“You will see at once that all argument upon this head should ·741· be urged, if at all, against the rule itself; and for this end we must examine the rationale of the rule. Now the human body, in general, is neither much lighter nor much heavier than the water of the Seine; that is to say, the specific gravity of the human body, in its natural condition, is about equal to the bulk of fresh water which it displaces. The bodies of fat and fleshy persons, with small bones, and of women generally, are lighter than those of the lean and large-boned, and of men; and the specific gravity of the water of a river is somewhat influenced by the presence of the tide from sea. But, leaving this tide out of question, it may be said that very few human bodies will sink at all, even in fresh water, of their own accord. Almost any one, falling into a river, will be enabled to float, if he suffer the specific gravity of the water fairly to be adduced in comparison with his own—that is to say, if he suffer his whole person to be immersed, with as little exception as possible. The proper position for one who cannot swim, is the upright position of the walker on land, with the head thrown fully back, and immersed; the mouth and nostrils alone remaining above the surface. Thus circumstanced, we shall find that we float without difficulty and without exertion. It is evident, however, that the gravities of the body, and of the bulk of water displaced, are very nicely balanced, and that a trifle will cause either to preponderate. An arm, for instance, uplifted from the water, and thus deprived of its support, is an additional weight sufficient to immerse the whole head, while the accidental aid of the smallest piece of timber will enable us to elevate the head so as to look about. Now, in the struggles of one unused to swimming, the arms are invariably thrown upwards, while an attempt is made to keep the head in its usual perpendicular position. The result is the immersion of the mouth and nostrils, and the inception, during efforts to breathe while beneath the surface, of water into the lungs. Much is also received into the stomach, and the whole body becomes heavier by the difference between the weight of the air originally distending these cavities, and that of the fluid which now fills them. This difference is sufficient to cause the body to sink, as a general rule; but is insufficient ·742· in the cases of individuals with small bones and an abnormal quantity of flaccid or fatty matter. Such individuals float even after drowning.
“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.
·743· “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.’
“The whole of this paragraph must now appear a tissue of inconsequence and incoherence. All experience does not show that ‘drowned bodies’ require from six to ten days for sufficient decomposition to take place to bring them to the surface. Both science and experience show that the period of their rising is, and necessarily must be, indeterminate. If, moreover, a body has risen to the surface through firing of cannon, it will not ‘sink again if let alone,’ until decomposition has so far progressed as to permit the escape of the generated gas. But I wish to call your attention to the distinction which is made between ‘drowned bodies,’ and ‘bodies thrown into the water immediately after death by violence.’ Although the writer admits the distinction, he yet includes them all in the same category. I have shown how it is that the body of a drowning man becomes specifically heavier than its bulk of water, and that he would not sink at all, except for the struggles by which he elevates his arms above the surface, and his gasps for breath while beneath the surface—gasps which supply by water the place of the original air in the lungs. But these struggles and these gasps would not occur in the body ‘thrown into the water immediately after death by violence.’ Thus, in the latter instance, the body, as a general rule, would not sink at all—a fact of which L’Etoile is evidently ignorant. When decomposition had proceeded to a very great extent—when the flesh had in a great measure left the bones—then, indeed, but not till then, should we lose sight of the corpse.
“And now what are we to make of the argument, that the body found could not be that of Marie Rogêt, because, three days only ·744· having elapsed, this body was found floating? If drowned, being a woman, she might never have sunk; or having sunk, might have re-appeared in twenty-four hours, or less. But no one supposes her to have been drowned; and, dying before being thrown into the river, she might have been found floating at any period afterwards whatever.
“‘But,’ says L’Etoile, ‘if the body had been kept in its mangled state on shore until Tuesday night, some trace would be found on shore of the murderers.’ Here it is at first difficult to perceive the intention of the reasoner. He means to anticipate what he imagines would be an objection to his theory—viz: that the body was kept on shore two days, suffering rapid decomposition—more rapid than if immersed in water. He supposes that, had this been the case, it might have appeared at the surface on the Wednesday, and thinks that only under such circumstances it could so have appeared. He is accordingly in haste to show that it was not kept on shore; for, if so, ‘some trace would be found on shore of the murderers.’ I presume you smile at the sequitur. You cannot be made to see how the mere duration of the corpse on the shore could operate to multiply