Xavier Bichat

Marie François Xavier Bichat was a French anatomist and pathologist, known as the father of modern histology. Although he worked without a microscope, Bichat distinguished 21 types of elementary tissues from which the organs of the human body are composed. He was also "the first to propose that tissue is a central element in human anatomy, and he considered organs as collections of often disparate tissues, rather than as entities in themselves". The buccal fat pad was named after him.