exercised in nutrition, developement, and reproduction. The principal part of the nourishment of plants, is derived from their roots; and their texture is composed of tissues and vessels formed for absorbing, retaining, and elaborating the nutritive juices, drawn from the soil and atmosphere. The vegetable kingdom, likewise, has this analogy among others, with the animal; that the function of reproduction is performed through the medium of sexual organs. These organs are protected by the corolla, or flower; and all the display of color and form in this essential part of vegetables, is, like the notes of many birds, connected with the important purpose of the continuation of the species. The number, form, and situation of these organs, has afforded to Linnæus the chief characters in his simple, though artificial arrangement of the classes and orders of plants, in consequence termed the sexual system; while what is called the natural system, proposed by Jussieu, is founded chiefly upon the presence or absence, and the nature of the seed, or germ-the relative position of the stamina— and upon the absence or presence, and form, of the corolla.

The MINERAL KINGDOM is distinguished from the other two great divisions, by the absence of vitality and organic structure. Forming the solid crust of the globe, the mineral kingdom, in its various compounds, affords support and sustenance to the organized beings existing on its surface. The constitution and arrangement of the mineral strata have given rise to various theories, to account for their present appearance; but facts have not yet been sufficiently multiplied to afford a satisfactory solution. One great line, however, is drawn between those mineral strata which have been termed primitive, in which no organized remains occur, and those of posterior formation, in which the remains of plants and animals are discovered. The principal external characters of the mineral kingdom are taken from their specific gravity, as compared with water,-hardness,— crystallization, when it exists, -and cleavage, or the direction of the lamella, which, in many minerals, is regulated by the relation of the external surfaces to the primary crystal, or form. Of a less constant kind are color, degree of transparency, fracture, and the streak which many minerals show, when scratched. The physical characters are fusibility, solubility, phosphorescence, electricity, magnetism, and refraction. Linnæus, in his Systema Naturæ, arranged the Animal kingdom into six classes, the Vegetable kingdom into twenty-four, and the Mineral kingdom into three. As this arrangement, though now modified and extended in many of its parts, as will be detailed else

where, forms the basis of modern classification, and was the first successful attempt at arranging in intelligible order, the various objects of Natural History, its principal divisions are subjoined.*

THE VEGETABLE KINGDOM

is divided into twenty-four classes, according to the number and position of the stamens; the greater part of the orders, from the number of pistils in the flower; others, by the situation of the seeds, and form of the seed-vessels; in compound flowers, from the arrangement of the florets; and the great class of cryptogamic plants, or plants without conspicuous flowers, form four orders, divided into Filices, Musci, Alga, and Fungi.

THE MINERAL KINGDOM

is divided into three classes, viz: I. PETRE; II. MINERE; III. FOSSILIA; and numerous subdivisions. But, as the mineral kingdom had attracted but little of the attention of Linnæus, and the progress of chemistry

* Systema Naturæ, ed. 12. Holmiæ, 1766.

has since changed the whole science of mineralogy, it is not necessary, here, to give the inferior details.

Such is the "field of realities," as M. Lamarck terms it, which the study of Nature offers to the intelligent mind. Life, in all its aspects, is exhibited in countless forms, and the regular succession of organized beings, present the creation in the attractive features of perennial youth. Without herbivorous races, the vegetable kingdom would soon encumber the surface of the globe; without carnivorous animals, the others would multiply beyond their means of support; and provision is made in those tribes, whose food is decomposing substances, to free the earth from dead animal remains. By no conceivable means, could the same amount of existence and happiness be attained; and the whole system is so wonderfully arranged, that among the numberless existences which people the earth, the air, and the waters, there is a constant harmony between the means of existence and the existing beings. While animals, useful to others, are produced in amazing numbers, the fecundity of others, whose physical powers might otherwise give them a superiority, are limited, and species apparently the most defenceless, are provided with means of protection, which insure their perpetuity. To Man alone, as the intelligent head of the whole, is given the dominion over the inferior creatures; his reason has enabled him to apply to his use the whole of the organized and inorganic bodies around him, and left him, within certain limits, the accountable Master of the creation.

On the utility of a knowledge of the objects of Nature, to a being depending on her productions for the supply of all his conveniences and wants, it is scarcely necessary to insist. No species of human learning is so well calculated to form habits of attention and correct observation, as the study of the different branches of Natural History; and none is more admirably adapted to the feelings and capacities of the young. Besides the improvement of the intellectual powers, which the examination of the structure and habits of any class of organized beings is calculated to produce, and the associations likely to be thereby awakened, there is something in the study of Nature which approaches to philosophy of a higher kind-something that, while it teaches man his place in this Creation of Wonders, infallibly leads him to admire the wisdom, and power, and goodness, displayed by its Great Author.

FIRST-THE ANIMAL KINGDOM.

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ACCORDING to Cuvier, there are four principal forms, after which all living beings seem to have been modelled. The basis of these distinctions is laid in the organization of the creatures themselves. Sensation and movement are the characteristics of animals. The heart and the organs of circulation, seem a kind of centre for those functions which may be called vegetative, while the brain and the nervous system, form the principal source of the functions more exclusively animal. Descending from the higher to the lower races of animals, both these systems are found gradually to become more imperfect, and finally to disappear altogether. In the lowest tribes in the scale, where nerves are no longer visible, the muscular fibre also ceases to be distinct, and the organs of digestion are reduced to a simple cavity in the homogeneous mass. In insects, the vascular system disappears, even before the nervous system; but in general, the dispersion of the medullary masses is connected with the agents of muscular motion: a spinal marrow, upon which knots, or ganglia, represent as many brains, or seats of sensation, corresponding to the structure of a body divided into numerous rings, and supported by pairs of limbs, distributed along these annulations. This relative proportion in the structure of general forms, which results from the arrangement of the organs of motion, from the distribution of the nervous masses, and from the energy of the circulating system, constitutes the basis upon which M. Cuvier has founded the principal divisions of the Animal Kingdom.

In the first of these general forms, which is that of Man, and the animals which resemble him most nearly, the brain and the principal trunk of the nervous system are inclosed in bony cases; the first called the cranium, the second the vertebra. To the sides of the vertebral column, as to a centre, are attached the ribs, and the bones of the members which form the frame-work of the body. The muscles, in general, cover the bones, which they put into action, and the viscera are inclosed in the head and trunk. Animals of this form are called VERTEBRATED ANIMALS, (Animalia Vertebrata.)

They have all red blood, a muscular heart, a mouth with two horizontal jaws, distinct organs of vision, hearing, smell, and taste, situated in cavities of the head, and never more than four limbs. The sexes are always separate, and the distribution of the medullary masses and the principal branches of the nervous system, is nearly the same in all.

On a close examination of any of the characters of this leading division, some analogy of conformation is always found, even in the species the most