Note 28 — ERRATUM. p. 78, note 1, l. 19; for “were in orders, for the most part in holy orders;” read “were generally speaking in holy orders;”

Held by Gilbert, and attributed to Averroes; but older than Averroes. In turning to Francis Bacon’s hypothesis I read (Ed. E. and S. ii. 263. Hist. Densi et rari—chapter, “Dilatationes per spiritum innatum se expandentem,” a Paracelsian sort of chapter) “Pulsus cordis et arteriarum in animalibus fit per irrequietam dilatationem spirituum, et receptum ipsorum, per vices.” The muscular quality of the heart was known to Galen, forgotten, and rediscovered. Spiritus vitalis, for Bacon, was “aura composita ex flamma et aere” (cf. Æn. vi. 747). Glisson has been fortunate in two generous judges, in Haller and Virchow; it would ill become me to depreciate a distinguished Fellow of my own College, and as a clinical observer Glisson had considerable merits; but as a physiologist he was sunk in realism. He was happy in the invention of the technical term “irritability,” but for him this virtue was as metaphysical an essence as the vital spirit; his prime motor was not physical. As a philosopher I fear the independent reader of his works will find him fanciful and wearisome.