Sometimes a dairyman thinks that his child has nothing more serious than tonsillitis, and goes on selling milk. A great many epidemics have resulted from such cases. Sore throats should not be treated lightly, for the most severe forms of diphtheria may develop from germs that come from a throat that is only slightly sore. If there is a case of diphtheria in the town where you live, and if your throat feels the least bit sore, have your doctor examine it at once. If you do not wish to have your family doctor look at your throat, go to the health officer. Had you not rather stay at home for a week or two than see your best friends ill or dead because of your carelessness? [Sidenote: (_2_) From diphtheria germs in throats that are not sore] There is another peculiar thing about the germ of diphtheria. It will often get into a throat and grow a little, just enough to keep alive, but without making the throat sore at all. The person in whose throat the germs are will have no idea that they are there, but when he comes in contact with some one who has a delicate throat, he may give diphtheria to that person. The disease does not develop in some throats because the body cells are all healthy and doing their work so well that, when the diphtheria germs try to take hold, they are driven off and not allowed to grow. This is the reason that, before he raises the quarantine, the careful health officer takes a "culture" from the throat of everyone in a house where there has been diphtheria. [Sidenote: How mild cases may be detected] The health officer takes a culture by wiping the throat with a little cotton on a long stick, which he then puts down into a long glass tube containing some substance that diphtheria germs like to grow on. If there are any diphtheria germs in the throat, they will soon show on this culture material. Then the health officer will say, "No, we cannot let you out yet, for the germs are still in your throat." No person who has been staying in a house where there is diphtheria should be allowed to go out until a culture proves that his throat is free from the germs of diphtheria. You see how hard it is to quarantine all cases of diphtheria, when children are sometimes allowed even to go to school with sore throats that are really diphtheritic. Only two things are necessary for getting rid of diphtheria: one is to quarantine every case, and the other, to have the people do just what they are told when under quarantine. This latter is just as important as the quarantine itself, for people often do not obey the health officer's directions. Now let us see what are some of these directions. [Illustration: FIG. 55. How pets may become carriers of disease.] [Sidenote: Rules of quarantine]