Fournier 1996

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Fournier, Marian. The Fabric of Life: Microscopy in the Seventeenth Century. Baltimore: The Johns Hopkins University Press, 1996.

early 1660s, Hooke anticipated the microscope would discover nature's hidden secrets; by 1690s, microscopy had been abandoned by all but Leeuwenhock and a few amateurs, who continued investigating well into the c18 but whose "discoveries" did not contribute significantly to scientific innovation (6-7)

  • principle investigators during this period: Hooke, Malpighi, swammerdam, Grew, and Leeuwenhoek

pre-1660, only one basic design for microscope used, which had been around ~50 years; post-1660, many different designs found in contemporary publications -- i.e., increased interest in microscope around 1660, although it had been around for almost half a century (4)

1. A New Instrument Appraised

1609-1610: Galileo creates an optical device for magnifying small things or distant objects; early version of the telescope

  • not the first -- generally invented by spectacles manufacturers ca. 1600
  • but Galileo did introduce telescope to scientific practice (10)
  • Sidereus nuncius, 1610; discuses observations of the moon using his "perspicillum"

Kepler, Dioptrice, 1611; introduced changes to Dutch telescope known as "Keplerian arrangemetn", which almost replaced Dutch telescope by 1640

1620s, Cornelius Drebbel began making/distributing microscopes of Keplerian arrangmeent

early problems: inadequate/poor-quality glass; spherical aberrations because of refraction through curved lenses; chromatic aberration

field lens, a third lens that increased field of vision, introduced around 1650; Hooke used it for some work, then took it out for more detailed examinations (12)

adding more lenses could increase magnification, but tended to increase distortions

1660s, others began using only one very powerful lens to reduce distortions (13)

no microscope dated "unquestionably" from before 1670 survives (14)

most magnified around 50x, but up to 100x; with a resolution of at most ca. 3 microns; simple microscope superior to compound; between 1670 and 1750, little improvement in performance of both simple and compound microscopes (14)

Leeuwenhoek produced a small number of microscopes of superior quality, but most of the ~350 he made during his lifetime were standard for the time (16-7)

improvement in pivot, staging and lighting were introduced ~1660-1750 (18-9)

various designs/improvements (20-24)

Early (pre-1660) Use of the Microscope

insects were the first objects of microscopic study

  • Galileo observed one in 1610
  • Peiresc and his companion observed insects ~1622
  • oldest extant illustration (1625) is of a bee, produced as two broadsheets: one entitled Apiarium, signed by Prince Cesi (studied in collaboration with Francesco Stelluti, Francesco Fontana), as a natural history of the bee; the second engraved illustrating the magnified external parts of the bee, headed Melissographia and signed by Stelluti (For images, see BibliOdyssey post: [[1]]; also, Digital Edition of the Apiarium/Melissographia: [[2]]
    • 1630, Stelluti re-used the illustration in his edition of Persius's poems, accompanied by more detailed description (book available online through ECHO: [[3]])
  • "The investigations of Galileo, Peiresc, and Stelluti were all concerned with the outer appearance of the insect body and a few other objects. In fact, the majority of references to microscopic observations in the period prior to 1660 are concerned with the external details of the bodies of insects, and these organisms were to remain favorite objects for a long time to come." (26)

Gioanbatista Odierna, L'occhio della mosca, 1644

  • studied the eye of the fly both from the outside and, post-dissection, the inside
  • concluded the insect eye is composed of 1000s of identical units, each being an eye
  • believed the insect eye both perceives and receives visual perception -- doesn't happen in the brain (27)
  • combined microscopic investigation with anatomical procedures -- described how to cut apart fly to better see its structure

Pierre Borel, De vero tellescopii inventore (1655), Observationum microscopicarum centuria

  • like most early microscopists, his investigations convinced him of divine order (28)
  • thought microscope could be used to study medicine and disease, even speculating that signs of death might be detected microscopically

Establishment of Microscopic Data

"Whereas prior to 1660 microscopic observations frequently appear to have been undertaken in order that scholars might marvel at the wondrous sight of hugely magnified crawling vermin, the natur of such investigations changed during the 1660s to the purposeful study of organic structure." (30)

preparation of the specimen:

  • Hooke couldn't observe porousness of cork until he cut a very thin slice
  • Grew also developed methodical way of slicing sections of plant material from different angles
  • anatomia subtilis, refined anatomical research, required other techniques like boiling, maceration, and injection (32)
  • Malpighi injected ink into a kidney, so that glomeruli showed up as black globules (32);
  • sometimes these alterations lead to false assumptions about how the tissue worked by changing the specimen (happened for Malpighi with brain)
  • desiccation altered the fabric of the body; could remedy by adding water or oil to it while investigating, then keeping dried specimen around for further investigation (as Leeuwenhoek did)

measurements were difficult; could be made by placing a rule next to the microscope, simultaneously looking at it and the specimen (Hooke, Leeuwenhoek), or a natural standard, such as sand or a strand of hair (34-5) -- micrometers not available until mid-18c


  • Theodoor Kerckring; warned Malpighi that the range of vision is small, colors are distorted; "difficult to distinguish what is original and real" (Kerckring quoted on 36)
  • Cherubin d'Orleans; warned that investigators must stitch together small images to make a whole; compared looking at large image then small magnified sections to reading, seeing letters pop out

plants and insects abundantly reproduced in images; anatomy of the animal and the human body were poorly illustrated in microscopy books

insect anatomy reproduced according to standing conventions of human anatomies; showing animal and human material was more difficult, as it required showing three-dimensional structures (38)

"there was no serious doubt that the microscope offered a reliable view of the fabric of organic structure", despite discussion of flaws (40)

Microscopic Publications

40-6: bibliometric analysis of microscopy from 1625-1750

looked at 3 journals: Journal des scavans (French intellectual circles, mostly repeating research findings); Philosophical Transactions (English, Royal Society, original research); Miscellanea curiosa (German, Collegium Naturae Curiosorum, original research)

Leeuwenhoek published early, at a time when few people were concerned with microscopy; Hooke and Malpighi published when little literature was available; Grew, Swammerdam and later Leeuwenhoek benefited from their predecessors

"the development of the microscope did not constitute a substantial factor in the establishment of microscopy. Thi is supported by the paradoxical fact that microscopy declined precisely at the time when microscopes, both compound and simple, could for the first time be purchased relatively easily from a much expanded body of instrument makers." (47-8)

2. The Leading Microscopists

Robert Hooke

Micrographia, published on the last day of 1664, though the title page says 1665

committed to Baconian program; use human senses to observe phenomena

instruments could augment senses, be a "new Genus" of the senses (51)

"Philosophical Algebra": method of scientific inquiry, proceeding from simple to complex, as in math -- begin with a point (in Micrographia, literally) (52)

matter organized by (successively) the principles of fluidity, orbiculation, fixation, cristallization, ebullition or ermination, vegetation, plantanimation, sensation and imagination (53)

plants show animation: hair on oat's beard responds to moisture

mechanistic view; animate matter composed of mechanical contrivances, so that different organisms can be composed of identical parts or like organisms from different parts (like putting together a clock); insects as automata (55)

Marcello Malpighi

applied anatomical method in physiology to microscopic investigation of organs; novel among his contemporaries

influenced by Giovanni Alfonso Borelli in Pisa, an anatomist and mechanist

long-standing connection with the Royal Society; became a member in 1668

aimed to elucidate the physiological processes of living bodies, particularly the human body, using observation, experiment and reaso used analogical reasoning; e.g. in later work, analogized animal structures to plant structures -- underlying sameness

assumed uniformity in nature; i.e., structures that looked the same must serve the same function

Jan Swammerdam

torn between passion for science and his religious devotion

committed to empirical method, but not strict mechanist

  • gave some causal explanations in early work, but mostly

Biblia naturae, published half-century after his death; describes the life cycle and behavior of various animals and insects and the function of their parts; used a microscope in his investigations

conception of nature based on rigorous order; no chance (and therefore no spontaneous generation)

insect metamorphosis was not spontaneous, but the act of a single individual insect undergoing different growth processes (69)

Swammerdam's views sometimes called preformationist: believed that the egg was the animal itself, etc. -- however, he clearly knew that parts rearranged themselves as the animal grew, so not (entirely) preformationist; just confused

Nehemiah Grew

appointed member of the Royal Society 16 November 1671; offered appointment as "Curator for the Anatomy of Plants", given a microscope at his disposal, supported by annuity of £50 (though the scheme for this salary never materialized)

reasoning by analogy, wanted to discover the "anatomy" of plants (as had been done with animals)

microscopic studies began in earnest around 1672 with publication of the anatomy of vegetables begun, put out by Royal Society

  • indebted to Hooke for discovering plant cells

Malpighi's Anatomes plantarum idea reached the Royal Society the very day Grew presented his book to the society; discouraged, but kept going with encouragement of fellow members

lectures were printed as An Idea of a Phytological History Propounded. Together With ... the Anatomy of ... Roots (1673), The Comparative Anatomy of Trunks (1675), and Experiments of Luctation (1678)

1677, became secretary of RS along with Hooke; then turned to inventorying the Society's possessions, published as Musaeum regalis societatis (1681)

1684, resigned from council of RS; last project he was involved with was preparation of his own Anatomy of Plants (1682)

influence of Hooke:

"Grew's subsequent researches on plant structure and his speculations on the life processes in pklants started from the groundwork laid out by Hooke, but the scope of his work went far beyond anything that Hooke had attempted." (74)

influence of Boyle:

"Grew's speculations and experiments concerning the chemical composition of plants closely follwoed Boyle's theories, and the number and range of his experiments on vegetable and animal substances matched Boyle's output." (74)

Grew's approach to the study of plants; prior to him, botanical books focused on the medicinal properties of plants

"Considering that both plants and animals 'came at first out of the same Hand, and were therefore the Contrivances of the same Wisdom' he thought it worthwhile to investigate plants in order to reveal the structures of these organisms." (74-5)
"through scientific investigation, the wisdom of God becomes evident to man" (75); "religion followed naturally from science" (75)

1701, last published work, Cosmologia sacra, aimed to demonstrate that "Religion is so far from being inconsistent with Philosophy, as to be the highest point of it" (qtd 75 in Fournier)

committed to Baconian principles

1673, Idea of a Phytological History: created a research program for the structure, nature and life process of plants, including growth, nutrition, the form and dimension of plant parts, development, propagation; five general methods (that he hoped would apply to other projects):

  • survey of external parts (morphology)
  • disposition of the original parts (anatomy)
  • analysis of the contents (saps, etc.)
  • analysis of the principles (i.e. chemical components)
  • examination of the raw materials from which the plant grows (76)

analogized plants to animals: "Ina niamls, the various vital functions were known to be related to specific structures. Therefore, reasoning by analogy, the structures observed in plants had to serve specific functions. ... Consequently Grew attempted to relate all the structures he had observed to their role within a comprehensive scheme of vegetation. This scheme accounted for respiration, nutrition, and generation, and involved a complicated circulation of air and nutritive saps through the plant." (77)

  • analogy mainly limited to structural details, though
  • see Grew quote on pg 77

used domestic analogies: fabrics, lace, basketry; frequently referred to the "warp and woof" of plant fibers

conception of nature derived from 1) microscopic research and 2) corpuscular philosophy of matter

"envisaged living matter as constructed from infinitely small, presumably hollow, fibers" (78)

believed chemical composition of parts determined their form (first cause); secondary cause is the arrangement of various parts of the plant, to carry on and improve what nature began (79)

Antoni van Leeuwenhoek

didn't begin microscopy until almost 40; no schooling after age 16, spoke and wrote only his native Dutch and therefore worked somewhat in isolation

presentation of his work was sloppy, but his letters show a consistent method: historians of science debate whether he was amateur or not

contributed largely through the Philosophical Transactions; addressed letters to the Royal Society, was appointed a member in 1680

letters (both to RS and other notables) were publsiehd in Dutch and Latin versions, but Leeuwenhoek didn't attempt to organize the contents

concentric method of working: would study a subject in fits and starts; would seem to result in getting closer to the truth, but actually he rarely changed from the views he formed early on

discovered "animalcules" in sperm, believed they were preformed organisms ("the Human Creature is enveloped in an Animalcule from the Male sperm", qtd on pg 83); plant seed had similar structure

particularly concerned with structure; because he lacked scientific training, would use the same denominator for the same structure in different places/plants, used common names instead of making up new ones (84)

quantitative approach

generally mechanistic, Cartesian conception of nature; favored an idiosyncratic corpuscular theory of matter

believed in uniformity in nature -- "the most important postulate in Leeuwenhoek's reasoning" (90)

3. The Substance of Living Matter

corpuscular philosophy: microscopists attempting to observe the minute particles that make up all life

Henry Power

physician by profession, but studies physical sciences; early member of Royal Society

1664, Experimental Philosophy: microscopic investigations, not well illustrated; concluded:

  • all imperfect animals have a pulsating heart and circulation of nutritive fluids, just like larger animals
  • nutritive liquid in imperfect animals is not blood
  • animal spirits circulate through the body just like blood, though
  • color is simply a modification of light
  • differences between compound and vertebrate eye

believed microscope would lead to better understanding of atoms, but his own investigations did not yield this; most successful at identifying a similarity of structures between small and large animals

Robert Hooke

most of the work for Micrographia was done in 1663

second period launched by Leeuwenhoek's discoveries of infusoria (animalculae) in a letter dated 9 Oct 1676; Nehemiah Grew asked to repeat Leeuwenhoek's experiments, but he wasn't heard from, so Hooke undertook the experiments

Microscopium, describing microscopes, various uses

Micrographia seen by historians as haphazard collection of materials; designed to promote empirical methods; Fournier argues it also shows how Hooke believed science could get at the "true nature" of things where the eye deceives

believed microscope could help discern the secrets of nature without doing violence to nature, the way vivisections do -- observe nature as it exists, peek in its window (101)

Hooke usually didn't delve into traditional physiological problems (respiration, digestion, generation, movement), but focused on structures, guessing at their function using mechanical parallels (103)

4. The "Animal Oeconomy"

physiology == "animal oeconomy"

"anatomical method": descrption and dissection; attempting to link the particulars of structure to the funciton of a specific organ

seventeenth-century: "the traditional explanation of the physiological processes on the basis of the imputed "qualities" of various organic structures was substituted for explanations based on the demonstrable characteristics of organic matter" (104)

Descartes, Traite de l'homme, 1664, mechanically-operated model of the human body (though he had little direct experience experimenting); Niels Stensen, Discours sur l'anatomie du cerveau, lecture advocating Cartesian physiology, then published in his Elementorum myologiae specimen (1667)

chemical analysis introduced into physiological research

"Whereas the findings of visual inspection were usually found to be compatible with a mechanical interpretation, the data of chemical analysis called for a corpuscular interpretation, in which physical phenomena are explained in terms of the mechanical interactions of the invisible and insensible particles of matter." (105)

in context of mechanical philosophy, plants began to interest scholars -- assumed "analogy between the mechanisms underlying the physiological processes in animals and plants" (105)

Mechanical Physiology: The Muscle Fiber

Descartes: muscle movement is caused by muscles inflating from an influxe of spiritus animalis rushing down the nerves

William Croone agreed, but knew nerves were not hollow tubes to carry liquids; proposed instead that spiritus animalis interacted with blood in the muscle tissue

however, Swammerdamn showed around 1664 that the volume of muscles actually shrinks when contracted (using frog leg stimulated in a jar of water); argued there could be no fluid in the nerves, but simply stimulation was enough for communication

Niels Stensen investigated the macroscopic structure of muscles; showed muscles are composed of innumerable motor fibers geometrically arranged, blood vessels and nerves

Croone adjusted position, argued muscle fibers were formed of numerous small bladders

Hooke supported this revised thesis with various experiments

(independently, Giovanni Alphonso Borelli was arguing muscles are composed of threads, with action caused by their arrangement as a series of mechanisms)

Leewenhoek showed that fibers were intertwined and connected to/part of the tendon; today, we see him as correct, but his findings were all but ignored by contemporaries, who had a hard time verifying it, and for whom the observation didn't fit with the mechanicistic philosophy

Marcello Malpighi

brief discussion of Malpighi's many small treatises on different body parts

De bombyce (on the silk moth), 1669, produced in response to Royal Society's instigation, first treatise to be abundantly illustrated (115)

observed chick egg, pursuing embryological research; discerned tiny parts in early stages

observed similarity between seeds and buds; young plant tucked inside seed; saw this as similar to saccules or vesicles in animal development, particularly silk moth (117)

"On the basis of these considerations Malpighi concluded that the developmental process invariably started from a 'compendium', contained within a baglike structure, which presently incorporated additional matter, gradually grew in size and eventually became visible." (117) -- whether in chicken, silk moth or a range of plants, emphasizing analogies rather than differences
  • see Malpighi quote on 117-8

organisms acquired their texture before any indicatino of structure could be detected visuallly, with microscope or without; but not preformationist -- believed fertilization caused matter to structure itself

plant research is bulkiest part of his published investigations; most illustrations

  • most insights condensed into essay, Anatomes plantarum idea, 1 Nov 1671, sent to the Royal Society, received one day before Nehemiah Grew's the anatomy of vegetables begun was presented
  • royal Society later published his Anatomes plantarum pars prima (1675), describing principle parts of the plant, and pars altera (1679), describing germination and growth, final chapter discusses the root
  • discerned the structure of plants is variation on two units: boxlike utricle and tubelike fiber
  • most of his plant research macroscopic, but used microscope to examine detailsm
  • imagined movement of liquids in plants as purely mechanical process (119-120)
  • '"The supposed analogy between animal and vegetable structures was emphasized by the application of the vocabulary of animal anatomy to vegetable structures. ... used animal anatomy and physiology as a model with which to interpret plant structure. In doing so he contradicted the premise that, he said, motivated his research on plants, namely, that by studying the simple mechanisms of plants the complex mechanisms of animals might be better understood." (120)
"he investigated the minutiae of organic matter in search of an explanation for the origin of the physiological processes" (120)

"the content of Malpighi's scientific career was therefore dominated by the mechanical philosophy" (121); never doubted this premise, saw everything he looked at as small machine and interpreted its function as such

Nehemiah Grew

1673-1677: Grew presented results on anatomy of plants, with some lectures on the chemical composition

believed all essential parts in a plant were the same; made of two different kinds of tissue: parenchymatous, mass of bubbles/bladders, all alike and discontinuous, and the ligneous, clusters of small vessels or concave fibers -- air vessels and sap vessels (122)

  • "Grew equated the plant vessels with the viscera in animals: as there is such a variety of viscera, there must be a similar variety in plant vessels. In Grew's view, therefore, animal and pklant physiology are very similar processes, requiring similar organs to be realized. Whether there was indeed such a strong analogy between platns and animals was currently widely debated, but by no means clear." (122)

all parts from two basic elements: bladders and vessels, though many different sizes/configurations

walls of the bladder are not mere "Paper-Skins" (124) -- warp and woof texture; stitched together like a "Floor-Mat" (124)

imagined mechanistic system of capillaries and bladders to allow fluid to rise in the plant without sinking; but was unsure how water transferred between blatters -- assumed something to do with the chemical composition of the fluid; "Grew's ideas on the subject of vegetation were therefore composed partly of mechanical and partly of chemical principles" (126)

major methods of investigation: observation with a microscope, and chemical experimentation (127)

"Grew arrived at a clear notion concerning the delicate structure of organic matter, which ensued directly from his microscopic studies"; however, understanding of the details of the operation of these structures w/i vegetable "oeconomy" eluded him, because he couldn't see them with his microscope

Vessels Galore

1666, Edmund King published in Philosophical Transactions on animal body as made entirely of fibers; Grew believed plants were woven together of fibers

today, Leeuwenhoek seen as putting the "finishing touches" on Harvey's theories; but wasn't seen that way by his contemporaries, who thought of capillaries as mechanistic contraptions (129)

capillaries began to be favored "as the seat of all physiological processes" (132); the physiologists used mathematical, rather than instrumental, tools

"Influenced by the recent developments in physics a 'Mathematical Physick' was introduced and physiological theory shifted from 'machinulae,' or mechanical actions, to the dynamics of fluids in tubes of various sizes. ... Hydraulic physiology, in several guises, dominated eighteenth-century physiology." (134)

5. The Fabric of Living Beings

second half of 17c, flourishing period for anatomy

survey of various discoveris; Malpighi, Willis, Bidloo's Anatomia humani corporis (1685) (did he use Malpighi's illustrations without direct observation of phenomena? -- 139) -- "landmark in human microscopic anatomy" (140)

human anatamies, like Bidloo's, benefitted from microscopic research; zootomies don't appear to have benefited greatly (141)

"Although anatomists declared the microscope to be a valuable contribution to their arsenal of techniques, and valued the microscopic examination fo specimens, in fact few anatomist attempted to investigate the texture of human organs with the microscope thoroughly, neither directly nor via the roundabout route of comparative anatomy. ... The study of the animal body, on the other hand, was certainly carried some way beyond the achievements of the 'fathers of microscopy', but this achievement was one of quantity rather than of quality." (143-146)

insect anatomies flourished, but most were derivative of Hooke and Swammerdam (156)

on Leeuwenhoek, 157-67

discovery of micro-organisms: Leeuwenhoek discovered many of them, but Joblot named them -- only with the name were other researchers across the continent able to identify and share findings (171-2)

6. Five Heroes of Microscopic Science

Hooke, Grew and Malpighi wanted to "elucidate the fundamental phenomena of life, that is, the fabric and operation of organic matter" (179); Swammerdam and Leeuwenhoek were less ambitious

Hooke's Micrographia clearly written from mechanical and corpuscular point of view; Grew applied these terms "in exactly the same way as Hooke" (181)

exchange of ideas limited by space; even when Hooke and Grew corresponded with the others in their official capacity as secretaries to the Royal Society, they only discussed business (publication, etc.), not their own interpretations (182)

  • one exception: Grew and Leeuwenhoek exchanged letters, which were published in the Philosophical Transactions in 1676
  • disagreed about the valves within the wood vessels (L thought they existed, G thought they were artifacts of slicing)

7. Measuring the Impact of the Microscope

"rising momentum of Baconianism in England" led to work of Hooke and Power; "reinforced ... by the impact of the corpuscular theory of matter" (187)

"From their books [Hooke, Power] it is apparent that the union of the empirical method of scientific investigation with a rational explanation of the phenomena of nature, whether on a corpuscular basis or a mechanical o9ne, transformed microscopic investigation fro ma disjointed series of casual observations into a sustained effort." (187)
"the microscopic observations published during the 1660s and early 1670s are deeply concerned with the issues raised by the corpuscular philosophy and Cartesian-inspired physiology. They also reveal a deep commitment to the experimental method on the part of the investigators. The beginning of the heyday of microscopy in the seventeenth century was therefor the result of a combination of the novel seventeenth-century conception of nature with the experimental method." (188)
  • corpuscular philosophy was the impetus; but in the end, microscopy could add little to corpuscular philosophy

by the end of the 1680s, was clear that "an overwhelming number of fibers and vessels constituted the principal structural element throughout organic nature" -- similar across a number of different organs, contradicting the belief that similar structure == similar function; therefore a new procedure of analysis was needed, supplanting Descartes [how does this relate to Grew's attraction to the book as a structure?] (193)

"The investigations in the closing decades of the century had given rise to a definite theory of the construction of organic matter, in which the fiber formed the essential unit, both in the vegetable and animal world. Although simple mechanisms like the lever and sieve were incompatible with the fabric of fibers and vessels, such a fabric agreed with the mechanical conception of nature. Indeed, this fabric, an intricate arrangement of vessels of various diameters, was thought to bring about the various physiological processes as a result of the fluids that circulated through the vessels. Such a system appeared an attractive subject for mathematical analysis, but did not need further ocular investigation. In a sense then, the goals of the early microscopists formed the basis for the decline in microscopy some decades later." (194)