In that general process of evolution by which the human ace, as well as the individual, is governed, each age appears to possess some distinguishing feature which stamps it with a special character. In all those branches of study and of speculation which, from the earliest dawn of mental cultivation, have engaged the attention of mankind—in theology, in history, in philosophy, in law, in science, and in medicine—the student, looking back upon the progressive achievements of his race, recognizes certain well-marked eras. These, although chronologically distinct, afford landmarks when reviewing the progress of the human intellect in its search after that perfect knowledge which stimulates, but ever eludes, the efforts of its votaries. To more than one period the student can point and say: These were days of deep theological disputes, and the schools of divinity attracted the best intellects of the age. of another period he may say: Historical research was here predominant. of another the remark would be true that, while it lasted, the different schools of philosophy divided the intellectual world. And again: Here was an age of great legists; at such a period constitutional and international law gradually acquired shape and recognition. At all periods, whether of intellectual progress or stagnation, the fascination of numbers has thrown its spell over some of the most gifted minds; and, in the exact science of mathematics, the student has enjoyed this singular advantage, that every theorem proved, every problem solved, has been a step gained once for all—alone among the sciences this, within its range, has been permitted to afford a convincing answer to the ever-perplexing question, “What is truth ?” As physicians, we should be ungrateful if, in the most cursory retrospective glance, we omitted to notice those votaries of science, whose patient search for the realization of the alchemist's dream led to so many discoveries in chemistry, and laid the foundations'of that modern science that has numbered among its disciples some of the most brilliant intellects of recent years. The study of medicine has passed through various gradations according to the theories that were predominant; until, in recent years, the cultivation of our art has become so interwoven with scientific investigation, so allied with strict inductive reasoning, and so associated with other and collateral branches of study, that the student of medicine may now be said to embrace in his curriculum the whole scope of scientific teaching, as well as the purely professional practice of the healing art.