dose, and in consequence of the local action of the drug on the nerves of the stomach. Besides this, the susceptibility of the cerebro-spinal system steadily declines. The proof of these statements is afforded by the action of morphine when used subcutaneously for long periods. A gradual increase of the dose becomes necessary in order to produce a given physiological effect; but the increase is much slower than when it is administered by the stomach.

Great pain lessens the influence of opium upon the centers of conscious impressions. The quantity in grains is of much less importance than the quantity as measured by the physiological reactions. Uraemia, or the retention in the blood of urinary excrementitious matters, is supposed to increase the narcotic influence of opium; but some facts, to be hereafter presented, render it probable that the state of uraemia and the influence of opium on the brain are antagonistic.