Twyble, Ellsworth2017-12-212017-12-211945194599208480211301161https://hdl.handle.net/2144/26076Thesis (M.D.)--Boston Universityen-USBased on investigation of the BU Libraries' staff, this work is free of known copyright restrictions.Ulcerative colitisThe etiology of chronic ulcerative colitisThesis/Dissertation