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, 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 useful insects. That is, the limited partnership of Oxygen, Hydrogen, & Co., under which they agreed to carry on the operations of sheep, fox, or fish, having terminated by the death of the animal, the partners make immediate use of their liberty and go off in inorganic form in search of new engagements, leaving sulphur, phosphorus, and the other subordinate elements of the animal, to shift for themselves. They were in the employ of a sheep; they will now carry on a man or an oak-tree, a colony of insects, or something else. Under the form of carbonate of ammonia, the four elements diffuse themselves through the air, or are absorbed by the earth, and offer themselves at once to the roots and leaves of the trees, as ready to go on with their vivifying operations as they were in behalf of the animals. There are some plants which seem not to be left to the chances of securing their nourishment from the carbonate of ammonia that the air and the soil contain, but are contrived so as to entrap living animals and hold them fast while they undergo decomposition, so that all their gases may be absorbed by them alone. Thus, "the little Sundew exudes a gluey secretion from the surface of its leaves, which serves to attract and retain insects, the decay of whose bodies seems to contribute to its existence." And the Dionaea, or Venus's Fly-trap of the Southern States, has some leaves which fold together upon any insect that alights upon their upper surface; and by means of a row of long spines that fringes the leaves, they prevent his escape. The more active the struggles of the captive, the closer grows the hold of the leaf, and speedily destroys him. The plant appears to derive nutriment from the decomposition of its victims. "Plants of this kind, which have been kept in hot-houses in England, from which insects were carefully excluded, have been observed to languish, but were restored by placing little bits of meat upon their traps,—the decay of these seeming to answer the same purpose."
The four elements already referred to are by no means all the material ingredients of animal bodies. There are, also, phosphorus, lime, magnesia, soda, sulphur, chlorine, and iron; and if you believe some chemists, there is hardly a mineral in common use that may not be found in the human body. We doubt, however, whether lead, arsenic, and silver are there, without the intervention of the doctor.
What becomes of the phosphorus and the rest, when an animal dies? Oh, they take up new business, too. They are as indispensable to the animal frame as the four most prominent ingredients. We eat a great deal of bread and meat, and a little salt,—but the little salt is as important to continued life as the large bread. There is hardly a tissue in the body from which phosphorus, in combination with lime, is absent; so that the composition of lucifer-matches is by no means the most important use of this element. The luminous appearance which some putrefying substances, particularly fish, present at night, is due to the slow combustion of phosphorus which takes place as this element escapes into the air from the decomposing tissues.
The necessity for the steady supply of phosphorus and lime to the body is the cause of the popularity of Mapes's superphosphate of lime as a manure. The farmers who buy it, perhaps, do not know that their bones and other parts are made of it, and that this is the reason they must furnish it to their land;
