[AS.] A firm, hard substance, of a white or pale rose color, composing the skeleton or firmer part of the body. There are 246 bones in the human body. They give shape and firmness to the body, protect the organs from injury, and afford a solid place for the attachment of muscles. All bones are curiously fashioned, and beautifully adapted to their various purposes. Where the object is to protect, the bone is strong and thick, and offers the greatest resistance with the least material, or is so placed as to defend the organ. Those designed for support are thick and solid. Long bones are hollow, and contain marrow, which is composed chiefly of blood-vessels and fat. The other bones are spongy and lattice-like inside, and hard on the outside. Bones are full of fine tubes through which the blood passes. The bones of the various animals vary in their texture, and are chiefly composed of phosphate and carbonate of lime and gelatine. Bones are covered with a tough membrane, except at the joints, where they are covered with cartilage. When this cartilage is removed the bone dies. The bones of the trunk are the pelvis, spinal column (see Backbone), the ribs, the breast-bone, the shoulder-blade, and the collar-bone. The bones of the arms are the humerus, the ulna, and the radius. The wrist has eight bones and the palm of the hand five. The bones of the legs are the femur, patella, tibia, and fibula. The ankle has seven and the body of the foot five bones. The skull is composed of a number of bones, which surround and protect the brain (q.v.).

THE ULNA.

THE ULNA.

THE HUMERUS.

THE HUMERUS.

THE SCAPULA.

THE SCAPULA.