DOCSLIB.ORG

An Unfolding Discovery

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
An Unfolding Discovery Proc. Nat. Acad. Sci. USA Vol. 68, No. 11, pp. 2875, November 1971 Photosynthesis Bicentennial Symposium: Introduction by the Chairman KENNETH V. THIMANN Crown College, University of California, Santa CruG, Calif. 95060 In early August 1771 Joseph Priestley, chemist of Birmingham, mainly from the underside of the leaves. But the biological England, and codiscoverer of oxygen, performed his famous "climate" was not ready for the correct interpretation of the experiment with the mouse and the mint plant. This experi- bubbles and Bonnet's discussion was wholly in terms of heat- ment provided the beginnings of our understanding of that ing and the consequent expansion of gases at the leaf surface. remarkable process whereby the organic matter of our bio- In the following symposium Eugene Rabinowitch presents sphere is produced and our atmosphere continuously purified. It is perhaps not widely known that the discovery was al- the sequential development of the leading ideas in the action most made some 20 years earlier by Joseph Bonnet, another of light on leaves, and then the current developments in the very active researcher of the time. For Bonnet observed that physiological, biochemical and photochemical aspects of the when leaves were immersed in water and exposed to sunlight, field at the present day are summarized by some of the leaders bubbles of gas were produced. He even noted that they came in the study of these aspects of photosynthesis in this country. Proc. Nat. Acad. Sci. USA Vol. 68, No. 11, pp. 2875-2876, November 1971 An Unfolding Discovery EUGENE RABINOWITCH State University of New York, Albany, New York, 12203 About 1648, a Dutch alchemist, van Helmont, grew a willow "Experiments and Observations on Different Kinds of Air". tree in a bucket of sand, and found that the sand weighed as This book included certain experiments on animals and much afterwards as it did before the tree had grown to sizable plants, among them the discovery that plants can restore the proportions. Although the law of conservation of matter was air that had been made unfit to support the life of animals established only a hundred years later (it was proposed by by burning candles in it. When a candle had burned in an zen- Lomonosov in Russia in 1748, and by Lavoisier in France in closed space until it went out, a mouse placed in the remaining 1770), van Helmont wondered where the material of which the air soon died. On August 17, 1771, Priestley put a sprig of mint tree was formed had come from, and decided that it must have into a quantity of air in which a wax candle had burned out been from the water used to wet the sand. and found that on the 27th of the same month, another candle In 1727, Stephen Hales, an English minister-naturalist, sur- burned perfectly well in it. A mouse was found to survive in mised that plants drew -a part of their nutrition from the air, this "restored?" (or, as it was then called, "dephlogisticated") and that sunlight may play a role in "ennobling the principles air. of vegetables". In 1971, we celebrate the 200th anniversary of this momen- Between 1770 and 1785, several chemists in England, tous experiment. France, Germany, and Scandinavia devised methods to catch, However, Priestley's observation was only the first step in transfer from vessel to vessel, and study the properties of dif- the unveiling of that basic process of life on earth that we now ferent gases. Oxygen, nitrogen, chlorine, carbon monoxide, and call photosynthesis. What he had shown is that plants con- carbon dioxide were discovered; the composition of air and vert "phlogistic" into "dephlogisticated" air-we would de- that of water were established by their experiments. scribe it now as replenishment with oxygen of air that has One of the most significant discoveries of this period, often become deficient in it; he had not shown what were the condi- called the age of pneumochemistry, was the discovery of oxy- tions needed for plants to do this. gen by Joseph Priestley, a nonconformist English minister, In the spring of 1779, Jan Ingenhousz, a Dutch court physi- who ended his stormy life as a self-exiled refugee in Pennsyl- cian to the Austrian Empress Maria Theresa, rented a villa vania. In 1776, he published an epoch-making book called near London to pursue Priestley's discoveries. In three summer 2875 Downloaded by guest on September 30, 2021 2876 Rabinowitch Proc. Nat. Acad. Sci. USA 68 (1971) over 500 before the end of months, he performed experiments; In 1796, Ingenhousz, who at first disbelieved Senebier's dis- the year, a book entitled "Experiments Upon Vegetables, Dis- photosynthesis, the Common Air in coveries concerning the role of "fixed air" in covering Their Great Power of Purifying reversed himself and proclaimed that carbon dioxide, taken Sunshine, and Injuring It In the Shade and at Night", was discovered that plants im- up from the air, is the only source of all organic matter pres- written and published. Ingenhousz ent in plants (and thus, indirectly, also in animals). This prove the air not slowly, by "vegetating" in it (as Priestley had Aristotelian belief that thought), but rapidly, by a "photo-chemical" reaction, taking meant breaking with the traditional He plants draw their nutrition from the "humus" of the soil. place in green leaves and green stalks exposed to sunlight. doctor, Julius Robert Mayer- thus identified the green plant pigment (which we now call Finally, in 1845, a German factors without one of the codiscoverers of the law of conservation of energy- "chlorophyll") and sunlight as two catalytic in addition to acting as a gigan- which plants cannot "improve the air". realized that the plant world, in Ge- tic chemical factory, which produces organic matter from in- In 1782, a Swiss pastor, Jean Senebier, published, a giant power station, neva, a three-volume treatise under the title "Physico-Chemi- organic raw materials, represented also in converting sunlight into chemical energy. The stored energy is cal Memoirs on the Influence of Solar Light Changing the or Nature of the Three Kingdoms, particularly that of the Vege- released suddenly in the combustion of wood or fossil fuel, table Kingdom". What Senebier added in this work to Ingen- slowly in respiration of plants and animals, and is by far the was the discovery that plants im- most important source of life energy on earth. housz' earlier observations became prove the air only if they are provided with a gas then called With this discovery, -the equation of photosynthesis "fixed air", which we now call carbon dioxide. Considering the complete: minute amounts (0.03%) in which carbon dioxide is present in the atmosphere, this was a remarkable discovery. -CO2 + H20 + Light 02, In 1804, another Swiss scholar, Nicolas Theodore de Saus- (Senebier) (de Saussure) (Ingenhousz) (Priestley) sure, who was one of the earliest chemists to make careful ana- + Organic Matter + Chemical Energy lytical measurements (and was armed with the knowledge of (Ingenhousz) (Mayer) the law of conservation of matter), published a treatise called "Chemical Studies on Vegetation". He determined that the The discovery of photosynthesis took (not counting the pre- sum of the weights of the oxygen produced by plants and the scient suggestions of van Helmont and Stephen Hales) from organic matter formed in them is considerably larger than the 1771 to 1845, and involved one Englishman, one Dutchman, weight of carbon dioxide consumed, and surmised that the dif- two Swiss, and one German. Two were churchmen, two medical ference must have been supplied by water-thus reviving the doctors and one a professional chemist-a characteristic ex- insight of van Helmont (as Ingenhousz had revived the in- ample of the international and interdisciplinary nature of ma- sights of Stephen Hales). jor scientific progress. Downloaded by guest on September 30, 2021.
Load more

Recommended publications
  • Occasional Papers from the Lindley Library © 2011
    Occasional Papers from The RHS Lindley Library IBRARY L INDLEY L , RHS VOLUME FIVE MARCH 2011 Eighteenth-century Science in the Garden Cover illustration: Hill, Vegetable System, vol. 23 (1773) plate 20: Flower-de-luces, or Irises. Left, Iris tuberosa; right, Iris xiphium. Occasional Papers from the RHS Lindley Library Editor: Dr Brent Elliott Production & layout: Richard Sanford Printed copies are distributed to libraries and institutions with an interest in horticulture. Volumes are also available on the RHS website (www. rhs.org.uk/occasionalpapers). Requests for further information may be sent to the Editor at the address (Vincent Square) below, or by email ([email protected]). Access and consultation arrangements for works listed in this volume The RHS Lindley Library is the world’s leading horticultural library. The majority of the Library’s holdings are open access. However, our rarer items, including many mentioned throughout this volume, are fragile and cannot take frequent handling. The works listed here should be requested in writing, in advance, to check their availability for consultation. Items may be unavailable for various reasons, so readers should make prior appointments to consult materials from the art, rare books, archive, research and ephemera collections. It is the Library’s policy to provide or create surrogates for consultation wherever possible. We are actively seeking fundraising in support of our ongoing surrogacy, preservation and conservation programmes. For further information, or to request an appointment, please contact: RHS Lindley Library, London RHS Lindley Library, Wisley 80 Vincent Square RHS Garden Wisley London SW1P 2PE Woking GU23 6QB T: 020 7821 3050 T: 01483 212428 E: [email protected] E : [email protected] Occasional Papers from The RHS Lindley Library Volume 5, March 2011 B.
    [Show full text]
  • The British Journal for the History of Science Mechanical Experiments As Moral Exercise in the Education of George
    The British Journal for the History of Science http://journals.cambridge.org/BJH Additional services for The British Journal for the History of Science: Email alerts: Click here Subscriptions: Click here Commercial reprints: Click here Terms of use : Click here Mechanical experiments as moral exercise in the education of George III FLORENCE GRANT The British Journal for the History of Science / Volume 48 / Issue 02 / June 2015, pp 195 - 212 DOI: 10.1017/S0007087414000582, Published online: 01 August 2014 Link to this article: http://journals.cambridge.org/abstract_S0007087414000582 How to cite this article: FLORENCE GRANT (2015). Mechanical experiments as moral exercise in the education of George III. The British Journal for the History of Science, 48, pp 195-212 doi:10.1017/ S0007087414000582 Request Permissions : Click here Downloaded from http://journals.cambridge.org/BJH, IP address: 130.132.173.207 on 07 Jul 2015 BJHS 48(2): 195–212, June 2015. © British Society for the History of Science 2014 doi:10.1017/S0007087414000582 First published online 1 August 2014 Mechanical experiments as moral exercise in the education of George III FLORENCE GRANT* Abstract. In 1761, George III commissioned a large group of philosophical instruments from the London instrument-maker George Adams. The purchase sprang from a complex plan of moral education devised for Prince George in the late 1750s by the third Earl of Bute. Bute’s plan applied the philosophy of Frances Hutcheson, who placed ‘the culture of the heart’ at the foundation of moral education. To complement this affective development, Bute also acted on seventeenth-century arguments for the value of experimental philosophy and geometry as exercises that habituated the student to recognizing truth, and to pursuing it through long and difficult chains of reasoning.
    [Show full text]
  • Hunt, Stephen E. "'Free, Bold, Joyous': the Love of Seaweed in Margaret Gatty and Other Mid–Victorian Writers." Environment and History 11, No
    The White Horse Press Full citation: Hunt, Stephen E. "'Free, Bold, Joyous': The Love of Seaweed in Margaret Gatty and Other Mid–Victorian Writers." Environment and History 11, no. 1 (February 2005): 5–34. http://www.environmentandsociety.org/node/3221. Rights: All rights reserved. © The White Horse Press 2005. Except for the quotation of short passages for the purpose of criticism or review, no part of this article may be reprinted or reproduced or utilised in any form or by any electronic, mechanical or other means, including photocopying or recording, or in any information storage or retrieval system, without permission from the publishers. For further information please see http://www.whpress.co.uk. ʻFree, Bold, Joyousʼ: The Love of Seaweed in Margaret Gatty and Other Mid-Victorian Writers STEPHEN E. HUNT Wesley House, 10 Milton Park, Redfield, Bristol, BS5 9HQ Email: [email protected] ABSTRACT With particular reference to Gattyʼs British Sea-Weeds and Eliotʼs ʻRecollections of Ilfracombeʼ, this article takes an ecocritical approach to popular writings about seaweed, thus illustrating the broader perception of the natural world in mid-Victorian literature. This is a discursive exploration of the way that the enthusiasm for seaweed reveals prevailing ideas about propriety, philanthropy and natural theology during the Victorian era, incorporating social history, gender issues and natural history in an interdisciplinary manner. Although unchaperoned wandering upon remote shorelines remained a questionable activity for women, ʻseaweedingʼ made for a direct aesthetic engagement with the specificity of place in a way that conforms to Barbara Gatesʼs notion of the ʻVictorian female sublimeʼ.
    [Show full text]
  • A Comedy of Scientific Errors BOVINES
    SACRED A COMEDY OF SCIENTIFIC ERRORS BOVINES DOUGLAS ALLCHIN, DEPARTMENT EDITOR William Shakespeare may well have foreshadowed the modern television experiment with balm, groundsel, and spinach. All modified the air to sitcom. His comic misadventures were expertly crafted. In A Comedy of support sustained burning. Animals, too, could breathe longer in the Errors, for example, twins (with twin servants), each separated at birth, treated air. Plants, Priestley had found, could restore the “goodness” of converge unbeknownst to each other in the same town. Mistaken iden- the air depleted by respiration or combustion. American correspondent tity leads to miscommunication. More mistaken identity follows, with Benjamin Franklin immediately perceived the global implications: plants more misdelivered messages and yet more misinterpretations. Hilarious help restore the atmosphere that humans and other animals foul. The consequences ensue. It is a stock comedic formula in modern entertain- system ensures our survival. That view fit neatly with Priestley’s religious ment. A character first makes an unintentional error. Then ironically, in belief in an intentionally designed (and rational) natural world. It was a trying to correct it, things only get laughably worse. remarkable discovery. For this and other work on airs, the Royal Society Science, we imagine, is safeguarded against such embarrassing in 1772 awarded Priestley the Copley Medal, then the most prestigious episodes. In the lore of scientists, echoed among teachers, science is honor in science. “self-correcting.” Replication, in particular, ensures that errors are Others were eager to build on Priestley’s discovery about plants and exposed for what they are. Research promptly returns to its fruitful tra- the restoration of air.
    [Show full text]
  • LAVOISIER-The Crucial Year the Background and Origin of His First
    LAVOISIER-THE CRUCIAL YEAR: The Background and Origin of His First Experiments on Combustion in z772 Antoine Laurent Lavoisier, 17 43-1794, a portrait by David (Photo Roger-Viollet) LA VOISIER -The Crucial Year The Background and Origin of His First Experiments on Combustion in 1772 /J_y llenr_y (Juerlac CORNELL UNIVERSITY CORNELL UNIVERSITY PRESS Ithaca, New York Open access edition funded by the National Endowment for the Humanities/Andrew W. Mellon Foundation Humanities Open Book Program. This work has been brought to publication with the assistance of a grant from the Ford Foundation. Copyright © 1961 by Cornell University First paperback printing 2019 The text of this book is li censed under a Creative Commons Attribution- NonCommerciai-NoDerivatives 4.0 International License: https://creativecommons.org/licenses/by-nc-nd/4.0/. To use this book, or parts of this book, in any way not covered by the li cense, please contact Cornell University Press, Sage House, 512 East State Street, Ithaca, New York 14850. Visit our website at cornellpress.cornell.edu. Printed in the United States of America ISBN 978- 1-501 7-4663-5 (pbk.: alk. paper) ISBN 978-1-5017-4664-2 (pdf) ISBN 978-1-5017-4665-9 ( epub/mobi) Librarians: A CIP catalog record for this book is available from the Library of Congress TO Andrew Norman Meldrum (1876-1934) AND Helene Metzger (188g-1944) Acknowledgments MUCH of the research and much of the writing of a first draft of this book was completed while I was a mem­ ber of the Institute for Advanced Study, Princeton, in 1953-1955.
    [Show full text]
  • Development of Preservice Biology Teachers‟ Skills in the Causal Process Concerning Photosynthesis
    Journal of Education and Training Studies Vol. 7, No. 4; April 2019 ISSN 2324-805X E-ISSN 2324-8068 Published by Redfame Publishing URL: http://jets.redfame.com Development of Preservice Biology Teachers‟ Skills in the Causal Process Concerning Photosynthesis Arzu Saka Correspondence: Arzu Saka, Trabzon University, Fatih Faculty of Education, Trabzon, 61335,Turkey. Received: February 12, 2019 Accepted: March 7, 2019 Online Published: March 11, 2019 doi:10.11114/jets.v7i4.4022 URL: https://doi.org/10.11114/jets.v7i4.4022 Abstract Photosynthesis is the most effective cycle and sustainable natural process known in nature. Students who learn the subject of photosynthesis well will also make better sense of other issues such as environmental problems, the state of the atmosphere, greenhouse gases, climate changes, carbon footprints and conservation of forests. The aim of this study is to present an example of a worksheet that investigates the skill levels possessed by preservice teachers‟ in the causal process, and also to examine their ability to write a photosynthesis equation by means of a history-based approach that also includes reading skills. The study was conducted with the action research method. The study sample consisted of a total of 71 preservice biology teachers. At the first stage, before the implementation of the worksheet, 34 teacher candidates from within the sample were asked a question with a diagram summarising the photosynthesis process. At the second stage, all the prospective teachers were asked for the skill levels they possessed in the causal process to be assessed via implementation of the worksheet. The answers given by the preservice teachers in the defining variables section in particular make up the least answered section of the worksheet.
    [Show full text]
  • Historical Review
    1 Historical Review INTRODUCTION This chapter presents a brief historical review of progress in the field of plant water relations because the authors feel that it is impossible to fully understand the present without some knowledge of the past. As the Danish philosopher Kierkegaarde wrote, "Life can only be understood backward, but it can only be lived forward," and this also is true of science. The present generation needs to be reminded that some generally accepted concepts have their origin in ideas of 17th or 18th century writers and although others were suggested many decades ago, they were neglected until recently. As might be expected, the importance of water to plant growth was recog- nized by prehistoric farmers because irrigation systems already existed in Egypt, Babylonia (modern Iraq), and China at the beginning of recorded history, and the first European explorers found extensive irrigation systems in both North and South America. However, irrigation was not used extensively in agriculture in the United States until after the middle of the 19th century and little research on plant water relations occurred until the 20th century. Early Research Although plant water relations appear to have been the first area of plant physiology to be studied, progress was slow from Aristotle who died in 322 B.C. to the middle of the 19th century. According to Aristotle, plants absorbed their food ready for use from the soil, and plant nutrition was controlled by a soul or vital principle that ailowed plants to absorb only those substances useful in 2 1. Historical Review growth. This idea only began to be questioned in the 17th century by Jung, van Helmont, Mariotte, and others, and it ~ersistedinto the 19th century.
    [Show full text]
  • Discovery of Photosynthesis Jan Ingenhousz Experiment John
    Cause / Effect TM This… Caused… Led To… Box-frame . Makes Sense Strategies © 2007 Edwin Ellis, All Rights© 2007 Reserved Edwin Published Ellis, byAll Makes Rights Sense Reserved Strategies, LLC, www.MakesSenseStrategies.com Lillian, AL www.MakesSenseStrategies.com MENU sample Name: Date: Discovery of Photosynthesis Is about … how the experiments of Van Helmont, Priestley, and Ingenhousz reveal that in the presence of light, plants transform C2O and H2O into carbohydrates and release O2. This Caused the… Which led to … Van Helmont John Priestly Jan Ingenhousz experiment experiment experiment · Led to the discovery of the · Led to the discovery of the · Led to the discovery that “hydrate,” or water portion of oxygen portion of the plants need light to produce the carbohydrate produced photosynthesis equation oxygen by photosynthesis · Placed a lit candle inside a jar, · Performed Priestly’s · Created and experiment to it burned out. Then, he place a experiment and discovered find out if plants grew by mint leaf inside the jar and that the candle only remained taking material out of the soil the candle remained lit lighted in the presence of – massed dry soil and a small because of the production of light seed, after five years the oxygen by the leaf mass of the soil was the sameèconcluded that the mass of the plant gained came from the water, did not realize air changed it too So what? What is important to understand about this? Photosynthesis is a series of reactions that uses energy from the sun to convert water and carbon dioxide into sugars and oxygen .
    [Show full text]
  • STEPHEN HALES* (1677-1761) by G
    STEPHEN HALES* (1677-1761) By G. E. BURGET PORTLAND, ORE. TEPHENS HALES was born at Bekes- Francis Darwin we learn that these two bourne in Kent, September 7, 1677, college friends roamed the surrounding the sixth son of Thomas and Mary country together. Hales carried an often- Hales. Only meager information is thumbed copy of Ray’s “Catalogue of obtainable in regard to his early life and Plants.’’ Everything from fossils to butter- training. In 1696, at the age of nineteen, flies was eagerly studied by the young he entered Bennet College, Cambridge. philosophers. They dissected frogs, dogs Although we have no definite record we and other animals together. John Francis may assume that he applied himself ear- Vigani (1650-1712) who became the first nestly to the study of religion and natural professor of chemistry at Cambridge in philosophy. He took a Bachelor of Arts 1703, seems to have attracted them. In a degree and was elected to a fellowship room at Trinity College, the laboratory of about 1702. In 1703 he was granted a Sir Isaac Newton, they repaired to repeat Master of Arts degree. William Stukclcy some of Boyle’s experiments and to watch (1687-1765) afterwards m.d ., f .r .s ., went the demonstrations of Vigani. They pre- to the college in 1704. A friendship arose pared various substances, “some of use, between him and Hales although Hales some of curiosity.’’ Hales studied astronomy. was Stukeley’s senior by ten years. From He knew well the Newtonian System. *Read before the University of Oregon Medical While yet in college he constructed a History Club, Portland, Orc., November 21, 1924.
    [Show full text]
  • Trinity College Cambridge
    trinity college cambridge Annual Record 2008 Trinity College Cambridge annual record 2007‒2008 trinity college cambridge cb2 1tq Telephone: 01223 338400 Fax: 01223 761636 e-mail: [email protected] website: www.trin.cam.ac.uk contents 5 The Master’s Commemoration Speech 11 College Notes 16 Alumni Associations 17 emembrance Day 2007 19 Commemoration of Benefactors 2008 24 Trinity and the Cambridge 800th Anniversary Campaign 26 Benefactions 36 College Clubs 57 Trinity in Camberwell 59 College Livings 61 James Clerk Maxwell Memorial 63 About the Chapel 71 Dr Bentley’s Laboratory 77 The Great Gate 78 Fellows’ Birthdays 99 Appointments and Distinctions 99 College Elections and Appointments 102 Cambridge University Appointments and Distinctions 103 Other Academic Appointments 105 Academic Honours 107 Other Appointments and Distinctions 111 Trinity College:The Master and Fellows 118 Obituary 141 Addresses wanted 3 the master’s commemoration speech The speech made by the Master, Professor Lord ees, at the Commemoration Feast on 14 March 2008 is printed with his kind permission. ommemoration ðay is one of Cour oldest traditions: a Chapel service to remember our founders and benefactors, followed by a dinner. The format of the dinner for Fellows and Scholars hasn’t always been the same; in the austere years before 1951, there was only one guest.The steady custom since then has been to invite about half-a-dozen, but this year there is another step change: we have eighteen guests tonight. This expansion signals a wish to engage more with old members of the College – to congratulate them on their achievements, and acknowledge the generosity that many of them show towards Trinity – and to do this now, rather than waiting until the Chapel service.
    [Show full text]
  • HUNTIA a Journal of Botanical History
    HUNTIA A Journal of Botanical History VolUme 11 NUmBer 1 2000 Hunt Institute for Botanical Documentation Carnegie mellon University Pittsburgh Huntia publishes articles on all aspects of the his- tory of botany and is published irregularly in one or more numbers per volume of approximately 200 pages by the Hunt Institute for Botanical Documentation, Carnegie mellon University, Pittsburgh, Pennsylvania 15213-3890. editor Scarlett T. Townsend Book reviews and Announcements editor Charlotte A. Tancin Associate editors Gavin D. r. Bridson T. D. Jacobsen Angela l. Todd Frederick H. Utech James J. White layout Lugene B. Bruno external contributions to Huntia are welcome. Please request our “Guidelines for Contributors” before submitting manuscripts for consideration. editorial correspondence should be directed to the editor. Books for announcement or review should be sent to the Book reviews and Announcements editor. Page charge is $50.00. The charges for up to five pages per year are waived for Hunt Institute Associates, who also may elect to receive Huntia as a benefit of membership; please contact the Institute for more information. Subscription rate is $60.00 per volume. orders for subscriptions and back issues should be sent to the Institute. Printed and bound by Allen Press, Inc., lawrence, Kansas. Copyright © 2000 by the Hunt Institute for Botanical Documentation All rights reserved ISSN 0073-4071 Huntia 11(1) 2000 Jamaican plant genera named by Patrick Browne (ca. 1720–1790): A checklist with an attempt at an etymology P. H. Oswald and E. Charles Nelson Abstract Patrick Browne’s generic names for Jamaican native them. Most meanings are taken from Liddell plants, published during 1756, are listed and their and Scott (1940) and Lewis and Short (1879).
    [Show full text]
  • Jean Senebier's Thoughts on Experimentation
    | Jean Senebier’s thoughts on experimentation and their relevance for today’s researcher | 185 | Jean Senebier’s thoughts on experimentation and their relevance for today’s researcher Edward E. FARMER * Ms. received the 22nd April 2010, accepted the 10th September 2010 T Abstract How are observation and experimentation related to one another? Jean Senebier (1742-1809) tackled this question in his philosophical works on The Art of Observing. However, Senebier was not only a theoretician and, not long after his first publications on observation, his own experiments contributed to resolve a major question in biology: what do the leaves of plants feed on? By analysing Senebier’s works on science theory in parallel with those reporting his scientific discoveries, this article shows that The Art of Observing series is not restricted to observation and contains deep insights into the process of experimenting with living organisms. Keywords: Senebier, plant physiology, photosynthesis, science didactics, epistemology T Résumé Les considérations de Jean Senebier sur l’expérimentation et leur intérêt pour les chercheurs d’aujourd’hui. – Quel est le lien entre l’observation et l’expérimentation? Jean Senebier (1742-1809) a abordé cette question dans sa série d’ouvrages sur l’Art d’observer. Cependant, Senebier n’était pas seulement un théoricien et, peu après ses premières publi - cations sur l’observation, il a commencé à travailler sur l’une des grandes questions de la biologie: « de quoi se nourrissent les feuilles des plantes? » S’appuyant sur ce qu’il avait appris en tant qu’expérimentaliste, Senebier a par la suite été en mesure d’approfondir ses brillantes analyses présentées dans ses deux premières publications sur l’Art d’observer.
    [Show full text]