Soft and yielding as vegetable structures appear to the touch, the expansive force of their growth is almost beyond calculation. The effects of this power, of which the experience of every one will furnish him with some instances, are perhaps nowhere more strikingly exemplified than amidst the ruins of its own creation. Coeval with many old brick fabrics of earlier times, perhaps embedded in the very mortar which holds them together, it may lurk there for centuries in quiescence, till once arousing its energies, it continues to exert them in ceaseless activity ever after. It has at Rome planted its pink Valerians on her highest towers, and its wild fig-tree in the breaches of her walls; nor are the granite obelisks of her piazzas, nor the classic groups in marble on her Quirinal mount, entirely exempt from its encroachments. A conspiracy of plants, one hundred strong, have long ago planned the destruction of the Coliseum; their undermining process advances each year, and neither iron nor new brickwork can arrest it long. That old Roman cement, which the barbarians gave up as impracticable, and the pickaxe of the Barberini had but begun to disintegrate, will, ere the lapse of another century, be effectually pulled to pieces by the rending arm of vegetation. Here, as erst in Juvenal’s time, the mala ficus finds no walls too strong to rive asunder, no tower beyond the reach of its scaling, no monument too sacred for it to touch. In the class of plants immediately under consideration, while the expansive effort of growth is equal to what it is in other cases, its effects are far more startling from their suddenness. M. Bulliard (to cite one or two instances out of a great many) relates, that on placing a Phallus impudicus within a glass vessel, the plant expanded so rapidly as to shiver its sides with an explosive detonation as loud as that of a pistol. Dr. Carpenter, in his ‘Elements of Physiology,’ mentions that “in the neighbourhood of Basingstoke a paving-stone, measuring twenty-one inches square, and weighing eighty-three pounds, was completely raised an inch and a half out of its bed by a mass of toadstools, of from six to seven inches in diameter, and that nearly the whole pavement of the town suffered displacement from the same cause.” A friend has seen a crop of puff-balls raise large flagstones considerably above the plane of their original level; and I have myself recently witnessed an extensive displacement of the pegs of a wooden pavement which had been driven nine inches into the ground, but were heaved up irregularly, in several places, by small bouquets of Agarics, growing from below.