BOOK THE THIRD.
Note 1, p. 131. The sentient organs, however, are con-
stituted, &c.] The senses were formed, according to that age, from the elements—as the hearing from air, and the eye, which alone was supposed to have a special organ, from the purest part of the fluid secreted by the brain; and vision is the result, according to Aristotle, of refraction. Thus, Democritus was held to be right in saying that the eye is water but to be wrong in supposing vision to be caused by reflection, (τὸ ὁρᾶν εἶναι τὴν ἔμφασιν) as vision is, not in the eye but, in the percipient; for "vision is re-
fraction" (ἀνάκλασις γὰρ τὸ πάθος). Aristotle shews that, according to the admitted doctrines, these two elements only constitute the sentient organs of all animals which are perfect; and adds, as if to guard against a possible objection, that the mole has eyes although they may not be very apparent. It is then argued that, unless there is some kind of body or mode of impression different from all
- De Sensu et Sens. 2. 10.