Autograph Letter Signed, to Dr. Marcet, Russell Square, introducing Dr. Alison “eldest son of the celebrated author”, and bearer of this letter. 2 pp. 9 x 7 inches, fine, with the address leaf. 5 George Street, Edinburgh, 13 July 1817. “When may we expect the appearance of your work on Calcule? I feel some interest in this as it is a subject which I have occasion to consider every year in my Lectures.” The uncommon autograph of John Thomson (1765-1846), physician and surgeon. He taught surgery as well as the nature and treatment of diseases and injuries familiar to military surgeons. Thomson was also a prolific writer and his major works included: Elements of Chemistry and Natural History (3 vols.; 1798 – 1800) which ran to five editions and Lectures on Inflammation: a View of the General Doctrines of Medical Surgery (1813) which was translated in German (1820) and French (1827) as well as being issued in America (1813 and 1817).