A more essential difference might be drawn from the faculty of sensation; but sensation includes such a variety of ideas, that we ought not to mention the word without giving some explication; for if by sensation we understand only a motion, occasioned by a check or resistance, we shall find the _sensitive_-plant is also possessed of it; if, on the contrary, we would have it signify to apprehend and compare ideas, we are not certain that brute animals possess it; if it is allowed to dogs, elephants, &c. whose actions seem to result from the same causes as those of men, it must be denied to an infinite number of others, especially to those which seem to be motionless. If we could give to oysters, for example, the same faculty of sensation as to dogs, though in an inferior degree, why should we not allow it to vegetables in a still lesser degree? This difference between animals and vegetables is not, therefore, general, nor well decided. A third difference seems to arise from their method of feeding. Animals, by the means of certain external organs, seize those things which are agreeable to them: they seek their pasture and chuse their food. Plants are reduced to the necessity of receiving such nutriment as the earth furnishes: they have no diversity in the manner of procuring it; no choice in the kind, but the humidity of the earth is their only aliment; nevertheless, if we attend to the organization and action of roots and leaves, we shall presently discover that there are in those parts external organs, which vegetables make use of to obtain their food; that the root avoids and turns from an obstacle, or vein of bad earth, to seek for one that is better; that they divide their fibres, and even go so far as to change their form to procure nutriment for the plant. The difference between animals and vegetables cannot, therefore, be established on the manner in which they receive their nutriment. This investigation induces us to conclude that there is no absolute essential and general difference between animals and vegetables, but that nature descends, by degrees imperceptibly from an animal which is the most perfect, to that which is the least, and from the latter to the vegetable. The water polypus may therefore be considered as the line where the animal creation ends and that of plants begin. If, after having examined the distinctions, we search after the resemblances between animals and vegetables, we shall find the power of reproduction is general, and very essential to both; a faculty which would almost lead us to suppose that animals and vegetables are nearly of the same order of beings.