HELMONT, Jan Baptista. Ortus Medicinae. -- Opuscula medica inaudita. Amsterdam: Elzevier, 1652. 2 works in one vol. 4o. Engraved frontispiece (detached and laid down on front free endpaper). Contemporary calf (upper cover detached). Provenance: William Sydner Thayer; Institutional (bookplates). Brunet III:91; PMM 135 (1648 edition); Williams 1141.