As in medicine I had been the pupil of Broussais, so in metaphysics I was the disciple of Condillac. I believed with that philosopher that "all our knowledge we owe to Nature; that in the beginning we can only instruct ourselves through her lessons; and that the whole art of reasoning consists in continuing as she has compelled us to commence." Keeping natural philosophy apart from the doctrines of revelation, I never assailed the last; but I contended that by the first no accurate reasoner could arrive at the existence of the soul as a third principle of being equally distinct from mind and body. That by a miracle man might live again, was a question of faith and not of understanding. I left faith to religion, and banished it from philosophy. How define with a precision to satisfy the logic of philosophy what was to live again? The body? We know that the body rests in its grave till by the process of decomposition its elemental parts enter into other forms of matter. The mind? But the mind was as clearly the result of the bodily organization as the music of the harpsichord is the result of the instrumental mechanism. The mind shared the decrepitude of the body in extreme old age, and in the full vigour of youth a sudden injury to the brain might forever destroy the intellect of a Plato or a Shakspeare. But the third principle,--the soul,--the something lodged within the body, which yet was to survive it? Where was that soul hidden out of the ken of the anatomist? When philosophers attempted to define it, were they not compelled to confound its nature and its actions with those of the mind? Could they reduce it to the mere moral sense, varying according to education, circumstances, and physical constitution? But even the moral sense in the most virtuous of men may be swept away by a fever. Such at the time I now speak of were the views I held,--views certainly not original nor pleasing; but I cherished them with as fond a tenacity as if they had been consolatory truths of which I was the first discoverer. I was intolerant to those who maintained opposite doctrines,--despised them as irrational, or disliked them as insincere. Certainly if I had fulfilled the career which my ambition predicted,--become the founder of a new school in pathology, and summed up my theories in academical lectures,--I should have added another authority, however feeble, to the sects which circumscribe the interest of man to the life that has its close in his grave.