Phrenologist, born in Trèves; went to study medicine at Vienna; attended the lectures of Gall and became a disciple, accompanying him on a lecturing tour through Central Europe, and settling with him in 1807 in Paris; in 1813 he separated from Gall, and went to lecture in England with much acceptance; in 1832 he proceeded to America with the same object, but he had hardly started on his mission when he died at Boston; he wrote numerous works bearing on phrenology, education, &c. (1776-1832).