There are five of these senses, viz.: touch, taste, smell, sight, and hearing, of which we shall speak more particularly presently. Each has its own nerve, or set of nerves, running from the brain to the organ of sense. Thus, there is one for smell running to the nose, one for sight to the eyes, one for hearing to the ears, while those for touch are more numerous, because the sense of touch belongs to the whole surface of the body.

The face is composed of fourteen bones, which are in pairs-(except the partition between the two nostrils and the lower jaw-bone) one to each side of the face; thus, there are two cheek-bones, two to form the upper jaw, two to the palate, two lower spongy bones, two protecting the eyes, and two forming the nose.

Besides these main bones in the face, there are thirtythree of a peculiar construction, called teeth, formed of a softish bone-like matter, covered with a polished enamel. They are thick in the part that is visible, and taper to one or more spiked roots or fangs, which fit into sockets in the jaw. Circulation takes place through a hole in these roots to the soft inner body of the tooth, and it is this part of the tooth which causes tooth-ache. Of these thirtytwo teeth there are three distinct kinds, differing in shape

according to the purpose for which they are used, and they are arranged in pairs. The two front are Incisors, or cutting teeth (with edges like chisels), for biting off a

portion of food from the main piece, as a mouthful from a slice of bread and butter; there are a pair, canine, or dog-teeth (one on each side), with a more pointed edge, for tearing anything; they are sharper than the cutting teeth: then follows another pair, bicuspids, resembling the former in having only a single root, but having double edges like the six molars, or grinders which masticate the food.

2. The trunk is the broad part between the head and legs, commonly called the body. It is made up of a great number of bones. The principal is the spinal column: a chain of little bones strung, as it were, together, like a string of beads, by a cord (called the spinal marrow) running up their centre. This gives the body its very easy movement, so that it can bend in every direction. You may have seen a toy in the shape of a snake, made of little bones, like buttons, strung together, and if you take hold of its tail, it will bend about and move its head as if it were alive. That is a very good illustration of the back-bone.

On the top of the spine, the head rests on a sort of double pivot; branching off on each side are the hooplike ribs, that make, as it were, the barrel of the body and protect the lungs and heart; behind them are the shoulder-blades, and above, in front, the two thin collarbones; below are the broad bones that protect the intestines, and to which the legs are hung. They form a sort of basin in the lower part of the trunk, and the chief bone is called a basin, or pelvis, which is its Latin You can feel the top edge of it just below the

name.

waist.

3. The limbs of a man, and of all four-legged animals, are the same in number and in their general plan; nor is there much difference in the number of bones composing each. In the latter we call them all legs, because they are all used for walking upon the ground, and none of them for grasping any object; but though the ox, horse, sheep, pig, &c., make no such use of their fore-legs as we do, yet we see a gradual approach amongst quadrupeds to such a use; for instance, the dog paws his master, holds

his food; the monkey grasps the branch of a tree, and

Dolphin's
Fore-foot.

Ape's
arm. Man's

Fig. 4.

arm.

holds nuts to his mouth with his fore-paw. But though all these bear a strong family likeness, they differ in the upper limbs (fore-legs or arms), the horse having no fingers or toes, the cow, sheep, pig, &c., only two on each foot; while of those which make use of their fore-limbs for any purpose approaching to our use of the hand (as the monkey), there is a marked distinction in the position of the thumb, which in man is so placed as to give the greatest power in grasping

and any one can see for himself how clumsy even a clever monkey is in handling a nut or a stick, compared with the delicacy with which a man can pick up a pin, or fit in the most delicate parts of a machine (such as a watch), or lightly paint a picture. A similar, but more marked distinction, is shewn in the position of the great toe, projecting backwards rather than forwards in other animals than man.

The arm and leg of a man almost exactly correspond in the number of bones, as well as in their arrangement. This will be clear from the following table:

:

Starting from the shoulder of the arm and the hip of

the leg, the first length consists of a single bone, working in a ball and socket joint, and the second, of two, capable of turning one over the other, so as to twist and roll the hand or foot. Between this length and the flat termination (called hand and foot) there is a set of small bones (composing the wrist and ankle), so as to admit of free motion in the hand and foot; then follow those which are seated in the broad part of the limb, and to which the fingers and toes are attached by joints working like hinges.

The joints. These bones would be of very little use to us, except Fig. 5.-FORM OF HAND AND LEG. for keeping the body erect, if it were not for the joints, which are like hinges fitting the various bones together, and enabling them to move one upon another. If it were not for these joints man would be no more able to walk than a lamp-post.

There are three principal kinds of joints, viz.: the ball and socket (of which that between the shoulder and upper arm form an example), the hinge, F (fig. 6), as that at the elbow and knee, and the pivot, F (fig. 7), as that at the wrist and ankle. The bones at these joints do not stick together, but are held in their places by certain tough strings fastened to the end of the muscles above