The bile obtained from the gall bladder of a bovine animal, usually a domesticated cow. It consists of a ropy. mucous, semi-transparent liquid, and contains sodium salts of taurocholic and glycocholic acids, cholesterol, lecithin, etc. Ox-gall is used as the expanding and binding medium for the colors used in MARBLING .
It is necessary in all marbling, and it is important that it be pure and free from water. When in its original state it is yellowish or greenish brown, but becomes clear and dark brown when allowed to settle. The liquid is then drawn off and mixed with alcohol. Its effect on the colors is to make them spread out in large flat rings when they are dropped on the size Ox-gall is also used in engraving and lithography