there was a note at the bottom of one of the pages at this part of the book , and henry read as follows : with regard to these vampyres , it is believed by those who are inclined to give credence to so dreadful a superstition , that they always endeavour to make their feast of blood , for the revival of their bodily powers , on some evening immediately preceding a full moon , because if any accident befall them , such as being shot , or otherwise killed or wounded , they can recover by lying down somewhere where the full moons rays will fall upon them .