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“fishes,” as Professor Owen observes, “perish when taken out of water, chiefly by the cohesion and desiccation of their fine vascular branchial processes, through which the blood is thereby prevented from passing.” Some fishes, as the Mackerel and Herring, are dead almost in an instant after exposure to the air; others, as the Eel and Flat-fishes, survive a long time: in the former, the gill-openings are enormously large, in the latter, they are very small. “The power of existing long out of water depends chiefly on mechanical modifications for detaining a quantity of that element in the branchial sacs,” and this is readily effected when the gill-aperture is small, for, “if sufficient water can be retained to keep the gill-plates floating, the oxygen which is consumed by the capillary branchial circulation is