ARABIC ACID, also known as arabin and gummic acid, is the chief constituent of gum arabic. (See Gums.) It can he obtained as an amorphous precipitate by treating with alcohol an aqueous solution of gum arabic in the presence of hydrochloric acid. It is soluble in water and insoluble in alcohol. Pure arabic acid, or X-arabinosic acid, C23H38022, differs from the naturally occurring gum acid which is a compound of arabinosic acid with the sugar residues, arabinan and galactan.