The motor habits which find expression in the forms of utensils are in part highly specialized,—like those required for the effective use of the throwing sticks just referred to,—but others are much more general in character, and it would seem as though large divisions of mankind were characterised by habits of this kind which influence the forms of their implements and household goods. The restriction to the islands of the Pacific Ocean of the process of producing fire by ploughing; the areas of different types of arrow release described by Edward S. Morse; the extended use of throwing clubs in Africa and their relative insignificance in many parts of America are other examples of this kind. A curious instance of the stability of motor habits is found among the Eskimo; notwithstanding their great inventiveness the ancient Eskimo does not seem to have used the saw for cutting large bones. The cutting was always done by drilling holes close together along the line on which the bone was to be divided. When enough holes had been drilled the parts were separated by a blow of a hammer or by means of a wedge; it seems that saws of flaked stone were entirely unknown to these people. Another instance may be cited; the Indians of the North Pacific Coast, from southern Alaska to central Vancouver Island, do not practice the art of stone chipping and flaking. All their stone work was made either in tough stones that are handled by sawing, battering, pecking and polishing, or in soft stones that can be cut with a knife and rubbed down with polishing materials. The beautiful chipped blades, characteristic of their Eskimo neighbors in the north and their Indian neighbors on the interior plateaus and of the southern coast tribes, are missing here entirely. Similar observations may be made in regard to the handling of the knife. The North American woodcarver of modern times uses principally the crooked knife, the blade of which forms part of a spiral surface. Archaeological specimens of this type are rare[86] so that it is not certain whether this method of cutting was extensively used in olden times. At present it is undoubtedly distributed over the whole continent.[87] The knife is used like a spoke-shave, being drawn towards the body. In Africa, on the other hand, carving is done with a rasp and a straight[88] double-bladed knife. I find the use of a crooked, sickle shaped knife mentioned only once, as being applied to the shaving down of an arrow shaft and, presumably, to similar purposes. Schweinfurth[89] mentions that the Mangbattu are the only people in the regions he visited,—including even Egyptians—, who are familiar with the use of the single-edged carving knife, while all the others use the double-edged knife. Of the Ila speaking people it is also said that they use a spear blade for carving[90].