A letter to Henry Cline, Esq., on imperfect developments of the faculties, mental and moral, as well as constitutional and organic; and on the treatment of impediments of speech

London: Richard Taylor, 1810. FIRST EDITION. Plain boards rebacked in dark calf, spine in compartments with morocco spine label; new endpapers, half-title glued to the verso of the fly-leaf in the gutter with small tear to upper left corner. A fine uncut copy. First edition of one of the earliest works on mental deficiency and one of Thelwall’s scarcest titles. “Thelwall recognized that sensory deprivation could be a cause of apparent mental defect through his work with handicapped children. He established criteria for distinguishing between intellectual capability and performance” (G&M).

Thelwall (1764-1834) showed little desire to operate his father’s silk merchant business after he died, instead being drawn to literature and the arts. His interest in radical politics grew with the French Revolution. After the turn of the century, Thelwall settled down as a teacher of oratory, gradually concentrating his attention upon the cure of stammering and more generally upon the correction of defects arising from malformation of the organs of speech. He was remarkably successful.

Cline (1750-1827), under whom Thewall studied and became lasting friends, was a lecturer in anatomy and medicine and president of the Royal College of Surgeons.

DNB, XIX, pp. 591-593; Garrison-Morton 4969.2. Hunter & Macalpine, pages 656-657.