Text-book of forensic medicine and toxicology

by R. J. M. Buchanan

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.

CARBON MONOXIDE

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.