Ox gall is gall, usually obtained from cows, that is mixed with alcohol and used as the wetting agent in marbling, engraving, lithography, and watercolor painting. It is a greenish-brown liquid mixture containing cholesterol, lecithin, taurocholic acid, and glycoholic acid. Bile (or gall) is a bitter, greenish-yellow alkaline fluid secreted by the liver of most vertebrates. ... Look up Cow on Wiktionary, the free dictionary Cow may refer to: Cattle regardless of sex (in vernacular usage). ... Surfactants, also known as wetting agents, lower the surface tension of a liquid, allowing easier spreading. ... Marbling has two common meanings: faux marbling is the art of painting walls or furniture to look like real marble. ... Engraving is the practice of incising a design onto a hard, flat surface, by cutting grooves into it. ... Lithography is a method for printing on a smooth surface, as well as a method of manufacturing semiconductor and MEMS devices. ... Carl Larsson, Crayfishing, watercolor, 1897 Watercolor is a painting technique using paint made of colorants suspended or dissolved in water. ... Cholesterol chemical structure Cholesterol is a steroid, a lipid, and an alcohol, found in the cell membranes of all body tissues, and transported in the blood plasma of all animals. ... Lecithin, also known as Phosphatidylcholine Lecithin is usually used as synonym for phosphatidylcholine, a phospholipid which is the major component of a phosphatide fraction which may be isolated from either egg yolk (in Greek lekithos - λεκιθος) or soy beans from which it is mechanically or chemically extracted using hexane. ... Hydrolysis of Taurocholic Acid yields Taurine, an amino acid. ...