[Illustration: 260 261 262 263] No. 260. Some changes have been made in the ankle joint, but the notable modifications are a foot with thick sponge-rubber removable sole, K-K, in place of the rubber-covered core; for thigh amputations an adjustable steel knee cord and spring piston, combined in one piece, E, and knee-joint tightener, A. The removable sole gives us an opportunity of strengthening the upper part of foot with a rawhide covering. Between the wooden part J and the rubber K at the toe part, layers of canvas and sole leather are placed to prevent breaking or turning up of the toe. This, however, is hardly necessary in most cases, but we consider it an additional protection. With rubber-covered cores the rubber first breaks away from the top of the core at the toe part, resulting in turning up of the toe, leaving little chance to repair it satisfactorily without making a new foot. This cannot very well take place with the rubber sole, as there is no rubber above the wood to break away. If, however, it becomes necessary for any reason to renew the rubber, the sole can be removed by simply taking a screw out at the bottom of foot, and a new sole or part of a sole put on at a trifling expense without sending the leg to us, as we keep on file a pattern of each individual foot made. The greater security by which the cord ends and the ankle-joint rods are kept in place, and the convenient method of getting at them, are additional strong points commending the change. See No. 261. The combination knee cord and spring consists of a steel rod carefully bushed at the joint and extending through a hickory bar in calf of the leg, with a thick, soft leather washer on the rod under the bar, and a nut at the end of rod that is reached with thumb and finger through holes in back of leg for readily adjusting the length. For the knee spring a suitably protected heavy elastic web is slipped over end of the rod and adjusted from outside of leg with buckskin strings; as leg is flexed in act of walking, the rod is forced through the hickory bar, stretching the web and forcing the lower part of the leg forward in position for next step; when lower part of leg is flexed at right angles with the thigh, as in sitting, the pressure of spring is automatically released. This change simplifies the knee-joint construction, is lighter and more convenient of adjustment. Figs. 262 and 263 illustrate a new knee joint for amputation below the knee. This is the latest and decidedly the most compact, lightest, and at the same time the best wearing joint that we have ever adopted, not excepting the ball-bearing joint, and is recommended in all cases. Joints of medium weight are usually applied. A heavier joint of same pattern is used, however, when the wearer is unusually heavy or desires an extra strong joint and does not mind the additional weight. Let us see if we can describe the uniqueness of it, so that it will be understood.