DIVISIONS OF ANIMALS.

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his cane. The other shows our bones, as they would appear without skin and flesh, and is called the human skeleton, which is the one we shall consider at the present time.

SKELETON OF A MAN.

3. I must first tell you that there are two great divis

2. To which will our attention be confined? 3. In what two great classes are all animals divided?

ions of animals called vertebral and invertebral, which you must all remember.

All animals are called vertebral which have a skeleton, and are sustained and nourished by red blood. They are also called warm-blooded, because they have heat in their bodies. Man, birds, fish, and quadrupeds belong to this class.

4. By quadrupeds, I mean all those animals that walk on four feet, as the cow, sheep, horse, etc. Man is called a biped, because he walks on two feet only.

5. All animals are called invertebral which have no skeleton, and have white blood, as worms, insects, shellfish, toads, frogs, and serpents. These feel cold when we touch them, and are called cold-blooded animals.

6. Our skeleton not only serves as a support, but also enables us to perform all our motions. In this view, we divide bones into two kinds-those which protect the body, and those which enable us to move. If the bones were all in one piece, every step we take would jar our whole bodies; and we should be in danger of breaking and injuring the bone every time we moved. In the top of the skeleton we see the bones of the head, called the cranium or skull.

7. This is composed of eight small bones, all very nicely fitted and dovetailed together, like the sides of a box. The places where the bones join are called

3. What is meant by vertebral? Why are they called warm-blooded? What are some of the animals that belong to this class? 4. What is meant by quadrupeds? What is a biped? 5. What is meant by invertebral ? Why are they called cold-blooded? 6. What are the uses of our skeleton? What two different kinds of bones are there? What would be the consequence if the bones of the body were joined in one piece? What is the skull, and where is it situated? 7. How many bones compose the skull? How are these bones arranged? What are sutures?

sutures. In the little infant, the bones are soft and do not unite until it is several months, and sometimes several years old. You will see what a wise provision this is; for small children are continually tumbling, and if these bones were not soft and yielding, they would soon be very much injured.

8. Being of an oval shape, it does not feel the force of blows so much as it would if it had any other shape. As the child becomes older, the bones are firmer and stronger, and give more support.

The skull contains the brain, which I may tell you about at some future time. It is very important that it should be guarded and well taken care of, as we find it is by its hard and firm covering.

9. There are several bones which form the face. The principal ones are the jaw bones, and those around the organs of seeing, smelling, tasting. As I told you

7. What wise provisions do we find in the construction of these bones in children? 8. What good results from its shape? How does age affect the bones? What does the skull contain? How important is the brain? 9. What are the bones of the face? What is the use of the teeth?

in my previous lesson, we have teeth prepared for us to grind or masticate our food.

10. Some of you may think that the teeth are not worthy of our notice; but be very patient, and hear me. They are of as much service, and bear as important a relation to our bodies as any part of our framework; and they are as different in different animals, as the food on which they live. They are composed of bone covered with a very hard substance called enamel. When this decays, or is injured, the tooth is useless for strength.

uses.

11. This is sometimes destroyed when the dentist cleans the teeth, by his instruments or acids, which he When the enamel is gone, the beauty and polish of the teeth are gone. The teeth are furnished with little nerves, thought by some to make our food pleasant to our taste.

Sometimes a tooth begins to decay, so that the nerve is exposed to the air, and then we experience acute pain. So tender is the nerve, that if it should be touched by an instrument or pin we could not endure the pain for half an hour. It is not the bone which aches when we say our tooth aches, but this little nerve which troubles us.

12. This nerve is covered by the enamel, and it is this which preserves the tooth sometimes for a hundred years, and even for thousands of years, as in the case of-mummies bodies which have been embalmed, or

10. How do some regard the teeth? How should they regard them? Do they differ in different animals? Of what are they composed? How important is this enamel ? 11. In what manner is it sometimes injured? What are the results of its decay? With what are the teeth furnished, and for what purpose? What occasions the tooth-ache? 12. How is the nerve protected? How durable is the enamel? What are mummies?

preserved from decay by being washed all over with spices and various substances.

13. Let us examine some of the different kinds of teeth, and see how well they are adapted to the food necessary for different kinds of animals, and different periods in the life of man.

14. Infants live on milk, and need no other nourishment-so they have no teeth. As they become older, their bodies enlarge, and they need firmer bones to support them, and also require more solid food; but their soft gums cannot masticate or chew their bread, and apples, etc. So what do we see ? The gums seem to enlarge, and what before was like jelly, makes its appearance, and the little infant has a tooth.

15. You, who have little brothers and sisters, know with what joy the first tooth is welcomed. "Why, baby has a tooth," cries the little prattler; but ah! she does not stop to think for what purpose it was given to her! Then one tooth after another grows, but these you know are only what is called the first set. If we could look inside of the gums we should see the little roots of another set.

16. The first teeth gradually fall out within five or six years, and then the other set enlarges and appears, to last us through life, if we will only take care of them There have been several instances where the third set grew after the person was forty or fifty years of age.

13. To what are the different kinds of teeth adapted? 14. Why have small infants no teeth? When does a tooth make its appearance? 15. How is the first tooth generally welcomed? How many sets are there? 16 How long does the first set generally last? What takes the place of the first set? How long will the second set last if we take care of them?