Chapter XCIX: Section II: Of the Action of Hydrocyanic Acid and the Symptoms it

excites in Man._

The effects of hydrocyanic acid on the animal system have been examined by several physiologists. The best experiments with the concentrated acid are those of M. Magendie; who says that, if a single drop be put into the throat of a dog, the animal makes two or three deep hurried respirations, and instantly drops down dead; that it causes death almost as instantaneously when dropped under the eyelid; and that when it is injected into the jugular vein, the animal drops down dead at the very instant, as if struck with a cannon ball or with lightning.[1855]

On repeating these experiments in order to determine less figuratively the shortest period which elapses before the poison begins to operate, as well as the shortest time in which it proves fatal,—two points it will presently be found important to know,—I remarked that a single drop, weighing scarcely a third of a grain, dropped into the mouth of a rabbit, killed it in eighty-three seconds, and began to act in sixty-three seconds,—that three drops weighing four-fifths of a grain, in like manner killed a strong cat in thirty seconds, and began to act in ten,—that another was affected by the same dose in five and died in forty seconds,—that four drops weighing a grain and a fifth did not affect a rabbit for twenty seconds, but killed it in ten seconds more,—and that twenty-five grains, corresponding with an ounce and a half of medicinal acid, began to act on a rabbit as soon as it was poured into its mouth, and killed it outright in ten seconds at farthest. Three drops injected into the eye acted on a cat in twenty seconds, and killed it in twenty more; and the same quantity dropped on a fresh wound in the loins acted in forty-five and proved fatal in 105 seconds. Dr. A. T. Thomson says he has seen the concentrated acid kill a strong dog in two seconds.[1856] Mr. Blake on the other hand alleges that all the accounts which represent the action of the poison to begin in less than ten seconds are exaggerated, because he could never find it to act more quickly, even when thirty minims of concentrated acid were injected at once into the femoral vein.[1857] But it is impossible that any negative results can outweigh positive observations, especially when made, as mine were, expressly with the view of ascertaining the shortest interval. In the slower cases enumerated above there were regular fits of violent tetanus; but in the very rapid cases the animals perished just as the fit was ushered in with retraction of the head. In rabbits opisthotonos, in cats emprosthotonos, was the chief tetanic symptom.—The practical application of these experiments will appear presently.

Of all the forms in which the pure acid can be administered, that of vapour appears the most instantaneous in operation. M. Robert found, that when a bird, a rabbit, a cat, and two dogs were made to breathe air saturated with its vapour, the first died in one second, the second also in a single second, the cat in two, one dog in five, and the other dog in ten seconds.[1858]

The effects of the diluted acid are the same when the dose is large, but somewhat different when inferior doses are given. These effects have been observed by many physiologists; but the most accurate and extensive experiments are those of Emmert published in 1805,[1859] those of Coullon in 1819,[1860] and those of Krimer in 1827.[1861] They found that when an animal is poisoned with a dose not quite sufficient to cause death, it is seized in one or two minutes with giddiness, weakness and salivation, then with tetanic convulsions, and at last with gradually increasing insensibility; that after lying in this state for some time, the insensibility goes off rapidly and is succeeded by a few attacks of convulsions and transient giddiness; and that the whole duration of such cases of poisoning sometimes does not exceed half an hour, but may extend to a whole day or more.—When the dose is somewhat larger the animal perishes either in tetanic convulsions or comatose; and death for the most part takes place between the second and fifteenth minute. I have seen the diluted acid, however, prove fatal with a rapidity scarcely surpassed by the pure poison. Thus in an experiment with Vauquelin’s acid, made on a strong cat at the same time with the second and third of the experiments with the pure acid detailed above, I found that thirty-two grains, which contain one of real acid, began to act in fifteen seconds, and proved fatal in twenty-five more. According to Schubarth’s experiments death may be sometimes delayed for thirty-two minutes;[1862] but if the animal survives that interval, it recovers. He farther states, that during the course of the symptoms the breath exhales an odour of hydrocyanic acid.[1863] Coullon once saw a dog die after nineteen hours of suffering; but cases of this duration are exceedingly rare.[1864] When the dose is very large Mr. Macaulay, as will afterwards be mentioned (p. 590), has found death take place in a few seconds, exactly as when the pure acid is given.

The body presents few morbid appearances of note. The brain is generally natural. Yet occasionally its vessels are turgid; and Schubarth once found even an extravasation of blood between its external membranes in the horse.[1865] The heart and great vessels are distended with black blood, which is commonly fluid, but occasionally coagulated as usual. The lungs, according to Schubarth, are sometimes pale, but much more generally injected and gorged with blood.[1866] The pure acid, according to Magendie, exhausts the irritability of the heart and voluntary muscles so completely, that they are insensible even to the stimulus of galvanism.[1867] The diluted acid has not always this effect. In the experiments of Coullon the heart and intestines contracted, and the voluntary muscles continued contractile, after death as usual.[1868] So too Mr. Blake remarked both by inspection of the body after death, and by means of the hæmadynamometer during life, that, when the poison is introduced directly into a vein, so as to prove fatal in forty-five seconds, the contractions of the heart, though irregular, are not materially impaired in energy.[1869] On the other hand Schubarth states that the heart is never contractile, although the intestines and voluntary muscles retain their contractility.[1870] The reason of these discrepant statements is that, as I have had occasion to observe, a considerable difference really prevails in experiments conducted under circumstances apparently the same. In eight experiments on cats and rabbits with the pure acid the heart contracted spontaneously, as well as under stimuli, for some time after death, except in the instance of the rabbit killed with twenty-five grains, and one of the cats killed by three drops applied to the tongue. In the last two the pulsations of the heart ceased with the short fit of tetanus which preceded death; and in the rabbit, whose chest was laid open instantly after death, the heart was gorged and its irritability utterly extinct. The later researches of Dr. Lonsdale likewise show great varieties in the condition of the heart; and he has been led to conclude that the diluted acid does not perceptibly influence the heart, while the pure acid enfeebles it, if introduced into the stomach, but arrests it, if injected into the windpipe.[1871]

The experiments of Emmert, Coullon, and Krimer show that the diluted acid acts most energetically through the serous membranes, and next upon the stomach; that it also acts with energy on the cellular tissue; that it has no effect when applied to the trunks or cut extremities of nerves, or to a fissure made in the brain or spinal marrow; that its action is prevented when the vessels of any part are tied before the part is touched with the poison; that its action is not prevented by previously dividing the nerves; and that it may sometimes be discovered in the blood after death by chemical analysis,[1872] and frequently by the smell when analysis cannot succeed in separating it.[1873] These results favour the supposition that hydrocyanic acid acts through the medium of the blood-vessels. But the extreme rapidity of its operation in large doses is usually considered incompatible with an action through the blood, or any other channel except direct conveyance along the nerves. The tremendous rapidity of action indicated by the experiments of Magendie, or of Mr. Macaulay (p. 543), of M. Robert, as well as in some of those performed by myself,—certainly appears rather inconsistent with the notion, that the acid must enter the blood-vessels before producing its effects.

This acid acts on the brain and also on the spine independently of its action on the brain. Its action on both is clearly indicated by the combination of coma with tetanus. The independent action on the spine is well shown by the following experiment of Wedemeyer. In a dog the spinal cord was divided at the top of the loins, so that no movement took place when the hind-legs were pricked: hydrocyanic acid being then introduced into a wound in the left hind-leg, symptoms of poisoning commenced in one minute, and the hind-legs were affected with convulsions as well as the fore-legs.[1874]

Hydrocyanic acid affects all animals indiscriminately. From the highest to the lowest in the scale of creation all are killed by it; and all perish nearly in the same manner. Such is the result of a very extensive series of experiments by Coullon.

It is scarcely necessary to observe that hydrocyanic acid acts energetically as a poison, through whatever channel it is introduced into the body. Whether it be swallowed, or injected into the rectum, or dropped into the eye, or applied to a fresh wound, or inhaled in the form of vapour, its action is exerted with tremendous energy. Perhaps it may even act through the sound skin. It has not, hitherto, indeed, been found to affect animals in this way, evidently because their skin is too thick and impermeable. But M. Robiquet informed me that once, while he was making some experiments on the tension of its vapour, his fingers, after being some time exposed to it, became affected with numbness, which lasted several days; I have repeatedly remarked the same effect when handling tubes which contained the concentrated acid; and Emmert found that the essential oil of bitter almond, applied to the uninjured skin of the back of a rabbit, produced the usual symptoms and death: and that the peculiar odour of the poison was quite distinct after death in the deep-seated muscles of the back.[1875]

This substance is poisonous in all its chemical combinations. Coullon remarked that two drops of the hydrocyanate of ammonia killed a sparrow in two minutes.[1876] Robiquet and Magendie found that a hundredth part of a grain of the cyanide of potassium killed a linnet in thirty seconds, and five grains a large pointer in fifteen minutes;[1877] Orfila has related an instance of death in the human subject within an hour after the administration of six grains of cyanide of potassium in an injection;[1878] and in a recent experimental investigation the same author found that this salt produces all the effects of hydrocyanic acid.[1879] Schubarth killed a dog in twenty minutes with twenty drops of the diluted acid neutralized by ammonia,[1880] and another in three hours with twenty-five drops neutralized by potass. These facts are a sufficient answer to a statement made by Mr. Murray of London, to the effect, that a considerable dose of the acid may be given without injury to a rabbit,[1881] if previously rendered alkaline by ammonia. But, nevertheless, as will be seen under the head of the treatment, ammonia, as Mr. Murray stated, is a good antidote when administered after the poison as a stimulant.

The _ferro-cyanates_, or prussiates, do not possess deleterious properties. These salts were at one time considered compounds of hydrocyanic acid with a double oxidized base, oxide of iron being one. Thus the prussiate of potass was considered a compound of hydrocyanic acid with potass and oxide of iron. But since the investigations of Mr. Porrett, it has been admitted that there is only one base, potash; and that it is in union with a hydracid, called ferro-cyanic acid, the radicle of which is a ternary body composed of carbon, azote, and iron. The physiological effects of this substance, which have been examined by many experimentalists, are favourable to Porrett’s opinion; for although some have found it poisonous, all agree in assigning it very feeble properties, and some have not been able to discover in it any deleterious quality at all. Coullon observes that Gazan killed a dog with two drachms, and Callies another with three drachms of the salt met with in commerce.[1882] Schubarth found that half an ounce had not any material effect on dogs, even when vomiting did not occur for half an hour;[1883] and Callies, who found the salt of commerce somewhat poisonous, also remarked, that when it was carefully prepared, several ounces might be given without harm.[1884] D’Arcet once swallowed half a pound of a solution without any injury.[1885] Similar results were obtained previously with smaller doses by Wollaston, Marcet,[1886] and Emmert,[1887] as well as afterwards by Dr. Macneven,[1888] and Schubarth,[1889] who found that a drachm or even two drachms might be taken with impunity by man and the lower animals.

The _sulpho-cyanic acid_, another substance analogous in chemical nature to the ferro-cyanic, was once supposed like it to be a poison of great activity, but this is doubtful. Professor Mayer of Bonn ascertained that a drachm and a half of a moderately strong solution of the acid sometimes killed a rabbit in ninety seconds when injected into the windpipe, and that the same quantity of a solution of sulpho-cyanate of potassa might occasion death in the course of four hours; but that some rabbits took half an ounce of the former and three drachms of the latter without material harm, both when administered through the windpipe, when injected into the rectum, and when introduced into the stomach by a gullet-tube. In the fatal cases death took place under symptoms of oppressed breathing, rarely attended with convulsions; and extensive traces of irritation were found in the alimentary canal.[1890] Dr. Westrumb of Hameln, however, seems to have found it more active in the form of sulpho-cyanate of potassa. Two scruples in an ounce of water produced in a dog spasmodic breathing, convulsions, efforts to vomit, and death in seven minutes; and forty grains killed another in less than two hours. In the latter animal he detected the poison by the sulphate of iron in the blood, lungs, liver, spleen and kidneys.[1891] Some experiments by Soemering would even make it out to be a poison of very great energy; for half a drachm of concentrated sulpho-cyanic acid given to a dog occasioned immediate death; and the same quantity of sulpho-cyanate of potassa killed another in one minute.[1892]

_Cyanic and cyanous acids_ are not poisonous, according to the experiments of Hünefield;[1893] but _cyanogen_ is a powerful poison, as will be mentioned under the head of the Narcotic Gases.

The symptoms of hydrocyanic acid observed in man are very similar to those witnessed in animals.

Coullon has given a good account of the effects of small doses as ascertained by experiment on himself. When he took from 20 to 86 drops of a diluted acid, he was attacked for a few minutes with nausea, salivation, hurried pulse, weight and pain in the head, succeeded by a feeling of anxiety, which lasted about six hours.[1894] Such symptoms are apt to be induced by too large medicinal doses. Another remarkable symptom which has been sometimes observed during its medicinal use is salivation with ulceration of the mouth. Dr. Macleod thrice had occasion to remark this in patients who had been using the drug for about a fortnight, and twice in one individual; and Dr. Granville says he had also twice witnessed the same effect.[1895]

As to the effects of fatal doses, it is probable that in man, as in animals, two varieties exist. When the dose is very large, death will in general take place suddenly, without convulsions. But for obvious reasons the symptoms in such cases have not been hitherto witnessed.

The most complete account of the symptoms from fatal doses when convulsions occur, is given in a case reported by Hufeland of a man, who, when apprehended for theft, swallowed an ounce of alcoholized acid, containing about forty grains of the pure acid. He was observed immediately to stagger a few steps, and then to sink down without a groan, apparently lifeless. A physician, who instantly saw him, found the pulse gone and the breathing for some time imperceptible. After a short interval he made so forcible an expiration that the ribs seemed drawn almost to the spine. The legs and arms then became cold, the eyes prominent, glistening, and quite insensible; and after one or two more convulsive expirations he died, five minutes after swallowing the poison.[1896]

In Horn’s Journal is recorded another case which also proved fatal in five minutes, with precisely the same symptoms.[1897] A short notice of what appears to have been a similar case is given in the Annales de Chimie. The person was a chemist’s servant, who swallowed a large quantity of the alcoholic solution by mistake for a liqueur, the poison having been accidentally left on the table by her master, who had been showing it as a curiosity to some friends. No account is given of the symptoms, farther than that she died apoplectic in two minutes.[1898] To these cases may be also added a short notice of the French physician’s case mentioned at the commencement of this chapter. It will convey a good idea of the operation of the poison when not quite sufficient to kill. Very soon after swallowing a tea-spoonful of the diluted acid he felt confusion in the head, and soon fell down insensible, with difficult breathing, a small pulse, a bloated countenance, dilated insensible pupils, and locked jaw. Afterwards he had several fits of tetanus, one of them extremely violent. In two hours and a half he began to recover his intellects and rapidly became sensible; but for some days he suffered much from ulceration of the mouth and violent pulmonary catarrh, which had evidently been excited by the ammonia given for the purpose of rousing him. This gentleman had eructations with the odour of the acid three or four hours after he took it; and during the earlier symptoms the same odour was exhaled by his breath.[1899] The hydrocyanic odour of the breath is of course an important distinguishing character, which would appear, from the observations of Dr. Lonsdale on animals,[1900] to occur more frequently than might be supposed from the silence observed on the subject by the reporters of cases.

Hydrocyanic acid is not considered a cumulative poison,—that is, the continued use of frequent small doses is not believed to possess the power recognised in iodine, mercury, and foxglove, of gradually and silently accumulating in the body, and then suddenly breaking out with dangerous or fatal violence. The frequent experience of practitioners in this and other countries seems to prove that hydrocyanic acid possesses no such property. It is right at the same time to mention, that a case published by Dr. Baumgärtner of Freyburg has been thought by some[1901] to establish the reverse. A man had taken for two months, on account of chronic catarrh, ten drops of Ittner’s acid daily in doses of one grain, without experiencing the slightest toxicological effect. At length he was found one morning in bed apparently labouring under the poisonous operation of the acid. He had headache, blindness, dilated insensible pupil, feeble irregular pulse, occasional suspension of the breathing, and rapidly increasing insensibility. The cold affusion and ammonia were immediately resorted to, and at first with advantage. But in no long time spasms commenced in the toes, and gradually affected the rest of the body, till at length violent fits of general tetanus were formed, lasting for six or ten minutes, and alternating in the intervals with coma. Venesection was next resorted to; after which the spasms were confined to the jaw and eyes. Delirium succeeded, but was removed by a repetition of the blood-letting. At four in the afternoon he was tolerably sensible; during the night delirium returned; at ten next morning he recovered his sight; and on the subsequent morning he had no complaint but headache and pain in the eyes.[1902] This case differs so much from every other in the collateral circumstances, as well as in duration, that, although the symptoms themselves correspond with those of poisoning with hydrocyanic acid, we may justly suspect either some other cause, or the accidental administration of too large a dose. It ought, however, to turn the attention of practitioners to the possibility of this poison acting by the accumulation of the effects of small doses frequently repeated for a great length of time.

The period within which hydrocyanic acid usually proves fatal is fixed with considerable accuracy, not only by the cases observed in the human subject, but likewise by the experiments of many physiologists, and more especially those of Schubarth (p. 583). It is probable that very large doses occasion death in a few seconds; and at all events a few minutes will suffice to extinguish life when the dose is considerable; but if the individual survive forty minutes, he will generally recover. In the course of a dreadful accident which happened a few years ago in one of the Parisian hospitals, when seven epileptic patients were killed at one time by too large doses of the medicinal acid, it was found that several did not die for forty-five minutes.[1903] But the researches of Schubarth would certainly justify the expectation that recovery will take place under active treatment when the patient survives so long.—These facts may be highly important in the practice of medical jurisprudence.

The period within which it begins to operate ought also to be accurately ascertained for the same reason. Indeed in a very interesting trial, which took place a few years ago in this country, the fate of the prisoner depended in a great measure on the question, within how short a time the effects of this poison must show themselves?[1904] The nature of the case was as follows: An apothecary’s maid-servant at Leicester who was pregnant by her master’s apprentice, was found one morning dead in bed; and she had obviously been poisoned with hydrocyanic acid. Circumstances led to the suspicion that the apprentice was accessary to the administration of the poison. On the other hand, it was distinctly proved that the deceased had made arrangements for a miscarriage by artificial means on the night of her death; and it was therefore represented, on the part of the prisoner, that she had taken the poison of her own accord. But the body was found stretched out in bed in a composed posture, with the arms crossed over the trunk, and the bed-clothes pulled smoothly up to the chin; and at her right side lay a small narrow-necked phial, from which about five drachms of the medicinal prussic acid had been taken, and which was corked and wrapped in paper. There naturally arose a question, whether the deceased, after drinking the poison out of such a vessel, could, before becoming insensible, have time to cork up the phial, wrap it up, and adjust the bed-clothes?[1905] To settle this point, experiments were made at the request of the judge, by Mr. Macaulay, Mr. Paget, and several other medical men of Leicester; and on the trial they, with the exception of Mr. Paget, gave it as their opinion, founded on the experiments, that the supposed acts of volition, although within the bounds of possibility, were in the highest degree improbable. The chief experiments were three in number, from which it appeared that one dog was killed with four drachms in eight seconds, another with four drachms in seven seconds, and another with four drachms and a half in three seconds; but in other experiments the interval was greater.—For these particulars I am indebted to Mr. Macaulay.

In the first edition of this work I expressed my concurrence with the majority of the witnesses. But some facts, which came subsequently under my notice, led me to think that this concurrence was given rather too unreservedly. I still adhere so far to my original views as to think it improbable that, if the deceased, after swallowing the poison, had time to cork the phial, wrap it in paper, pull up the bed-clothes, and place the bottle at her side, the progress of the symptoms could have been so rapid and the convulsions so slight, as to occasion no disorder in the appearance of the body and the bed-clothes,—and I still likewise think, that after swallowing so large a dose it was improbable she could have performed all the successive acts of volition mentioned above—with ordinary deliberation. But I am informed on good authority, that some gentlemen interested in the case found by actual trial, that all the acts alluded to might be accomplished, if gone about with promptitude, within the short period, which, in some of their experiments, the witnesses found to elapse, before the action of the poison commenced. And such being the fact, we ought not perhaps to attach too great importance to the other argument I have employed,—the probability of disorder in the body and bed-clothes from the convulsions; for if the poisoning commenced very soon, the convulsions might have been slight. The results of my own experiments related in p. 582, although on the whole confirmatory of those of Mr. Macaulay and his colleagues, are nevertheless sufficient to prove that large doses occasionally do not begin to operate with such rapidity as was observed in their experiments; for in one instance four drops of concentrated acid, equivalent to two scruples of medicinal acid, did not begin to act on a rabbit for twenty seconds; and certainly, for so small an animal, two scruples are as large a dose as five drachms for a grown-up girl.

The two following cases will throw some farther light on the time within which this poison begins to act on man when taken in large quantity. The first case shows, that even when an enormous dose is taken, a few simple voluntary acts may be executed before the symptoms begin. In this instance which is related by Dr. Gierl of Lindau, the dose was no less than four ounces of the acid of the Bavarian Pharmacopœia, which contains four per cent. of pure acid, and is equivalent to five ounces at least of that commonly used in Britain and France. The subject, an apothecary’s assistant, was found dead in bed, with an empty two-ounce phial on each side of the bed,—the mattrass, which is used in Germany instead of blankets, pulled up as high as the breast,—the right arm extended straight down beneath the mattrass,—and the left arm bent on the elbow.[1906] The second case proves that, although one or two acts of volition may be accomplished, the interval is so very brief that these acts can only be of the simplest kind. An apothecary’s apprentice-lad was sent from the shop to the cellar for some carbonate of potass; but he had not been a few minutes away, when his companions heard him cry in a voice of great alarm, “Hartshorn! Hartshorn!” On instantly rushing down stairs, they found him reclining on the lower steps and grasping the rail; and he had scarcely time to mutter “Prussic acid!” when he expired,—not more than five minutes after leaving the shop. On the floor of the cellar an ounce-phial was found, which had been filled with the Bavarian hydrocyanic acid, but contained only a drachm. It appeared that he had taken the acid ignorantly for an experiment; and from the state of the articles in the cellar, it was evident that, alarmed at its instantaneous operation, he had tried to get at the ammonia, which he knew was the antidote, but had found the tremendous activity of the poison would not allow him even to undo the coverings of the bottle.[1907]

When the quantity of the poison is small, a much longer interval may elapse before the commencement of its action. Thus, when the dose is barely short of what is required to occasion death, the effects may be postponed even for fifteen minutes, as in a case which occurred to Mr. Garson of Stromness.[1908] This, so far as I am at present aware, is the extreme limit of interval hitherto observed.

In the trial related above the prisoner Freeman was found _Not Guilty_.

It is important to fix, if possible, the smallest fatal dose of hydrocyanic acid. This will vary with particular circumstances, such as the strength of the individual, and the fulness or emptiness of the stomach at the time. The cases of the Parisian epileptics, who were killed each by a draught containing two-thirds of a grain of pure acid,[1909] will supply pointed information. For, on the one hand, considering the long time they survived, it is not probable that a dose materially less would have a fatal effect on man. And on the other hand repeated instances of recovery have been observed, where the dose was as great or even greater. Thus Dr. Geoghegan had a patient who recovered from a state of extreme danger after taking two-thirds of a grain;[1910] and Mr. Banks of Lowth met with a case of recovery in similar circumstances, where the dose was very nearly a whole grain.[1911]

It is almost unnecessary to add, that in man, as in animals, this poison will act violently, through whatever channel it may be introduced into the body. It has not been positively ascertained to act with force through the unbroken skin. The chemist Scharinger indeed was supposed to have been killed in consequence of accidentally spilling the acid on his naked arm;[1912] but this was in all probability a mistake. Should the skin be freely exposed to the air it seems reasonable to expect that the poison will evaporate before it could act with energy; but if confined by pledgets or otherwise, a different result might ensue. Through every other surface, however, besides the unbroken skin, hydrocyanic acid acts with very great power; and it is in particular important to remember that its power is very great when inhaled, so that dangerous accidents have ensued even from its vapour incautiously snuffed up the nostrils. I have known a strong man suddenly struck down in this way; a French physician, M. Damiron, has related the case of an apothecary who remained insensible for half an hour subsequently to the same accident;[1913] and cases of the kind are more apt to occur than might at first view be thought, because, contrary to what is generally believed and stated in chemical as well as medico-legal works, its smell is for a few seconds barely perceptible, and never of the kind which these accounts would lead one to anticipate. Accidental death may readily arise from its action on a wound or an abraded surface. Sobernheim mentions that Mr. Scharring, a druggist at Vienna, was poisoned in consequence of a phial of the acid breaking in his hand and wounding it; and he expired in an hour.[1914]

The only case with which I am acquainted of poisoning with the artificial compounds of hydrocyanic acid is that formerly alluded to as having been occasioned by the cyanide of potassium. Six grains dissolved in a clyster amounting to six ounces, occasioned general convulsions, palpitations, slow laboured breathing, coldness of the limbs, dilated pupil, fixing of the eyeballs, and death in one hour,—phenomena much the same with those produced by the acid itself.[1915]—Another case has been published, in which a French physician, ignorant of the correct dose, prescribed a potion with three grains of cyanide of potassium twice a day. Immediately after the first dose the patient was seized with the usual symptoms of poisoning with hydrocyanic acid; and expired in three-quarters of an hour.[1916] In noticing the first of these cases, Orfila draws the attention of practitioners particularly to the fact, that not long before a similar dose of a sample of cyanide, which had been moist for some time, was twice administered with impunity. The reason is that the cyanide of potassium undergoes decomposition when acted on by water, or when long kept.