by MURIEL BEADLE 251 pages. Simon & Schuster. $9.95.
They were gods in Egypt. Some two millenniums before the birth of Christ, cats were buried with the pomp of pharaohs, hi bronze coffins and mausoleums complete with mummified mice for delectation hi the afterlife. A drastic decline from this lordly state occurred when the early Christian church decided that the feline was a pagan minion of Satan intimately connected to wicked deeds of darkness. In pictures of the Last Supper, for example, the "bad cat" of Christendom sits at Judas' feet.