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Howard Gest - The Remarkable Vision of Robert Hooke (1635-1703): First Observer of the Microbial World - Perspectives in Biology and Medicine 48:2 Perspectives in Biology and Medicine 48.2 (2005) 266-272

The Remarkable Vision of Robert Hooke (1635–1703)

First Observer of the Microbial World

Department of Biology and Department of History and Philosophy of Science, Indiana University, Bloomington, IN 47405.
Robert Hooke played important roles in the early development of the Royal Society of London. As Curator of Experiments of the Society, he became a pioneering microscopist, prolific inventor, astronomer, geologist, architect, and an effective surveyor of the City of London following the Great Fire of 1666. Hooke's Micrographia (1665) revealed the microscopic structures of numerous biological and inorganic objects and became an important source of information for later studies. Aside from the body of detailed observations reported and depicted in Micrographia, the Preface is in itself an extraordinary document that exhibits Hooke's fertile mind, philosophical insights, and rare ability to look into the future.
What Galileo's Sidereus Nuncias had done for the telescope and its heavenly vistas, Hooke's Micrographia now did for the microscope. Just as Galileo did not invent the telescope, neither did Hooke invent the microscope. But what he described seeing in his compound microscope awakened learned Europe to the wonderful world within. . . .
—Daniel J. Boorstin (1986) [End Page 266]

Microscopic view of a mold colony described by Robert Hooke in 1665. The reproductive structures (sporangia) are characteristic of the microfungus Mucor. Sporangia in different stages are identified by the letters A, B,C, and D. Hooke included a scale reference; the length of the bar under the diagram represents 1/32 of an inch. Source: From 'Micrographia,' reproduced courtesy of the Lilly Library, Indiana University, Bloomington, Indiana.
Click for larger view
Figure 1
Microscopic view of a mold colony described by Robert Hooke in 1665. The reproductive structures (sporangia) are characteristic of the microfungus Mucor. Sporangia in different stages are identified by the letters A, B,C, and D. Hooke included a scale reference; the length of the bar under the diagram represents 1/32 of an inch.
Source: From "Micrographia," reproduced courtesy of the Lilly Library, Indiana University, Bloomington, Indiana.

Micrographia, published by Robert Hooke in 1665, is one of the great classics of science. It was the first publication that illustrated objects as seen in a microscope, and it included the first accurate description and depiction of a microorganism, the microfungus Mucor (Figure 1). Hooke's discovery of a microorganism was made long before Antoni van Leeuwenhoek reported the existence of bacteria and other single-cell microbes. It has become clear that, contrary to conventional wisdom, Leeuwenhoek's initial microscopic observations were not made in isolation, but were based on findings and technical details in Hooke's Micrographia (Ford 1991; Gest 2004 a, 2004b,).

Hooke's description of Mucor was one of 60 detailed "Observations," many of which were of diverse biological objects such as the head of a fly, a flea, an ant, the sting of a bee, the teeth of a snail, hair, surfaces of leaves, and a thin section of cork tissue. Hooke observed that cork and other plant tissues consisted of "a great many little Boxes," for which he introduced the word cells. He estimated that there were more than 1 million cells in a square inch of cork tissue. Since [End Page 267] Hooke had broad interests in nature, he used Micrographia to speculate on a variety of topics including: "Of diamonds in flints; Of fantastical colours; On the inflection of the rays of light in the air; Of the fixt stars; Of the moon."

The Head of a Fly

The style of Hooke's writing in Micrographia is exemplified by Observation 39, "The Head of a Fly." The index entry reads:

1. All the face of a Drone-fly is nothing almost but eyes. 2. Those are of two magnitudes. 3. They are Hemispheres, and very reflective and smooth. 4. Some directed towards every quarter. 5. How the fly cleanses them. 6. Their number. 7. Their order: divers particulars observ'd in the dissecting a head. That these are very probably the eyes of the Creature; argued from several Observations and Experiments, that Crabs, Lobsters, Shrimps, seem to be water Insects, and to be framed much like Air Insects. Several Considerations about their manner of Vision.

The text of Observation 39 is almost six pages long. The following short section (slightly abbreviated) shows Hooke's literary skill, and Figure 2 exemplifies his excellent ability as a draughtsman.

I took a large grey Drone-Fly that had a large head and cutting off its head, I fix'd it with the forepart or face upon my Object Plate. . . . I found this Fly to have the biggest cluster of eyes in proportion to his head of any small kind of Fly that I have yet seen . . . the greatest part of the face, nay, of the head, was nothing else but two large and protuberant bunches . . . the surface of each of these was shaped into a multitude of small Hemispheres, plac'd in a triagonal order, that being the closest and most compacted, and in that order, rang'd over the whole surface of the eye in very lovely rows . . . which I was assured of by the regularly reflected Image of certain Objects which I mov'd to and fro between the head and the light. . . . Every one of these Hemispheres reflects as exact, regular and perfect an Image of any Object from the surface of them, as a small Ball of Quick-silver of that bigness would do . . . in each of these Hemispheres I have been able to discover a Landscape of those things which lay before my window, one thing of which was a large Tree, whose trunk and top I could plainly discover, as I could also the parts of my window, and my hand and fingers, if I held it between the Window and the Object.

Toward the end of Observation 39, Hooke says:

We may be sure that the filaments or sensitive parts of the Retina must be most exceedingly curious and minute, since the whole Picture itself is such; what must needs the component parts be of that Retina which distinguishes part of an object's Picture that must be many millions of millions less than that in a man's eye? And how exceeding curious and subtile must the component parts of the [End Page 268] medium that conveys light be, when we find the instrument made for its reception or refraction to be so exceedingly small?
Head of a 'drone-fly' (dragon-fly). According to Hooke, there were close to 14,000 hemispheres in the eye.
   	Source: from 'Micrographia,' reproduced courtesy of the Lilly Library, Indiana University, Bloomington, Indiana.
Click for larger view
Figure 2
Head of a "drone-fly" (dragon-fly). According to Hooke, there were close to 14,000 hemispheres in the eye.
Source: from "Micrographia," reproduced courtesy of the Lilly Library, Indiana University, Bloomington, Indiana.

The Vision of Linceus

Under Hooke's name on the title page of Micrographia is a quotation from Horace's Epistles, Book 1:

Non possis oculo quantum contendere Linceus,
Non tamen idcirco contemnas Lippus inungi.

In English, the thought behind this quotation is

You may not be able to see as far with your eyes as Linceus,
But, if something were wrong with them, you would still put medicine on them.

Linceus was a mythological figure famous for his ability to see for extremely long distances. Hooke obviously chose this quotation because one of his great passions was the acquisition of new knowledge through the improvement of microscopes and telescopes. In the Preface to Micrographia, Hooke says: [End Page 269]

By the means of Telescopes, there is nothing so far distant but may be represented to our view; and by the help of microscopes, there is nothing so small as to escape our inquiry; hence there is a new visible World discovered to the understanding. By this means the Heavens are open'd and a vast number of new Stars and new Motions, and new Productions appear in them, to which the ancient Astronomers were utterly strangers. By this the Earth it self, which lyes so neer to us, under our feet, shews quite a new thing to us, and in every little particle of its matter, we now behold almost as great a variety of Creatures, as we were able before to reckon up in the whole Universe itself.

Hooke's Vision of Progress through Experimental Science

Hooke had unshakeable optimism in the prospect of obtaining useful knowledge through experimental research. As Curator of Experiments of the Royal Society from 1662 to 1677, Hooke's duties included conducting "considerable experiments" and demonstrations at meetings of the Society, and in this capacity he became an important influence on his contemporaries. Hooke's confidence in the power of experiment is emphasized in the Preface of Micrographia in several ways, for example:

If once this method were followed with diligence and attention, there is nothing that lyes within the power of human Wit or of human Industry, which we might not compass; we might not only hope for Inventions to equalize those of Copernicus, Galileo and others, but multitudes that may far exceed them. . . . Talking and contention of Arguments would soon be turn'd into labours; all the fine dreams of Opinions, and universal metaphysical natures, which the luxury of subtil Brains has devis'd would quickly vanish, and give place to solid Histories, Experiments and Works.

Hooke as Inventor

Biographies of Hooke emphasize his outstanding gifts as an inventor (Bernal 1965; Westfall 1972). The Preface of Micrographia contains long sections detailing Hooke's new inventions for improving microscopy and suggestions for possible devices to discover the "effluvia" (gaseous emanations) of the earth and for mea-suring the refraction of light rays.

Aside from details of practical experimentation, the main thrust of the Preface of Micrographia is to convince the reader that the future of inventions that will help explore and understand our world and the universe is unlimited:

From hence the World may be assisted with variety of Inventions, new matter for sciences may be collected, the old improv'd, and their rust rubb'd away; and as it is by the benefit of Senses that we receive all our Skill in the works of Nature, so they also may be wonderfully benefited by it, and may be guided to an easier [End Page 270] and more exact performance of their Offices; 'tis not unlikely, but that we may find out wherein our Senses are deficient, and as easily find wayes of repairing them.

The Indeavours of Skilful men have been most conversant about the assistance of the Eye, and many noble Productions have followed upon it; and from hence we may conclude, that there is a way open'd for advancing the operations, not only of all the other Senses, but even of the Eye it self; that which has been already done ought not to content us, but rather to incourage us to proceed further, and to attempt greater things in the same and different wayes.

'Tis not unlikely, that there may be yet invented several other helps for the eye, as much exceeding those already found, as those do the bare eye, such as by which we may perhaps be able to discover living Creatures in the Moon, or other Planets, the figures of the compounding Particles of matter, and the particular Schematisms and Textures of Bodies.

And as Glasses [lenses] have highly promoted our seeing, so 'tis not improb-able that, but that there may be found many Mechanical Inventions to improve our other Senses of hearing, smelling, tasting, touching.

Hooke expands on the possibilities and also makes some amazing predictions. Thus:

There may be also some other mechanical wayes found out, of sensibly per-ceiving the effluvia of Bodies; several Instances of which, were it here proper, I could give of Mineral steams and exhalations; and it seems not impossible, but that by some such wayes improved, may be discovered, what Minerals lye buried under the Earth, without the trouble to dig for them.

Hooke in Retrospect

Hooke's extraordinary versatility is clearly evident from The Posthumous Works of Robert Hooke, published two years after his death (Hooke 1705). This collection consists mainly of lectures given by Hooke at the Royal Society on a wide diversity of topics, including methods of advancing and promoting "Natural Philosophy" (science), the nature of light, geology, fossils, comets, gravity, magnetism, astronomy and navigation, the Boyle-Hooke air pump, and microscopical observations.

In a recent book on Hooke, London's Leonardo, M. Cooper comments that "Hooke's career was a virtuoso display of energy, genius, and probity across an astonishing variety of activities" (Bennett et al. 2003). He was a genuine polymath whose very active life was plagued by sickness, financial problems, and involvement in several notorious controversies regarding scientific priority (one with Sir Isaac Newton). This kind of a scenario has attracted some biographers to dwell excessively on Hooke's persona. However, a more balanced evaluation and appreciation of Hooke as an outstanding visionary scientist of great accomplishments will shortly be available in a book entitled Robert Hooke and the English [End Page 271] Renaissance (Kent and Chapman 2004). This is the product of the Robert Hooke Tercentenary Commemoration Symposium held at the University of Oxford on October 2, 2003. The Symposium was largely devoted to Hooke's contributions to the physical sciences. Hooke's important work and discoveries in advancing microscopy, described in Micrographia and in Microscopium (1678), which had a great impact on later biological research, have been reviewed by Gest (2004a; see also Singer 1955).

The Preface of Micrographia is a unique document in many ways, and it could stand on its own as a précis of the status of basic science concepts during the flowering of a scientific renaissance. Hooke's unusual breadth of knowledge and interests gives us insights into the kinds of lectures and discussions that took place at meetings of the Royal Society in its earliest days. Hooke's energy, dedication, imagination, and remarkable foresight are apparent throughout the Preface. The great possibilities of understanding the workings of natural phenomena through experiment are paramount, and Hooke sees no limit to what may be achieved in the future. Interspersed among his philosophical discourses are technical sections written with great clarity and detail, in a fashion that would become common in scientific journals centuries later. Even after the passage of 340 years, a reading of the Preface would be an exemplary assignment for young students about to embark on studies in medicine or graduate work in the basic sciences.

The author is indebted to Prof. Timothy Long of Indiana University for translating the quotation from Horace.


Bennett, J., et al. 2003. London's Leonardo: The life and work of Robert Hooke. Oxford: Oxford Univ. Press.

Bernal, J. D. 1965. Science in history. New York: Hawthorn Books.

Boorstin, D. J. 1986. The discoverers. Harmondsworth: Penguin.

Ford, B. J. 1991. The Leeuwenhoek legacy. Bristol: Biopress.

Gest, H. 2004a. The discovery of microorganisms by Robert Hooke and Antoni van Leeuwenhoek, Fellows of the Royal Society. Notes Records R Soc 58:187–201.

Gest, H. 2004b. The discovery of microorganisms revisited. Am Soc Microbiol News 70: 269–74.

Hooke, R. 1665. Micrographia; or some physiological descriptions of minute bodies made by magnifying glasses with observations and inquiries thereupon. London. Repr. New York: Dover, 2003. Also available in CD-ROM format, 1998.

Hooke, R. 1678. Lectures and collections; Microscopium. London.

Hooke, R. 1705. The posthumous works of Dr. Robert Hooke: Collected and published by Richard Waller. London.

Kent, P., and A. Chapman, eds. 2004. Robert Hooke and the English renaissance. Leominster, UK: Gracewing Press.

Singer, C. 1955. The first English microscopist: Robert Hooke (1635–1703). Endeavour 14:12–18.

Westfall, R. S. 1972. Robert Hooke. In Dictionary of scientific biography, vol. 6, ed. J. Hachette and J. Hyrtl, 481–88. New York: Scribner.

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