Monsieur Constantin Hugens of Zulichem was pleased to shew me the Comparative Anatomy of the Trunks of Plants, written by Doctor Grew, and told me, that he had very ingeniously and learnedly discoursed upon that subject; though I, by reason of my unskillfulness in the English Tongue, could have little more than the contentment of viewing the elegant Cuts.

I have formerly written unto you, viz. in my Letter of August 15 1673. That I had discovered in several Trees (1) two sorts of vessels or pores, and did conceive, that the matter which serves for the increase of Trees was in (2) the greater vessels sent upwards, and that some small particles did again descend in the smaller Vessels to the roots, whereby was maintained a (3) Circulation also in Trees.

But not finding by the figures of Dr. Grew, that he hath discover’d those (4) two sorts of Vessels in the wooddy>woody part, I here take (654) the liberty of sending you the Eight part of the transverse Slice of an Ash-sprig of a years growth; and shall withall acquaint you, that besides those two sorts of Vessels in wood, I have discover’d a (5) third sort; these two going directly upward, and this third issuing out of the middle or the pith, going horizontally to the circumference: So that the (6) whole body of Wood hitherto viewed by me, consists of nothing but finall hollow pipes.