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"Why," said William, "because I am hungry, to be sure; and I can scarcely wait to come to the table."

That is right, William; but what becomes of your bread, and butter, and cheese, and apples?

William could not answer a word; but Alfred instantly replied, "My mother says, that what we eat makes us grow; but how I cannot tell.”

13. Here are William, and Alfred, and Sarah, and Jane, and a great many more children, who are eating, eating all they can get, and yet they do not even think whether it does them any good or not, or in what way it benefits them.

14. But, children, our food makes blood, and our blood increases our size. Now let us examine this curious subject for a few moments, and see how it is done. You have probably been at a mill where corn, wheat, and other grain, were ground into flour and meal. For this purpose, they have large stones, which, by turning round, cut the kernels of corn, and press them very fine. We have also something prepared to grind our food.

15. We have teeth, sharp and strong, with which to chew our food, and there are also in the mouth little vessels called glands, that contain a fluid like water, which is called saliva. This moistens the food, the same as a cracker becomes soft when put into water. This saliva is called by boys and girls who do not know any better, spittle.

16. If this saliva did not exist, the mouth would soon

12. Could William tell what became of his food? What was Alfred's reply? 13. Do children generally think why they eat? 14. Why do we eat? How and where is grain ground? 15. With what do we chew our food? What do the glands in the mouth contain? How does the saliva act? What is this saliva sometimes called? 16. Is this saliva of any use in the mouth?

become very dry and parched. In the back part of the mouth, there are three passages: one which leads into the nose or nostril; one into the wind-pipe, through which we breathe; and the third, which is called the gullet or œsophagus, goes down into the stomach. The latter is the one through which we wish the food to pass. But how do we know that it will take the right course? for if it should pass down either of the other ways, the person would not be able to breathe, and would soon become sick, and perhaps die.

17. Listen, and I will tell you how it is prevented from going wrong. There is a little piece of flesh at the root of the tongue which moves upward and downward, called a valve or trap-door, which shuts down over the wind-pipe when we swallow, just like the cover to a book or box, and fits so nicely that the food passes along down the throat, until it reaches the stomach.

18. The following cut represents the stomach, which is shaped like a bag, and usually contains about two or three pints in an adult or full-grown person. It is capable of being contracted or extended, as the case may require. The letter C is the tube through which the food passes, called the cardiac orifice. The letter P shows the outward passage, which is called the pylorus or "door-keeper,” as it prevents the food from passing out until it is properly digested, and also prevents it from returning after it has been sent out. I shall give you only a few hard names, and these I wish you to remember.

16. What passages are in the back part of the mouth? Through which does the food pass? What would be the consequence if it should take either of the other passages? 17. How is it prevented from taking a wrong course? 18. Describe the stomach. How much does it usually

contain?

19. The stomach is situated on the left side of the body, under the ribs, and has three coats or coverings. The stomach has also a fluid resembling that in the mouth, called the gastric juice, which mixes with the outside portion of the food, making it into a soft substance called chyme. All the water that we drink is

taken up by the veins of the stomach, and is absorbed in about three minutes. It is for this reason, that, when a person has fasted, or has not taken food for some length of time, he derives nourishment quicker from drinking than from eating, because the water is soon sent all over his body. Many ignorant persons suppose that there is one passage to the stomach for all the water which we drink, and another for all the food which we eat.

19. Where is the stomach situated? What fluid does the stomach contain? How is chyme made? What becomes of the water which we drink? Why does a person derive nourishment from water quicker than from food? What idea do many persons have in reference to eating and drinking?

20. Dr. Wieting, an interesting lecturer on Physiology, tells an amusing story of an ignorant Irishman, who began to think about eating and drinking, but who, becoming puzzled, went to a physician, and asked him whether indeed there were two passages to the stomach, one for the solids and the other for liquids. The doctor replied that there was only one.

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"Well," said he, "I thought they must be wide awake down there to separate the puddin' from the milk when I ate them."

21. If the nerves that lead from the stomach to the brain were cut off, the sensations of hunger and thirst which we all feel, would be destroyed. After the chyme has been formed, it passes out of the stomach through the pylorus into the duodenum, or second stomach, as it is sometimes called, which is the upper part of the intestines. As soon as one portion of the food is sent out of the stomach, another portion is formed into chyme, and so on, till all has been mixed with the gastric juice, which soon takes place, unless we have eaten too much food, or that of an improper kind.

22. The chyme which is prevented from returning to the stomach by a little valve in the pylorus, is now mixed with the bile that is secreted by the liver, which lies at the right side of the stomach, and a juice called the pancreatic, which comes from the pancreas, situated near the stomach. These two fluids convert it into a white fluid called chyle. It now travels along over the

20. Relate the anecdote of the Irishman. 21. What effect have the nerves on the stomach? How is the whole of the food converted into chyme? What prevents the return of the chyme to the stomach? Where are the liver and the pancreas situated? How is chyle made? Over what does the chyle pass?

whole internal surface of the intestines, which are six times the length of the body, but are folded in so com pact a manner that they occupy but a small space.

23. As the chyle is passing, that part of it which will make good blood, or is fit for the growth and nourishment of the body, is taken up by thousands of little tubes, called lacteals-because the fluid is white-also called capillary vessels-because the Latin word capilla means a hair—and these tubes are as small as a hair. It travels along through these tubes in the same manner that the particles of oil travel along through the little tubes in the wick of a lamp, till they unite in larger tubes.

24. These terminate in glands, from which larger tubes or pipes collect and carry the chyle from all parts into one common vessel, called the receptacle or thoracic duct, which holds about a table spoonful. From this bag a large pipe proceeds, which runs up the back part of the chest, and along till it reaches the neck at the top of the left shoulder.

25. It is now poured into a large vein called the subclavian vein, which carries the chyle, together with the old blood coming from the veins, situated all over the body, to the heart, the great fountain of life. The blood, now formed, runs along, being of a dark

color, but

which is not yet healthy, to the lungs. Here the air we inhale or breathe in, changes the dark color of the blood to red, as we see it when we prick our fingers.

26. Then it flows back to the heart, and by a con

23. What are the lacteals, and what is their office? In what manner does the chyle pass through them? 24. Explain the further passage of the chyle. 25. How does the chyle and old blood finally reach the heart? Where does this blood run, and what change takes place in it?