Two previously unpublished letters by John Thelwall offer us a window into the understudied topic of his work in the field of speech pathology, a venture to which he dedicated three decades of his life. In the fall of 1810, and again in the early summer of 1811, Thelwall wrote detailed reports to Dudley Ryder, the 1st Earl of Harrowby (1762–1847) about the progress Ryder’s son was making at Thelwall’s ‘Institution for the Cure of Impediments, the Remedy of Organic Defects, and Preparation of Youth for the Pulpit, Bar, & c’. A Tory and close friend of Thelwall’s nemesis William Pitt, Ryder seems an unlikely Thelwall client, but he was a politically progressive Tory, and even supported electoral reform. Still, the fact that a Pittite Tory would trust his son to Thelwall’s care indicates that the notorious radical found some success in his reinvention at the opening of the nineteenth century: from the infamous ‘Jacobin Fox’ hounded by the Home Office and vilified by the loyalist press, he refashioned himself ‘John Thelwall, Esq., Professor of the Science and Practice of Elocution’. This new Thelwall emerged in the early 1800s, though his interest in science was apparent a decade earlier. A lifelong autodidact, Thelwall dabbled in anatomy in the early 1790s, and was elected a member of the Physical Society of Guy’s Hospital in London, where he gave lectures on ‘animal vitality’ and the ‘origin of mental action’. It was after the Pitt ministry hounded him out of public politics that Thelwall returned to his early interest in science. Driven ‘into temporary retirement’, he recalled, ‘former trains of reflection were gradually renewed; and the treasured remembrances of anatomical and physiological facts, mingling with the impressions that had resulted from the oratorical habits of twelve preceding years’, led to the discovery, Thelwall claimed in a Frankensteinian flourish, of ‘some of the most hidden mysteries of the Science of Human Speech’. Thelwall was one among many contemporary elocutionists, but what distinguished his work, what revealed those hidden mysteries, was his corollary interest in anatomy and physiology. The Romatic-era culture of popular medical study allowed amateurs like Thelwall, operating outside of university settings, to develop novel areas of medical expertise. London, in particular, had a ‘climate of intellectual pluralism’, notes Roy Porter, that ‘allowed new medical specialties to flourish’. It was the new field of speech pathology that emerged from the disciplinary meeting that Thelwall described as his ‘Union of Physiological and Elocutionary Science’. If the energy of amateur scientific endeavor in