Religious teaching itself affords us an illustration of our subject to a certain point. It does not indeed seat itself merely in centres of the world; this is impossible from the nature of the case. It is intended for the many, not the few; its subject matter is truth necessary for us, not truth recondite and rare; but it concurs in the principle of a University so far as this, that its great instrument, or rather organ, has ever been that which nature prescribes in all education, the personal presence of a teacher, or, in theological language, Oral Tradition. It is the living voice, the breathing form, the expressive countenance, which preaches, which catechises. Truth, a subtle, invisible, manifold spirit, is poured into the mind of the scholar by his eyes and ears, through his affections, imagination, and reason; it is poured into his mind and is sealed up there in perpetuity, by propounding and repeating it, by questioning and requestioning, by correcting and explaining, by progressing and then recurring to first principles, by all those ways which are implied in the word "catechising." In the first ages, it was a work of long time; months, sometimes years, were devoted to the arduous task of disabusing the mind of the incipient Christian of its pagan errors, and of moulding it upon the Christian faith. The Scriptures indeed were at hand for the study of those who could avail themselves of them; but St. Irenaeus does not hesitate to speak of whole races, who had been converted to Christianity, without being able to read them. To be unable to read or write was in those times no evidence of want of learning: the hermits of the deserts were, in this sense of the word, illiterate; yet the great St. Anthony, though he knew not letters, was a match in disputation for the learned philosophers who came to try him. Didymus again, the great Alexandrian theologian, was blind. The ancient discipline, called the _Disciplina Arcani_, involved the same principle. The more sacred doctrines of Revelation were not committed to books but passed on by successive tradition. The teaching on the Blessed Trinity and the Eucharist appears to have been so handed down for some hundred years; and when at length reduced to writing, it has filled many folios, yet has not been exhausted.