Agnes Arber

“ Grew devotes a good deal of space to the study of seed structure, dealing chiefly with such features as can be observed with the naked eye (Pl. 5) . He invented the term "radicle" for the embryonic root, and used the word "plume" for the organ which we now speak of in the diminutive as the plumule. The cotyledons he called "lobes," but he recognised that they might in some cases appear above ground and turn green, becoming in his terminology "dissimilar leaves." ”

“ Although Grew cannot be called a great experimenter, he frequently took the easier course of throwing out suggestions for such work. "The generation of Experiments" he describes as "being like that of Discourse, where one thing introduceth an hundred more which otherwise would never have been thought of." ”

“ To give any kind of short summary of Grew's botanical work is well-nigh impossible. Some men are remembered for individual discoveries, and in such cases it is not difficult to give a précis of their contributions. But Nehemiah Grew is remembered because, contemporaneously with Malpighi, he actually created the science of plant anatomy,—a subject which, before his day, was practically non-existent. ”

“ It is usual to regard Ecology as a very recent development of botanical science, but Nehemiah Grew seems to have been alive to the importance of the ecological standpoint,—though he did not describe it by this name. ”

“ The pressure also expressed a certain amount of sap from the pith, where vessels were absent, but here the sap was not sucked in again when the root was no longer squeezed, shewing that the liquid had only been forced out by the wounding of the cells. Had they been open tubes like the vessels, the release of the pressure would have caused the sap to disappear. Grew recognised that the vascular tissue of the root is centrally placed, whereas in the stem it is circumferential, and he points out that this difference is connected with the diverse mechanical needs of the two organs. ”

“ As the Plant grows, it will follow, that at length the Stalk will rise upward, and the Root on the contrary, arch it self downward. Which evidently shews, That it is not sufficient, that the Root hath Earth to shoot into, or that its Motion is only an Appetite of being therein lodged, which way soever that be: but that its nature is, though within the Earth already, yet to change its Position, and to move Downwards. And so likewise of the Trunk, that it rises, when a Seed sprouts, out of the Ground, not meerly because it hath an Appetite of being in the open Aer ”

“ Amongst other details of root anatomy, Grew discovered that all the tissues outside the central cylinder sometimes peel off when the root becomes old, or as he says, "the whole body of the Perpendicular Roots, except the woody Fibre in the Centre, becomes the second skin." Turning to stem structure, we find that he understood the difference in origin between stem buds and adventitious roots. ”

“ Whereas the Bones of Animals, being joynted, are made Inflexible."
In plants, as in animals, Grew looked for "vessels," and discovered by means of a simple experiment that continuous tubes, worthy of being called by this name, existed in the outer parts of the root, whereas the pith consisted of closed chambers. He cut a fresh root transversely, and then gently pressed the side of it with his finger nail. He was able to detect the vessels with the naked eye, and he observed that where they occurred, sap oozed out under pressure, but was sucked in again when the pressure was removed. ”

“ Ancestry and Life narrative—his versatility—state of Botany—Grew and Malpighi—Grew's bona fides vindicated—The Anatomy of Vegetables Begun—seed structure—his treatise on the Root—its dedication—The Anatomy of Trunks—The Anatomy of Plants—illustrations—Grew's conception of cells and tissues—the plant as a textile fabric—analogy with the animal body—medullary rays—secondary thickening—his understanding of external morphology—physiological notions—suggestions for experiments—importance of the habitat—the sexes of flowers—floral and seed structure—estimate of his contributions to Botany. ”

“ He quotes with approval Hooke's description of Elder-Pith as "an heap of Bubbles" It would be unsafe however 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 continuous 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 ”

“ His idea, which is somewhat confusing, is perhaps best understood from his comparison of plant structure with pillow lace. The "most unfeigned and proper resemblance we can," he writes, "at present make of the whole Body of a Plant, is, To a piece of fine Bone-Lace, when the Women are working it upon the Cushion, For the Pith, Insertions [2] , and Parenchyma of the Barque, are all extream Fine and Perfect Lace-Work: the Fibres of the Pith running Horizontally, as do the Threds in a Piece of Lace ”

“ Amongst other proposals he recommends that trial should be made of growing plants in common water, snow water, milk, oil, wine, ink, etc., or in any of these with solid bodies, such as nitre and salt, dissolved in them. He points out that the effect both on the plant and on the liquid should be noted. The solid body should be weighed before solution, and then, after the experiment is over, the liquid should be evaporated and the solid again weighed. ”

“ It shews how strong the influence of fashion can be, when we find such bombast coming from the pen of a man who, only a few lines earlier, has written, with the perfection of simplicity, "Withal, I looked upon Nature as a Treasure so infinitely full, that as all men together cannot exhaust it ”

“ 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 ”

“ The mystical belief that characteristic "principles" permeate all things, finds expression in his idea that the "frost flowers," sometimes to be seen on a window pane, are evidence that the air is impregnated with "Vegetable Principles." ”

“ Great however as were his actual contributions to botanical knowledge, they were perhaps less important than the far-reaching service which he rendered in helping to free biological thought from the cramping belief that the one and only object of the existence of the organic world was for the use and pleasure of man. ”

“ 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 ”

“ Grew believed that the "Outward Elegancies of Plants" might be for the purpose of giving delight to the human race, but he was the first to point out that as the "Inward Ones, which, generally, are as Precise and Various as the Outward," are so seldom seen, their purpose can hardly be for this, but must be for the benefit of the plants themselves, "That the Corn might grow, so ”