While the heretical character and tendencies of discoveries in astronomy and anatomy awoke active opposition from the Church, the work of men of the type of Gesner, the eminent Swiss naturalist, and of Caesalpino, professor of botany at Padua, passed unquestioned. No dogma was endangered by the classification of plants and animals. But when a couple of generations after the death of Copernicus had passed, the Inquisition found a second victim in the famous Galileo, who was born at Pisa in 1564. After spending some years in mechanical and mathematical pursuits, he began a series of observations in confirmation of the Copernican theory, of the truth of which he had been convinced in early life. With the aid of a rude telescope, made by his own hands, he discovered the satellites of Jupiter; the moon-like phases of Venus and Mars; mountains and valleys in the moon; spots on the sun's disk; and the countless stars which composed the luminous band known as the Milky Way. Nought occurred to disturb his observations till, in a work on the Solar Spots, he explained the movements of the earth and of the heavenly bodies according to Copernicus. On the appearance of that book the authorities contented themselves with a caution to the author. But action followed his supplemental Dialogue on the Copernican and Ptolemaic Systems. Through that convenient medium which the title implies, Galileo makes the defender of the Copernican theory an easy victor, and for this he was brought before the Inquisition in 1633. After a tedious trial, and threats of "rigorous personal examination," a euphemism for "torture," he was, despite the plea--too specious to deceive--that he had merely put the _pros_ and _cons_ as between the rival theories, condemned to abjure all that he had taught. There is a story, probably fictitious, since it was first told in 1789, that when the old man rose from his knees, he muttered his conviction that the earth moves, in the words "e pur si muove." As a sample of the arguments used by the ecclesiastics when they substituted, as rare exception, the pen for the faggot, the reasoning advanced by one Sizzi against the existence of Jupiter's moons, may be cited. "There are seven windows given to animals in the domicile of the head, through which the air is admitted to the tabernacle of the body, viz.: two nostrils, two eyes, two ears, and one mouth. So, in the heavens, as in a macrocosm, or great world, there are two favourable stars, Jupiter and Venus; two unpropitious, Mars and Saturn; two luminaries, the sun and moon, and Mercury alone undecided and indifferent. From these and many other phenomena of Nature, which it were tedious to enumerate, we gather that the number of planets is necessarily seven. Moreover, the satellites are invisible to the naked eye, and, therefore, can exercise no influence over the earth, and would, of course, be useless; and, therefore, do not exist."