Nature, therefore, in its most significant meaning, is the great whole that results from the collection of matter, under its various combinations, with that contrariety of motion, which the universe presents to our view. Nature, in a less extended sense, or considered in each individual, is the whole that results from its essence; that is to say, the peculiar qualities, the combination, the impulse, and the various modes of action, by which it is discriminated from other beings. It is thus that MAN is, as a whole, or in his nature, the result of a certain combination of matter, endowed with peculiar properties, competent to give, capable of receiving, certain impulses, the arrangement of which is called _organization_; of which the essence is, to feel, to think, to act, to move, after a manner distinguished from other beings, with which he can be compared. Man, therefore, ranks in an order, in a system, in a class by himself, which differs from that of other animals, in whom we do not perceive those properties of which he is possessed. The different systems of beings, or if they will, their _particular natures_, depend on the general system of the great whole, or that Universal Nature, of which they form a part; to which every thing that exists is necessarily submitted and attached. Having described the proper definition that should be applied to the word NATURE, I must advise the reader, once for all, that whenever in the course of this work the expression occurs, that "Nature produces such or such an effect," there is no intention of personifying that nature which is purely an abstract being; it merely indicates that the effect spoken of necessarily springs from the peculiar properties of those beings which compose the mighty macrocosm. When, therefore, it is said, _Nature demands that man should pursue his own happiness_, it is to prevent circumlocution--to avoid tautology; it is to be understood, that it is the property of a being that feels, that thinks, that acts, to labour to its own happiness; in short, that is called _natural_, which is conformable to the essence of things, or to the laws, which Nature prescribes to the beings she contains, in the different orders they occupy, under the various circumstances through which they are obliged to pass. Thus health is _natural_ to man in a certain state; disease is _natural_ to him under other circumstances; dissolution, or if they will, death, is a _natural_ state for a body, deprived of some of those things, necessary to maintain the existence of the animal, &c. By ESSENCE is to be understood, that which constitutes a being, such as it is; the whole of the properties or qualities by which it acts as it does. Thus, when it is said, it is the _essence_ of a stone to fall, it is the same as saying that its descent is the necessary effect of its gravity--of its density--of the cohesion of its parts--of the elements of which it is composed. In short, the _essence_ of a being is its