2 INTRODUCTION TO CYTOLOGY 



The Discovery of the Cell. Cytology may be said to have begun with 

 the discovery of the cell by Robert Hooke (1635-1703) in 1665. Hooke, 

 who lived in London and has been described as a man of eccentric appear- 

 ance and habits, showed a remarkably varied scientific activity. For a 

 time he was a professor of geometry, and later became an architect. He 

 performed many original experiments in mechanics and for a number of 

 years was curator of experiments to the Royal Society. His interest in 

 optics led him to examine all sorts of objects with the compound micro- 

 scope. In charcoal and later in cork and other plant tissues he found 

 small honeycomb-like cavities which he called "cells." He had no dis- 

 tinct notion of the cell contents, but spoke of a "nourishing juice," 

 which he inferred must pass through pores from one cell to another. 

 His many observations were embodied in his Micrographia (1665), a 

 large work illustrated with 83 plates. The chapter containing his re- 

 marks on cells is entitled "Of the schematisme or texture of cork and 

 the cells and pores of some other such frothy bodies." Quaint and crude 

 as it now appears to us, the Micrographia takes its place as the earliest 

 cytological classic. 



Three other names even more prominent in the early history of micro- 

 scopy are those of Malpighi, Grew, and Leeuwenhoek. Marcello Mal- 

 pighi (1628-1694), an Italian physiologist and professor of medicine at 

 Bologna, Pisa and Messina, is best known for his important pioneer work 

 in anatomy and embryology. Most of his observations on plants were 

 included in his Anatome Plantarum (1675) and had to do largely with the 

 various kinds of elements making up the body of the vascular plant. 

 Malpighi made a distinct step in advance in studying tissues with the 

 cell as a unit; a clear fore-shadowing of the Cell Theory is seen in his 

 remarks concerning the importance of the "utriculi" in the structure of 

 the body. At Pisa Malpighi was associated with G. A. Borelli, who was 

 one of the first to use the microscope on the tissues of higher animals. 



Nehemiah Grew (1641-1712) was an English physician and botanist. 

 He began a careful study of plant structure in 1664, and in 1670 read his 

 first important paper before the Royal Society. Further contributions 

 followed at intervals until 1682, when all of them were published under 

 the title The Anatomy of Plants. Like Malpighi, an abstract of whose 

 first work on plants was presented to the Royal Society in 1671, Grew was 

 interested in tissues, and gave particular attention to the combinations 

 of these tissues in different plant organs. He was strongly impressed 

 by the manner in which the cells, which he also called "vesicles" and 

 " bladders," appeared to make up the bulk of certain tissues : " . . . the paren- 

 chyma of the Barque," he said, "is much the same thing, as to its con- 

 formation, which the froth of beer or eggs is, as a fluid, or a piece of fine 

 Manchet, as a fixed body" (p. 64). He further believed the walls of 

 the cells to be composed of numerous extremely fine fibrils : in the vessels 



