The cells of Robert Hooke: wombs, brains and ammonites

Abstract

Robert Hooke (1635–1703) is commonly credited for introducing the term cell into biology when describing the microscopic structure of plant tissues in his Micrographia of 1665. This narrative ignores that, at the time, cell was an established term denoting linearly arranged elements of structures with functions in the storage, modification and transport of materials (e.g. the uterus, colon, brain, etc.). In analogy to the cells of these organs, Hooke interpreted plant cells as elements of continuous tubes for the storage and regulated movement of vital fluids. Hooke also was one of the few British natural philosophers who regarded ‘serpentine-stones’, the fossilized chambered shells of cephalopods (e.g. ammonites) that seemed to lack living counterparts, as remnants of organisms. He considered Nautilus a living serpentine-stone and referred to the chambers in its shell as cells, postulating that gas and liquid were transported along and stored within these cavities for buoyancy regulation. Hooke published this theory in 1696, but probably developed it much earlier. In Micrographia , he described ammonite cells just before plant cells, suggesting an overlooked rhetoric function of his report of cells in plants. By visualizing microscopic equivalents of macroscopic cellular structures for the first time, Hooke reinforced the common notion that living matter generally was characterized by such structures. Consequently, the presence of cells in serpentine-stones implicitly supported his organismic interpretation of these fossils.