after death, such transudation is capable of taking place. The possibility is proved by a simple experiment. If prussiate of potash be introduced into a vein or artery of a dead body, and some sulphate of iron be deposited outside the vessel, a blue colour will, in a short time, manifest that the prussiate has reached the iron through the sides of the vessel. The transudation of bile, which in almost every dead body stains the adjacent parts, is a familiar exemplification of this mode of escape. In still later periods after death, several chemical affinities come into action, and produce appearances of hyperæmia which are liable to be mistaken for the effects of disease.
These statements, taken from Andral, brief and imperfect as they are, may yet suffice to shew how much care is required in discriminating the changes produced by disease, from those to which mere physical or chemical influences give rise; and to suggest to those who undertake the examination of dead bodies, a due reserve in pronouncing determinately respecting the cause of death, or of the pre-existing disease, from the appearances which dissection displays. On this subject, much greater accuracy is needed than is generally evinced. For such examination, it is too often deemed sufficient for the operator to be expert in the use of the knife. This is a great error; no anatomical process requiring from the person performing it, such matured knowledge, so much familiar acquaintance with natural structure, and so much pathological information. As in Chemistry, the analysis of mineral waters is said to demand the largest portion of chemical skill
