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 52 the foot we find the note "Air-Vessels out of Parenchyma, transformed, as Caterpillars to Flys," shewing that Grew had arrived at some idea of the formation of vessels. The whole section of the book to which this page belongs is very much remodelled in the 1682 edition, but the analogy just quoted is introduced and Grew proceeds accurately to describe the origin of vessels. "And as the Pith it self, by the Rupture and Shrinking up of several Rows of Bladders, doth oftentimes become Tubulary: So is it also probable, that in the other Parenchymous Parts, one single Row or File of Bladders evenly and perpendicularly piled; may sometimes, by the shrinking up of their Horizontal Fibres, all regularly breakone [sic] into another and so make one continued Cavity."

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.

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