By Thee disposed into congenial soils, Stands each attractive plant, and sucks, and swells By wintry winds; that now in fluent dance, I shall now consider the very curious and admirable process of nature in the vegetation of plants, which is described to this effect by the excellent Malpighi and others: The seed of the plant, after it has dropped from the pod or husk, may be considered as an impregnated egg, within which the embryo plant is securely lodged. In a few days after it has been committed to the earth, may be observed the rudiments of the future plant, every part of which appears to exist in miniature. The nutricious juices of the soil insinuate themselves between the original particles of the plant, and bring about an extension of its parts. This is called the growth of the vegetable body; and, with regard to this increase by addition and extension, there seems to be a great analogy between the animal and vegetable kingdoms, on which, however, I shall not enlarge. To illustrate the subject of vegetation, let us take a view of what happens to a bean, after it has been committed to the earth. In a few days, sooner or later, according to the temperature of the weather and the disposition of the soil, the external coverings open at one end, and discover to the naked eye part of the placenta, or body of the grain. This substance consists of two lobes, or divisions, between which the seminal plant is securely lodged. Soon after the opening of the membranes, a sharp-pointed body appears, which is the root. By a kind of principle, which seems to bear some appearance of instinct, it seeks a The passage downward, and fixes itself into the soil. At this period, the root is a smooth and polished body, and has, perhaps, but little power to absorb any thing from the earth, for the nutriment of the germ or sprout. The two lobes now begin to separate, and the germ, with its leaves, may be plainly discovered. As the germ increases in size, the two lobes are further separated, and the tender leaves, being closely joined, push themselves forward in the form of a wedge. These leaves take a contrary direction to the root. They seek a passage upward, which having obtained, they lay aside their wedge-like form, and spread themselves in a horizontal direction, as being the best adapted for receiving the rain and dew. root, increasing every hour in size and vigour, pushes itself deeper into the earth, from which it now draws some nutritive particles. At the same time, the leaves of the germ, being of a succulent nature, assist the plant, by attracting from the atmosphere such particles as the tender vessels are fit to convey. These particles, however, are of a watery kind, and have not in their own nature a sufficiency of nutriment for the increasing plant. Vegetables, as well as animals, during their tender state, require a large share of balmy nourishment. As soon as an animal is brought into life, the milk of its mother is supplied in a liberal stream; while the tender germ seems to have only the crude and watery juices of the earth for its support. This, however, is not the case: for the vegetable lives upon a similar fluid, although differently supplied. For its use, the farinaceous lobes are melted down into a milky juice, which, as long as it lasts, is conveyed to the tender plant by innumerable small vessels, which are spread through the substance of the lobes. These vessels, aniting into one common trunk, enter the body of 0 VOL. I. the germ, and perform the office of an umbilical chord. Without this supply of balmy liquor, the plant must inevitably have perished, its root being then too small to absorb a sufficiency of food, and its body too weak to assimilate it into nourishment. Turnips, and all the tribe of cabbages in opposition to the leguminous and farinaceous plants, spread their seminal leaves upon the surface: these leaves contain all the oil of the seed, which, when diluted by the moisture of the atmosphere, forms an emulsion of the most nourishing quality; and, on account of its sweetness, the seminal leaves are greedily devoured by the fly. A grain of wheat, as soon as the germ has made its appearance, shows the milky liquor to the naked eye; but the umbilical chord, with its ramifications, can be discovered only by the assistance of the nicest glasses. As the plant increases in size, the balmy juice diminishes, till, at last, it is quite exhausted. The umbilical chord then dries up, and the external covering of the grain appears connected with the root in the form of a shrivelled bag. In the pro All seeds have two coverings, which answer to the chorion and amnion in anatomy, and two lobes, or divisions, which perform the office of the placenta. These lobes constitute the body of the seed; and, in the farinaceous kinds, they are the flour of the grain. Innumerable small vessels run through the substance of the lobes, which, uniting as they approach the seminal plant, form a small chord to be inserted into the body of the grain. Through this the nutriment supplied by the placenta or lobes is conveyed for the preservation and increase of the embryo plant. Here it may be observed, that the lobes of farinaceous grains are fixed in the earth; they are, therefore, improperly termed seminal leaves, being rather the placenta or cotyledons of the plant. On the contrary, vegetables that have an oily seed, as rape, hemp, and turnip, carry their lobes upward, and spread them upon the surface in the form of broad leaves. These, though they perform the office of a placenta, are properly seminal leaves. cess of vegetation, there is no mortality: from the moment that the seed is lodged in its parent earth, the vegetative principle begins its operations, and, in the whole successive gradation of them, illustrates the wisdom, the power, and the bounty of Providence. It is worthy of observation, moreover, that farinaceous vegetables and oviparous animals are nourished in their tender state nearly in the same manner. The embryo plant is supported by the farina melted down into a milky liquor, and conveyed into its body by means of an umbilical chord, at a time when the radicle was unable to supply a sufficiency of nutriment. An oviparous animal, from the time that it is brought into light, seems to receive all its nourishment from without; but this is in appearance only. The yolk of the egg, remaining entire during incubation, is received into the body of the animal, and, in a manner similar to the milky juice of the vegetable, is slowly conveyed into the vessels of the tender chick; and thus a sweet nourishment is prepared at a time, when neither the industry of the animal, nor the attention of its mother, could have procured a sufficient supply. That the whole plant is contained in the seed, is an opinion as old as Empedocles; and it is still the prevailing doctrine among the generality of naturalists. Experience, the microscope, and the modern philosophy, give great countenance to it: for it is certain, that by the use of good microscopes, we discover, in the seed, several of the parts of the future plant, only in miniature; particula ly a little root called the radicle, and the stem called the plumule. In the life of Malpighi, we have a debate between him and signor Triumphetti, provost of the physic garden at Rome, whether the whole plant be actually contained in the seed. The affirmative is maintained by Malpighi, with cogent arguments; among which this is one, that in a kidney bean, before sown, the eye, assisted by the microscope, easily discovers leaves, a bud, and even the knots or implantations of the leaves on the stem. The stem itself also is very conspicuous, and plainly consists of woody fibres, and a series of little utricles. And Triumphetti having objected, that by poverty, transplantation, &c. several plants degenerated into others, particularly wheat into tares, and tares again into wheat; in answer to this, which is one of the strongest objections against that opinion, Malpighi replies, that he is not fully satisfied as to the truth of the objection; for that both he himself, and his friends, having made the experiment, no metamorphosis of the wheat succeeded; but, granting the metamorphosis, it is the soil, or the air, or the culture, that is in fault. Now, from a morbid and monstrous condition of Nature, there is no inferring her genuine and permanent state. On this subject of seeds, there is one circumstance, which is too curious and remarkable to be passed over; namely, that in all countries, whether agriculture be promoted or neglected by mankind, Nature assists to sow and plant, as well as to fertilize the earth. The seeds of lofty trees are many of them winged; and, when they are ripe, the autumnal winds blow them off, and scatter them at a great distance from their mother plants. Others are in pods or husks, and not capable of being carried by the motion of the air; but Providence has given them as foods to birds, who carry them to distant places, and, in feeding, scatter part of the seed in soils proper for them to take root in and spring up. Even the droughts of the autumn contribute to increase and propagate trees and plants; for by causing deep chinks in the earth, the seeds of trees, and larger plants, that require depth, are lodged at pro |