great number of _Fibres_ together; and every _Pore_, being not meerly a space betwixt the several parts of the Wood, but the _Concave_ of a _Fiber_." He noticed the medullary rays, for which he uses the expressive term "Insertions." "These _Insertions_," he says, "are likewise very conspicuous in Sawing of _Trees_ length-ways into Boards, and those plain'd, and wrought into _Leaves_ for _Tables_, _Wainscot_, _Trenchers_, and the like. In all which, ... there are many parts which have a greater smoothness than the rest; and are so many _inserted Pieces_ of the _Cortical Body_; which being by those of the _Lignous_, frequently intercepted, seem to be discontinuous, although in the _Trunk_ they are really extended, in continued Plates, throughout its Breadth." Nehemiah Grew was interested in the process of secondary thickening, but he only arrived at a dim notion of how it took place. He grasped, however, the important point that in a tree trunk the meristematic zone lies near the surface, "the young _Vessels_ and _Parenchymous Parts_" being formed annually "betwixt the _Wood_ and _Barque_." He describes how, "every year, the _Barque_ of a _Tree_ is divided into Two Parts, and distributed two _contrary_ ways. The outer Part falleth off towards the _Skin_; and at length becomes the _Skin_ it self.... The inmost portion of the _Barque_, is annually distributed and added to the _Wood_; the _Parenchymous Part_ thereof making a new addition to the _Insertions_ within the _Wood_; and the _Lymphæducts_ a new addition to the _Lignous pieces_ betwixt which the _Insertions_ stand. So that a _Ring_ of _Lymphæducts_ in the _Barque_ this year, will be a _Ring_ of _Wood_ the next; and so another _Ring_ of _Lymphæducts_, and of _Wood_, successively, from year to year." Exactly what Grew meant by the term "Lymphæduct" is not always clear. In some cases he seems to refer to the phloem and cambium by this name, and in other cases to the perimedullary zone. The annual rings in Oak, Elm, Ash, etc. came under his observation, and he remarks that the difference between the Spring and Autumn wood, as we should now call it, arises from the fact that "the _Aer-Vessels_ that stand in the inner _margin_ of each annual _Ring_, are all vastly bigger, than any of those that stand in the outer part of the _Ring_." [Illustration: _Plate VII_ From Grew's _Anatomy_ Sheweth the Parts of a Goosberry Part of a Vine Branch cut transversly, and splitt half way downe y^e midle]