4. (B. P.) Take of chlorinated lime 10 lbs.; rectified spirit, 30 fluid ounces; slaked lime, a sufficient quantity; water, 3 gallons; sulphuric acid, a sufficient quantity; chloride of calcium in small fragments 2 oz.; distilled water, 10 fluid ounces. Place the water and the spirit in a capacious still, and raise the mixture to a temperature of 100° F. Add the chlorinated lime, and 5 lbs. of the slaked lime, mixing thoroughly. Connect the still with a
condensing worm, encompassed by cold water, and terminating in a narrow-necked receiver; and apply heat so as to cause distillation, taking care to withdraw the fire the moment that the process is well established. When the distilled product measures 50 fluid ounces the receiver is to be withdrawn. Pour its contents into a gallon bottle, half filled with water; mix well by shaking, and set it at rest for a few minutes, when the mixture will separate into two strata of different densities. Let the lower stratum, which contains crude chloroform, be washed by agitating it in a bottle with 3 fluid ounces of the distilled water. Allow the chloroform to subside, withdraw the water, and repeat the washing with the rest of the distilled water, in successive quantities of 3 oz. at a time. Agitate the washed chloroform for five minutes in a bottle with equal volume of sulphuric acid, allow the mixture to settle, and transfer the upper stratum of liquid to a flask, containing the chloride of calcium, mixed with 1⁄2 oz. of slaked lime, which should be perfectly dry. Mix well by agitation. After the lapse of an hour connect the flask with a Liebig condenser, and distil over the pure chloroform by means of a water bath. Preserve the product in a cool place in a bottle furnished with an accurately ground stopper. The lighter liquid which floats on the crude chloroform after its agitation with water, and the washings with distilled water, should be preserved and employed in a subsequent operation. Sp. gr. 1·456.
Prop., &c. Liquid; transparent; colourless; odour fragrant, ethereal, and apple-like; taste ethereal, sweetish, but slightly acrid; soluble in 2000 parts of water; mixes in all proportions with alcohol and ether; dissolves (readily) bromine, camphor, caoutchouc, gutta percha, iodine, oils, resins, wax, and several other like substances; boils at 141·8° Fahr.; kindles with difficulty; burns, when strongly heated, with a greenish flame; and communicates a dull, smoky-yellow colour to the flame of alcohol. Sp. gr. 1·48 (1·497, Miller); density of vapour 4·2. The vapour has the remarkable property of rendering a person breathing it temporarily insensible to pain.
Chloroform is frequently adulterated with alcohol and ether; and owing to careless manipulation, is also sometimes contaminated with other substances, as chloral, hydrochloric acid, free chlorine, aldehyde and certain chlorinated oils. These latter compounds are not only the most objectionable and prejudicial of the impurities found in chloroform, but if present in it to any appreciable extent, they render its anæsthetic administration not only inefficient, but frequently absolutely dangerous. These deleterious chlorinated oily compounds may be removed by agitation with strong sulphuric acid, or by distillation from it. Chloroform made from wood spirit is said to be more impure than that from alcohol. When pure it is free from colour, and of a pleasant odour. It is not perfectly soluble in water; and does not turn the colour of litmus red. Rubbed on the skin it quickly evaporates, scarcely leaving any odour. Dropped into water, it falls to the bottom and remains bright and limpid; but if it contain alcohol the surface of the drop becomes opaline. If the same experiment be made with diluted sulphuric acid, sp. gr. 1·44, the drop of pure chloroform will fall to the bottom; but that which contains spirit, if not shaken, will float or remain suspended in the acid solution. When contaminated with heavy hydrocarbon oils, a drop evaporated from the palm of the hand leaves behind a strong smell. Hydrochloric acid and free chlorine are detected by the ordinary tests.
Mr Shuttleworth, writing to the ‘Canadian Pharmaceutical Journal,’ says:—“In regard to the restoration of chloroform which has become spoiled, I would recommend that the chloroform be well agitated with a dilute solution of hyposulphite of soda.
“It should then be separated by means of a glass funnel from the supernatant liquid, and again washed; this time with simple water. After being separated the chloroform should be passed through filtering paper to free it from traces of moisture, when it will be found much improved and comparatively sweet, good enough in any case for external use.
“There are, of course, certain other impurities of chloroform which the hyposulphite will not remove. These are of a more stable character, and as they possess a higher boiling point than chloroform, may be separated by distillation, or by treatment with sulphuric acid in the usual manner.”
Uses, Action, &c. Chloroform is anodyne, antispasmodic, sedative, stimulant, and anæsthetic. In small doses (5 to 12 or 15 drops, in water, mixed with a little syrup or mucilage) it is employed in spasmodic disorders, and as a stimulant and diaphoretic. It is now chiefly used as an anæsthetic to produce insensibility to pain during surgical operations. The dose for inhalation is 1 fl. dr., which is repeated, in a few minutes, if no effect is produced, until 3 fl. dr. have been thus exhibited; the effects being carefully watched, and the source of the chloroform vapour removed as soon as a sufficient degree of anæsthesia is produced, or any unpleasant symptoms develop themselves.
Chloroform in large doses depresses the heart’s action, and causes profound coma, and death. It is therefore dangerous in all cases complicated with diseases of the heart or brain, or any visceral affections of a congestive character.
The treatment of asphyxia from chloroform is—the horizontal position, cold affusion to the head and spine, artificial respiration, and, if possible, either the application of electricity, or the inhalation of protoxide of nitrogen or oxygen gas, largely diluted with atmospheric air.