Animal jelly; glutinous material obtained from animal
   tissues by prolonged boiling. Specifically (Physiol. Chem.), a
   nitrogeneous colloid, not existing as such in the animal body, but
   formed by the hydrating action of boiling water on the collagen of
   various kinds of connective tissue (as tendons, bones, ligaments,
   etc.). Its distinguishing character is that of dissolving in hot water,
   and forming a jelly on cooling. It is an important ingredient of
   calf's-foot jelly, isinglass, glue, etc. It is used as food, but its
   nutritious qualities are of a low order.