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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    OBSERVATIONS ON THE PHYSIOLOGICAL ACTION OF ACONITINA * By Dyce Duckworth, Esq., Student in Medicine in the University of Edinburgh. The special physiological actions of aconitina have re¬ ceived able attention and observation at the hands of Drs. Fleming and Headland. Upon reading over care¬ fully the different kinds of action said to be exerted by this body, I was particularly struck with a singular in¬ congruity in the accounts as to the condition of the pupil, both during the time when the poison was acting, and also after death had resulted. This fact, amongst others, led me to make a series of experiments with the alkaloid, which extended over a period of five months, and were performed whenever leisure and circumstances permitted. The first object was to obtain pure aconitina; for I imagined that possibly the incongruous statements regarding its action might in some measure, at least, be due to the employment of impure samples of the alka¬ loid. From its costliness, it is apt to be adulterated, or met with in an impure condition. I therefore obtained three samples—one prepared by Messrs. Smith of Edin¬ burgh ; another by Mr. Morson of London ; and a third foreign one, which was not quite pure. I could rely upon the purity of the first two samples, by applying the only test known for the alkaloid, viz., confidence in the characters of the chemists who prepared and sold it; and I found them equally efficacious and infinitely supe rior to the foreign specimen. I experimented upon rabbits, cats, and kittens, inter¬ nally ; and topically upon the conjunctiva of two human adults. Action of Aconitina given internally. When aconitina in solution is given by the mouth, the first effect pro¬ duced is a most intense tingling sensation in the tongue and fauces: this is followed instantly by a copious secre¬ tion of saliva, over which the patient appears to lose con¬ trol, since it is not swallowed, but flows over the lips in a frothy and slimy condition. This is seen to the greatest excess in the case of the cat; not nearly so much is secreted in the rabbit. Dr. Headland thinks this condi¬ tion is due in some measure to paralysis of the fauces. In the human subject, the patient is observed to clutch at the throat after aconite-poisoning; and all animals exhibit uneasiness in that region, as if to assist or accomplish deglutition, which function seems to be lost in all cases, while pharyngeal and oesophageal actions appear rather to be reversed. The respiratory func¬ tions are next apparently interfered with; the breathing becomes laboured and spasmodic; and cries are uttered with more or less vigour, according to the amount of the dose. Next vomiting occurs, and may continue several times ; this is attributed, with good reason, by Headland, to derangement of the function of the vagus, since post mortem examination reveals no appreciable change in the coats of the stomach. Sensation next appears en¬ tirely lost; and the animal, as if mad, tosses itself about wildly; endeavours to walk, but cannot; falls over on its side; takes prodigious leaps; and is then prostrated. Convulsions generally appear at this time, and the breathing becomes slower and more difficult. Finally, total paralysis is observable, and death ensues. Condition of the Pupil. During the action of the poison, the pupils are slightly contracted ; but I have noticed in all cases that, about two or three minutes be¬ fore death, and at the time of death, they dilate enor¬ mously, and generally continue so after death, though I observed in some cases that, in an hour or two after death, one pupil contracted, while the other remained unchanged; and I have even seen the contraction vary * Excerpt, from a Dissertation upon the Physiological and The¬ rapeutical Actions of the Alkaloids. Read before the Royal Medical Society of Edinburgh, December 14th, 1860. in the same pupil several times within twelve hours after death. The action on the pupil differs, however, according to the manner in which the poison is intro¬ duced into the system. I find the prevailing opinion to be, that aconite causes contraction ; Headland gives it as his opinion, that dilatation is produced. It is a very difficult matter to say what the real effect is. Dr. Fleming states, in his admirable dissertation on Aconite (p. 11), that “in general the pupil is more or less con¬ tracted, dilating to its natural size immediately on the cessation of respiration”. This statement is the most correct one I have met with, though I differ from it in that I hold the pupils to dilate considerably beyond their normal size at the time of death ; in fact, this was a most constant and striking symptom in every case in which I employed sufficient, to cause death. Hence I would say, as a rule, the pupil is more or less contracted, dilating enormously a few moments before and at the time of death. As to the cause of this, Fleming states that the symptoms seem to him attributable to the same patho¬ logical cause as the convulsions. He attributed the convulsions to cerebral congestion, since they only occurred when the poison acted slowly, and the respira¬ tions were diminished ; so that, from advancing asphyxia, the venous system must have been highly congested. “ Contraction was present in all the cases in which con¬ vulsions occurred.” I can verify this latter statement. He found that, when muriate of aconitina was injected into the veins, the pupils dilated before any amount of venous congestion could have taken place (and I have always observed that dilatation occurs speedily when a large dose is given, which acts fatally soon); hence he concluded that dilatation is the specific or direct effect on the pupil. We must believe that dilatation ensues upon cerebral congestion; and our main difficulty, it seems, is to account for the subsequent final dilatation after con¬ traction : this, I conceive, we must trace to purely cerebral influences. We shall refer to this subject again in considering the manner in which aconitina causes death; but I may give briefly a case of poisoning by aconite which hap¬ pened this year, and which has been most minutely com¬ municated to me through the kindness of Dr. Nevins, of Liverpool. He writes, “ I had a patient, a young lady, who swallowed a fluiddrachm of the officinal tincture of aco¬ nite. . . . For about six hours her life was in imminent danger. She recovered at last, however. When first seen by her father, an hour after taking it, the pupils were so di¬ lated that no iris could be seen, and this condition lasted till the following day. It was a fortnight before she had entirely lost the tingling and numbness, and feeling of malaise, and for weeks after she was subject to sudden fits of numbness in the feet, so severe as to cause her to fall, even six months afterwards she washable to vomitings and sensations of cramp in the throat, to which she was not subject before she took the poison.” This was a very remarkable case. One of the most marked features in poisoning by aconite in the human subject, and which I have not met with in any treatises on the matter, is, the total inability to act or speak, though consciousness is to a considerable extent maintained up to the time of death ; the mind, too, is often peculiarly active. Patients describe their sensations as if their tongues were gummed to their mouth; and they could give no alarm as to their condition. The eyes are kept wide open ; and there is confusion of vision, sometimes with inability to close the eyes at the command of the will. Topical Action of Aconitina. When aconitina is ap¬ plied to the skin in solution or in the form of ointment, it quickly paralyses the superficial sensory nerves, causing the usual* benumbing sensation. I tried topical application of about one-fortieth of a grain of the alka¬ loid mixed with water to the human conjunctiva, in two
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