Cut the kidneys in halves, lengthwise, remove all the fat, and skin them. Wash them and lay them in cold water for half an hour and then cut them crosswise, in thin slices.
Slice the bacon thin, and cut each slice into 2 pieces. Place a piece of bacon on a skewer, then a piece of kidney, and thus alternate them until you have 5 pieces of each on a skewer. Dip the pieces of kidney into melted butter before they are put on the skewer.
Place the skewer on a broiler and hold it over a bright fire, turning frequently until all sides are cooked. When the kidneys are broiled, place each skewer on a finger of toast and sprinkle lightly with pepper. Put a tiny bit of butter on each piece of kidney and serve immediately.