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 Rh simple an organ as the leaf of a plant. The agency of the vital principle alone can account for these wonders, though it cannot, to our understanding, explain them. "The thickest veil," says Dr. Thomson at the end of his chapter on vegetation, "covers the whole of these processes; and so far have philosophers hitherto been from removing this veil, that they have not even been able to approach it. All these operations, indeed, are evidently chemical decompositions and combinations; but we neither know what these decompositions and combinations are, nor the instruments in which they take place, nor the agents by which they are regulated."

The vain Buffon caused his own statue to be inscribed "a genius equal to the majesty of nature," but a blade of grass was sufficient to confound his pretensions.