Some people may tell you that antitoxin is a poison and should not be used. The statement that it is in itself a poison is true. But it is also true that in your body there are many things that would poison you if you got too much of them. For instance, there is a gland in your throat (the thyroid) which secretes a substance that is necessary for your health, but if you were to take the secretion of ten such glands it would kill you at once. Now, if the cells in your body make antitoxin when you have diphtheria, it is probable that antitoxin is the very thing needed. And if you can help these cells by giving them antitoxin, ready-made, does it not seem a reasonable thing to do? People who give the name of poison to a substance which is known to have saved many lives are not worthy of attention. Anything may prove a poison if taken in excess; too much play will prove a poison, and too much work also. =Questions.= 1. What is the poison of diphtheria called? 2. What is antitoxin? 3. Compare the action of antitoxin on the blood with the action of an acid on the litmus solution. 4. Tell about the discovery of antitoxin. 5. How do we know that antitoxin saves lives? 6. How does antitoxin prevent diphtheria? 7. Why should antitoxin not be regarded as a poison? =Remember.= 1. Antitoxin is what the cells in your body make when you have diphtheria. 2. By using the antitoxin taken from a horse, you save your own cells the struggle necessary to make it fast enough to kill the diphtheria germs. 3. If you have diphtheria, and antitoxin is given promptly, you will get well. 4. If you have been exposed to diphtheria, antitoxin will prevent your having the disease. 5. Antitoxin is no more a poison than are many other medicines. CHAPTER XXV HOW TYPHOID FEVER GERMS ARE CARRIED [Sidenote: How typhoid fever germs get into the system] There are certain diseases, the germs of which get into bodies through our mouths. That is, we eat or drink them. Some of these diseases are typhoid fever, cholera, the summer complaints of children, tuberculosis, and diphtheria. At present we shall learn about the germ that causes typhoid fever, how it gets into our food and drink, and how we may prevent the disease by getting rid of this germ. Typhoid fever, like all other diseases caused by germs, is caused by one kind of germ, and one kind only. You cannot get typhoid fever by eating cholera germs any more than you can get diphtheria from typhoid germs. [Sidenote: Animals free from typhoid] So far as we know, there is no animal except man that has typhoid fever. Since the germs of any disease must come from an animal suffering from that disease, and as man is the only animal that has typhoid fever, it naturally follows that the only way to get typhoid fever is from some person who has the fever or has had it. [Sidenote: How typhoid germs leave the body]