The classification of the various topics of forensic medicine has ever been a fertile source of controversy; and we will venture to assert that, from the diversity, as well as versatility of the numerous subjects involved in the study of medical jurisprudence, no arrangement can ever be constructed which shall vie, in perspicuity and precision, with that of most branches of natural science, the objects of which, however numerous, maintain a mutual relationship, and admit of being displayed in a striking and natural order of connection. If an arrangement be attempted to meet the legal view of the subject, such, for instance as that proposed by _Professor Plenck_, of Vienna, and adopted by _Tortosa_ and many others, viz. of distributing the subjects according as they relate to the _criminal_, _civil_, or _ecclesiastical_ court, we shall immediately perceive that the same subject will frequently belong with as much propriety to one division, as to another, and may require to be considered under all; thus, insanity must come before a _civil_ court when the person is supposed incapable of managing his own affairs; and before a _criminal_ tribunal, when the soundness of a murderer’s intellect is disputed. _Professor Foderé_, it must be admitted, escapes from this difficulty by creating, under the term “_Medecine Lègale mixte_,” a division that comprehends subjects appertaining at once to the civil and criminal law; but it will be immediately perceived that such a scheme is far too general and indefinite to ensure the advantages of systematic arrangement, or even to merit the appellation of a classification. If, on the other hand, an arrangement be projected upon purely physiological and pathological principles, such as that adopted by _Valentini_, in his “_Corpus juris Medico-legale_,” and which was followed by _Roose_, and very lately preferred by _Dr. Elliotson_,[58] we shall find that similar embarrassments will arise, with respect to their legal relations, as we have just stated must attend their physiological bearings, where the basis of the classification has an exclusive reference to the law. The same objections will apply to the divisions of our respected cotemporary _Dr. Gordon Smith_, who appears to have appreciated all the difficulties of the subject, and, like ourselves, to have despaired of the success of any attempt to surmount them. He arranges the subjects of forensic medicine into three parts, viz. 1. _Those which regard the extinction of human life_; particularly by unusual or violent means; such are many kinds of sudden death, and all cases of homicide. 2. _Injuries done to the person, not leading to the extinction of life_; such are disfiguring and maiming, causing diseases, the violation of females, &c. 3. _Circumstances connected with the physical system, that disqualify for the discharge of civil offices, or the exercise of social functions_; such are mental alienation, the existence of certain diseases, the want