I have passed over these three treatises in a somewhat cursory fashion, because Nehemiah Grew's botanical work is perhaps better studied in his final pronouncement on the subject,--a folio volume published in 1682 under the title of "The Anatomy of Plants. With an Idea of a Philosophical History of Plants. And several other Lectures, Read before the Royal Society." This work consists of second editions of his three earlier treatises, largely rewritten, with a great deal of additional matter, including a section on the anatomy of flowers, and many new figures. Some of the plates are excellent, and especially remarkable for the way in which Grew shews the anatomy in drawings which represent the organ in three dimensions (Pl. 7). He himself laid great stress on this. In his own words, "In the _Plates_, for the clearer conception of the _Part_ described, I have represented it, generally, as entire, as its being magnified to some good degree, would bear.... So, for instance, not the _Barque_, _Wood_, or _Pith_ of a _Root_ or _Tree_, by it self; but at least, some portion of all three together: Whereby, both their _Texture_, and also their Relation one to another, and the _Fabrick_ of the whole, may be observed at one _View_." One cannot help wishing that botanists of the present day would more often take the trouble to illustrate their papers on this principle.
A page from _The Comparative Anatomy of Trunks_, Nehemiah Grew, 1675. The annotations are believed to be in the author's own handwriting. [British Museum. Printed Books Dept. (_972.a.10_)]]
It is as a plant anatomist that Grew is chiefly famous, and it is important to try to realise exactly how far his conception of the anatomical structure of plants has been confirmed by 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 microscope, 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 confirmed 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.