Now we will look at the ribs. They are fastened to the spinal column at the back, and all but four are fastened to the breast-bone in front. There are twelve ribs on each side. There are two bones on the upper part of the back, which seem to dance every time you move your arm. These are the “shoulder blades.” They are thin, flat bones, which help make the shoulder joint. You can feel two bones near your neck in front, which are called “collar bones.” They are shaped much like the letter _f_, and serve to preserve the shape of the shoulders. [Illustration: _Ribs._] AMY: How many bones do we have in our arms, mother? [Illustration: _Bones of the arm._] MOTHER: There are three in each arm,--one from the shoulder to the elbow, and two from the elbow to the wrist. There are a large number of bones in the wrist and hand. [Illustration: _The pelvis._] The middle part of the body below the spinal column is called the pelvis. In this picture we see two curious bones. These are the hip bones. They are like the sills of a house, which, you know, are large and strong. There is a deep hole in each one as large as a toy teacup, which holds the round head of the leg bone. There are three bones in each leg, the same as in the arm, one from the hip to the knee, and two from the knee to the ankle, besides a funny little bone or cap which covers the knee. Then we come to the ankle bones and bones of the feet. HELEN: How do the bones stay in their proper places, mother? I should think they would fall apart. MOTHER: They would if they were not tied together. ELMER: But what are they tied with? [Illustration: _Bones of the leg and foot._] MOTHER: With strong white bands or cords called lig´a-ments. Perhaps you have seen them on the leg of a chicken. When a joint is “sprained,” that means the lig´a-ments are stretched or hurt in some way. AMY: I should think the bones would get dry so they would squeak and rub hard against one another. [Illustration: _Wrist bones tied together._] MOTHER: So they would if the Maker of the body-house had not put soft cushions of gristle or car´ti-lage between them. A soft, thin skin covers them, which pours “joint water” over the ends, and keeps them oiled just right, so they bend easily, and never squeak at all. You have seen the driver of an engine oiling it so it would run easily and not wear out; but think of a machine which will mend and oil itself for seventy years without wearing out! We have a most wonderful frame. The Bible says, “Thou hast fenced me with bones and sinews,” and, “He knoweth our frame.” Sometimes if we are ill a long time “the bones that were not seen stick out;” but when we are well, flesh covers them over so we hardly know we have any bones at all. I once read a poem which I will repeat for you. It may help you to remember how many bones we have and where they are:—