Note 21 — Chapter III · CATEGORIÆ.
Reading edition
Categor. p. 2, a. 15, seq. In Aristotle phraseology it is not said that Second Essences are contained in First Essences, but that First Essences are contained in Second Essences, i.e. in the species which Second Essences signify. See the Scholion to p. 3, a. 9, in Waitz, vol. i. p. 32.