ng strong
liquor is almost the same. Beer and hard cider also do the kidneys harm,
sometimes producing incurable disease of these important organs.

SUMMARY.

1. The kidneys somewhat resemble the skin in their structure and in
their work.

2. The kidneys remove from the blood some poisonous substances.

3. To keep the kidneys healthy we should drink plenty of water, avoid
irritating foods and drinks, and keep the skin in health by proper
bathing.

4. The drinking of strong liquors often causes incurable disease of the
kidneys.

CHAPTER XVIII.

OUR BONES AND THEIR USES.

~1. The Bones.~--In an earlier chapter we learned something about the
bones. This we must try to recall. You will remember that we called the
bones the framework of the body, just as the timbers which are first put
up in building a house are called its frame.

~2. The Skeleton.~--All the bones together make up the _skeleton_. (See
page 95.) There are about two hundred bones in all. They are of many
different shapes. They vary in size from the little bones of the ear,
which are the smallest, to the upper bone of the leg, which is the
largest in the body.

~3.~ The skeleton is divided into four parts: the _skull_, the _trunk_,
the _arms_, and the _legs_. We must learn something more about the bones
of each part.

~4. The Skull.~--The _skull_ is somewhat like a shell. It is made of a
number of bones joined together in such a way as to leave a hollow place
inside to hold the brain. The front part of the skull forms the
framework of the face and the jaws. In each ear there are three curious
little bones, which aid us in hearing.

~5. The Trunk.~--The bones of the trunk are, the _ribs_, the
_breast-bone_, the _pelvis_, and the _back-bone_. The bones of the trunk
form a framework to support and protect the various organs within its
cavities.

~6. The Ribs.~--There are twelve _ribs_ on each side. The ribs join the
back-bone at the back. They are connected by cartilage to the
breast-bone in front. They look somewhat like the hoops of a barrel.
With the breast-bone and the back-bone they form a bony cage to contain
and protect the heart and the lungs.

~7. The Pelvis.~--The pelvis is at the lower part of the trunk. It is
formed by three bones, closely joined together. The large bones at
either side are called the hip-bones. Each hip-bone contains a deep
round cavity in which the upper end of the thigh-bone rests.

~8. The Back-bone.