Letter, from Antoni van Leeuwenhoek to the Royal Society, dated at Delft Signed autograph Theory that bark tissue is formed from the wood; cross sections and pictures of vessels and cells of bark and wood tissue from different species (eg lime, cinnamon, cherry, birch); cross sections and pictures of vessels and cells from cork Read to the Royal Society on 25 April 1705 16 figures in red chalk attached English translation is EL/L3/78 Transcribed and translated in 'Alle de brieven van Antoni van Leeuwenhoek', edited, illustrated and annotated by Committee of Dutch Scientists, vol 15, p 157 English translation printed in 'Philosophical Transactions', vol 24, no 296, p 1843 27 March 1705