1.Every boy and girl has seen blood at one time or other，from some cut or scratch，but no one likes to see it.Many people faint at the sight of blood，and some young people think that a hurt which bleeds a little must be very serious indeed.A century or two ago it was believed that the loss of some blood was good for one’s health.People used to go to doctors，and even to barbersand others who knew how to open a veinand bandageit again，in order that they might be bled；nowadays we think that a holiday with change of air is a better thing than bleeding for keeping us in good health.
2.While the loss of a little blood does not hurt a healthy person，the loss of too much is certain to cause death.The loss of less than half of the whole quantity in the body would be fatal.We speak of it as our “life-blood，”and you will see that the name is well deserved when you think of its uses to us.
3.Every part of the body-flesh，skin，bones，and the rest-was at one time blood.All the parts of the body are constantly wasting away，some of them quickly，andothers more slowly，and this waste must be made up by new material，which has to be got from the blood.Where does the blood get its supplies of material for building up the body？You know in a general way，no doubt，that all our nourishment comes from our food.This nourishment must be changed into blood，however，before it is of real service to the body.Let us see how this change takes place.
4.The first part of the change takes place in the mouth.The food is ground by the teeth and mixedwith the salivain the mouth.Our food should bewell chewed if we want it to do us good.Birds swallow their food without chewing it，and dogs seem able to swallow and digest anything except a bone with very little chewing.Our power of digestion is not so great as theirs，however，so we should eat our food in a different and slower way，even though we feel very hungry.
5.When we swallow our food，it passes into the stomach.There it is mixed with a fluid which comes from the walls of the stomach，and it is kept turning round and round by the slow movements of thosemuscularwails until it becomes a creamy like fluid.
Then it leaves the stomach and passes into the very long and crooked tube known as the intestines.
6.In this tube it is mixed with various other fluids，the most important of which is bile from the liver；and as it receives these fluids，it becomes completely digested，or ready for mixing with the blood.All over the walls of the stomach and intestines there are little openings，the ends of very fine tubes，which suck up the food as it is fully digested.These pipes join，like brooks forming a river，and carry their load of nourishment to one of the large veins above the heart，where it is poured into the blood.
7.Since the nourishment of our body depends so much on what we eat and drink，young people，as well as old，should learn to avoid what is useless and hurtful in food and drink.This is specially important for the young，for the body is more easily injured in some ways during youth.Besides，young people，while they are growing，have to attend to some extent to the making of their bodies，and they should learn to do it well.
8.Young people should take the kind of food that suits them，not the kind that may suit older people.
may be needed by old people，but are always hurtful to the young.The most dangerous habit in our country，however，is the use of stimulating and intoxicatingSeasoned，flavoured with spices.
They are not only dangerous to health，but theincreasing desire for them，which often arises after one begins to use them，leads to many terrible evils.
9.No alcohol
person unless it is specially ordered by a doctor，and even tea and coffee should be very little used if at all.These drinks contain little or no nourishment，and young people do not need them as stimulants.
10.Doctors tell us that people are as much givento excessin eating as in drinking，and that muchof their weak health comes from eating too much.Eating quickly，and eating too much，alike throw extra work on the stomach，and the result is that its work is badly done，the blood is imperfectly supplied with nourishment，and the health suffers.The same result follows if our food is not properly cooked.
11.We should take our meals regularly.The stomach seems to expect this，and is ready to pour out its fluid and mix it with the food at the usual time.When we eat at irregular times，the work of digestion is not so well done.These are the most important things to attend to as regards the food that gives nourishment to the blood.In addition，a supply of fresh air is as necessary as food itself to keep the blood in a proper state.