right position, a dislocated shoulder blade; and in order to make himself appear wondrous wise, as quacks are apt to do, he tried to encourage his patient to endure the severe pain he was causing him, " for," said he, "I have got three of the bones into their place already, and shall soon have the rest of them right!"

Here is a representation of this bone, about which the pretender or quack affected to know so much, and yet knew so little.

CHAPTER VI.

BODY OF THE HOUSE.-CONTINUED.

The arms, or appendages. Account of the hand. Uses of the hand.

ARMS. These are not posts, for, in their natural position, they support nothing. They are not braces, for they strengthen no part of the frame. They are properly appendages, but they are very convenient ones; and though they can be torn off without spoiling the building, their loss very much injures it. They seem to answer, in some good degree, the purposes of stairs, ladders, tackles, pulleys, and other machinery for raising things from the ground, and conveying them to the upper part of a building. These appendages-we will at once call them arms and hands-however, answer a much better purpose than any

of those.

The arm and hand, taken together, constitute a most wonderful apparatus for motion.

The particular structure of the joints, as well as the peculiarities of the hand, must be reserved for another place; but it is necessary to say a little about the arm.

The bones of the arm have a slight resemblance to those of the leg. The upper part consists of only one bone. This is long and round, and is called the humerus. It is fastened above to the scapula. Below, at the elbow, it is connected to the two bones of the lower half of the arm, by a joint like a hinge, and by ligaments or straps, which extend from near the lower end of the topmost end of the others.

upper bone to the

The largest of the

two latter bones is called the ulna, which is a Latin word for cubit; because the arm, below the elbow, is usually considered about a cubit in length. The smaller one is called the radius or spoke, from its supposed resemblance to the spoke of a wheel. It is the bone from the elbow on a line with the thumb.

The connection at the shoulder is such, that the arm can be moved in almost every conceivable direction. The elbow joint only admits of one sort of motion, viz., forward and backward, like a door on its hinges. But the

connection of the radius, or smaller bone of the arm, with the ulna, or larger one, is such that it more than makes up for this deficiency. The upper end of the radius having a rotatory motion, in a depression of the ulna, allows the hand, to be placed with each of its surfaces upwards with great facility. These motions are usually called pronation, when the palm. of the hand is downwards, and supination, when the palm of the hand is upwards. Then the wrist, consisting, as it does, of eight bones, all movable, and being so connected with the lower bones of the arm as to admit of very free motion, renders the arm one of the most useful contrivances in the world. It will perform as varied and rapid movements as the trunk of the elephant; and were it not common, would probably excite equal surprise.

It was said that this whole portion of the building could be torn off without spoiling it. Cheselden, an English anatomist, relates that a miller had the whole arm, shoulder-blade and all, torn off, and yet his life was not injured. The great danger, in such cases, is from bleeding; but torn blood-vessels do not bleed so freely as those which are cut.

THE HAND.-I wish to give you a few particulars about the hand. This extremity of the arm is by far the most curious part of it. I do not know that there is a greater curiosity in the whole world than the human hand.

The truth is, many of the best, as well as the most curious objects in the world, are neglected in the same manner. Think of the thousand uses of water. could exist without it? for so valuable a gift?

What living thing

And are we thankful