Circumstances under which it occurs accidentally.—Death may result where several persons are sleeping in the same room, and the ventilation is imperfect; from the admission of the vapour of charcoal into a room from an adjoining vent; or from incautiously sleeping in a brewery close to a vat in which fermentation is going on. Many deaths have occurred from this gas, due to the incautious descent into wells. It must also be borne in mind that death may result from the presence of this gas in an atmosphere which will permit the combustion of a candle. For a candle will burn in an atmosphere containing 25 per cent. of CO₂, whereas 5 per cent. will cause death. The burning of a candle is therefore no test of security from danger in an atmosphere where the presence of carbonic acid is suspected. Carbonic acid does not, as is generally supposed, sink to the lower portions of a room; and Dr. Taylor, from his experiments, states “that in a small and close room persons are liable to be suffocated at all levels, from the very equal and rapid diffusion of carbonic acid during combustion.”
Symptoms.—When the carbonic acid is pure, that is, unmixed with other gases, spasm of the glottis at once occurs, and the sufferer falls down insensible, and death is almost immediate. When the gas is diluted the early symptoms are a feeling of weight and fulness in the head, accompanied with giddiness, throbbing of the temporal arteries, drowsiness, palpitation of the heart, gradually increasing insensibility, stertorous breathing, ending in death from asphyxia or apoplexy. Sometimes the victim dies convulsed, at other times a deep sleep quietly merges into death. The symptoms will, of course, depend upon the quantity and purity of the gas present in the apartment.
Action on the Animal Economy.—The opinions of observers vary greatly—Berzelius maintaining that an atmosphere containing 5 per cent. was not injurious to life; Allen and Pepys, on the other hand, stating that 10 per cent. of the gas would cause death. Bernard considers that it is not poisonous, as it can be injected into the bodies of animals without injury, and that its action is purely negative; it is irrespirable in the same sense as pure hydrogen or nitrogen is—simply, therefore, causing death by suffocation. Whatever may be the true explanation of its action, it is enough for all practical purposes to know that death follows when it is breathed, even when mixed with a normal amount of oxygen.
Post-mortem Appearances.—The face may be pale and composed, or swollen and livid. The vessels of the brain are frequently greatly congested, and the heart and great vessels gorged with black fluid blood. The blood in some cases, however, is of a cherry-red colour. This may probably be due to the presence of carbon monoxide, which appears to have the power of preventing the change of arterial into venous blood, the opposite effect to that of carbon dioxide. The tongue may or may not be protruded beyond the teeth; in most instances the latter is the case. Animal heat is long retained after death, and the rigor mortis occurs as in other forms of death.
Treatment.—Bleeding from the arm, cupping from the nape of the neck, and the employment of cold affusion to the head. The patient should be removed without delay into the open air. Artificial respiration and galvanism have been successfully employed in some cases, and inhalations of oxygen should be used if possible.
How the proportion of Carbon Dioxide may be estimated.—The air to be examined is drawn into a vessel capable of holding one and a half gallons, to which is added a clear solution of lime or baryta. The vessel, after being well agitated, is allowed to remain untouched for from eight to twenty-four hours. The carbonic acid is absorbed by the lime or baryta, and the difference in the causticity of the lime solution before and after it is placed in the vessel gives the amount of carbonic acid present in the air. A simple method of collecting the air in a mine is by lowering a bottle full of fine sand, so arranged that at any depth it may be turned upside down, and the sand allowed to run out, its place being taken by the air of the mine. The bottle may now be quickly drawn up, corked, and reserved for examination.
How may an Apartment, Well, or Mine be cleared of it?—Free ventilation in the first case. In the case of a well, a basket of slaked lime may be let down; but in mines a steam fanner or a jet of steam must be blown through the mine. No one, of course, should be allowed to enter the well or mine until it has been cleared of the carbonic acid.
This gas is formed in a variety of ways, one being the oxidation of carbon at a very high temperature in a limited supply of oxygen. It is given off by iron stoves at a red heat. It is one of the chief ingredients of the vapour of burning charcoal.
To this gas is due the suffocating quality of air in which coke or charcoal is burnt. It is inodorous, hence the dangerous insidiousness with which it produces its fatal results. It is said that 0.5 per cent. will cause death, and even 0.1 per cent. is injurious. The vapours from brick kilns and “burnt ballast” heaps are injurious to health, and the owners of them may be indicted for causing a nuisance.
The fumes from burning charcoal are taken advantage of for purposes of suicide, a method frequently used on the Continent, but almost unheard of in England. The suicide generally shuts himself up in a room, which he has closed against any ventilation, and in which he has placed a receptacle containing burning coke or charcoal.
Poisoning by carbon monoxide occurs in two forms—acute and chronic.
Symptoms: Acute.—The first symptoms may be those of excitation, which are quickly followed by intense headache, giddiness, throbbing of the temples, and nausea followed by vomiting. Muscular weakness occurs, sensation and the reflexes are lost, drowsiness and coma follow, and in fatal cases convulsions often come on before death. The pulse becomes imperceptible at the wrist. The conjunctivæ become hyperæmic, the eyes staring, the pupils dilated and insensible. The voluntary and involuntary muscles are relaxed, the skin cold and cyanotic, and the lips covered with froth.
Chronic.—The symptoms are headache, neuralgic pains, anæmia, shortness of breath, and wasting; when advanced they are those of peripheral neuritis and mental disturbances.
The less severe symptoms of chronic carbon monoxide poisoning are not uncommon, and occur in those who occupy small and badly ventilated rooms, in which there may be a heating stove, gas stove, or imperfect gas fittings; the last are especially dangerous when water gas is used for illuminating purposes, as it contains a high percentage of carbon monoxide.
It is a very powerful gas, speedily causing death by acting chiefly on the nervous system, the symptoms being those produced by a pure narcotic.
The post-mortem signs are redness of the face, with reddish patches on different parts of the body. The blood—and this is chiefly characteristic of carbon monoxide poisoning—is cherry-red, due to a chemical compound formed by the action of the gas on the colouring matter of the blood, thus paralysing the oxygen-carrying power of the blood corpuscles. The gas is supposed to combine with the hæmoglobin forming a fixed compound, the spectroscopic examination showing the two absorption bands of the hæmoglobin nearer to the violet end of the spectrum than under normal conditions. (See Blood Spectra, p. 103.)
These bands resemble those of O₂Hb, so their position must be compared with a spectrum of O₂Hb, the two spectra being side by side.
There is another important difference, however, determined by the action of a reducing agent such as ammonium sulphide. The bands of COHb are unaltered, while those of O₂Hb are reduced. Death frequently takes place before all the Hb has been changed into COHb, so that the blood contains a mixture of COHb and O₂Hb, and on the addition of a reducing agent the spectrum is a composite one of COHb and reduced Hb. Only the broad band of reduced Hb is to be seen if the amount of COHb present be less than 28 per cent. In an atmosphere containing a large percentage of carbon monoxide death may occur before the blood contains sufficient COHb to give the characteristic spectrum.
The treatment consists in the removal of the sufferer into the fresh air, artificial respiration, venesection, and the transfusion of arterialised defibrinated blood. Oxygen inhalations should be given. In two cases subcutaneous injections of nitro-glycerine were followed by recovery.
This gas is prepared by passing steam through incandescent carbon, and is a compound of nearly equal parts of carbonic oxide and hydrogen. It owes its dangerous properties to the first-named gas. When water gas, pure and simple, is supplied for heating purposes, its leakage cannot be detected, as the gas possesses no odour. When used for lighting and carburetted, its escape is more readily detected by the smell, but even then it is more dangerous than coal gas as the proportion of CO is higher. Several deaths have resulted from the use of water gas for heating and lighting purposes, and also for steel smelting in Leeds. The symptoms of poisoning are those of carbon monoxide.
Sulphuretted hydrogen is a gas possessing a powerful odour of rotten eggs. It is largely used as a test for most of the metals; and its presence may be detected by filter paper, moistened with a salt of lead, becoming black.
Symptoms.—When the gas is moderately diluted the symptoms produced are giddiness, throbbing of the temples, pain and oppression of the stomach, nausea, and vomiting; delirium and convulsions sometimes occur, together with laborious respiration and an irregular pulse. When the gas is but slightly diluted, the person becomes suddenly weak and insensible, and rapidly dies.
Post-mortem Appearances.—Fluidity and blackness of the blood, loss of muscular contractility, and a tendency to rapid putrefaction. The bronchial tubes are reddened, and the internal vascular organs may appear almost black.
Treatment.—This will consist in the immediate removal of the person into fresh air, and the administration of stimulants, together with the respiration of chlorine gas evolved from bleaching powder by the action of an acid.
Coal gas is composed of several hydrocarbons, the chief of which is marsh gas, together with free hydrogen, carbon monoxide and carbon dioxide, ammonia, hydrogen sulphide, and sulphides of carbon, which give to it its peculiar odour. The poisonous properties of coal gas are due to the carbon monoxide, 7.5 per cent. being present in ordinary gas as supplied for illuminating purposes. It can be detected by passing the coal gas through an acid solution of cuprous chloride, which becomes black by the formation of a compound CuCOCl. A dangerous explosive compound is formed when the gas reaches the proportion of 1 in 10 of the atmosphere. Poisoning by this gas is, as a rule, accidental.
Symptoms.—Headache, nausea, vomiting, giddiness, ending in coma. Stertorous breathing is noticed in some cases. Should the sufferer be removed from the gas, the breath smells strongly of the gas. The murderer Chantrelle tried to cover his crime by admitting gas into his wife‘s bedroom, but the attempt failed. The pupils are, as a rule, dilated before death.
Post-mortem Appearances.—Cherry-red colour of the blood, redness of the pulmonary tissue, and froth in the air-passages. The vessels of the brain are engorged, and rose-coloured patches appear on the thighs.
Treatment.—This consists in removing the patient into the fresh air, artificial respiration, oxygen inhalations, &c., as in carbon monoxide.
Toxic effects have been produced by inhalation of the gases caused by explosives. The principal gases are carbon dioxide, carbon monoxide, and nitrogen. Gunpowder yields a considerable amount of CO and sulphuretted hydrogen. Nitro-glycerine, dynamite, and gun-cotton yield a large amount of CO. Tonite yields very little CO, and roburite none. Smokeless powders give off CO.
The manufacture of “roburite” and “sicherheit,” which contain dinitro-benzine, is fraught with danger from this substance, causing, in acute cases, cyanosis of the face or the whole body, headache, vertigo, paresis, coldness, quick pulse, dyspnœa, shallow breathing with long intervals, and coma. Vomiting may occur, and the blood becomes a chocolate colour. A chronic form of poisoning produces lividity and cyanosis, with gastritis, hepatic enlargement and jaundice, paræsthesia, numbness, and cramps in the muscles, amblyopia with concentric contraction of vision-fields, and central scotoma. The blood is like that of pernicious anæmia, and the urine brown or blackish.
This gas has a peculiar odour of geranium. It is a product of the incomplete combustion of hydrocarbons, and is formed when lamps or gas jets are burned with insufficient air, e.g. a Bunsen burner which has “lighted back,” also from the use of oil stoves, and gas cooking and heating apparatus. It is used for illumination, and formed by the action of water on calcium carbide. It forms a highly explosive mixture with air. It is not a potent poison. Continued exposure to it causes anæmia, malnutrition, and nervous symptoms. On animals it produces narcosis. It does not combine with hæmoglobin, but acts as an indifferent gas.
This is known as laughing gas; it has a sweetish taste and smell. When breathed in small quantities it produces tingling sensations and induces laughter, hence its name. When breathed for anæsthetic purposes the skin becomes livid, the blood pressure raised, and unconsciousness follows. It acts first upon the higher nerve centres, then upon the spinal cord, medulla, and heart. If pushed too far it causes death by asphyxia. In ordinary use for anæsthesia, the latter is rapidly produced, and recovery follows quickly when the administration is stopped. It has peculiar effects upon certain people, who may not only show the symptoms of hilarity, but, in some cases, become extremely violent.
Petrol fumes produce toxic effects upon those who breathe them, comprising perverted taste, dysphagia, headache, giddiness, cyanosis, insensibility, mania and imbecility. Maniacal outbreaks occur during recovery. Peripheral neuritis may follow.
This causes poisoning when swallowed or inhaled, e.g. glove cleaning, waterproofing, &c. Death has taken place in either way.
Symptoms.—In acute poisoning there is excitement, flushing of the face, cyanosis, dilated pupils, headache, slow breathing, stupor and coma, with gastro-intestinal irritation.
Hallucinations and delirium may occur amongst workers in it; idiosyncrasy plays a part. Women may become intoxicated, excited, and hysterical. It may cause headache, vertigo, narcosis, and inability to walk, with vomiting. Small hæmorrhages may occur. Rapid coma and death may occur when the vapour is concentrated.
Treatment.—When swallowed, the stomach tube should be used and ether and strychnine given hypodermically. When overcome by vapour, removal to the open air, artificial respiration, oxygen inhalations, and restoratives are required.
This is an irrespirible gas with the odour of burning sulphur. It is a preservative and bleaching agent, is used for disinfection, and occurs in certain industries.
The inhalation of the fumes causes a feeling of suffocation, with spasm of the glottis, and irritation of the nose, trachea, and bronchi, producing sneezing and cough; opacity of the cornea, dyspnœa, cyanosis, and convulsions may occur.
The gas is used for disinfection and bleaching. In chemical works chronic poisoning may occur causing anæmia, emaciation, gastritis, dental caries, bronchitis, and emphysema. If concentrated, it causes dyspnœa, violent cough, hæmoptysis, stupor, and syncope.
Treatment.—Fresh air, steam inhalations, and the general treatment of the lung conditions.
This is a very poisonous gas. Deaths have occurred on board ships carrying cargoes of electrolytic ferrosilicate containing calcium phosphide. It reduces the oxyhæmoglobin. It may produce rapid, followed by slow and laboured breathing and convulsions.