MRCS 1839, LSA 1839.
Lucas trained at the Westminster Hospital, London. He was a general practitioner, practicing in the 1840s in Milford, Pembrokeshire. By 1856 Lucas was practicing in Rusholme, Manchester, and he later moved to Withington, Manchester. In 1864-1866 a St John Welles Lucas of Withington was a medical pupil at MRI and Manchester Royal School of Medicine. This was probably Lucas' son, but he does not appear to have practised medicine.