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CH. III.] individual species. But still there is an analogy between the faculties of Vital Principle and geometrical figures; for as in vital properties, so in geometrical figures, the antecedent is ever present potentially in the sequences, and as the triangle is in the square, so the nutritive is in the sentient faculty. Thus, the inquiry must be conducted with reference to individuals, in order to learn what is the Vital Principle of each, as of a plant, a man, or a brute; and wherefore beings are thus ranged in a series.

Without the nutritive function there can be no sensibility, but in plants the nutritive exists without the sentient; so again without the Touch there can be no other sense, while Touch can exist alone, for many animals have neither sight nor hearing, and are altogether without smell. Among sentient creatures some have and some have not locomotion, and, finally, to a few calculation and judgment have been imparted; and to such among mortal beings as are so endowed all other faculties have been imparted likewise. But to such as possess some one only of the faculties, calculation has not been allotted, as some of them have not even imagination, while others live by it alone; it would be foreign to our present inquiry to enter upon the speculative intellect.

It is, then, clear that the definition which comes closest to each one of those faculties is also the fittest for the elucidation of Vital Principle.