Animals also help us in many important ways. We drink their milk and eat their meat. We make make clothes from their skins and stay warm in winter. When scientists learn about animals, they understand people better too. With the help of animals, alive and dead, scientists can help ill people. Many years ago, people were afraid of smallpox. When somebody had smallpox, 30 per cent of people near them died. But other people did not get ill, because people did not move much from place to place and from country to country. when people began to visit different countries more often, smallpox went more quickly and easily from one person to another. The scientist Edward Janner found the answer to this problem: it was a vaccine, and it came from cows. With the help of cows, nobody in the world has smallpox now.