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 effort to give as clear a representation as possible of what he sees. Though he too everywhere introduces physiological considerations into his anatomical investigation, yet he keeps himself free from many preconceptions which his successors imported in this way into phytotomy. To mention one point by anticipation, he avoided the erroneous notion so common at a later time, and first definitively removed by von Mohl in 1828, that the cell-walls must have visible openings to serve for the movement of the sap.

Grew's work, as has been said, separates into two main divisions; the first, 'The anatomy of plants begun, with a general account of vegetation founded thereupon,' was printed in 1671, and contains a brief and rapid account of the general anatomy and physiology of plants in forty-nine folio pages. Then the anatomy of roots, stems, leaves, flowers, fruits and seeds appeared as separate treatises in the following years up to 1682. We may pass over the chemical researches embodied in this work and the enquiries into the colours, taste and smell of plants, as well as the previously issued treatise, 'An idea of a philosophical history of plants,' which, as it was first laid before the Royal Society in 1672, we may imagine to have been intended as a counterpart to Malpighi's 'Anatomes plantarum idea,' though it is very different in character and admits much that is foreign to vegetable anatomy and physiology.

With Grew as with Malpighi the main point of enquiry is not the individual cell, but the histology; after distinguishing, like Malpighi, between the parenchymatous tissue and the longitudinally elongated fibrous forms, the true vessels and the sap-conducting canals, he is chiefly bent on explaining the combination of these tissues in the different organs of the plant; and in this point he is superior to Malpighi both in carefulness of description and in the beauty of his delineations. Grew's numerous figures on copper plates, more carefully executed than Malpighi's, give in fact so clear an idea especially