upon them, it is as ready to aid in their destruction.  Like calumny, which blackens whatsoever is suspected, oxygen pounces upon the failing and completes their ruin.  The processes of fermentation and putrefaction cannot commence in any substance, until it has first taken oxygen into combination.  Thus, cans of meat, hermetically sealed, with all the air first carefully expelled, undergo no change so long as the air does not get access to them.  If the minutest opening remain, the oxygen of the atmosphere combines with the contents of the can, and fermentation or putrefaction follows.  Rust, which takes the keen edge from the knife, is only another name for oxydation:  keep the knife bright, and no oxygen dares touch it; but the slightest blemish is made a loophole for the entrance of the ever-watchful enemy, who never again leaves it until its destruction is complete.

All the elements have a great love of society; they cannot live alone; they have their likes and their dislikes; they contract alliances which endure for a time, but are dissolved in favor of stronger attractions.

We have mentioned the names of several natural elements.  Let us see what they are, and what they have to do with man and the kingdoms of Nature.  Beginning with man, let us see what becomes of him in course of time, what physical metamorphoses he undergoes, to what vile but excellent uses he is put.

That which forms the bone and muscle of a man this year may be upon his own table in the shape of potatoes or peaches one summer later.  When Hamlet talked of turning the clay of Alexander into the bung of a beer-barrel, he spoke the simple truth.  In that great play, Shakspeare appears to have had the transformations of material things much in his mind; for we find him alluding, in several passages, to the reciprocity which subsists between the elements of animate and inanimate things, and between the different members of the same kingdom;—­as when, in conversation with the king about the dead Polonius, he makes Hamlet say, “A man may fish with the worm that hath eat of a king, and eat the fish that hath fed of the worm”; or where, over the grave of Ophelia, he traces the two ancient heroes back to their mother earth, in words some of which we have quoted.

The ancient mythology, which shadowed forth some truth in all its fables, turned these facts of Nature to its purpose.  The gods of Greece, when they saw fit to remove a human being from life, sometimes reproduced him in another form of beauty, without any intermediate stages of decay.  Apollo seemed to have a particular fancy for planting the boys and girls whom he had loved where he might enjoy their fragrant society.  Thus, a boy named Cyparissus, who had the misfortune to kill a favorite deer, was so unwilling to be consoled, that he besought Apollo to make his mourning perpetual; and the kind god changed him into a cypress, which is still a funereal tree.  The modest virgin Daphne,