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 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