When Scholastic Philosophy ceased to be the subject of systematic study in Protestant U niversities, and was regarded as possessing an historical rather than a scientific interest, there was one branch of it that was treated with less dishonour than the rest. In Ethics and Metaphysics, in Psychology and Natural Theology, the principles handed down by a tradition unbroken for centuries came to be looked upon as antique curiosities, or as merely illustrating the development of human progress and human thought. Thesesciences were either set aside as things of the past, consisting of fine - spun subtleties of no practical value, or else they were reconstructed on an entirely new basis. But with Logic it was different. Its underlying principles and its received method were not so closely and obviously interlaced with the discarded system of theology. It admitted of being more easily brought into apparent harmony with the doctrines of the Reformation, because it had not the same direct bearing on Catholic dogma. It was, moreover, far less formidable to the ordinary student. Those who had no stomach for the Science of Being, were nevertheless quite able to acquire a certain moderate acquaintance with the Science and the Laws of Thought. Men chopped Logic harmlessly, and the Logic they chopped was the traditional Logic of the Schoolmen, with some slight modifications. The. Text-book of Dean Aldrich, which has not yet disappeared from Oxford, is medireval in its phraseology and its method; medireval, too, in its principles, except where an occasional inconsistency has crept in unawares from the new learning. It still talks of "second intentions," . and assumes the existence of an Infima Species, and has throughout the wholesome flavour of the moderate realism of sound philosophy. But this state of things could not last. Sir W. Hamilton, the champion of conceptualism, put forth in his Lectures on Logic a theory of intellectual apprehension quite inconsistent with the traditional doctrine which still lingered in the meagre and obscure phraseology of Dean Aldrich. Sir W. Hamilton's disciple, Dean Mansel, who carried on the work of philosophic scepticism which his master had inaugurated, published an edition of Aldrich, with explanatory notes and appendices, which pointed out his supposed errors, while John Stuart Mill, with far more, . ability and a wider grasp than either of the two just named, substituted for the halting conceptualism of Hamilton a nominalism which had but a thin veil of plausible fallacies to hide from mankind the utter scepticism which lay beneath it. Since then, the Kantian principle of antinomies which underlies the Logic of Mansel and Hamilton has boldly come to the front in England under the shadow of the great name of Hegel, and English logicians have either ranged themselves under the banner of one or other of these new schools, or else have sought to cover the glaring inconsistencies of some one of them with patches borrowed from the others, until the modern student has a bewildering choice among a series of guides, each of whom follows a path of' his own, leading in the end to obscurity. and confusion and selfcontradiction, but who are all united in this, that they discard and misrepresent the traditional teaching of Aristotle and of the mediaeval logicians. Their facility in so doing is partly owing to the fact that Aristotle has no methodical treatise cover the ground of modern Logic, and St. Thomas gives merely a rapid sketch of the technical part of it in one of his Opuscula. But from the pages of the great philosopher of Pagan times and of the Angelic Doctor of the middle ages, can be gathered by the careful student all the principles necessary for the modern logician. Every Catholic teacher of Logic follows of necessity closely in their steps, and finds in them the solution of every difficulty, and the treatment-at least the incidental treatment-of almost every question that Logic can propose.