For this use of πνεύματα as applied to the senses, we may cite Plutarch (De placitis philosophorum, iv. 21), who, speaking with reference to the Stoic philosophy, says, ἡ μὲν ὅρασις ἐστὶ πνεῦμα διατεινον ἀπὸ τοῦ ἡγεμονικοῦ μέχρις ὀφθαλμῶν.