C1. Solutions of the alkaloid or its salts in water cause numbness when applied to the tongue and dilation of the pupil when applied to the eye.

C2. Concentrated sulfuric acid dissolves the cocaine or its salts without discoloration. When warmed it turns brown, the hydrochloride giving the odor of hydrochloric acid. The vapors produced by heating with the concentrated sulfuric acid deposit benzoic acid on the sides of the test-tube on cooling.

C3. Concentrated nitric acid gives no color with cocaine in the cold.

C4. With 1 percent solution of potassium permanganate, cocaine yields a precipitate of cocaine permanganate. This upon standing collects in radiating clusters of thin, tabular crystals, a bright reddish-purple in color, very plainly to be seen with a low power of the microscope.

C5. An aqueous solution of cocaine acidulated with dilute sulfuric acid, to which enough potassium permanganate solution has been added to give a violet color does not lose this after standing half an hour at the ordinary temperature.

C6. If a little cocaine hydrochloride is powdered with as much mercurous chloride in a dry porcelain dish the mixture is white, but it becomes gray in presence of a little moisture, even
by being breathed upon.

C7. Cocaine or its hydrochloride when evaporated to dryness on the steam-bath, after the addition of 1 cc of concentrated nitric acid, leaves a colorless residue. With a few drops of alcoholic potassium hydroxide it develops the pleasing and per-manent odor of benzoic ethyl ester.

C8. Cocaine hydrochloride solution with a few drops of potassium dichromate gives a yellow precipitate which quickly disappears. On acidifying the solution then with hydrochloric acid an orange-yellow crystalline precipitate of cocaine chromate appears which is soluble in excess of the acid.