Chloroform is a transparent, colorless liquid, sometimes of a slightly yellowish tinge, heavier than water, of a peculiar, apple-like odor, of a sweet, but slightly acrid taste, readily dissolved in alcohol and ether, and in 2000 parts of water. An American chemist, Mr. Guthrie, of Sackett's Harbor, New York, made in 1830 a substance which he called chloric ether, us^ing in its preparation chloride of calcium and alcohol. He claimed it to be akin, in its action, to sulphuric ether. The preparation proved to have been chloroform, diluted with alcohol. Various experiments, made by Sonberan, Liebig and Dumas resulted in a more perfect understanding of the manufacture and chemical composition and of 712 CHLOROFORM. the physiological properties of this substance, now known as "terchlo- ryde of formyle," or "chloroform." Chloroform is neutral and should have no acid reaction. It may be adulterated with ether, alcohol, sulphuric acid. The lighter specific gravity would betray the presence of alcohol or ether, that of the pure article being 1.48. Sulphuric acid may be detected by adding a solution of a salt of baryta to water with which it has been shaken. The following rules are also valuable: 1. Poor preparations are characterized by a sharp, disagreeable odor and a caustic action upon the skin and mucus membrane; hence its inhalation produces a strong desire to cough and dyspnoea, and creates considerable irritation and smarting where it comes in contact with the skin. 2. A pure article, if poured into distilled water, falls to the bottom in pure, clear, round and well-defined drops ; an unreliable prepara- tion, containing an admixture of alcohol, becomes cloudy as soon as it touches the water, and the separate drops become pearly, opaque. 3. If pure chloroform is added to an equal mixture of pure, con- centrated sulphuric acid and distilled water, which mixture, after cooling, has a specific gravity not greatly differing from that of the chloroform, the pure article will still sink to the bottom; if the chlo- roform refuses to do so, it contains alcohol. Pure chloroform remains perfectly colorless when boiled with potassa ; the presence of aldehyde causes a brown coloration. When shaken with concentrated sulphuric acid and allowed to stand for half an hour, the two liquids should separate into two colorless layers. The presence of alcoholic chlorides produces a brown coloration. Physicians who are called upon to administer chloroform should use the utmost care in securing an absolutely pure article ; many accidents can undoubtedly be traced to the use of adulterated chloroform. The physiological effects of chloroform are unique. It is a stimu- lant, sedative, anti-spasmodic and anaesthetic. The interest of the profession centres mainly in its anaesthetic properties. The late Dr. Anstie, one of the most careful and painstaking inquirers into the properties of chloroform, attributes to it, admin- istered in small doses, purely stimulating properties, producing by this stimulating action