CHAPTER IV.

SILLS OF THE HOUSE.

Situation of the hip bones. Structure. The hip joint. An abuse.

You well know, I suppose, that after the foundation walls of a common building-say a dwelling house-are well prepared, and made level, they lay on large sticks of timber, called sills. On these sills they place the body or principal portion of the building, and by means of joints, fasten it at the corners, as well as at other places.

SITUATION OF THE HIP BONES.-The sills of the house I live in are two large irregular bones, placed at the top of what I have, for the sake of convenience, called the pillars. These two large bones are very firm and strong. You will find so much difficulty in understanding my explanations of their shape without it, that I will show you a picture of them.

These bones are called in books the ossa innominata. Os is a Latin word for bone; and ossa is its plural, meaning more bones than one. Innominata means without a name, or nameless; but the very word innominata makes a tolerable name, though rather long. So if a very young child, found in the streets, whom nobody knew, should be called Peter Nameless, that word nameless would answer all purposes.

STRUCTURE.-I have said that the ossa innominata were very firm and strong. They are so in grown persons-but in a child they are less so, and are in three pieces, each of which has a different name. They are joined together by a firm gristle or cartilage. Behind, however, is a strong wedge-like bone, between them. Between this last bone, called the sacrum, and each of the ossa innominata, there is also a very strong gristle; but it is not so thick or strong as the one I have just men

tioned. The ossa innominata and sacrum make a kind of cup, or deep bowl-open at the bottom, it is true, but still bowl-like in its shape. This bowl is called the pelvis.

HIP JOINT.-The manner of fastening the thigh bone, or femur, to the hollow of the innominatum, is very remarkable. I shall give a particular account of it, with an engraving, farther along in the book; so that a few words must answer, for the present.

The hollow, where the femur is fastened, is shaped like the inside of an egg shell, with the small end broken off, and has received the name of acetabulum, from its supposed resemblance to the cup with which the ancients. measured vinegar. The round end of the femur is fastened in this deep cavity by a very large and strong cord. The shoulder is often dislocated, or slipped out of its place; but this hollow is so deep, and the cord so strong, that nothing but very great violence will break the cord, or slip the femur out of its place.

AN ABUSE.-I have said that these two great bones are united by a very strong carti

lage. This is true; but it is also true that while we are young, and even after we are older, if we have lived temperately, this cartilage, which is very thick, will stretch or yield much more than you would at first suppose possible. It is of very great importance to everybody-though much more so to some than to others—to preserve the soft and yielding nature of these cartilages as long as possible. To do this, you must run about and play much while young-not with violence, but like the lamb; you must labor moderately every day, as you grow older; you must rise with the lark, and go to bed almost as early as the fowls; you must breathe pure air; your drink must be water, and your food must be of the plainest and purest kinds, and not in excessive quantity and must be well masticated or chewed. Then may you hope to preserve your bones and cartilages in a good and healthy state till you are quite old. But some of these things will be adverted to in other chapters.

CHAPTER V.

BODY OF THE HOUSE.

Height. The spine. Each vertebra.

General de

scription. The ribs. The breast bone. The collar bone. The shoulder blade.

HEIGHT.-Houses consist of one or more stories, according to the taste or design of the builder. Each story, as you know, forms a separate row or tier of rooms. The best houses are those with fewest stories. But most people prefer, if they are able, to have at least two stories-some three. In cities, where land is very costly, they sometimes have them four, five, seven, ten and eleven stories high. Four stories, in our large towns and cities, is very common. A house ten stories high, accommodating ten rows or tiers of people, one above another, is a curious sight. Houses of this description are to be met with in Edinburgh, and Paris, and some