action and influence of the printing-press. The Church includes in its responsibilities the relation of the father to the child and of the Government to the citizen. Its rulers must watch not only the matter of morality but that of sound doctrine and wholesome influence. If the ruler of a modern State finds it impossible to permit the circulation of writings which assail the character or the person of king or emperor, how much less is it possible for those who direct the government of the Church to permit the circulation of writings which assail the wisdom and the authority of the Lord of Hosts or of his Son. The realm of the Church is that of faith and of conduct, a realm which is of necessity directly influenced by the spoken word and still more by the word circulated in print. It is this realm that must be defended and protected against the invasion of the poison of pernicious and unsound writings. As in the modern State, a special system is required for the organisation of the defensive power represented by such bodies as the army and the police, so is it necessary for the Church, with the organisation of its own ecclesiastical army of bishops, priests, deacons, and soldiers of the Faith, to establish regulations for discipline, for defence, and, when the time comes, for assault upon the powers of evil. This system of the Church is expressed most logically through its control of thought and of literature, for the Church works through the mind with spiritual forces. The authorities of a city are prepared to prohibit, under the severest penalties, miscellaneous disturbances or a careless handling of dynamite; such precautions in regard to personal harm as the mayor finds necessary for the safety of his community, the bishop is under similar necessity of adopting for the preserving of his flock against spiritual assaults.”[81] In 1595, the astronomer, Johann Kepler, completed his first astronomical treatise, the _Mysterium Cosmographicum_, which was to be printed in Tübingen. Before the book could come into print, it was necessary to secure the approval of the senate of the university. The theological faculty gave permission for the printing only after cancelling the chapter in which the author undertook to bring the Copernican system into accord with the Scriptures. In Leipsic, the printing of the book was prohibited. The great Elector of Brandenburg, in 1670, ordered that, for the purpose of avoiding religious strife and controversy, there should be a thorough censorship of all books, whether printed within his territory or imported from without, which were concerned with matters of theology or religion. An order issued in Cologne in 1662 prescribes that the preachers shall engage in no disputations or conferences and shall bring into print no controversial writings, without the specific permission of the Elector himself.