4270. To Test the Purity of Opium

4270.    To Test the Purity of Opium. Macerate 100 grains opium for 24 hours in 2 fluid ounces water; filter and express tho residue; then precipitate with a solution of 1/2 ounce carbonate of soda in 2 fluid ounces cold water; gently heat tho precipitate until it fuses, then cool and weigh it. It should weigh at least 10 grains; and, when powdered, bo entirely soluble in a solution of oxalic acid.

4271. Chloroform

4271.     Chloroform. A thin, colorless liquid, of agreeable ethereal odor, and sweetish but slightly acrid taste. Its specific gravity (water standard) is 1.49, and the specific gravity of its vapor (air standard) is 4.2. It kindles with difficulty, burning with a greenish flame, and gives a dull, smoky-yellow color to tho flame of alcohol. It occupies a prominent place among tho ancesthetics (substances used to produce insensibility to pain by inhaling them), but has in later times been, to a certain extent, superseded by nitrous oxide. (See No. 40G0.) Externally applied, it is refrigerant, soothing, and allays pain. It neither reddens nor bleaches litmus paper.

4272. To Obtain Chloroform

4272.    To Obtain Chloroform. This is prepared on the largo scale, by mixing, in a capacious retort or still, 4 pounds chloride of lime, 12 pounds water, and 12 fluid ounces rectified alcohol; distill cautiously as long as a dense liquid is produced, which sinks in and separates from the water with which it passes over. Separate the lower stratum of chloroform from the water, agitate it with a little sulphuric acid, and distill it by the heat of a water-bath from carbonate of baryta. (Dumas.)

4273. To Obtain Pure Chloroform

4273.    To Obtain Pure Chloroform. Place in a capacious still 3 gallons water and 30 fluid ounces rectified spirit and raise the temperature to 100° Fahr. Add 10 pounds chlorinated lime (slacked lime saturated with chlorine gas), and 5 pounds slacked lime, mixing thoroughly. Apply heat, which must be withdrawn as soon as distillation has commenced, and distill 50 ounces; agitate it with 1/2 gallon water, and allow the crude chloroform to settle. Separate and wash the chloroform with 3 fluid ounces distilled water, repeating this operation 3 times, each time with fresh distilled water. Next agitate the chloroform

• for 5 minutes with an equal volume of sulphuric acid; when settled, transfer the upper stratum to a flask containing 2 ounces chloride of calcium in small pieces, and 1/2 ounce perfectly dry slacked lime. Agitate thoroughly, and, after an hour, distill the pure chloroform over a water-bath. Keep in a well-stoppered bottle, in a cool place. The TJ. S. Dispensatory has transferred this from the British Pharmacopoeia, consequently avoirdupois weight and Imperial measure are adopted.

4274. To Purify Commercial Chloroform

4274.    To Purify Commercial Chloroform. To 102 troy ounces commercial chloroform add 17 troy ounces sulphuric acid, occasionally shaking during 24 hours. Separate the lighter liquid and mix it with 6 fluid drachms stronger alcohol. Then add 2 troy ounces carbonate of potassa, previously heated to redness, and rubbed into powder while warm. Agitate thoroughly and distill to dryness. Keep the distilled liquid in well-stopped bottles. (U. S. Ph.)