On Breath
On Breath (Greek: Περὶ πνεύματος; Latin: De spiritu) is a philosophical treatise included in the Corpus Aristotelicum but usually regarded as spurious. Its opening sentence raises the question: "What is the mode of growth, and the mode of maintenance, of the natural (or 'connate': emphutos) vital spirit (pneuma)? " == Authorship == Among the ancient catalogues of Aristotle's works, a work On Breath (but in three books, not one) is listed only by Ptolemy-el-Garib, and Pliny the Elder (N.H. XI.220) and Galen (De simpl.