Such are the changes which an animal body undergoes after death, that unless the anatomist be intimately acquainted with their nature and extent, it is impossible that he should be able to derive any safe conclusions from his dissection; thus, said _Mr. John Hunter_, we may see appearances which are natural, and may suppose them to have arisen from disease; we may see diseased parts, and suppose them to be in a natural state, and we may suppose a circumstance to have existed before death, which was, in reality, a consequence of it; or we may imagine it to be a natural change after death, when it was truly a disease of the living body. It is not difficult, therefore, to perceive, how a person in such a state of ignorance must blunder, when he attempts to connect the appearances in the dead body, with the symptoms that were observed during life; and indeed it may be safely asserted, that the great utility of anatomical inspections depends upon the accuracy, judgment, and sagacity with which such comparisons are made. In our chapter, on the art of conducting dissections, we have endeavoured to point out each fallacy which is likely to present itself to the inexperienced anatomist, we shall therefore confine ourselves, on the present occasion, to the consideration of those points whose obscurity must be admitted to belong intrinsically to the subject, and to be wholly independent of the ignorance or skill of the dissector. Amongst the signs of the action of poison on the human body, disclosed by the light of dissection, the separation of the villous coat of the stomach has been generally considered the most certain criterion. _Hebenstreit_, whose opinion has been adopted by _Mahon_, and many other forensic physicians, has delivered his unreserved judgment upon the question, in the following emphatic sentence. “_Præterea sola atque infallibilis deglutiti veneni nota est, separata et veluti decorticata simulque cruenta interna ventriculi tunica: nam separatio ista supponit applicatam superficiei internæ ventriculi materiam fervidam, igni similem, quæ tunicam istam a substrata solvit vasculari nervea._”[178] In opposition to such an opinion, it is our duty to state that several cases stand recorded[179] in which the detachment of the villous coat of the stomach and intestines has taken place, without the slightest ground to suspect the administration of poison, while many vegetable poisons destroy life without occasioning any inflammation in the _primæ viæ_, and consequently leave no traces of disorganization. But there still remains another source of fallacy connected with the present question which demands a full and impartial inquiry, viz. that the gastric juice, by its action upon the dead stomach, can occasion such changes in structure, as may be mistaken for the effects of a corrosive poison; these changes are according to circumstances liable to vary in every possible degree of intensity, from the slight erosion of the interior