The cells of Robert Hooke: pores, fibres, diaphragms and the cell theory that wasn't

Abstract

The early microscopist Robert Hooke (1653–1703) is commonly credited with the discovery and naming of biological cells in the course of his studies of plant tissues. Surprisingly, the theoretical context of this apparent discovery is rarely evaluated when Hooke's contribution to the development of modern biology is discussed. Hooke worked within the conceptual framework of the developing fibre doctrine, and consequently interpreted plant and animal structures as solid yet porous materials that directed and regulated the movements of fluids. The strength of his theory-derived expectations is exemplified by his postulate of valve-like passages in plant cell walls despite his admitted inability to detect any. Neglecting Hooke's theoretical background, modern commentators regularly misread important parts of his anatomical works. This shows, for instance, in the common assertion that Hooke used pore and cell interchangeably when in fact they represented the whole and its part, or in the claim that his cells were closed structures. Here I present a reconstruction of what Hooke and contemporary scholars meant when they spoke of cells in plant materials, namely elements of continuous pipes for fluid transport, and evaluate alternative interpretations.