Dice the 4 slices of white bread with crusts and spread in the bottom of a slightly greased casserole. Spread over the cooked, cut up chicken. Chop, mix together and spread over the top of chicken, the celery, onion, green pepper and mayonnaise. Remove the crusts from 4 slices of bread and place on top of this. Beat lightly 4 eggs and 2 1/2 cups of milk. Pour over bread. This can then be placed in the refrigerator for an hour or overnight, or frozen. Bake at 325ºF.  for 15 minutes. Spread over top of 1 can of cream of mushroom soup and 1 cup of grated cheese. Bake at 325ºF. for an hour longer.