Observations and experiments on the use of enemata, and the external application of medicines to the human body : being an inaugural thesis, submitted to the examination of the Rev. John Ewing, S.T.P. provost, the trustees, and medical faculty of the University of Pennsylvania, on the 22d day of May, 1798, for the degree of Doctor of Medicine. / By John Hahn, of Pennsylvania, honorary member of the Philadelphia Medical and Chemical Societies.