savour is among tangible qualities. Hunger and thirst are desires: the former for what is dry and warm, the latter for what is liquid and cold ; and savour is the condiment, as it were, for both. As, however, we shall be more explicit upon those points hereafter, it may, for the present, suffice to say, that all such creatures as have the sense of Touch have appetite ; it is uncertain whether or not they have imagination, but this also shall be considered hereafter. There are creatures to which, besides those faculties, locomotion has been imparted; and others again, as man, to which have been allotted both reflexion and mind, together with any other and yet nobler faculty, if such there be, than mind.
It is clear, then, that there can be but one definition for Vital Principle, as there is but one for a geometrical figure; for as in geometry there is no figure but the triangle and its sequences, so neither are there any kinds of Vital Principle save those which have been enumerated. Could there, however, be any such common expression for figures, as without being peculiar to any one, should yet be applicable to all, so might there be for the Vital Principles alluded to. It would be idle, however, to seek for any such expression, in the case either of Vital Principles or geometrical figures, as should neither be applicable to any one of them individually, nor, putting aside individuals, be applicable to them as an
