Observations on the physiological action of aconitina / by Dyce Duckworth.

  • Dyce Duckworth
Date:
1861]
Catalogue details

Licence: Public Domain Mark

Credit: Observations on the physiological action of aconitina / by Dyce Duckworth. Source: Wellcome Collection.

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    cases. Slight congestion of the membrane occurred, and photophobia in both cases; also slight contraction of the pupil. The tingling sensations continued for six hours; and at the end of that time the eyeball, in one case, protruded an eighth of an inch from the socket; in the other, the tingling was referred to the angle of the jaw and down the side of the neck. These were severe experiments and not to be repeated; they further lost an entire night’s rest to both patients. Now the contraction which was induced in these cases was attributable, not to any specific action of the alka¬ loid, but to irritation produced mechanically by its fine particles. Dr. Fleming is of this opinion, and we know that dust and irritants of all kinds induce contraction when directly applied to the eye. Fleming found that when aconitina ointment was applied to the conjunctiva con¬ traction occurred speedily, which lasted for several hours ; but when it was applied to the forehead or temple the pupil became occasionally dilated and partial blindness ensued—this he attributes to reflex action through the third and fifth nerves. I applied one-thirtieth of a grain of pure aconitina in ointment between the eyes of a cat, but, as this animal possesses evident volition over the iris.it was impossible to state with any confidence the pupillary state after¬ wards ; in two hours time the animal was foaming at the mouth and not breathing quite normally, also suffering from general malaise; she had probably been cleaning herself and may have licked her paws. It is clear that we can never make use of aconitina as a direct local therapeutic agent for the eye. Mode in ivhich Aconitina causes Death. This is a question which can hardly be called settled. Some au¬ thorities attribute death to asphyxia; others, including Dr. Headland, to cardiac syncope. The subject was brought before the British Association at Oxford last year by Dr. E. R. Harvey ; he performed his experiments upon dogs, rabbits, and frogs with Fleming’s tincture of aconite; and he considers they went to prove that aconite acts first on the nerves, and then on the muscles, killing by its action on the heart; the blood and urine, he stated, were found normal. In the discussion on this paper, Sir B.Brodie remarked that in his experiments many years ago with the ex¬ pressed juice of aconite, he found it to act as a narcotic, and to arrest respiration ; and he recommended artificial respiration for recovery from the effects. Dr. Sharpey said that in some experiments of his, he had noticed the same effects as Dr. Harvey; viz., the stoppage of the heart’s action, and of muscular irritability, the nerves also leading to the affected muscles were deprived of their excitability. Thus Drs. Harvey and Sharpey attri¬ bute death to syncope, and Sir B. Brodie to asphyxia. Professor Bennett remarks, in his Principles and Prac¬ tice of Medicine, on a case of aconite poisoning, that “ it is difficult to separate the effects of syncope from those of asphyxia in such a case, since the first condition must induce the other.” Fleming states that three varieties are observable in the symptoms and mode of death : first, it may prove fatal by a powerfully sedative inpression on the nervous system; secondly, by suspen¬ sion of the respiratory functions; and thirdly, by syncope; he further remarks that the latter conditions are always more or less conjoined. My own observations have led me to the following conclusions. When a large dose of aconitina is given, I think death is caused speedily either by direct cardiac syncope, or by a powerfully sedative impression on the nervous system, and certainly the action of the heart ceases. In this case there are no convulsions as in death from asphyxia, and the dilated pupils may here be the direct and perhaps specific effect of aconitina when it acts so speedily as to prevent any amount of cerebral congestion. When a small dose is employed, death is averted for a time, the heart’s action is enfeebled by degrees, so that the pulmonary and systemic circulation go on very slowly. Meantime, the phrenic and respiratory system of nerves are becoming affected ; respirations are per¬ formed less frequently, and are accompanied with deep spasmodic action of the diaphragm, which will also ac¬ count for the cries uttered, the laryngeal muscles being paralysed; the venous system becomes engorged, and the pupils dilate finally from cerebral congestion, while the heart and lungs cease to act. In this case, I con¬ sider, a combination of asphyxia and syncope causes death. In both cases sensibility is soon lost, and mus¬ cular paralysis is observable early. The poison may be classed as a general sedative. 2 . ' /£& U—
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