born Nov. 11/14, 1771, Thoirette, Fra. died July 22, 1802, Lyon French anatomist and physiologist. In addition to bedside observations of patients, he conducted autopsies to study the changes disease causes in various organs. With no knowledge of the cell as the functional unit of living things, Bichat was among the first to see the organs of the body as being formed through the specialization of simple, functional units (tissues). Without using a microscope, he distinguished 21 kinds of tissues that, in different combinations, form the organs of the body. His systematic study of human tissues helped create the science of histology