The view that diffuse lustre on the sharp edge of a flint indicates that the flint has been used for cutting corn, or at least grass, has often been put forward. It has recently been criticized by M. René Neuville, and these criticisms have been countered by fresh experimental evidence which has convinced the writer that this interpretation holds good. Flint flakes, some worked, some apparently unworked, are frequently found in Egypt, Palestine, and elsewhere, bearing diffuse lustre on both faces adjacent to one or more edges, and such flakes are generally recognized as having served as parts of flint sickles, for some have actually been found in their wooden mounts. The possibility of analogous implements having been used in Britain has not so far received much attention, except that the beautifully worked crescentic ‘knives’ of Scandinavian type are now generally recognized as having been sickles. A few of these latter show the characteristic corn-lustre on their concave edges.