Surprise of the Century—Three More Leeuwenhoek Microscopes
Brian J. Ford
University of Cardiff , Cathays Park , Cardiff CF10 3XQ , Wales , and Gonville & Caius College , Cambridge University , Trinity Street , Cambridge CB2 1TA , England brianjford@cardiff
.ac.uk
Leeuwenhoek’s Legacy
Microscopes are envisaged as large and impressive items of equipment. A microscope symbolizes science. Everyone knows that microscopes can reveal hidden details that allow us to penetrate the otherwise invisible secrets of nature. Yet the science of microscopy originated with small and simple instru- ments. T e pioneer of microbiology was the Dutch microscopist Antony van Leeuwenhoek (1632–1723) whose life was meticu- lously spelled out by Cliff ord Dobell [ 1 ]. Leeuwenhoek used single lenses to explore the world of microbes. He mounted the lenses in microscopes little larger than a postage stamp. Nine microscopes of this standard design claimed to be made by him were known to have survived, and I described them all in my book Leeuwenhoek Legacy [ 2 ]. Now we have an extraor- dinary revelation: three new examples have come to light aſt er centuries during which all others were believed lost. Leeuwenhoek was a draper and town offi cial who discovered the world of microbes in 1674, using one of his tiny microscopes to observe lake water in which he described fl agellates such as Euglena and algae including Spirogyra . In the following year he studied blood and erythrocytes, calibrating them alongside a sand grain 1/30 inch in diameter. He found that human red blood cells were “somewhat less than” 8.5 micrometers (µm) across. T e living cells are actually 7.5 µm in diameter, showing how meticulous he was as an observer. In 1677 he recorded spermatozoa in a number of species; he also noted that although disc-shaped erythrocytes of humans have no cell nucleus, those of fi sh do contain a nucleus. In 1683 he certainly observed bacteria in tartar from the teeth, and also in feces. T at same year he identifi ed Giardia as an intestinal parasite. Many of his descriptions are so good that we can identify the organisms he described (including Vorticella, Stentor and Volvox ). By 1684 he had described the pointed needles of uric acid associated with gout. He correctly recognized that the crystals caused the painful symptoms. In the early 1700s he was studying diatoms and rotifers, discovering that rotifers could be revived from the dried state (which we now term anhydrobiosis).
Robert Hooke’s Micrographia
In 1981 I unearthed packets of original specimens that Leeuwenhoek sent to the Royal Society of London and which had not been investigated since [ 2 ]. Nobody could understand where Leeuwenhoek obtained his inspiration until I realized that the specimens he had sent to London were the same as Robert Hooke had described in his book Micrographia (and they were listed in the same order) [ 3 ]. Hooke’s book was the fi rst popular work on the microscope. It was published in 1665 and shortly thereaſt er Leeuwenhoek paid his only visit to London. Clearly he saw Hooke’s book, for I recognized the importance of a previously overlooked
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section of the Preface of the book which described how to grind lenses of high power and how to mount them in small metal plates … precisely the method that Leeuwenhoek was to use [ 2 ]. Leeuwenhoek’s Surviving Microscopes. T e fate of all the
microscopes leſt aſt er Leeuwenhoek died remains unresolved, though traditional historians confi dently list nine of them. For example, he bequeathed a box containing 26 silver microscopes to the Royal Society, and it was hoped that they might one day reappear. However, they were taken away by a celebrated Victorian surgeon, Sir Everard Home. Professor Derek de Solla Price concluded that they were melted by a fi re that destroyed
Figure 1: Much media interest in Leeuwenhoek followed my discovery of his specimens in 1981 [2], and this microscope was subsequently brought into the Boerhaave Museum in Leiden, Netherlands. It is the smallest of them all; the plates measure 17×34 mm. It was locked away in the museum for twenty years until it became the subject of a single paper in an obscure journal in 2002 [6].
doi: 10.1017/S1551929515000978
www.microscopy-today.com • 2015 November
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