Cork

On March 25 (1663) Hooke was “solicited” – that is, instructed – by the Royal Society to conduct microscopical observations and demonstrate them to the fellows. . . . . On April 8 he “delighted” the fellows by showing them common moss under the microscope. The following week he brought in thin slices of cork, cut in both transverse and perpendicular slices. The fellows observed that viewed under the microscope the cork was made up of empty spaces surrounded by walls. Hooke later recalled,

“I with . . . [a] sharp Pen Knife, cut off from the former smooth surface an exceeding thin piece of it, and placing it on a black object Plate, because it was it self a white body, and casting the light on it with a deep ‘plano-convex Glass,’ I could exceedingly plainly perceive it to be all perforated and pores, much like a Honey-comb, but that the pores of it were not regular. . . .”

He next cut a piece at right angles from the first piece, discovering that the pores “were not very deep, but consisted of a great many little boxes, separated out of one continued long pore, by certain ‘diaphragms”. No one had ever seen these spaces before, or imagined them to exist. Hooke called these box-like pores “cells” because of their resemblance to monks’ chambers. By his careful sectioning the cork, he had discovered the named cells, the building block of all life. ~ Page 198