NATURE HER OWN SURGEON.
Equally worthy of admiration, and all but equally complex, is the process by which Nature repairs a fractured limb, especially when the injury is such that the broken ends of bone cannot be brought exactly into their proper positions. It is remarkable, too, how she adapts her process to the different habits of her patients. In the case of a simple fracture, if the parts that have been disjoined are set close together in their normal line—if it be the leg of a dog, for example—there is first a hard sheath, called a "callus," formed round the fracture, and this "callus" permits a restricted use of the injured limb, even before the two parts have grown together. It is, however, only a temporary provision, necessitated by the natural restlessness of the lower animals. After the fracture has completely healed the "callus" gradually disappears. A human case is treated differently. Here, unless it be a broken rib (which requires the provision in consequence of its incessant motion in respiration), the healing takes place ordinarily without the formation of any outer "callus." Sometimes the broken ends cannot be—or at all events are not—brought into their proper relative positions. Is it possible, it may be asked, that Nature can provide the means for meeting such an emergency, when, that is to say, the two portions of bone to be joined are all awry, and something quite new—in fact, a kind of bridge, and a bridge not merely serving the purpose of a solid connection between opposite banks, but like the bridges which carry the appliances of modern civilization, connecting the nerves, which answer to the telegraph wires, and the veins and arteries corresponding to our water and other conduits, has to be constructed? Nature's engineering is equal even to this task.—Quiver.