Vegetables and fruits that are partially decayed should not be eaten. Even if an orange is decayed only on one side, the products of decomposition--that is, the poisons produced by decay--have extended all through the orange. You cannot see them, but they are there. It is the same with a decaying apple, potato, or melon. It never pays to buy partially decayed or stale fruits or vegetables, for not only are they dangerous to health, but they are so reduced in nourishing qualities by decomposition that you get little value for the money you spend. It is always better economy to buy fresh fruits and vegetables, or even canned vegetables, when the latter are properly put up. [Sidenote: What causes decomposition] All decomposition (rotting) in fruits and vegetables is due to the action of germs. If you will look at a bunch of old grapes, you will notice that some of the grapes are rotten, while others have dried up. Now, if you examine them very carefully, you will find that all the decomposed grapes have breaks in the skin. The break may be very small, but it is there, and through this break the germs that cause decomposition have entered. You will find also that there is not the slightest break in the skin of any grape that has dried up. The germs could not enter, hence there has been no decomposition. It is the same with other fruits and vegetables: if the germs that cause decomposition cannot get inside, the fruit or vegetable will dry up, but will not rot. [Illustration: FIG. 19. Fruits displayed for sale, but properly protected from flies, dust, and dirty hands.] Germs can go through a very small opening--so small that you may not be able to find it; but if there is decomposition, the hole is there. The skin of the body acts in the same way as the skin of the grape and keeps out a great many germs that would make us sick were they able to get through the skin. They often get through the skin when we cut ourselves. Meats decompose as well as fruits and vegetables, and the decomposition is due to the presence of germs in the meat. We cannot keep all germs out of meat, but we can keep out a great many of them by having everything clean about the meat, by keeping it covered as much of the time as possible, and by handling it only with clean hands. [Illustration: FIG. 20. Fruits for sale, not properly protected from flies, dirt, and other sources of filth.] [Sidenote: Why foods do not decompose in very cold places]