MEDICAL JURISPRUDENCE[1] may be defined, a science by which medicine, and its collateral branches, are made subservient to the construction, elucidation, and administration of the laws; and to the preservation of the public health. It accordingly resolves itself into two great divisions—into _Forensic Medicine_, comprehending the evidence and opinions necessary to be delivered in courts of justice; and into _Medical Police_, embracing the consideration of the policy and efficiency of legal enactments for the purpose of preserving the general health, and physical welfare of the community. Under no circumstances does medical science assume so imposing and dignified an attitude, as when regarded as a branch of legislation. Disentangled from the web with which worldly caprice, credulity, and empiricism, are ever seeking to embarrass the more ordinary path of her labours, she at once displays her pride and strength in the number and variety of her resources, and in the extent and importance of their applications; while the professor of our art is thus enabled to support additional claims upon the respect of the learned, the confidence of the oppressed, and the gratitude of the public. In the active exercise of his duties as a medical jurist, how exalted and honourable is the occupation of the physician!—there is scarcely a circle of natural science, upon the boundaries of which he does not impinge in some point or other, of his extensive orbit. Trace his progress, for instance, through the subject of poisons, and we shall soon perceive that it involves within its range the departments of anatomy, physiology, botany, mineralogy, zoology, and chemistry. If, again, we follow his steps through the deviating and perplexing course of homicide, in how many new and interesting forms will the principles of physiology present themselves; how frequently shall we find ourselves engaged in the solution of problems connected with the knowledge of pneumatics, hydrostatics, and mechanics? If we attend him in the investigation of nuisances, as affecting the health and comfort of the surrounding inhabitants, we shall perceive that an acquaintance with the various branches of natural philosophy, can alone enable him to appreciate the nature and extent of the evil, or the value of the different plans that may be proposed for its removal. While the intricate and perplexing subjects of quarantine and plague police, will require for their elucidation, the energies of a peculiarly constructed and well disciplined mind, to concentrate the genuine lights into a focus, and to dissipate the many specious, but false appearances, with which the question of contagion has been distorted.