Although Zacharias invented the microscope, it was Galileo who introduced it to the scientific world. He published a book in 1610 in which he wrote: “About ten months ago a rumour reached me of an ocular instrument made by a certain Dutchman, by means of which an object could be made to appear distinct and near to an eye that looked through it, although it was really far away. And so I considered the desirability of investigating the method, and reflected on the means by which I might come to the invention of a similar instrument. I first prepared a leather tube at the ends of which one placed two lenses each of them flat on one side, and as to the other side I fashioned one concave and the other convex. Then holding the eye to the concave one, I saw the objects fairly large and nearer, for they appeared three times nearer and nine times larger than when they were observed by the naked eye. Soon after I made another more exactly, representing objects more than sixty times larger. At length, sparing no labour and no expense, I got to the point that I could construct an excellent instrument so that things seen through it appeared a thousand times greater and more than thirty-fold nearer than if observed by the naked eye.” Galileo had his enemies, who accused him of having picked Zacharias’s brains; he admitted that he had taken his idea from the Dutchman’s invention, but further than that he would not go; in fact, he replied that the invention of Zacharias was a mere accident but that his own instrument was discovered by a process of reasoning. It would serve no good purpose to tell the story of all the scientists who have helped to bring the microscope to its present state of perfection, although many of their descriptions of objects and apparatus are as quaint as the latter. Scheiner, for example, who wrote in 1630, mentions “that wonderful instrument the microscope, by means of which a fly is magnified into an elephant, and a flea into a camel.” To Kircher belongs the credit of being the first worker to construct an instrument with coarse and fine adjustment and with a substage condenser, which could be used either for concentrating the sun’s rays or those from a lamp. With an instrument of this pattern Malpighi saw the circulation of blood in a frog’s lung. By 1685, when instruments with four and six lenses were being used, the compound microscope was firmly established as a help to scientists, and the simple lens was used thereafter as an adjunct but not a rival to the newer instrument.