Deep wounds made with small instruments, such as small knives, nails or toy pistols, are especially dangerous, because they are hard to clean and because they quickly heal up on the surface and leave the germs to grow at the bottom of the wound. Such wounds as these are dangerous for another reason. [Sidenote: Where germs of lockjaw grow] There is a germ that gets into wounds but does not cause suppuration. It is the germ of tetanus, or lockjaw. It lives in the ground, especially in the ground about barns, and its peculiar feature is that it will not grow in the air. If it gets into a large, open wound, it is easily killed, because it cannot grow where there is air. But when it gets into a small, deep wound where it cannot be reached, it stays there until the wound heals over on the surface, and then it begins to grow. It does not make the parts swell, as the germs of suppuration do, but quietly continues to grow, without the wound showing any sign of infection. Finally it develops a very severe poison that is taken up by the blood; then the victim suddenly begins to have spasms about the face, and finally these spasms extend to the entire body and kill him. Whenever you get a wound so deep that you cannot wash it thoroughly, go to a doctor and let him clean it out with some medicine that will kill the germs that cannot be reached by washing. [Sidenote: How boils are caused] Sometimes the germs that cause suppuration get under the skin at a point where a hair has been pulled out, or even work down beside the hair itself. When this happens, they cause suppuration under the skin, and the result is a boil. A boil is merely an infection with the germs that cause suppuration. =Questions.= 1. How do germs get through the skin? 2. Can we get rid of all the germs that cause suppuration? 3. Why is it impossible for "bad blood" alone to cause suppuration? 4. How does the surgeon prevent suppuration? 5. How may you prevent suppuration? 6. What is the danger of cutting corns with an ordinary knife or razor? 7. Where do germs of lockjaw grow? 8. What causes boils? =Remember.= 1. Germs and not "bad blood" are the cause of suppuration. 2. Always keep as clean as possible, and immediately wash any cut, no matter how small. 3. If you have a deep wound, go at once to a doctor, and let him clean it out and kill the germs that may be at the bottom of the wound. CHAPTER XXIII TRANSMISSION OF DIPHTHERIA [Sidenote: How germs may cause sickness without entering the body] Some germs that cause disease do not get into the body, but grow upon its surface, that is, they grow on the mucous membranes--the skin of the mouth, the throat, and the nose. As they grow, they develop poisons that are absorbed by the body, and that make us very sick. The germs that cause diphtheria belong to this class. [Sidenote: Prevalence of diphtheria]