The influence of physicians and surgeons on Leeuwenhoek's observations of crystal formation.

Crystals, such as quartz, table salt various gems and snowflakes, were noticed and documented by humankind for as long as we have records, but it took the development of microscope lenses to observe crystallization in detail. Robert Hooke used his 30X power compound microscope to describe crystals in his 1665 master work Micrographia. Leeuwenhoek was a Delft haberdasher, town hall chamberlain and metrologist, and creator of the world's most powerful microscopes until the last quarter of the 19th-century. He was the first person to observe and document dynamic crystallization and sublimation processes. Antoni Leeuwenhoek observed and documented the processes of crystallization and sublimation in dynamic detail, documenting the changes in letters to The Royal Society and to others. Unlike Hooke, who attended Oxford University, Leeuwenhoek was from the Dutch mercantile class and had little formal education. He is thought to have acquired a copy of Micrographia and, possibly inspired by Hooke's observations, would send improved descriptions to The Royal Society of materials Hooke had described (for instance, various fungi and insect parts). Hooke could not have been his only influence, as Leeuwenhoek's observations seem to concentrate on crystals forming from herbaceous materials used by physicians and found in an apothecary. The highly detailed nature of his observations also hints at influences, probably provided second-hand by some of his physician friends, at other influences. He documented these processes with his usual poetic flair, and his usual tendency to observe anything he thought might be interesting, including crystals found in plants and those found in gout sufferers. He sketched out what he saw, although he knew his drawing skills were poor, a fact he related in his correspondence. Examples of his observations, including illustrations and relevant comments from the various editors of his collected letters, are presented.