Michael Cox said this quote

The boundaries of this world are forever shifting – from day to night, joy to sorrow, love to hate, and from life itself to death; and who can say at what moment we may suddenly cross over the border, from one state of existence to another, like heat applied to some flammable substance? I have been given my own ever-changing margins, across which I move, continually and hungrily, like a migrating animal. Now civilized, now untamed; now responsive to decency and human concern, now viciously attuned to the darkest of desires.