so far as it is known, with greater safety than these two anaesthetics where the operation lasts only a short time, the effects passing off more rapidly and usually leaving no unpleasant after-consequences. In these cases, too, it has been administered in doses not of quarts and diluted, as in the early experiments of Davy, but of gallons, and undiluted. At the same time nitrous oxide cannot be substituted for atmospheric air without danger to life. It cannot produce in the blood those oxidation changes on which life depends, which are produced by the uncombined oxygen of the air. It is absorbed into the blood and alters its colour to a deep purple, as indicated by the blueish or livid colour of the lips. An animal soon dies in this gas when air is not supplied; and from the symptoms preceding death, namely, convulsions and insensibility, it must be regarded as a neurotic poison, but not of a dangerous kind. The experiments of L. Hermann have proved that when breathed without admixture of atmospheric air and oxygen, nitrous oxide acts like other indifferent gases, killing simply by asphyxia (simple deficiency of oxygen). When inhaled in a mixture of four parts of nitrous oxide to one of oxygen-as in Davy's original experiments-it produces in human beings the cheerful narcosic or inebriation previously described; and consciousness and sensation are not completely abolished. In Jan. 1873 it was administered by a dentist to a lady, æt. 38, at her own desire, in order to annul pain during the extraction of a molar tooth. A physician carefully examined her before the operation, and found nothing to preclude the use of the gas. The nitrous oxide was pure; it had been safely used for other patients from the same condenser, and an apparatus was employed so as to secure the removal of the expired air. The total quantity administered was about six gallons. Davy himself breathed with safety five gallons in one of his experiments. Soon after the commencement of the inhalation it was observed that the pulse became rapid and less full; the patient was then sensible, and the apparatus was removed. The operation was commenced, but the lady insisted on having the gas again. She took it; insensibility came on, and the operation was completed. Immediately afterwards the face became livid, the features began to swell, and the tongue protruded. In spite of every effort to restore her, she did not recover from the state of insensibility; she breathed two or three times, and the pulse then ceased. No inspection of the body was made. The above-mentioned facts were given in evidence at the coroner's inquest, and the medical opinion was that death had been caused by the gas in producing paralysis of respiration, and that in this case no forethought could have prevented the result. The jury returned a verdict of homicide by misadventure. (Lancet,' 1873, 1, p. 178.) It has been suggested that in this case death may have taken place from suffocation, in consequence of blood entering the air-passages; but while there were no symptoms indicative of this, the facts conclusively prove that the gas operated as a blood-poison to destroy life. Since this date, other fatal cases have occurred; but considering the enormous number of cases in which the gas is administered, the fatality from its use must be regarded as very small, and it may be concluded that there is no great danger attending its administration by proper hands, and with due caution. In the cases which have been placed upon record death appears to have been simply due to suffocation, Some observations on the comparative effects of nitrous oxide, bichloride of methylene, and chloroform as anaesthetics, have been published by Rendle.. (Brit. Med. Jour.' Oct. 16, 1869.) He gave nitrous oxide in twentyfour cases, the gas being rebreathed and the carbonic acid of the expired air at the same time removed by slaked lime. The persons to whom it was given varied from 3 to 73 years of age. It was given chiefly for short NITROUS OXIDE AS AN ANESTHETIC. 117 operations on the eyes or teeth. The shortest period in which anathesia was produced was 60 seconds, the longest 150; the average was about a minute and a half. Anæthesia was maintained thirteen minutes in one case, six minutes in five cases, four minutes in five, two minutes in twelve, and one minute in one case. Intervals of breathing air were allowed in all but one. The period during which air was admitted, varied very much, and herein lies probably the secret of preventing fatal accidents. When the quantity of air admitted was small, anaesthesia was still produced, though less rapidly, and the blueness of the lips and skin was less marked. A woman, æt. 48, was under the influence of the gas in one minute. It was continued for five minutes longer, without any admission of air. At the end of this time she was unusually blue, and the breathing and pulse were very slow and failing. The gas was removed and the woman was turned over on her left side. This woman must have been very near death, and probably would have died had she been in the sitting posture. She gradually recovered, and walked away in five minutes more. One man who began to imbibe the gas for the extraction of a tooth, pushed away the inhaler, and refused to continue breathing the gas. He complained of very unpleasant symptoms in his head for some hours after, but these passed off. One woman complained of headache. In one case, that of a child æt. 4, vomiting followed. In a child æt. 3, where anaesthesia was maintained for a minute and a half, two intervals of breathing air having been allowed, the respiration ceased and the pulse sank so as to be scarcely perceptible for several seconds. The gas was removed, and the child was turned slowly over on his left side. He gave a deep sigh; the pulse and breathing gradually returned, and he completely recovered in five minutes. According to Rendle the advantages of nitrous oxide are, the rapid production of and recovery from anesthesia, the absence of sickness, and the agreeable taste. He considers it safe for all operations, short or long, even to a duration of twenty minutes, provided there be a due admission of air at proper intervals. But that great care is required in its use is shown by the alarming symptoms which occurred in some of the cases. Among its disadvantages are these: it is apt to produce rigidity of the muscles, with muscular twitching and congestion. Tomes met with cases in which recovery was slow: there was feeble pulse, irregular breathing, loss of appetite, and a necessity for stimulants. In one instance coma was produced; and other cases are reported of sudden supervention of dangerous symptoms-sickness and apparent death. It would appear therefore that the danger from nitrous oxide arises chiefly from the continuous administration of the gas without allowing proper intervals for the breathing of air. In one case, supra, Rendle gave the pure gas for six minutes without the admission of air. Death did not result, although the symptoms produced were very alarming. ('Brit. Jour. of Dent. Sc.' May, 1871.) Rendle did not meet with a case which proved fatal out of some hundreds of cases of the administration of this gas, and his experience in this respect is corroborated by that of others. His conclusion is, 'that those agents which produce well-marked alarming symptoms of approaching danger will not so frequently cause death, and therefore may be considered the safest, while others which require greater skill and watchfulness on the part of the administrator to recognize approaching danger, will cause death frequently, and therefore may be regarded as more dangerous.' Although in the numerous cases in which he gave nitrous gas and other anesthetics at Guy's Hospital he did not meet with an accident, several of the cases would easily have been lost by a moment's inattention. The fatal case related at p. 116 ante gave rise to some difference of opinion. As the body was not inspected, the cause of death can only be a matter of inference, but all the facts known, point to this conclusionthe only practical one which concerns the public-that but for the administration of the nitrous oxide this lady would not have died. Whether the proximate cause was asphyxia from paralysis of the muscles of respiration, or from the entrance of blood into the air-passages, is unknown. According to the report of a committee appointed to investigate the effects of nitrous oxide as an anesthetic, this gas operates by preventing oxidation-changes in the blood, and, as in death from asphyxia, the respiration is arrested before the heart ceases to beat. ('Lancet,' 1872, 2, p. 687.) See asphyxia, vol. 1, p. 164. For some additional remarks on the case see Lancet,' 1873, 1, p. 245, and at page 254 of the same volume will be found a further report by Mason. It is evident that much is still to be learned respecting the operation of nitrous oxide on the human body. One experienced administrator contends that air must be occasionally admitted in order to prevent fatal effects, while another states that, according to his experience, the giving of air prevents complete insensibility, and therefore does not fulfil the purpose for which the gas is administered. (Lancet,' 1872, 2, p. 762.) Nitrous oxide has beyond doubt caused fewer accidents than the vapours of ether and chloroform; but there is a very narrow line between life and death in the action of this as well as of all anæsthetics, and it should therefore only be given by a skilled administrator. CHAPTER 59. SULPHURETTED HYDROGEN GAS-ITS POISONOUS PROPERTIES-SYMPTOMS-POST- SEWERS-ANALYSIS SULPHURETTED HYDROGEN has a powerful action on the body. Persons are sometimes accidentally killed by it; but the very offensive odour which a small portion of it communicates to a large quantity of air is sufficient to announce its presence, and thus, with due caution, to prevent any dangerous consequences. Sulphuretted hydrogen gas, when breathed in its pure state, is instantaneously fatal. It exerts equally deleterious effects upon all orders of animals, and upon all the textures of the body. It has been found to destroy life even when it is allowed to remain in contact with the skin. Donovan states that a rabbit enclosed in a bladder of sulphuretted hydrogen gas, but allowed to breathe freely in the atmosphere, perished in ten minutes. When introduced into the lungs of animals, even in a diluted state, it has given rise to fatal consequences. Thus Thénard found that air which contained only 1-800th of its volume of this gas would destroy a dog, and that when the gas existed in the proportion of 1-250th it sufficed to kill a horse. The researches of Parent-Duchâtelet have, however, shown that the poisonous effects of the gas have been somewhat exaggerated, at least in the application of these results to man. He observed that workmen breathed with impunity an atmosphere containing 1 per cent. of sulphuretted hydrogen; and he states that he himself had breathed, without serious symptoms ensuing, air which contained three per cent. In drains and sewers, rats and other vermin are found to live in large numbers; and, according to Gaultier de Claubry, when the air in these localities contains from 2 to 8 per cent. (Devergie, Méd. Lég.' vol. 2, p. 520.) Thus SULPHURETTED HYDROGEN. SYMPTOMS. 119 sulphuretted hydrogen does not appear to be so energetic as Thénard's experiments would lead us to suppose. An atmosphere containing from 6 to 8 per cent. of the gas might speedily kill, although nothing certain is known of the smallest proportion required to destroy human life. One fact, however, is worthy of attention, namely, that the breathing of an atmosphere only slightly impregnated with the gas may, if long continued, seriously affect a person, destroy health, and even cause death. Three young and healthy men died successively, in the course of a few years, under similar symptoms. The lodging consisted of a bedroom with a chimney, and an ill-ventilated ante-room. The pipe of the privy passed down one angle of the room by the head of the bed, and the wall in this part was damp from infiltration. At the time of the examination there was no perceptible smell in the room, although it was small and low. D'Arcet attributed the mortality in the lodging to the slow and longcontinued action of the emanations from the pipe. ('Ann. d'Hyg.' Juillet, 1836.) The men who were engaged in working at the Thames Tunnel suffered severely during the excavation, from the presence of this gas in the atmosphere in which they were obliged to work. The air, as well as the water which trickled through the roof, was found to contain sulphuretted hydrogen: it was probably derived from the action of the water on ironpyrites in the clay. The gas issued in sudden jets, so as to be at times perceptible by its odour. As a result of breathing this atmosphere the strongest and most robust men were, in the course of a few months, reduced to an extreme state of exhaustion, and several died. The symptoms with which they were first affected were giddiness, sickness, and general debility; they became emaciated, and fell into a state of low fever, accompanied by delirium. In one case, the face of the man was pale, the lips of a violet hue, the eyes sunk with dark areolae around them, and the whole muscular system was flabby and emaciated. Chloride of lime and other remedies were tried for the purification of the air; but the evil did not entirely cease until the tunnel was so far completed that there was a communication from one side to the other, and free ventilation established throughout. Symptoms. The symptoms produced by sulphuretted hydrogen vary according to the degree of concentration in which it is breathed. When breathed in a moderately diluted state, the person speedily falls inanimate. An immediate removal to pure air, and the application of stimulants, with cold affusion, may, however, suffice to restore life. According to the account given by those who have recovered, this state of inanimation is preceded by a sense of weight in the stomach and in the temples, giddiness, nausea, sudden weakness, and loss of motion and sensation. If the gas in a still less concentrated state be breathed for some time, insensibility, coma, or tetanus with delirium supervenes, preceded by convulsions, or pain and weakness over the whole body. The skin in such cases is commonly cold, the pulse irregular, and the breathing laborious. When the air is but slightly contaminated with the gas, it may be breathed for a long time without producing any serious symptoms; sometimes there is a feeling of nausea or sickness, accompanied by pain in the head, or diffused pains in the abdomen. The symptoms are often observed to affect those who are engaged in chemical manipulations with this gas. Sulphuretted hydrogen appears to act like a narcotic poison when highly concentrated, but like a narcotico-irritant when much diluted with air. It is absorbed into the blood, to which it gives a brownish-black colour by combining with the red blood-pigment, and it is in this state circulated throughout the body. In all cases a noxious atmosphere containing this gas is indicated by an offensive smell producing nausea and sickness. For a case of poisoning by this gas, in which the person recovered, see 'Med. Gaz.' vol. 43, p. 871. Appearances after death.-On examining the bodies of persons who have died from the effects of sulphuretted hydrogen, when breathed in a concentrated form, and the inspection was recent, the following appearances have been observed :-The mucous membrane of the nose and throat is commonly covered by a brownish viscid fluid. An offensive odour is exhaled from all the cavities and soft parts of the body. These exhalations, if received into the lungs of those engaged in making the inspection, sometimes give rise to nausea and other unpleasant symptoms, and may even cause syncope or asphyxia. The muscles of the body are of a dark colour, and are not susceptible to the electric stimulus. The lungs, liver, and the soft organs generally, are distended with black liquid blood. There is also great congestion of the right side of the heart, and the blood has been found everywhere liquid and dark-coloured. The body rapidly undergoes the putrefactive process. When death has occurred from the breathing of this gas in a more diluted form, the appearances are less marked. There is then general congestion of the internal organs, with a dark and liquid state of the blood. In fact, in such cases the appearances can scarcely be distinguished from those produced by carbonic acid. Four men lost their lives in the Fleet Lane Sewer in Feb. 1861: they were found dead, and there was no doubt sulphuretted hydrogen was the cause of death. An account of the appearances presented by the bodies was given by Holden and Letheby ('Lancet,' 1861, I. p. 187). The eyes and mouth were open, the lips and tongue livid, the pupils widely dilated, the blood black and fluid, the lungs congested, the heart full of black fluid blood, the right side gorged, and there was a bloody froth in the windpipe. In the brain the large vessels of the dura mater were full of black fluid blood. In 1857, six persons lost their lives, at Cleator Moor, by the respiration of sulphuretted hydrogen in a diluted form, by reason of their having slept in small close non-ventilated rooms, into which the gas had penetrated. Three of the deceased persons-a husband, wife, and child, of one familyhad retired to rest, in their usual health. Two of them were found the next morning dead in bed, and a third (the child) was found in a state of insensibility, and lingered until the afternoon of the same day, when she died. The fourth, a healthy adult, retired to sleep in his bed, with his door closed, and he was found dead in an hour. The fifth, a child, was taken ill on the morning of the 11th, and died the same day. The sixth was taken ill on the morning of the 10th, and died on June 12th. The symptoms complained of by those who recovered were nausea, sickness, giddiness, and insensibility. In one child, the pupils were found dilated, viscid mucus escaped from the nostrils, and there was congestion of the lungs and kidneys, as well as of the membranes of the brain. In the adult who died in an hour, the pupils were natural, the jaws firmly clenched, the fingers contracted, and the nails blue; there was great cadaveric lividity, and a quantity of fluid with frothy mucus issued from the nostrils and mouth. The lungs were much congested, and serum was effused in the cavity of the chest. The heart contained a little fluid blood, and was somewhat flaccid. The mucous membrane of the windpipe and gullet was redder than natural. In the windpipe there was frothy mucus. The stomach, as well as the large and small intestines, were highly congested, but otherwise healthy. The brain and its membranes were greatly engorged with blood, which, as in the body generally, was very dark and fluid. Wilson, who examined the body of the child, drew the conclusion, which was confirmed by the subsequent inquiry, that death had been caused by sulphuretted hydrogen. Thompson, who examined the body of the man, also inferred that some noxious gas or gases had destroyed life. The cottages in which the accidents had occurred |