PARIS, John Ayrton. PHARMACOLOGIA OR THE HISTORY OF MEDICINAL SUBSTANCES WITH A VIEW TO ESTABLISH THE ART OF PRESCRIBING AND OF COMPOSING EXTEMPORANEOUS FORMULAE UPON FIXED AND SCIENTIFIC PRINCIPLES. London: W. Phillips, 1820. Fourth edition, much enlarged. 578 pp. Quarto. Original paper-covered boards with old repair work to spine: a "new" cloth back was laid down some time ago to reattach the boards. Hand-lettered spine labels. Ex-Library, with ink-stamps to front endpaper and page 50. Text leaves are lightly foxed throughout and untrimmed. Good plus.