Secondly, Professor Rolando of Turin having found that the land tortoise sustained little injury when the great air-tube of one lung was tied,—he contrived to make it breathe carbonic acid gas with one lung, while atmospheric air was inhaled by the other; and he remarked that death took place in a few hours.[2053]
Thirdly, the symptoms caused by inhaling the gas may be also produced by applying it to the inner membrane of the stomach or to the skin. On the one hand aërated water has been known to cause giddiness or even intoxication when drunk too freely at first;[2054] and the sparkling wines probably owe their rapid intoxicating power to the carbonic acid they contain. And, on the other hand, M. Collard de Martigny has found that, if the human body be enclosed in an atmosphere of the gas, due precautions being taken to preserve the free access of common air to the lungs, the usual symptoms of poisoning with carbonic acid are produced, such as weight in the head, obscurity of sight, pain in the temples, ringing in the ears, giddiness, and an undefinable feeling of terror; and that if the same experiment be made on animals and continued long enough, death will be the consequence.[2055]
When a man attempts to inhale pure carbonic acid gas, for example by putting the face over the edge of a beer-vat, or the nose into a jar containing chalk and weak muriatic acid, the nostrils and throat are irritated so strongly, that the glottis closes and inspiration becomes impossible. Sir H. Davy in making this experiment, farther remarked, that the gas causes an acid taste in the mouth and throat, and a sense of burning in the uvula.[2056] I have remarked the same effects from very pure gas disengaged by tartaric acid from carbonate of soda. Hence, when a person is immersed in the gas nearly or perfectly pure, as in a beer-vat, or old well, he dies at once of suffocation.
The effects are very different when the gas is considerably diluted; for the symptoms then resemble apoplexy. As they differ somewhat according to the source from which the gas is derived, and the admixtures consequently breathed along with it, it will be necessary to notice separately the effects of the pure gas diluted with air,—of the emanations from burning charcoal, tallow, and coal,—and finally of air vitiated by the breath.
1. M. Chomel of Paris has related a case of poisoning with the gas diluted with air, in the person of a labourer, who was suddenly immersed in it at the bottom of a well, and remained there three-quarters of an hour. He was first affected with violent and irregular convulsions of the whole body and perfect insensibility, afterwards with fits of spasm like tetanus; and during the second day, when these symptoms had gone off, he continued to be affected with dumbness.[2057]—It is worthy of particular remark that, contrary to general belief, these effects may be produced in situations where the air is not sufficiently impure to extinguish lights. Thus M. Collard de Martigny relates the case of a servant, who, on entering a cellar where grape-juice was fermenting, became suddenly giddy, and, under a vague impression of terror, fled from the place, dropping her candle on the floor and shutting the door behind her. She fell down insensible outside the door, and those who went to her assistance found on opening the door that the light continued to burn.[2058]—Mr. Taylor indeed has since ascertained that a candle will burn in air, which contains ten, or even twelve per cent. of carbonic acid,[2059]—a proportion more than sufficient to cause poisoning in no long time. It is also important to observe, that, contrary to what would be expected from the statements of Sir H. Davy and other experimentalists on the effects of the pure gas, it will often happen that no odour or taste is perceived. M. Bonami, in an account of an accident which happened at Nantes to two workmen who descended an old well, says that the first while descending uttered a piercing cry and fell down; and that as soon as his comrade, who tried to rescue him, was lowered ten or twelve feet, he felt as if he was about to be suffocated for want of breath, but perceived no strong or disagreeable smell.[2060] It should be remembered therefore by workmen, that there may be danger in descending pits where none is indicated by the sense of smell, or by the extinguishing of a light.
2. The fumes of burning charcoal have been long known to be deleterious. The early symptoms caused by them have been little noticed; for, as this variety of poisoning generally occurs during sleep, the patient is seldom seen till the symptoms are fully formed. In an attempt at self-destruction described in a French journal, the first effects were slight oppression, then violent palpitation, next confusion of ideas, and at last insensibility.[2061] Tightness in the temples, and an undefinable sense of alarm have also been remarked;[2062] and others have, on the contrary, experienced a pleasing sensation that seduced them to remain on the fatal spot.[2063] The best account of the incipient symptoms has been given by Mr. Coathupe of Wraxhall, in an account of an experiment he made with Joyce’s stove,—a preposterous invention, the fuel of which was supposed by the inventor to burn without contaminating the air, although it was neither more nor less than prepared charcoal. Having closed every aperture in a room of the capacity of eighty cubic yards, Mr. Coathupe kindled the stove and watched the results. In four hours he had slight giddiness, in five hours and a half intense giddiness, the desire to vomit without the power, excessive prostration and incapability of muscular effort, a frequent full throbbing pulse, a sense of distention of the cerebral arteries, agonizing headache, chiefly in the hindhead, but no sense of suffocation. At this time he experienced great difficulty in opening the window and removing the stove; and in seven hours, when his wife entered the room, he was unable to tell what was the matter, although quite conscious of all that was passing. He then slowly recovered.[2064] A similar account has also been given by Mr. Chapman of Tooting of the effects of this notorious stove. A young gentleman, after being only one hour in a chamber heated by it, felt first slight giddiness and headache, and afterwards violent pain in the head and tightness round the forehead and temples; the pupils became excessively dilated and nearly insensible; there was constant ringing in the ears, a feeble frequent pulse, paleness of the features and lividity of the lips and hands, coldness of the extremities, laborious irregular breathing, and extreme prostration. A temporary relief, obtained by stimulants, was succeeded by violence; which, however, was subdued by blood-letting; and he recovered.[2065] A set of cases, 70 in number, similar to the last two, but milder, occurred in January, 1836, in the church of Downham in Norfolk, which was heated by two of these stoves.[2066]
The following abstract of a case by Dr. Babington will convey an accurate idea of the advanced symptoms. The waiter of a tavern and a little boy, on going to bed, left a choffer of charcoal burning beside it; and next morning were found insensible. The boy died immediately after they were discovered. The waiter had stertorous breathing, livid lips, flushing of the face, and a full, strong pulse; for which affections he was bled to ten ounces. When Dr. Babington first saw him, however, the pulse had become feeble, the breathing imperfect, and the limbs cold; the muscles were powerless but twitched with slight convulsions, the sensibility gone, the face pale, the eyelids closed, the eyes prominent and rolling, the tongue swollen and the jaw locked upon it, and there was a great flow of saliva from the mouth. The employment of galvanism at this time caused an evident amendment in every symptom. But it was soon abandoned; because each time it was applied, the excitement was rapidly followed by corresponding depression. Cold water was then dashed upon him, ammonia rubbed on his chest, and oxygen thrown into the lungs; through which means a warm perspiration was brought out, and his state rapidly improved. He was nearly lost, however, during the subsequent night by hemorrhage from the divided vein; but next day he was so well that he could even speak a little. For two days afterwards the left side of the face was paralyzed, and his mental faculties were somewhat disordered.[2067]—In such cases as this the stupor is generally very deep. There is a case in a French Journal of a girl, who, after remaining some time in a small close chamber heated by a charcoal choffer, fell down insensible, remained in that state for three hours, and found, on recovering from her lethargy, that the choffer had fallen, and burnt the skin and subjacent fat of the thighs to a cinder.[2068]
Occasionally the stage of stupor is followed, as in some other varieties of narcotic poisoning, by a stage of delirium, at times of the furious kind, or by a state resembling somnambulism.[2069] It does not follow that recovery is certain because coma has thus given place to delirium,—an alteration, which in most varieties of narcotic poisoning is considered a sure sign of recovery. Collard de Martigny has related a case which eventually proved fatal, notwithstanding this sign of improvement.[2070]
The narcotism induced by breathing charcoal fumes often lasts a considerable length of time,—much longer indeed than the effects of other narcotic poisons. This will appear sufficiently from the case described by Dr. Babington. One of the people, mentioned at the commencement of this chapter as having been suffocated at Gerolzhofen, lingered five days in a state of coma before he expired.
Commonly in cases of recovery, there is found to have been no consciousness of any thing going on around, or recollection of what passed subsequently to the first impressions of poisoning. The reverse, however, occurred in Mr. Coathupe’s experiment; and a similar instance has been published, where the individual, though apparently insensible, knew when the room was first entered by strangers, and heard them call him by name and bid him put out his tongue, and stretch forth his arm,—without, however, his having the power to answer, or in any way to express the consciousness of understanding them.[2071]
Poisoning with charcoal vapour has become a subject of great importance in French medical jurisprudence, partly on account of the frequency with which it is resorted to for the purpose of committing suicide, and partly because repeated attempts have been made to conceal murder by arranging matters so as to present the appearances of suicide. M. Devergie says, that in the years 1834 and 1835 no fewer than 360 cases of poisoning with charcoal-vapour occurred in Paris, of which nearly four-fifths proved fatal; and he has given the particulars of two attempts to conceal murder under the appearance of death from this cause.[2072]
The subject has therefore been carefully examined by various authors, but by none so successfully as by M. Devergie; of whose important researches the following is a brief analysis.
In stating the various sources whence charcoal-vapour may become incidentally the cause of death, he dwells particularly on the risk of its admission from adjoining vents, even in other houses from that where the accidents happen,—because there may be currents in the apartment which occasion back-draught. Three remarkable cases of this kind, very obscure in their origin, have been related by M. d’Arcet.[2073]
The very discrepant effects of the poison on different individuals, simultaneously and to appearance alike exposed to it, have usually been explained by reference to the great density of the gas, which consequently accumulates near the floor. Some, however, have doubted the fact that the gas is unequally diffused. Mr. Taylor in particular says he ascertained by analysis, that air collected above and below a choffer of burning charcoal was equally contaminated, that what was collected a foot above its level contained 4·65 per cent., and that another portion taken the same distance below it contained 4·5 of carbonic acid.[2074] M. Devergie has discovered the source of these discrepant opinions. He has found,[2075] that, notwithstanding the high density of carbonic acid gas, the currents caused by the heat, disengaged when charcoal is burnt in a room, without an issue for the products of combustion, produce an equable mixture of gases at all elevations in the apartment, provided the air be examined while still warm, and not long after the charcoal has burnt out; but that, at a later period, such as twelve hours, the carbonic acid partly separates and sinks, so that, while the air at the top contains only a 78th, that near the floor contains four times as much, or a 19th of carbonic acid gas.
Disputes have also arisen as to the precise nature of the emanations from burning charcoal,—some believing that carbonic acid is alone discharged in such quantity as to prove injurious, and is singly sufficient to account for the effects which have been observed,—while others maintain that carbonic oxide, carburetted-hydrogen, or some peculiar pyrogenous vapour, may be also formed, and prove the real cause of the active properties of the vapour. According to the researches of Orfila, charcoal in a state of vivid ignition emits carbonic acid only, a hundred parts of the consumed air having been ascertained by him to be composed of 42 azote, 46 common air, and 12 carbonic acid. But when the combustion is low, a hundred parts consist of 52 azote, 20 common air, 14 carbonic acid, and 14 carburetted-hydrogen; so that not only is the air more thoroughly consumed; but likewise an additional poisonous gas is brought into action.[2076] The difference thus indicated has been supposed to account for what is often observed in countries where charcoal choffers are much in use for warming close apartments,—namely, that the practice is attended with most danger when the combustion is low, and that it is unsafe to close the doors of an apartment till the fuel is in a state of vivid ignition. M. Guérard again maintains, that when the supply of air is incomplete and combustion low, carbonic oxide gas is formed in considerable quantity; and that this gas, confessedly a much more powerful narcotic than carbonic acid, is probably the cause of many cases of poisoning with charcoal fumes.[2077] M. Devergie doubts the exactness of Orfila’s experiments on this head, but gives no new analysis. He observes that charcoal-vapour gives the air of a room a peculiar odour and bluish misty appearance, the latter of which slowly diminishes, and in twelve hours disappears; and that possibly there may be both a little carbonic oxide and carburetted-hydrogen in the air. But nevertheless he is of opinion that the carbonic acid alone is adequate to occasion all the effects observed in man or animals.[2078] Professor Hünefeld is of a different opinion, and has supplied the most satisfactory explanation of the important fact, that charcoal fumes are most noxious when the fuel has been just kindled and burns low; for he ascertained that at first it gives out a pyrogenous acid, which occasions headache and tendency to sickness, and which is not a product of combustion at the moment, but exists ready formed; and that when charcoal is at a full red heat, this noxious substance is no longer given off.[2079] Mr. Coathupe also thinks the cause of poisoning by charcoal fumes is an unknown pyrogenous body, and not carbonic acid gas.[2080]—This department of inquiry is obviously susceptible of more precise information. But meanwhile, whatever may be the probability that, besides carbonic acid, some other gases, or some peculiar pyrogenous body, may occasionally exist in charcoal fumes, and increase their poisonous property, little doubt can exist that the carbonic acid is singly sufficient to account for all the leading phenomena.
M. Devergie has been led to the opinion that air, in which a fourth part of its oxygen has been converted into carbonic acid, and which therefore contains five per cent. of that gas, is amply enough impregnated to occasion death.[2081] This corresponds with the observations of M. Ollivier, who found that three per cent. was as much as could be breathed with impunity even for a moderate length of time.[2082] Less, however, will suffice to prove injurious or even fatal, if the air be breathed long. Mr. Coathupe inferred from a rough estimate, that in the dangerous experiment he made upon himself, the carbonic acid, if uniformly diffused in the apartment, which was probably the case, amounted to only two per cent.; but his data were inadequate.[2083]
Proceeding from the fact that five per cent. of carbonic acid is sufficient to cause death, Devergie points out what quantity of charcoal is required to form that proportion,—a question of no small moment in respect to charges of murder, concealed under the semblance of suicide by suffocation with charcoal fumes. And he shows, that a French bushel, or decalitre, weighing 3000 grammes, is sufficient for a close apartment of 1275 cubic mètres, that is 6·6 pounds avoirdupois for a space of 1666 English cubic yards, provided the gas be uniformly diffused.[2084] The quantity of charcoal burnt in a given case may be arrived at pretty nearly from the weight of ashes left, which is estimated in round numbers at a twenty-fifth by himself,[2085] and at a twentieth by Ollivier.[2086]
It is important to remark that complete closure of an apartment is by no means essential for the action of carbonic acid, whether disengaged within it or introduced from without. For poisoning has occurred, even where a window was partially open.[2087]
3. It is probable that in some circumstances a very small quantity of the mixed gases proceeding from the slow combustion of tallow and other oily substances will produce dangerous symptoms. Dr. Blackadder remarked in the course of his experiments on flame, that the vapour into which oil is resolved, previous to its forming flame round the wick, excites in minute quantities intense headache.[2088] The emanations from the burning snuff of a candle, which are probably of the same nature, seem to be very poisonous. An instance indeed has been recorded in which they proved fatal. A party of iron-smiths, who were carousing on a festival day at Leipzig, amused themselves with plaguing a boy, who was asleep in a corner of the room, by holding under his nose the smoke of a candle just extinguished. At first he was roused a little each time. But when the amusement had been continued for half an hour he began to breathe laboriously, was then attacked with incessant epileptic convulsions, and died on the third day.[2089]—The effects of such emanations are probably owing to empyreumatic volatile oil, which will be presently seen to be an active poison.
4. The vapours from burning coal are the most noxious of all kinds of emanations from fuel, and cause peculiar symptoms. But they are less apt to lead to accidents than the vapour of charcoal, as they are much more irritating to the lungs. This effect depends on the sulphurous acid gas which is mingled with the carbonic acid.
Sulphurous acid gas is exceedingly deleterious to vegetable life, being hardly inferior in that respect to hydrochloric acid. Dr. Turner and I found that a fifth of a cubic inch diluted with ten thousand times its volume of air destroyed all the leaves of various plants in forty-eight hours.[2090] I am not acquainted with any experiments on animals or observations on man regarding the effects of the pure gas. But it will without a doubt prove a powerful irritant.
Some of the peculiarities in the cases now to be mentioned were possibly owing to the admixture of sulphuric acid gas with the carbonic, both being inhaled in a diluted state. The cases are described by Mr. Braid, at the time surgeon at Leadhills. In March, 1817, several of the miners there were violently affected, and some killed, in consequence, it was supposed, of the smoke of one of the steam-engines having escaped into the way-gates, and contaminated the air in the workings. Four men who attempted to force their way through this air into the workings below were unable to advance beyond, and seem to have died immediately. The rest attempted to descend two hours after, but were suddenly stopped by the contaminated air. As soon as they reached it, although their lights burnt tolerably well, they felt difficulty in breathing, and were then seized with violent pain and beating in the head, giddiness and ringing in the ears, followed by vomiting, palpitation and anxiety, weakness of the limbs and pains above the knees, and finally with loss of recollection. Some of them made their escape, but others remained till the air was so far purified that their companions could descend to their aid. When Mr. Braid first saw them, some were running about frantic and furious, striking all who came in their way,—some ran off terrified whenever any one approached them,—some were singing,—some praying,—others lying listless and insensible. Many of them retched and vomited. In some the pulse was quick, in others slow, in many irregular, and in all feeble. All who could describe their complaints had violent headache, some of them tenesmus, and a few diarrhœa. In a few days all recovered except the first four and three others who had descended to the deeper parts of the mine.[2091]—Another accident of the same nature, and followed by the same phenomena, happened more lately at Leadhills.[2092] Similar accidents have been also witnessed by Mr. Bald, civil engineer, among the coal-miners who work in the neighbourhood of a burning mine belonging to the Devon Company. It is worthy of remark, that the men sometimes worked for a considerable length of time before they were taken ill. Such being the case, it will be readily conceived that the burning of the lights was not a test of the wholesomeness of the air. Here, as at Leadhills and in other instances already mentioned, the lights continued to burn where the men were poisoned.[2093]
5. Somewhat analogous to the symptoms now described are the effects of the gradual contamination of air in a confined apartment. Every one must have read of the horrible death of the Englishmen who were locked up all night in a close dungeon in Fort William at Calcutta. One hundred and forty-six individuals were imprisoned in a room twenty feet square, with only one small window; and before next morning all but 23 died under the most dreadful of tortures,—that of slowly increasing suffocation. They seem to have been affected nearly in the same way as the workmen at Leadhills.[2094] A similar accident happened in London in 1742. The keeper of the round-house of St. Martin’s, crammed 28 people into an apartment six feet square and not quite six feet high; and four were suffocated.[2095]
The morbid appearances left on the body after poisoning with carbonic acid gas have been chiefly observed in persons killed by charcoal vapour. According to Portal the vessels of the brain are congested, and the ventricles contain serum; the lungs are distended, as if emphysematous; the heart and great veins are gorged with black fluid blood; the eyes are generally glistening and prominent, the face red, and the tongue protruded and black.[2096]—Gorging of the cerebral vessels seems to be very common. Yet sometimes it is inconsiderable, as in two cases related by Dr. Bright, where, except in the sinuses and in the greater veins of the ventricles and substance of the brain, no particular gorging or vascularity seems to have been met with,—the external membranes in particular having been very little injected.[2097] This, however, is certainly a rare occurrence. Serous effusion in the ventricles and under the arachnoid membrane is very general, yet not invariable.—Dr. Schenck, medical inspector of Siegen, in reporting two cases of death caused by the vapours of burning wood, notices paleness of the countenance as a singular accompaniment of cerebral congestion; and calls the attention of medical jurists to the extreme calmness of the features as a general character of this variety of poisoning.[2098] Although the same appearance has also been noticed by others,[2099] the countenance nevertheless is often livid. But whether livid or pale, it is always composed.—It appears from an account in Pyl’s Essays of several cases of suffocation from the fumes of burning wood, that besides the appearances mentioned by Portal, there is usually great livor of the back, frothiness as well as fluidity of the blood, and more or less gorging of the lungs with blood.[2100]—A common appearance where the poisonous emanation has been charcoal vapour, is a lining of dark, or sometimes actually black dust on the mucous membranes of the air passages, thickest near the external opening of the nostrils, and disappearing towards the glottis. There are obvious reasons why this appearance cannot always be expected to occur; but when present, it may be in doubtful circumstances a very important article of evidence.[2101] In Wildberg’s collection of cases there is a report on two people who were suffocated in bed, in consequence of the servant having neglected to open the flue-trap when she kindled the stove in the bed-chamber; and in each of them Wildberg found all the appearances now quoted from Portal and Pyl. The tongue was black and swelled.[2102]—Mertzdorff has related a case of death from the same cause, in which, together with the preceding appearances, an effusion of blood was found between the arachnoid and pia mater over the whole surface of both hemispheres.[2103] In one of Dr. Bright’s cases there was a small ecchymosis in the cortical substance on the outer side of the anterior lobe, and not extending into the medullary matter. Fallot mentions an instance of suffocation from charcoal vapour, where a little coagulated blood was found between the layers of the arachnoid membrane of the cerebellum in the region of the left occipital hollow.[2104] Three instances of extravasation are enumerated in a list of German cases analysed by Dr. Bird.[2105] Such appearances might be expected more frequently, considering the manifest tendency of this kind of poisoning to cause congestion in the head.—The blood is generally described as being liquid and very dark. But M. Ollivier has lately called attention to the fact, that the blood both before and after death is not unusually more florid in the veins than natural.[2106] In a case mentioned by M. Rayer globules of an oily-looking matter were found swimming on the surface of the blood and urine.[2107] This is a solitary observation.—The body usually remains flaccid, and the customary stage of rigidity is imperfect. In some instances, however, as in those related by Dr. Schenck, the stage of rigidity is passed through in the usual manner. It is not uncommon to find vomited matter lying beside the body, a circumstance which may naturally mislead the unpractised. This is represented by Professor Wagner of Berlin to have occurred uniformly in his experience;[2108] and it is also mentioned in many of the cases reported by others;[2109] but it is not invariable.—A red appearance in the stomach and intestines has been noticed in many cases,[2110] and often ascribed to inflammation; but it is probably nothing more than the result of the venous congestion, which pervades most of the membranous surfaces of the body.
The least variable appearances according to Dr. Bird are general lividity, protrusion of the tongue, a calm expression and attitude, cerebral congestion, and serous effusion. This author’s paper in the Medical Gazette, 1838–39, i., or in Guy’s Hospital Reports, iv., enters very fully into the appearances after death, and may be consulted with advantage for further details.
The treatment of poisoning with carbonic acid consists chiefly in the occasional employment of the cold affusion, and in moderate blood-letting either from the arm or from the head. In a case which happened at Paris, where a lady tried to make away with herself by breathing charcoal fumes, and was found in a state of almost hopeless insensibility, various remedies were tried unsuccessfully, till cupping from the nape of the neck was resorted to; and she then rapidly recovered.[2111] Another instance where blood-letting was also singularly successful deserves particular mention; because for three hours the patient remained without pulsation in any artery, and without the slightest perceptible respiration. At first neither by cupping nor by venesection could any blood be obtained; and it was only after the long interval just mentioned, and constant artificial inflation of the lungs, that the blood at length trickled slowly from the arm. The pulse and breathing were after this soon re-established; but it was not till eight hours later that sensibility returned.[2112]
Of Poisoning with Carbonic Oxide Gas.—Carbonic oxide gas, according to Nysten, has not any effect on man when injected into the pleura; but when thrown slowly into the veins, it gives the arterial blood a brownish tint, and induces for a short time a state resembling intoxication.[2113] The quantity injected into the veins was probably too small to produce the full effect, or it was discharged in passing through the lungs; for this gas certainly appears to be very deleterious when breathed by man, or the lower animals. M. Leblanc found by experiment that a sparrow was killed almost immediately in air containing only a twentieth of it, and that so little even as a hundredth part proved fatal in two minutes.[2114]
A set of interesting but hazardous experiments were made with it in 1814 by the assistants of Mr. Higgins of Dublin. One gentleman, after inhaling it two or three times, was seized with giddiness, tremors, and an approach to insensibility, succeeded by languor, weakness, and headache of some hours’ duration. The other had almost paid dearly for his curiosity. Having previously exhausted his lungs, he inhaled the pure gas three or four times, upon which he was suddenly deprived of sense and motion, fell down supine, and continued for half an hour insensible, apparently lifeless, and with the pulse nearly extinct. Various means were tried for rousing him, without success; till at last oxygen gas was blown into the lungs. Animation then returned rapidly: but he was affected for the rest of the day with convulsive agitation of the body, stupor, violent headache, and quick irregular pulse; and after his senses were quite restored, he suffered from giddiness, blindness, nausea, alternate heats and chills, and then feverish, broken, but irresistible sleep.[2115] A French aëronaut, who used for his balloon a mixture of carbonic oxide and hydrogen, obtained by decomposing water with red-hot charcoal, lately suffered from similar symptoms in a milder degree, in consequence of the gas being disengaged upon him from the safety-valve of his balloon.[2116]
Of Poisoning with Nitrous Oxide Gas.—The nitrous oxide or intoxicating gas is the last of the narcotic gases to be noticed. Nysten found, that, when slowly injected in large quantity into the veins of animals, it only caused slight staggering.[2117] Frequent observation, however, has shown that it is by no means so inert when breathed by man. Sir H. Davy, who first had the courage to inhale it, observed that it excited giddiness, a delightful sense of thrilling in the chest and limbs, acuteness of hearing, brilliancy of all surrounding objects, and an unconquerable propensity to brisk muscular exertion. These feelings were of short duration, but were generally succeeded by alertness of body and mind, never by the exhaustion, depression, and nausea, which follow the stage of excitement brought on by spirits or opium.[2118] Although many have since experienced the same enticing effects, yet they are by no means uniform. For others have been suddenly seized with great weakness, tendency to faint, loss of voice, and sometimes convulsions; and two of Thenard’s assistants, on making the experiment, fainted away, and remained some seconds motionless and insensible.[2119] It is a remarkable circumstance in the operation of this gas, that, unlike other stimulants, it does not lose its virtues under the influence of habit. Neither does the habitual use of it lead to any ill consequence. Sir H. Davy, in the course of his researches, which were continued above two months, breathed it occasionally three or four times a day for a week together, at other periods four or five times a week only; yet at the end his health was good, his mind clear, his digestion perfect, and his strength only a little impaired.[2120]
Nitrous oxide gas is one of the few gases that are not injurious to vegetables. Dr. Turner and I found that seventy-two cubic inches, diluted with six times their volume of air, had no effect on a mignionette plant in forty-eight hours.[2121]
Of Poisoning with Cyanogen Gas.—Cyanogen gas has been proved by the experiments of M. Coullon to be an active poison to all animals,—the guinea-pig, sparrow, leech, frog, wood-louse, fly, crab; and the symptoms induced were coma, and more rarely convulsions.[2122] These results are confirmed by the later experiments of Hünefeld, who found that it produces in the rabbit anxious breathing, slight convulsions, staring of the eyes, dilated pupils, coma, and death in five or six minutes.[2123] Buchner likewise found that small birds, held for a few seconds over the mouth of a jar containing cyanogen, died very speedily; and on one occasion remarked, while preparing the gas, that the fore-finger, which was exposed to the bubbles as they escaped, became suddenly benumbed, and that this effect was attended with a singular feeling of pressure and contraction in the joints of the thumb and elbow.[2124] It would undoubtedly be most dangerous to breathe this gas, except much diluted, and in very small quantity.
Of all narcotic gases it is the most noxious to vegetables. Dr. Turner and I found that a third of a cubic inch, diluted with 1700 times its volume of air, caused the leaves of a mignionette plant to droop in twenty-four hours. As usual with the effects of narcotic gases on vegetables, the drooping went on after the plant was removed into the open air; and in a short time it was completely killed.[2125]
Of Poisoning with Oxygen Gas.—Of all the narcotic gases, none is more singular in its effects than oxygen. When breathed in a state of purity by animals, they live much longer than in the same volume of atmospheric air. But if the experiment be kept up for a sufficient length of time, symptoms of narcotic poisoning begin to manifest themselves. For an hour no inconvenience seems to be felt; but the breathing and pulse then become accelerated; a state of debility next ensues; at length insensibility gradually comes on, with glazing of the eyes, slow respiration and gasping; coma is in the end completely formed; and death ensues in the course of six, ten, or twelve hours. If the animals are removed into the air before the insensibility is considerable, they quickly recover. When the body is examined immediately after death, the heart is seen beating strongly, but the diaphragm motionless; the whole blood in the veins as well as the arteries is of a bright scarlet colour; some of the membranous surfaces, such as the pulmonary pleura, have the same tint, and the blood coagulates with remarkable rapidity. The gas in which an animal has died rekindles a blown out taper. These experiments, which physiology owes to the researches of Mr. Broughton,[2126] furnish a solitary example of death from stoppage of the respiration, although the heart continues to pulsate, and the lungs to transmit florid blood. Death is probably owing to hyper-arterialization of the blood.
The third class of poisons, the narcotico-acrids, includes those which possess a double action, the one local and irritating like that of the irritants, the other remote, and consisting of an impression on the nervous system.
Sometimes they cause narcotism; which is generally of a comatose nature, often attended with delirium; but in one very singular group there is neither insensibility nor delirium, but merely violent tetanic spasms.
At other times they excite inflammation where they are applied. This effect, however, is by no means constant. For Orfila justly observes, that under the name of narcotico-acrids several poisons are usually described which seldom excite inflammation. Those which inflame the tissues where they are applied rarely occasion death in this manner. Some of them may produce very violent local symptoms; but they generally prove fatal through their operation on the nervous system.
For the most part, their narcotic and irritant effects appear incompatible. That is, when they act narcotically, the body is insensible to the local irritation; and when they irritate, the dose is not large enough to act narcotically. In large doses, therefore, they act chiefly as narcotics, in small doses as irritants. Sometimes, however, the narcotic symptoms are preceded or followed by symptoms of irritation; and more rarely both exist simultaneously.
Most, if not all, of them, to whatever part of the body they are applied, act remotely by entering the blood-vessels; but it has not been settled whether they operate by being carried with the blood to the part on which they act, or by producing on the inner membrane of the vessels a peculiar impression, which is conveyed along the nerves. Some of them produce direct and obvious effects where they are applied. Thus monkshood induces a peculiar numbness and tingling of the part with which it is placed in contact. The organs on which they act remotely are the brain and spine, and sometimes the heart also.
The appearances in the dead body are, for the most part, inconsiderable; more or less inflammation in the stomach or intestines, and congestion in the brain; but even these are not constant.
As a distinct class, they differ little from some poisons of the previous classes. Several of the metallic irritants, and a few vegetable acrids are, properly speaking, narcotico-acrids: they excite either narcotism or irritation, according to circumstances. But still, the poisons about to be considered form a good natural order when contrasted with these irritants. For the irritants which possess a double action are nevertheless characterized by the symptoms of inflammation being at least their most prominent effects; while the most prominent feature in the effects of the poisons now to be considered is injury of the nervous system. It is more difficult to draw the line of separation between the present class and the pure narcotics; for many narcotico-acrids rarely cause any symptom but those of narcotism.
The narcotico-acrids are all derived from the vegetable kingdom. Many of them owe their power to an alkaloid, consisting of oxygen, hydrogen, carbon, and azote.
The characters which distinguish the symptoms and morbid appearances of the narcotico-acrids from those of natural disease, do not require special mention; for almost all the remarks made in the introduction to the class of narcotics are applicable to the present class also. A few of the characters, however, which have been laid down, do not apply so well to the narcotico-acrids as to the narcotics. In particular, it appears that what was said on the short duration of the effects of the narcotics does not apply so well to the present class of poisons; some of which, in a single dose, continue to cause symptoms even of narcotism for two or three days. But the rule, that they seldom prove fatal if the case lasts above twelve hours, is still applicable,—at all events they rarely prove fatal after that interval by their narcotic action. The poisonous fungi, however, have proved fatal as narcotics so late as thirty-six hours, or even three days, after they were taken; and perhaps digitalis has proved fatal narcotically at the remote period of three weeks. But such cases are extremely rare.
Some narcotico-acids, such as the different species of strychnos, are quite peculiar in their effects; so that their symptoms may be distinguished at once from natural disease.
Orfila divides the narcotico-acrids into six groups, and this arrangement will be followed in the present work; but they are not all very well distinguished from one another.