This sounds exceedingly well. Disinterested words, from whatever quarter they come, always produce--perhaps, on account of their comparative rarity--an admirable effect. But what is their real value? To ascertain it, the listener must be able to seize, like so many luminous threads, all the emotions which are acting upon the heart and tongue of the speaker. But we are very far from having arrived at this degree of perfection. Shall we ever attain to it? Yes, because we can conceive its possibility. But, until that golden epoch, the pure love of science will always remain a myth, and we shall not have universally understood the necessity of seeking in the profound study of nature the grand destiny of man. It is among the weeds and noxious plants that we shall find the species capable of enduring longest the cold of winter. What part, then, do they fulfil in the economy of creation? An ambitious, but not a novel question, which has often been propounded in reference to our parasitical insects. The best answer which we can make to it is this: Everything invites us to work. Labour is imposed even upon him who least desires it. Earth will yield a return only in proportion to the care we bestow upon her. If, after having toiled and sown, we had nothing to do but to gather in the harvest, every person would become an agriculturist. But a soil which is not manured will soon grow exhausted; and if it be neither ploughed nor harrowed, instead of barley or vegetables, it will soon be covered with tares; rank weeds will flourish in every field. Such is the chastisement reserved for sloth,--the true "original sin" of the human race. Well, then, it is among the weeds, everywhere so common, that we meet with the plants best able to brave the rigours of frost. THE DOG MERCURY. The annual _Dog Mercury_ (_Mercurialis annua_) is one of the most tenacious. It attracts the passer-by, if he condescend to bestow a glance upon it, only by its extreme abundance; it propagates very largely, though it is by no means partial to all localities. For instance, it avoids the woods as persistently as its congener, the common Dog Mercury (_Mercurialis perennis_) seeks them. It prefers the vicinity of human habitations and uncultivated fields. If let alone, it spreads with a dangerous rapidity, and invades every garden which is not kept in the most exquisite order. Still, we must not deal too harshly with it. It is not altogether unfriendly to man. In truth, owing to its laxative properties, it renders him invaluable services. The country people have great faith in fomentations of Dog Mercury and honey. Understand, we pray you, that not an atom of mercury enters into it, despite its significant name; but a decoction of the annual Dog Mercury, mixed with a little thick honey, answers all the purposes of those lenitive clysters which are so beneficial to excitable temperaments. The leaves of the plant are eaten in Germany like spinach.