The same method used to produce double tails in the lizard can also be used to produce double legs. The femur is broken in the vicinity of the hip-joint, and the soft parts are cut into over the break. Then, or better somewhat later, the leg is amputated below the broken part. A new limb regenerates from the cut-end, and at the same time another limb grows out from the broken femur (Fig. 43, _C_). The same result is reached if the femur has a slit cut into it in the region of the hip-joint, so that it is much injured. Later the leg is cut off below the place of injury. A double leg is the result. Feet with supernumerary digits can also be produced by artificial wounds. If the first and second and then the fourth and fifth toes are cut off, as indicated by the lines in Fig. 43, _E_, so that a part of the tarsus and a part of the tibia and fibula are cut away (the third finger being left attached to the remaining middle portion), more toes grow out from the wounded surface than were removed, as shown in Fig. 43, _F_. A similar result may be obtained in another way. If the first and second toes are cut off by an oblique cut (Fig. 43, _G_), and then after the wound has healed the third, fourth, and fifth toes are also cut off by another oblique cut (a part of the tarsus being removed each time), more toes are regenerated than were cut off[64] (Fig. 43, _H_). Tornier suggests that the double feet that are sometimes formed in embryos--even in the mammalia--have resulted from a fold of the amnion constricting the middle of the beginning of the young leg, in the same way as is brought about artificially by tying a string over the growing end of the regenerating leg of triton. In many of these cases, in which the double structure is the result of splitting the part in the middle line, the completion of the new part is exactly the same as though the parts had been entirely separated. The only special problem that we meet with in these instances is that this doubling is possible while the piece remains a part of the rest of the organism. This shows that there is a great deal of independence in the different parts of the body in regard to their regenerative power, and that local conditions may often determine the formation of double structures.