“The corpse, being supposed at the bottom of the river, will there remain until, by some means, its specific gravity again becomes less than that of the bulk of water which it displaces. This effect is brought about by decomposition, or otherwise. The result of decomposition is the generation of gas, distending the cellular tissues and all the cavities, and giving the puffed appearance which is so horrible. When this distension has so far progressed that the bulk of the corpse is materially increased without a corresponding increase of mass or weight, its specific gravity becomes less than that of the water displaced, and it forthwith makes its appearance at the surface. But decomposition is modified by innumerable circumstances—is hastened or retarded by innumerable agencies; for example, by the heat or cold of the season, by the mineral impregnation or purity of the water, by its depth or shallowness, by its currency or stagnation, by the temperament of the body, by its infection or freedom from disease before death. Thus it is evident that we can assign no period, with any thing like accuracy, at which the corpse shall rise through decomposition. Under certain conditions this result would be brought about within an hour; under others, it might not take place at all. There are chemical infusions by which the animal frame can be preserved forever from corruption; the bi-chloride of mercury is one. But, apart from decomposition, there may be, and very usually is, a generation of gas within the stomach, from the acetous fermentation of vegetable matter (or within other cavities from other causes), sufficient to induce a distension which will bring the body to the surface. The effect produced by the firing of a cannon is that of simple vibration. This may either loosen the corpse from the soft mud or ooze in which it is imbedded, thus permitting it to rise when other agencies have already prepared it for so doing; or it may overcome the tenacity of some putrescent portions of the cellular tissue; allowing the cavities to distend under the influence of the gas. “Having thus before us the whole philosophy of this subject, we can easily test by it the assertions of L’Etoile. ‘All experience shows,’ says this paper, ‘that drowned bodies, or bodies thrown into the water immediately after death by violence, require from six to ten days for sufficient decomposition to take place to bring them to the top of the water. Even when a cannon is fired over a corpse, and it rises before at least five or six days’ immersion, it sinks again if let alone.’