686 MEDICAL JURISPRUDENCE Chemical Analysis. — The resin is contained in the acid ether extract of the suspected organic material obtained by the Stas-Otto process, arid is recognized by the following tests : — 1. Beam's Alkaline Test.— The extract is treated with a small quantity of animal charcoal to remove the colouring matter, especially the chlorophyll of the crude drug, and is filtered before evaporating to dryness in a small porcelain capsule. A few drops of a 5 to 10 per cent alcoholic solution of potash are added, when a violet colour gradually develops, which may be hastened by warming. This test may also be performed by dissolving the residue in a few drops of petroleum ether and soaking a piece of filter paper in this solution. The paper is then evaporated spontaneously and moistened with a drop of the alcoholic potash, when a violet colour appears at once. 2. Beam's Acid Test. — A few drops of absolute alcohol saturated with dry hydrochloric acid gas are added to the residue dissolved in a few drops of petroleum ether, when a red colour is produced, The preparations of cannabis indica, such as the tincture and extract, often fail to respond to this test. 3. Bouquet's Test. — If a few drops of a freshly prepared mixture of concentrated sulphuric acid (2 vols.) and absolute alcohol (3 vols.) are added to the extracted residue dissolved in a few drops of acetone after it is de- colourized by animal charcoal, if necessary, a dark colour appears, which becomes cherry red in about an hour. The addition of a few drops of water renders the solution colourless but opalescent. 4. Aldehyde Test. — A few drops of the reagent made by dissolving 1 g, of para-dimethylamino-benzaldehyde in 100 cc. of alcohol and adding 20 drops of concentrated sulphuric acid are added to the residue in a porcelain, basin, The mixture is then evaporated to dryness, when a bright violet colour appears. Bhang and other forms of cannabis sativa used by addicts may be identi- fied under the microscope by the presence of retort-shaped, short, unicellular, cystolithic hairs and long, thin tapering hairs, having no cystoliths. The following method is recommended for carrying out the microscopic exami- nation : — The suspected particles are placed on a slide, and a drop of dilute caustic soda solution is added. They are then covered with a cover-slip and examined first under the 1/3" and then under the 1/6" objective, when the morphological features of the hairs will be observed distinctly. The ganja hairs appear smooth, and the hairs found in charas are warty, For the microscopic examination of majun, sugar, butter and other substances should first be removed by washing successively with petroleum ether, alcohol and hot water. The residue is then treated with dilute alkali and examined. In the case of ganja or charas mixed with tobacco or any other dry substance the sus- pected particles should be freed from foreign matter, rubbed with a little water in a mortar and mixed with some chloral hydrate solution The mixture is transferred to a test tube and - boiled for a few seconds, wheix the finer parti- r*C™<^ Fig. 187,— Cannabis sativa Hairs : °" <an]a Hairs' b* char^ Hairs.