DERIVATION.--Obtained by pulverizing and macerating aloes in cold water, and evaporating the resulting solution in vacuo. Aloin crystallizes out and is dried between folds of bibulous paper. It is purified by repeated solution in hot water, filtration, recrystallization, and finally by solution in hot alcohol and crystallization. PROPERTIES.--A micro-crystalline powder or minute acicular crystals, lemon yellow or dark yellow in color, possessing a slight odor of aloes and intensely bitter taste. Soluble in water and alcohol. DOSE.--Horses and cattle, 2 to 3 dr.; sheep, 20 to 60 gr.; pigs, 10 to 40 gr.; dogs, 11 to 20 gr.; combined with other purgatives. PREPARATIONS TINCTURA ALOES ET MYRRHAE--TINCTURE OF ALOES AND MYRRH Made by maceration and percolation of purified aloes, 100 parts; myrrh, 100 parts, and liquorice root, with alcohol and water to make 1000. DOSE.--Dogs, ¹⁄₂ to 1 dr. ACTION.--Aloes is a purgative, acting chiefly on the large intestines; small doses are bitter tonics; it stimulates both peristalsis and secretion, increases secretion of bile; is also diuretic; applied externally it is stimulant and desiccant; the Barbadoes is the most active and uniform in its effects. Aloes should be kept in lumps in tin cans or other good containers, only powdered for immediate use; in melting aloes don’t let the temperature rise above 120 degrees as it impairs the activity by converting the active aloin into inert resin. Aloes operate in from 12 to 24 hours after administration; don’t repeat an aloetic purge until 24 hours have elapsed. It also does not cause catharsis. In about 15 hours, the patient should be exercised, but returned to the stall as soon as the desired effect is evident. If it fails to act in 24 hours, linseed oil may be given. Aloin appears to contain the active principles of aloes, and is usually as operative, but some manufactures are ineffective.