The Royal Society read part of Letter L-173 about bone and wood

June 5, 1686

Birch, History, vol IV, p. pp. 485-86, 26 May 1686 (O.S.) in London:

Part of a letter of Mr. LEEWENHOECK was read, giving an account of the texture of bone, observed in his microscopes, which he found to be composed of four several sorts of pipes or vessels running lengthwise, and ranged in circles about the cavity, and proposing an analogy between the growth of bones and that of wood by the accession of new circles, as it is annually in trees, and comparing the periosteum to the bark of the tree.