Bichat, Marie Francois Xavier, bee SHAH, ma REE frahn SWAH gzah VYAY (1771-1802), was a French surgeon, anatomist, and physiologist. He was the first scientist to base anatomy and physiology on the study of tissues rather than of organs. Bichat was one of the founders of histology, the study of the minute structure of animal and vegetable tissues. He also urged the use of autopsies in studying diseases and performed more than 600 autopsies himself.