lowest levels the mineral and organic nutriment for vegetation; and vegetation, thus originated, carries them back again up the slopes, preparing a soil for its own progress as it goes. The slimmest and scantiest vegetation is always in the advance, like the pioneers and light troops who clear the ground for the heavy columns of an army.' ""*

The plant is thus, as we see, a manufacturer of soil, and what, in this respect, is true of it, is equally so of all the living and moving beings that walk the face of earth. The development commenced in the stomach of the plant is continued and carried out in that of the man, who has been well compared to a locomotive engine. Into the stomach of the latter we introduce fuel under circumstances tending to promote its decomposition, or motion of the elements of which it is composed-and this motion gives force. The man takes into his stomach, as fuel, the various products of the vegetable and animal kingdom, and there they are subjected to the process of decomposition, whence result vital heat and force. The manner in which plants and animals combine to produce this increasing motion, is well exhibited in the following passage :

"Man himself, and other animals, assist in the same conversion. They consume vegetable food with the same final result as when it perishes by actual decay, or is destroyed by the agency of fire. It is conveyed into the stomach in the form in which the plant yields it; it is breathed out again from the lungs and the skin, in the form of carbonic acid and water. We can follow out this operation, however, more closely, and it will be both interesting and instructive to do so.

"The leaf of the living plant sucks in carbonic acid from the air and gives off the oxygen contained in this gas. It retains only the carbon. The roots drink in water from the soil, and out of this carbon and water the plant forms starch, sugar, fat, and other substance. The animal introduces this starch, sugar or fat, into its stomach, and draws in oxygen from the atmosphere by its lungs; and with these materials it undoes the previous labors of the living plant, delivering back again from the lungs and the skin both the starch and the oxygen in the form of carbonic acid and water. The process is clearly represented in the following scheme :

* Smith. Manual of Pol. Econ. p. 38.

"The circle begins with carbonic acid and water, and ends with the same substances. The same material-the same carbon, for example-circulates over and over again, now floating in the invisible air, now forming the substance of the growing plant, now of the moving animal, and now again dissolving into the air, ready to begin anew the same endless revolution. It forms part of a vegetable to-day-it may be built into the body of a man to-morrow; and, a week hence, it may have passed through another plant into another animal. What is mine this week is yours the next. There is, in truth, no private property in ever-moving matter."*

§ 3. In the early periods of society the changes of form are very slow, and thus we see that, in the days of the Plantagenets, and for centuries afterwards, the yield of an acre of land was but six or eight bushels of wheat. Small as it was, it was, nevertheless, attended with constant improvement in the form of matter resulting from the motion that thus far had been obtained. The rocks had been decomposed, and the clays and the sands had taken upon. themselves a higher form-and the beautiful green of the wheat had replaced the sombre brown of the earth. Step by step, however, man is seen obtaining higher command of the various forces provided for his use, and passing onward until at a later period he obtains thirty, forty, and fifty bushels to the acre; while of other commodities they count by hundreds.

Without vital heat this command could not be obtained, and without fuel there could be no heat. That fuel, as we see, is food, without which there can be no vital action-and thus it is that we reach the point at which man and other animals stand upon a level with each other. In common with them all, he eats, drinks, and sleeps, and in common with them he must obtain supplies of food. Looking around, he sees vast bodies of matter held in a quies

* Blackwood's Magazine, May, 1853.

cent state, by reason of the force of gravitation, and therefore unproductive. It is a magazine of power, latent, waiting help to set it free. The hard soil yields scanty herbage, but he now loosens it so as to expose its particles to the action of the sun and the rain, and, that done, he places therein a seed ready to receive into its stomach the food required for its nourishment. It sprouts, and the plant grows by aid of earth and atmosphere, yielding the oats, the rye, or the corn required for his support, or that of the animals on which he feeds. In all this, however, he has done no more than is done by the man who feeds the locomotive, placing matter in a situation to become decomposed, and thus giving individuality to its atoms, by help of which they are enabled to combine with other atoms. The act of combination is one of motion, and that motion gives force.

To accomplish this, he has ploughed deeper, and has enabled a larger quantity of soil to become presented to the action of the rain and the sun. He has dug drains, and has thus enabled the water to run off, that otherwise would have remained stagnant and would have destroyed his seed; and precisely as he has thus facilitated the motion of matter he has found himself rewarded by a more rapid increase in the quantity that has taken upon itself the form required for his purposes.

The greater the motion, the more rapid is the improvement in the form. The stiff pine gives way to the graceful barley, while beautiful fields of clover replace the rank weeds of the swamp, and the gaunt wolf disappears from the land that now maintains the high-bred horse and well-formed man.

With increased control over the natural forces, he is thus enabled to obtain a constant increase of food from any given surface, with steady increase in the power to live in connection with his fellow man. Association grows, giving in its turn power to bring into activity other forces that thus far have remained dormant and waiting the help of man. He turns up the limestone and subjects it to the process of decomposition, furnishing carbonic acid to the air, and giving quicklime to the earth. He digs the coal, and that in its turn is decomposed, furnishing to the atmosphere new supplies of the material that is to be recomposed in the form of vegetables for his nourishment. He mines the iron ore, to be decomposed by help of coal, and here again are new supplies of the materials

required for the support of organic life; and furnished, too, by the very process required for giving him instruments needed for the work of cultivation. The matter thus decomposed continues in motion, and must so continue while men increase in the power of association. The various ores never again return to their original form, nor does the lime become again limestone, after it has entered into the composition of food. Eaten, it returns again to the atmosphere, or to the earth, and the man himself at length dies and is buried, and thus repays the debt he owes to nature. Even, however, while still living, he is constantly absorbing and giving out again to the earth and atmosphere the atoms of which his system is composed, as is well explained in the following passage:

"In natural forests, where the leaves are annually shed and the trees periodically die, the mineral matter quits the soil for the plant, and again, in the decaying plant, returns to the soil, thus making but a short stage up and down from earth to plant, and from plant back to the earth again. And it is so also in natural meadows, where yearly in autumn the grass ripens, withers, and returns its mineral matter to the soil, and yearly again in spring the young herbage springs up and feeds on the relics of the previous year. But it is different when the vegetable produce is consumed by animals. It then enters into their stomachs, is dissolved or digested, and its several parts taken up by vessels provided for the purpose, to be conveyed to the parts of the body where their services are required. The saline matter we need not at present follow further than the blood and the tissues. The phosphoric acid and the lime-in the form of phosphate of lime-are chiefly deposited in the bones.

"The importance of this phosphate of lime to the animal economy will be apparent, when we mention that ordinarily dry bones leave, on burning, half their weight of a white ash, which consists for the most part of phosphate of lime.

But, as we have already explained, all the parts of the body, even the most solid, are in a constant course of renewal. To this law of change the bones are subject equally with the soft parts, and the phosphoric acid carried in to-day is in a few days carried out again, mixed up with the other refuse and excretions of the body; and finally the body itself dies, and all its material parts are at once returned to the earth from which it came. There they

undergo, through the agency of the air, a complete breaking-up or decomposition, by which their mineral matter itself is brought into a condition in which it can enter usefully into the roots of new plants. There are other minutiæ in reference to the revolution of this mineral matter which are full of interest, but we will not try the patience of our readers by insisting upon them in this place. The general changes we have indicated are represented briefly as follows:

THE PLANT,

THE ANIMAL,

THE SOIL,

Taken in by

Phosphoric acid, line, com

Produced

mon and other salts from Perfect substance of plants. the soil.

a. Parts of plants.

f Perfect bone, blood, and tis

{

sues.

b. The bone and tissues, with ƒ Phosphates and other salts
oxygen from the lungs.
in the excretions.

Excretions of animals, dead ƒ Phosphoric acid, lime, &c.
animals and plants.

&c.

"It may be that a careful hunter after human earth might scrape together as much as would 'stop a hole to keep the wind away.' But our science teaches us that the earth is not the kind of stuff that clay is made of, and such vile uses are, after all, only imaginary slights to which our cherished ashes can never be subjected. They have another appointed use, from which, treat them as they may, they cannot long be kept. The plant is wonderfully framed, so as not to grow without the phosphoric acid, &c., which it is bound to gather up and supply to the growing animal. And the soil is so poorly provided with these and other necessary substances, that plant and animal are both ordained to return without fail their borrowed material to mother earth when the term of life has come. Thus a constant circulation of the same comparatively small quantity of mineral matter is secured, and a duty is laid upon each particle zealously to prepare for a new service, as soon as each earlier commission is performed. As we have no property in, so we ought to have no foolish affection or reverence for dead ashes; and certainly we ought to have no fear that they can ever long be withheld from connecting themselves, in some form or other, with new phases of vegetable and animal life.”*

"Plant and animal are both," as we here see, ordained to return

* Ibid.