Diphtheria kills a great many children, and to play with your friends after you have had diphtheria, and before the health officer tells you that you may, is almost like trying to kill them. They might be very sick and die, or they might be very sick and get well, or they might not be sick at all; but you never can tell what will happen if they are exposed to the disease. If you were to take a gun and shoot at a friend, you might kill him, or you might shoot his leg off, or you might not hit him at all; but you would be trying to hit him, and it would not be your fault if you did not. It is just the same if you play with a friend when you have a communicable disease; you shoot the disease germ at him, and if you do not hit him, it is not your fault. [Sidenote: Why quarantine is not raised sooner] Sometimes people who have been sick with a communicable disease feel perfectly well, but the health officer tells them he cannot let them out of quarantine. This is because he knows that such people still have in their bodies the germs that cause the disease, and that as long as these germs are there they can give the disease to other people. It is not pleasant to have to stay in quarantine when you feel that you are well, and children, as well as older people, are very likely to become restless under the circumstances. You see an illustration of such a patient in Figure 60, where the little girl, who is under quarantine for scarlet fever, but who is feeling quite well, is giving a book to two of her friends. The book contains the germs that cause scarlet fever, and the boys are very likely to contract the disease by handling the book. [Sidenote: Why some cases of diphtheria escape quarantine:] [Sidenote: (_1_) From failure to detect mild cases] If every case of diphtheria were quarantined, and the people obeyed the health officer, there would soon be no more diphtheria. But how does it happen that every case of diphtheria is not quarantined? Diphtheria is a very peculiar disease. Sometimes it makes people so sick that they die in spite of everything that can be done for them; sometimes it makes the throat only a little sore, and the child seems so slightly ill that his mother says to herself, "He is fretful," and does not call the doctor. In the latter case the child often keeps on going to school, and exposes other children to the disease; some of them catch it, and become very sick or even die. In still other cases, the mother thinks that a child has only a case of tonsillitis and does not call a doctor; the child's brothers and sisters go to school and may carry the germs to other children. I have known a great many cases of diphtheria to be spread in this way. [Illustration: FIG. 54. The old, insanitary slates and sponges have gone out of use, but many people of to-day still follow the dangerous habit of putting pencils into their mouths.]