ROBERT HOOKE 53 



more recent research. In appraising his work it must be 

 remembered that he was essentially the pioneer of the science. 

 It is true that some observations on plant anatomy occur in 

 Robert Hooke's Micrographia, which was published six years 

 before Grew sent in his first manuscript to the Royal Society ; 

 but Hooke never really attempted to make a systematic study of 

 the subject. He had succeeded in greatly improving the micro- 

 scope, and his chief interest was in applying his instrument to 

 all kinds of bodies, vegetable and otherwise. Cork, charcoal, 

 pith, etc., came under his observation, and to some extent he 

 understood their structure. Grew acknowledges indebtedness 

 to "the Learned and most Ingenious Naturalist M r Hook" and 

 tells us that some of the results which Hooke obtained, inspired 

 him to study certain of his plants again with a better microscope. 

 For instance Hooke was able to see smaller pores in wood than 

 Grew had been able to detect, but, with better glasses, he con- 

 firmed the accuracy of Hooke's observation. However, although 

 Hooke must certainly be credited with priority in the discovery 

 of the fact that plant tissues are characterised by a cellular 

 structure, his botanical work, considered in its entirety, is of very 

 slight significance compared with that of Grew. 



Grew's clearest account of plant cells is perhaps to be found 

 in his description of root parenchyma, which he compares to 

 "the Froth of Beer or Eggs" or to "a fine piece of Manc/iet 1 " 

 or again, to " a most curious and exquisitely fine-wrought 

 Sponge." He quotes with approval Hooke's description of 

 Elder -Pith as " an heap of Bubbles" It would be unsafe how- 

 ever to conclude that he had really arrived at what is known as 

 the Cell Theory. His conception of the nature of plant tissues 

 was not by any means that of the modern botanist. He believed 

 the cell-walls to consist of interwoven fibres, which were con- 

 tinuous from cell to cell. He did not consider that these fibres 

 were invariably wrought together in such a fashion as to enclose 

 bladder-like spaces, or cells ; in some cases he held that the 

 tissue was non-cellular, consisting simply of interwoven fibres. 

 It was these hypothetical fibres, rather than the cells, which he 



1 Manchet = a loaf of fine wheaten bread. (An Etymological Dictionary of the 

 English Language. W. W. Skeat. New ed. 1910.) 



