It having been settled that the nerve-tubes can very commonly be traced directly to the nerve-cells, the object of all the observers in this department of anatomy is to follow these tubes to their origin. We have an infinite snarl of telegraph wires, and we may be reasonably sure, that, if we can follow them up, we shall find each of them ends in a battery somewhere. One of the most interesting problems is to find the ganglionic origin of the great nerves of the medulla oblongata, and this is the end to which, by the aid of the most delicate sections, colored so as to bring out their details, mounted so as to be imperishable, magnified by the best instruments, and now self-recorded in the light of the truth-telling sunbeam, our fellow-student is making a steady progress in a labor which I think bids fair to rank with the most valuable contributions to histology that we have had from this side of the Atlantic. It is interesting to see how old questions are incidentally settled in the course of these new investigations. Thus, Mr. Clarke's dissections, confirmed by preparations of Mr. Dean's which I have myself examined, placed the fact of the decussation of the pyramids--denied by Haller, by Morgagni, and even by Stilling--beyond doubt. So the spinal canal, the existence of which, at least in the adult, has been so often disputed, appears as a coarse and unequivocal anatomical fact in many of the preparations referred to. While these studies of the structure of the cord have been going on, the ingenious and indefatigable Brown-Sequard has been investigating the functions of its different parts with equal diligence. The microscopic anatomists had shown that the ganglionic corpuscles of the gray matter of the cord are connected with each other by their processes, as well as with the nerve-roots. M. Brown-Sequard has proved by numerous experiments that the gray substance transmits sensitive impressions and muscular stimulation. The oblique ascending and descending fibres from the posterior nerve-roots, joining the “longitudinal columns of the cornua,” account for the results of Brown-Sequard's sections of the posterior columns. The physiological experimenter has also made it evident that the decussation of the conductors of sensitive impressions has its seat in the spinal core, and not in the encephalon, as had been supposed. Not less remarkable than these results are the facts, which I with others of my audience have had the opportunity of observing, as shown by M. Brown-Sequard, of the artificial production of epilepsy in animals by injuring the spinal cord, and the induction of the paroxysm by pinching a certain portion of the skin. I would also call the student's attention to his account of the relations of the nervous centres to nutrition and secretion, the last of which relations has been made the subject of an extended essay by our fellow countryman, Dr. H. F. Campbell of Georgia.