This fact is true for animals. Mammals, including dogs, cats, and monkeys, sometimes have dreams during their sleep like humans do. During sleep, they also show intense activity in parts of their brain. One scientist observed a monkey that was trained to push a lever whenever they saw a picture on a screen. At different times during its sleep the monkey pushed the lever as if it were respond-ing to a picture.

  There are two aspects of medicine: primitive and mod-ern. They are in complete opposition to one another. The former is based on the belief that disease is caused by mysterious forces. Those who have such a belief think that diseases are related to evil spirits. They make attempts to drive them away by strange magic words or other superstitious measures. On the other hand, the modern medicine is based on a different kind of conception.

 Progress was made, however. In the early 1970s, a women's football league was formed. Women broke in as jockeys and ran in the Boston Marathon. A woman became a minor-league baseball umpire. By court order, a female student could become a member of a college ski jump team in Hopkins, Minnesota. The state of New Jersey ruled that all boys and girls in public schools have the same right to take part in the sports.  

  Just about everybody has heard of the population explo-sion. Some people warn us that the world will soon come to an end if we don't control the birth rate. They say that there aren't enough resources or food. Even though most of them want to limit the number of people on earth, they do not seriously consider human potential and cre-ativity. In recent years, this world crisis has caused some progressive scientists to discover the now idea of using space.