Fat
in anatomy, an animal substance of a more or less oily character deposited in vesicles in adipose tissue. It forms a considerable layer under the skin, is collected in large quantity around certain organs, as, for instance, the kidneys, fills up furrows on the surface of the heart, surrounds joints, and exists in large quantity in the marrow of bones. It gives to the surface of the human frame its smooth, rounded contour. In chemistry, fats are glycerides of acids belonging to the fatty or acetic series and of acids belonging to the acrylic series, being the ethers of the triatomic alcohol glycerine. They are insoluble in water, but soluble in ether. They vary in consistence from a thin oil (olive oil) to a hard, greasy substance (suet). When fats are boiled with any caustic alkali they are decomposed, and yield an alkaline salt of the fatty acid (see SOAP), and GLYCERINE (q. v.). In printing, copy which affords light work, as blank or short pages or lines. The fat is in the fire: All is confusion, or all has failed.