In what experimental philosophers have styled the THREE ORDERS OF NATURE, that is to say, the mineral, the vegetable, and animal worlds, they have established, by the aid of motion, a transmigration, an exchange, a continual circulation in the particles of matter. Nature has occasion in one place, for those particles which, for a time, she has placed in another. These particles, after having, by particular combinations, constituted beings endued with peculiar essences, with specific properties, with determinate modes of action, dissolve and separate with more or less facility; and combining in a new manner, they form new beings.