With the help of the Bible and Aristotle, the most brilliant men of the Middle Ages now set to work to explain all things between Heaven and Earth in their relation to the expressed will of God. These brilliant men, the so-called Scholiasts or Schoolmen, were really very intelligent, but they had obtained their information exclusively from books, and never from actual observation. If they wanted to lecture on the sturgeon or on caterpillars, they read the Old and New Testaments and Aristotle, and told their students everything these good books had to say upon the subject of caterpillars and sturgeons. They did not go out to the nearest river to catch a sturgeon. They did not leave their libraries and repair to the backyard to catch a few caterpillars and look at these animals and study them in their native haunts. Even such famous scholars as Albertus Magnus and Thomas Aquinas did not inquire whether the sturgeons in the land of Palestine and the caterpillars of Macedonia might not have been different from the sturgeons and the caterpillars of western Europe. When occasionally an exceptionally curious person like Roger Bacon appeared in the council of the learned and began to experiment with magnifying glasses and funny little telescopes and actually dragged the sturgeon and the caterpillar into the lecturing room and proved that they were different from the creatures described by the Old Testament and by Aristotle, the Schoolmen shook their dignified heads. Bacon was going too far. When he dared to suggest that an hour of actual observation was worth more than ten years with Aristotle and that the works of that famous Greek might as well have remained untranslated for all the good they had ever done, the scholiasts went to the police and said, “This man is a danger to the safety of the state. He wants us to study Greek that we may read Aristotle in the original. Why should he not be contented with our Latin-Arabic translation which has satisfied our faithful people for so many hundred years? Why is he so curious about the insides of fishes and the insides of insects? He is probably a wicked magician trying to upset the established order of things by his Black Magic.” And so well did they plead their cause that the frightened guardians of the peace forbade Bacon to write a single word for more than ten years. When he resumed his studies he had learned a lesson. He wrote his books in a queer cipher which made it impossible for his contemporaries to read them, a trick which became common as the Church became more desperate in its attempts to prevent people from asking questions which would lead to doubts and infidelity. [Illustration: THE MEDIÆVAL WORLD]