who succeeded in escaping the violence of his passion, was transformed into a laurel, which is ever green and pure.  And the sweet youth Hyacinthus, beloved of Apollo, being accidentally killed by a quoit which the god of day was throwing, that divinity, in his grief, caused those sweet flowers which bear his name to spring from his blood, where it fell upon the ground.  It is only in the annihilation of the intervals of time between different forms of existence that these old metamorphoses, which Ovid relates, are fabulous.  If our readers will bear us company a few steps, through ways which shall have diversions enough to forbid weariness, we will endeavor to satisfy them that these apparent fables are very near to every-day truths.  We must begin with some plain statements.

The air which we expel from the lungs at every breath has a large proportion of carbonic acid.  Let a man be shut up in an air-tight room for a day, and he will have changed nearly all the oxygen in it into this carbonic acid, and rendered it unfit for animal life.  Dogs, cats, and birds would die in it.  But, poisonous as it is to man and other animals, it is a feast to plants.  They want it all day and every day; not in the night,—­at that time they have a taste for oxygen.  This effete air, which men and animals exhale, so charged with carbonic acid, the plants drink in through every pore.  They take it from the mouth of man, appropriate it to their daily uses, and in time render it back to him mingled with other ingredients in wholesome fruit.  Carbonic acid is death when it combines with the blood,—­as it does when we inhale it; but not so when it enters the stomach in small quantities.  One inspiration of it is enough to make us dizzy,—­as when we enter an old well or stoop over a charcoal fire; but a draught of water fully charged with it is exhilarating and refreshing, as we know by repeated experiences at marble fountains that meet us on so many city-corners.

If plants had souls, they would be pure ones, since they can bear such contamination and not be harmed,—­nay, since even from such foul food as we give them they can evolve results so beautiful.  We give them our cast-off and worn-out materials, and they return us the most beautiful flowers and the most luscious fruits.

Beside carbonic acid, there are two other principal materials, which are every day passing off in an effete state, though capable of being transferred to the uses of plants.  But when an animal dies, the whole substance is then at Nature’s disposal.  We must set aside a great deal of it for the ants and flies, who will help themselves in spite of us.  If any one has never seen a carcass rapidly disappearing under the steady operations of the larvae of the flesh-fly, he has yet to learn why some flies were made.  The ants, too, carry it off in loads larger, if not heavier, than themselves.  But carcasses of animals may go to decay, undisturbed by the ravages of these