Thixotropy

Thixotropy  :  is sometimes offered as an explanation as to why the blood of St. Januarius allegedly liquefies twice a year.  Thixotropy is actually a property that is exhibited by certain gels (semisoild, jellylike colloids).  A thrixopic gel seems at first to maintain its shape and act and behave like a solid.  However once subjected to forms of disturbance such as shaking, it then flows freely and takes on the properties of a sol or semifluid colloid.