=ACONITE ROOT.= (B. Ph.). _Syn._ ACONITI RADIX, L. The dried root of _aconitum napellus_. Imported from Germany, or cultivated in Britain, and collected in the winter or early spring before the leaves have appeared. _Prep._ Aconitia, the active principle; Linimentum Aconiti, 1 ounce to 1 fluid ounce; Tinctura Aconiti, 54-1/2 grains to 1 fluid ounce. _Char._ Usually from one to three inches long, not thicker than the finger at the crown, tapering, blackish-brown, internally whitish. A _minute_ portion, cautiously chewed, causes prolonged tingling and numbness. =ACONITI FOLIA.= See ACONITE LEAVES. =ACONITI RADIX.= See ACONITE ROOT. =ACONITIA.= C_{30}H_{47}O_{7}N. (B. P.) _Syn._ ACONITIA, L. An alkaloid obtained from aconite. Take of Aconite root, in coarse powder, 14 pounds. Rectified spirit } Distilled water } of each Solution or ammonia } a sufficiency. Pure ether } Diluted sulphuric acid} Pour upon the aconite root three gallons of the spirit, mix them well, and heat until ebullition commences; then cool and macerate for four days. Transfer the whole to a displacement apparatus, and percolate, adding more spirit, when requisite, until the root is exhausted. Distil off the greater part of the spirit from the tincture, and evaporate the remainder over a water bath until the whole of the alcohol has been dissipated. Mix the residual extract thoroughly with twice its weight of boiling distilled water, and when it has cooled to the temperature of the atmosphere, filter through paper. To the filtered liquid add solution of ammonia in slight excess, and heat them gently over a water bath. Separate the precipitate on a filter, and dry it. Reduce this to coarse powder, and macerate it in successive portions of the pure ether with frequent agitation. Decant the several products, mix and distil off the ether until the extract is dry. Dissolve the dry extract in warm distilled water acidulated with the sulphuric acid; and, when the solution is cold, precipitate it by the cautious addition of solution of ammonia diluted with four times its bulk of distilled water. Wash the precipitate on a filter with a small quantity of cold distilled water, and dry it by slight pressure between folds of filtering paper. _Characters and Tests._ A white, usually amorphous, solid, soluble in 150 parts of cold, and 50 of hot water, and much more soluble in alcohol and in ether; strongly alkaline to reddened litmus, neutralising acids, and precipitated from them by the caustic alkalies, but not by carbonate of ammonia or the bicarbonates of soda or potash. It melts with heat, and burns with a smoky flame, leaving no residue when burned with free access of air. When rubbed on the skin it causes a tingling sensation, followed by prolonged numbness. It is a very active poison.