i8o Rohertson: The Plant Cell. 



that he always has in mind a certain sand of a specified degree 

 of fineness. Leeuwenhoek's observations were apparently 

 quite discredited in England until Robert Hooke confirmed 

 the existence of these 'infusoria,' and exhibited them under 

 his microscope in 1667 at a meeting- of the Royal Society. The 

 importance of this observation was felt to be so great, that a 

 document attesting to its truth was drawn up and signed by all 

 those who were satisfied on the evidence of their own eyesight. 

 Two years earlier, Robert Hooke had published a book called 

 the ' Micrographia,' in which he figures the cellular formation 

 of various plant tissues, such as cork and charcoal, which he 

 had observed under his compound microscope. His description 

 of his method of observation has some interest : — ' I took a 

 good clear piece of cork, and with a penknife, sharpen'd as 

 keen as a razor, I cut a piece of it ofl^, and thereby left the 

 surface of it exceeding smooth, then examining it very 

 diligently with a Microscope.'' The structures which Hooke 

 saw, and to which he gave the rather unfortunate name 'cells,' 

 from their resemblance to the compartments of a honey-comb, 

 were not the living cells at all, but the dead cell-walls. It was 

 probably because plant cells are characteristically clothed with 

 cell-walls, while animal cells, as a rule, are naked, that cells 

 were seen in plants before the}' were recognised in animals. 

 The existence of the li\ing jelly, protoplasm, which we now 

 know to be the essential part of the cell, corresponding to the 

 honey in the honey-comb, was not realised in Hooke's day. 



The Italian, Marcello Malpighi, and the Englishman, 

 Nehemiah Grew, followed Hooke a little in point of time, but 

 have more claim than he to be regarded as the fathers of plant 

 histology. They were the first to begin to realise the real 

 importance of the cell. Grew's description of the structure of 

 the soft tissue of the root (in the book which he published in 

 1672, and modestly called ' The Anatomy of Vegetables begun ') 

 though it sounds quaint in our ears, yet shows that he had quite 

 a good idea of its nature. ' The Contexture of the Cortical 

 Body may be well illustrated by that of a Spoinye, being a Body 

 Porous, Dilative, and Pliable. Its Pores, as they are innumer- 

 able, so extream small. These Pores are not only susceptive of 

 so much moisture as to fill, but also to enlarge themselves, and 

 so to dilate the Cortical Body, wherein they are ; . . . . 'tis a 

 body also sufficiently pliable, or, a most exquisitely fine-wrought 

 Sponge.' Grew speaks with respect of his countryman, Robert 

 Hooke, saying in his chapter called 'Of the Trunk,' 'that 



Naturalist, 



