So long as the mental and moral instruction of man is left solely in the hands of hired servants of the public--let them be teachers of religion, professors of colleges, authors of books, or editors of journals or periodical publications, dependent upon their literary incomes for their daily bread, so long shall we hear but half the truth; and well if we hear so much. Our teachers, political, scientific, moral, or religious; our writers, grave or gay, are compelled to administer to our prejudices and to perpetuate our ignorance.