CARBON MONOXIDE 733 is a just perceptible effect, perhaps a slight headache and lassitude ; when it equals 9, severe headache and nausea result; when it equals 15, the condition is dangerous, and when it rises above 15, the conditions are such as will be quickly fatal. Chronic Poisoning.—This form of poisoning is found in persons, who are constantly exposed to the action of the gas in gas houses and automobile workshops, and in those inhabiting ill-ventilated rooms, in which fire is burning. This is a result of frequent tissue injury due to intermittent con- tact with the gas. Symptoms.—These are headache, nausea, digestive disturbances, dyspnoea, dizziness, mental torpidity, loss of,memory, wasting of the muscles, anaemia, and in some cases symptoms of peripheral neuritis and glycosuria. Treatment.—Remove the patient at once into fresh air. Commence artificial respiration and supplement it by the administration of oxygen at high tension. Donald and Paton 7 are of the opinion that mixtures of oxygen and carbon dioxide should not be administered in the resuscitation of sub- jects requiring and receiving artificial respiration, as there is a grave risk o£ high and dangerous tensions of carbon dioxide being induced in the subject. Inject hypodermically 0.5 to 1 cc. of adrenaline and intravenously 5 cc. of 25> per cent coramine solution, and repeat them, if'necessary, at intervals of from half an hour to an hour. Keep the patient warm by applying hot-water- bottles to the extremities and by covering the body with blankets. In severe collapse administer subcutaneously normal saline or resort to blood transfusion. A dose of 0.5 g. of procaine hydrochloride in 500 ml. of 5 per cent dextrose may be administered intravenously once a day in acute and chronic poisoning and may be continued for five days. After breathing is established, watch the patient carefully for the after- effects of carbon monoxide poisoning, and give him hot tea or coffee when he is conscious enough to swallow. Post-mortem Appearances.—Externally, the lips and finger-nails have a bright red colour. Irregular patches of a bright red colour are scattered over the anterior surface of the body, and post-mortem stains appearing on the dependent parts have also the same bright red colour. Internally, the blood is fluid and of a bright cherry-red colour due to the formation of carboxyhaemoglobin. The internal organs are hypersemic and are bright red owing to the colour of the blood. The mucous membrane of the air- passages is bright red, and is often covered with froth. The lungs are con- gested, and may occasionally be oedematous. There may be haemorrhagic and laecrotic lesions in the heart muscle. There is serous effusion into the ventricles of the brain. Punctiform haemorrhages and softening in the cor- tex and the lenticular nuclei may be found in chronic carbon monoxide poisoning. Tests.—1. Spectroscopic Test.—The spectrum of the blood will show two absorption bands similar to those of oxyhsemoglobin, but placed nearer the violet end. The addition of ammonium sulphide does not alter the spectrum. 2. Hoppe-Seyler's Test.—Caustic soda of specific gravity 1.3 produces a greenish colour, if added to normal blood, but retains the bright red colour, if carbon monoxide is present in the blood. 3. Kurikel's Test.—The suspected blood, diluted with 4 volumes of water, is mixed with 3 times its volume of 1 per cent tannic acid solution and shaken well. Carbon monoxide blood forms a crimson-red coaguhim, 7. Brit. Med. Jour., Feb. 5, 1955, p. 315.