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History of Ecological Sciences, Part 43: Plant Physiology, 1800s

2012; Ecological Society of America; Volume: 93; Issue: 3 Linguagem: Inglês

10.1890/0012-9623-93.3.197

2327-6096

Frank N. Egerton,

Biocrusts and Microbial Ecology

The Bulletin of the Ecological Society of AmericaVolume 93, Issue 3 p. 197-219 CONTRIBUTIONSFree Access History of Ecological Sciences, Part 43: Plant Physiology, 1800s Frank N. Egerton, Frank N. Egerton Department of History, University of Wisconsin-Parkside, Kenosha, Wisconsin 53141. E-mail: frank.egerton@uwp.eduSearch for more papers by this author Frank N. Egerton, Frank N. Egerton Department of History, University of Wisconsin-Parkside, Kenosha, Wisconsin 53141. E-mail: frank.egerton@uwp.eduSearch for more papers by this author First published: 01 July 2012 https://doi.org/10.1890/0012-9623-93.3.197Citations: 4AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Click here for all previous articles in the History of the Ecological Sciences series by F. N. Egerton Plant geography and plant physiology were two foundations upon which plant ecology arose during the later 1800s. Plant geographers Alexander von Humboldt, Hewett Watson, Joseph Hooker, and de Candolle, father and son, were discussed in previous parts of this history. Building on the outstanding experimental studies on plant growth conducted during the 1700s, and on Antoine Lavoisier's chemical revolution, botanists, agronomists, and chemists established a flourishing plant physiology during the 1800s. Scientists in Britain, France, Germany, and Switzerland led the way. Two poorly developed theories accepted at the beginning of the 1800s, humus as fertilizer and vitalism, became discredited during the 1800s. Humus was disintegrated plant matter, which varied in composition from place to place, intermixed with topsoil. It was different from animal manure, though both seemed to have similar effects. There was a long tradition of using humus as fertilizer. Two early founders of agricultural chemistry were Scotsman Francis Home (1719–1813) and Swede Johan Gottschalk Wallerius (1709–1785). Home, a physician and later a medical professor at the University of Edinburgh, published his important Principles of Agriculture and Vegetation in 1757. USDA agronomist Charles Browne nicely summarized Home's book in his Source Book of Agricultural Chemistry (1944:117–126). Wallerius was Sweden's first professor of chemistry, at Uppsala University (Partington 1962:169–172, Boklund 1976, Frängsmyr 1985:6). Wallerius' Agriculturae Fundamenta Chemica (1761) appeared in both Latin and Swedish, as a dissertation defended by his student, Count Gustavus Adolphus Gyllenborg, and bibliographies list it under either name. Its similarity to Home's Principles makes it likely that Wallerius was indebted to Home's book (Browne 1944:128). The earliest discussion of humus that Browne quotes (in translation, Browne 1944:130–131) is from Agriculturae Fundamenta Chemica, which Browne also summarized (Browne 1944:126–134). Wallerius had not invented the humus term or concept, but his understanding of it seemed to be what was generally accepted (Waksman 1942). Both Browne (1944:208, 211) and botany historian Alan Morton (1981:392–393) viewed the humus theory as impeding understanding, and as leaving room for vitalism. We will see, however, that when mycorrhiza on roots are involved, something like a humus theory was invoked. Figure 1Open in figure viewerPowerPoint Nicolas-Théodore de Saussure. Trembley 1987:433. We reach the 1800s, where we left off in Part 28 (Egerton 2008:169), with the Recherches chimiques sur la végétation 1804 by Genevan Nicolas-Théodore de Saussure (1767–1845). He was indebted not just to Lavoisier and plant experimentalists of the 1700s, but also to his own father, Horace Bénédict de Saussure, a prominent geologist with serious interests in botany and meteorology (Carozzi 2005). The elder Saussure trained his son to be his assistant (Hart 1930, Pilet 1975). Although Saussure's Recherches apparently lacks a modern edition, more recent authors provide discussions and/or quotations in English or French (Browne 1944:193–202, Weevers 1949:6–7, Gabriel and Fogel 1955:338–342, Nash 1957:225–231, Morton 1981:338–342, Buchs 1987:171–180, Naef 1987:333–337, Magnin-Gonze 2004:160–161). Saussure was the most sophisticated experimentalist thus far in the history of botany (Sachs 1890:497–502, Reed 1942:215, 241–242). Where his predecessors had been content to record whether a plant did well or poorly under experimental conditions, he measured how well or poorly they did, and compared that result with measurements on control plants or plants in other experiments. Plants grow faster in air enriched by carbon dioxide, but only to a maximum of 8% carbon dioxide; at a higher percentage, plants do poorly. Where his predecessors tried something to see what happened, he designed experiments to test hypotheses. His experimental techniques and equipment represented advances that later physiologists copied. Saussure sometimes refined experiments conducted by his predecessors. For example, Van Helmont had conducted an experiment in which he weighed a tub of dirt into which he planted a willow stem, and five years later he removed the tree and found the amount of dirt was the same (Egerton 2004:209). Van Helmont thought he had proved that the tree gained all its weight from rain or distilled water that he added, not noticing the possibility that it absorbed gases from the air, despite his having coined the word "gas" (Egerton 2004:209). That 1600s fallacy had been corrected during the 1700s, but Saussure added that van Helmont's scale had not been precise enough to detect minute amounts of minerals that his tree absorbed from the earth. When plants are removed from where they grow, minerals within them are also removed, causing a loss of soil fertility. Saussure also resolved some past disputes left hanging by his predecessors. Priestley and Ingen-Housz had thought that nitrogen was absorbed by plants from the air; Senebier was skeptical, but had not found a way to settle the argument. Saussure did so by showing that only oxygen and carbon dioxide were absorbed from the air. Although he realized that nitrogen in the air was not absorbed by plants, he thought atmospheric ammonia might be (Saussure 1804:207, Partington 1962:283–284, Aulie 1970b:453). Saussure's goal was to gain a comprehensive understanding of plant physiology. He developed a conceptual scheme that allowed him to assign the source and route of supply of every major element that chemical analysis discovered in mature plants (Nash 1957:431, Partington 1964:311, Fussell 1971:154). He was the first to make regular analyses of plant ashes, and his were the most accurate and extensive analyses yet attempted. He found that not all the oxygen and hydrogen in plants could come from air, and therefore he concluded that water was a major nutrient of plants and not just a medium for transferring material from soil to roots. He recognized that plant liberation of carbon dioxide at night indicated a fundamental similarity to animal respiration, studied by Lavoisier (Morton 1981:338). No experimentalist is infallible, and occasionally he was less diligent than he should have been. He overlooked sulfur in the ashes. Another example: since the red variety of Atriplex hortensis produces as much oxygen as the green variety, he concluded green color was not essential for growth, when he might have seen with a microscope green cells below the red epidermis of red leaves (Sachs 1890:503, Morton 1981:340–341). Recherches was a pivotal book: it culminated past researches and potentially opened doors for the future. Yet Morton (1981:392) thought that "The basis of plant nutrition seemed to have been so thoroughly settled by de Saussure that for a long time botanists gave the subject no serious attention." Sachs (1890:508) attributed the lack of progress to the deadening influence of vitalism theory. Both authors were thinking of Continental chemical studies on plants. In Britain, the physiological approach by Thomas Andrew Knight (1759–1838) was more physical than chemical. He graduated from Oxford University and assumed management of his brother Richard Payne Knight's 10,000-acre estate (Simpkins 1973, Browne 2004, Elliott 2004). He began experiments on improving the breeds of fruits, vegetables, and cattle, which led to correspondence with botanist Sir Joseph Banks (1743–1820), president of the Royal Society of London (Knight 2004a). He sent Banks 23 reports on his agricultural experiments, which Banks published in the Royal Society's Philosophical Transactions (1795–1812), but The Banks Letters (Dawson 1958:496–509, 906) lists and summarizes 97 letters that Knight wrote to him. Knight's early experiments on the movement of sap in trees were less decisive than he had hoped, because they were not informed by an adequate general theory of physiology (Harvey-Gibson 1919:82–83, Reed 1942:176). Knight's most important discovery was geotropism (1806), named by Julius Sachs in 1868 (Harvey-Gibson 1919:83–87, Singer 1959:376–377, Morton 1981:390). Knight attached germinating seeds to rapidly rotating discs—some experiments with horizontal and others with vertical discs—attached to a water wheel in a stream. Figure 2Open in figure viewerPowerPoint Apparatus to determine the changes effected in the composition of air by a twig stripped of some leaves (Fig. VI), by the leafless part of a branch (Fig. VII), and by leaves in an enclosed amount of air (Fig. VIII). Saussure 1804; from Browne 1944:195. He discovered that roots have positive and stems have negative geotropism. Sachs named Knight's experimental device a klinostat. In 1811 Knight showed that roots can be diverted from the vertical by moist earth, and in 1812 he showed also that tendrils of Vitis and Ampelopsis show negative heliotropism (Sachs 1890:549). Many of his papers on experiments were collected and republished posthumously (Knight 1841). Humphry Davy (1778–1829) was a successful chemist as both researcher and public lecturer at the Royal Institution in London (Jones 1871:312–403, Treneer 1963, Ihde 1964:127–131, Partington 1964:32–39, Hartley 1966, Russell 1966:66–76, Knight 1971, 1992:66–76, Knight 2004b, Fullmer 2000, Tuttle 2004). He became famous by being first to use electrolysis to separate certain compounds not previously decomposed, and thus discovered sodium, potassium, calcium, strontium, barium, magnesium, and chlorine. In 1802, before de Saussure's Recherches was published, the Board of Agriculture asked him to teach a course on agricultural chemistry. Since there was a substantial overlap in members of the Board and Proprietors of the Royal Institution, that diversion from pure to practical chemistry was easily arranged (Wilmot 1990:23). Davy taught the course from 1802 through 1812, revising his lectures yearly, and published his lectures as Elements of Agricultural Chemistry 1813, which was an important synthesis of more than 100 previous studies, including the works of both de Saussure and Knight. Davy and Knight became close friends, and Davy dedicated the fourth edition of Elements 1827 to Knight. Elements went through six English and five American editions and was translated into German (1814), Italian (1815), and French (1819). It was the most popular book ever written on the subject (Miles 1961:128). Davy divided Elements into eight lectures, and if he read one per evening, they were long evenings. Browne (1944:205–210) summarized Elements, including two illustrations. Lecture 1 was introductory, partly historical. Lecture 2 discussed gravity (Knight's work, Fig. 3 above), heat, light, electricity, and plant substances. Lecture 3 was on plant organization—roots, trunks, branches, leaves, flowers, seeds—and plant compounds. Lecture 4 was on soils, their analysis and improvements. In 1805 the Board of Agriculture provided a laboratory near the Royal Institution for such analyses, and Davy designed equipment for analyses that is preserved in the History of Science Museum, Oxford University (Knight 1992:47). Figure 3Open in figure viewerPowerPoint Knight's experimental design to study geotropism. Davy 1839, VII: facing 202, 1972. Figure 4Open in figure viewerPowerPoint (a) Thomas Andrew Knight. Simmonds 1954: Fig. 127. (b) Humphry Davy, 1821. By Thomas Philips. National Portrait Gallery, London. Thorpe 2007: cover. Figure 5Open in figure viewerPowerPoint Davy's apparatus for studying the gases evolved by meadow grass. Browne 1944:209. Lecture 5 was on the atmosphere and its influence on plant growth and seed germination. Lecture 6 was ostensibly on "manures of vegetable and animal origin," but mostly on animal manures, and rather than using actual plants as manures, he grew plants in various plant substances, like sugar water, mucilage, and tanning solution. Lecture 7 was on mineral or fossil manures, and he discussed experiments—some of which were his own—using as fertilizers calcium carbonate, quicklime, slaked lime, dolomite, gypsum, peat ash, calcium phosphate, and the salts of sodium, potassium, and ammonia. Lecture 8 was on improvements of land by burning, irrigation, fallowing, crop rotation, and pasturage. An appendix provides data that the Duke of Bedford had his gardener, George Simpson, at Woburn Abbey, collect at field trials on which forage species were most nutritious as livestock feed (Davy 1839, VIII:89–141). Simpson's extensive data were quite precise (Fig. 6), but Davy was only able to make a few imprecise comments about them (Davy 1839, VIII:144–148). Davy is credited with making agricultural chemistry into a coherent subject, but he deemphasized mineral fertilizers (Wilmot 1990:26). Davy's support for humus theory was a negative influence (Browne 1944:208, 211, Morton 1981:392–393). Figure 6Open in figure viewerPowerPoint George Simpson's field data for Holcus mollis, number 66 of 97 species he analyzed for Davy. Curt. Lond. = William Curtis, Flora Londinensis (two volumes, London, 1798). Wither. B. = William Withering, Botanical Arrangements (four volumes, London, 1801). Davy 1839, VIII:129. The popularity of Davy's Elements of Agricultural Chemistry began to wane in 1835, when an English translation of Chaptal's Chimie appliquée à l'agriculture appeared (Miles 1961:133). As a scientist-educator, Jean Antoine Chaptal (1756–1832) was as capable as Hermbstädt (see the discussion on Hermbstädt below) and Davy, but he was also a prominent government official under Napoleon (Browne 1944:183–189, Crosland 1971, Matagne 1999:38–39). Chaptal obtained a doctorate in medicine at Montpellier and then went to Paris for further study, but soon became more interested in chemistry. He became wealthy, partly by marriage and by a large gift from an uncle, and also by investing in chemical industries. On an estate in the Loire Valley, he raised sheep and sugar beets. He published the first edition of his Élémens de chimie (three volumes, 1790) a year before Hermbstädt published his comparable work. Surprisingly, Hermbstädt not only translated Lavoisier into German, but also Chaptal. Others translated Chaptal's Élémens into English, Italian, and Spanish. Part 4 of the Élémens was on the chemistry of plants (149 pages) and animals (88 pages). While this work was very popular, in 1823 Chaptal published Chimie appliquée à l'agriculture (two volumes, edition 2, 1829), which became his most popular work and was translated, as mentioned above, into English (1835, three American editions) and German. French chemists Pierre-Joseph Pelletier (1788–1842) and Joseph-Bienaimé Caventou (1795–1877) studied the chemistry of plants, including green pigment in leaves, naming this compound chlorophyll (1817) (Reed 1942:197, Delépine 1951, Partington 1964:241–243, Berman 1971, 1974). University of Utrecht Professor of Chemistry Geradus Johannes Mulder (1802–1880) continued these studies in the 1830s and correctly analyzed phytol (Reed 1942:167, Browne 1944:252–262, Partington 1964:319–320, Snelders 1974:558). In 1851, University of Tübingen Professor of Botany Hugh von Mohl (1805–1872), who had coined the term protoplasm and founded Botanische Zeitung 1842, discovered that chlorophyll does not occur throughout green cells, but occurs in granules (now chloroplasts) (Reed 1942:166, Weevers 1949:9, Klein 1974). Chlorophyll was a complex substance that was slowly elucidated in the later 1800s and early 1900s, when four constituents were separated (Reed 1942:197–199). Figure 7Open in figure viewerPowerPoint (a) Henri Dutrochet. Medallion by David d'Angers. (b) Endosmometer. Dutrochet 1837. Carls 1954:164. René-Joachim-Henri Dutrochet (1776–1847) grew up in an aristocratic family during the French Revolution (Kruta 1971, Schiller and Schiller 1975:5–21, Aron 1990). After participating in revolutionary conflicts, he studied medicine in Paris, 1802–1806, and then became an army medical officer. After contracting typhoid, he retired from the army and later turned to biological research. In 1831 he became a member of the Académie des Sciences. He studied both animal and plant physiology; his Recherches anatomiques et physiologiques sur la structure intime des animaux et des végétaux et sur leur motilité 1824 contained an early defense of the cell theory (translated by Gabriel and Fogel 1955:6–9), though his studies were not precise enough to establish it (Harris 1999:27–31). His discovery of osmosis and his studies on gas exchanges between organisms and their environments were relevant to all forms of life (Sachs 1890:508–514, Reed 1942:176, Carles 1954:163–174, Schiller and Schiller 1975:27–60, Morton 1981:390–392, Magnin-Gonze 2004:180–181). He synthesized almost three decades of research in his Mémoires pour server a l'histoire anatomique et physiologique des végétaux et des animaux 1837. His discussion of the similarity between plant and insect respiration is translated by Bodenheimer (1958:378–379). Dutrochet fastened membranes to a perforated metal disc and attached a mercury monometer, creating the first osmometer, with which he measured osmotic pressure. He concluded that osmotic pressure increases with the density of the substance on the opposite side of the membrane from water, though he overlooked concentration of the substance as a cause. He decided that osmosis causes water uptake by roots and sap movement. He also studied the response of leaves of the sensitive plant Mimosa pudica to touch, and he used a thermo-electric apparatus to measure heat produced by growing shoots. He believed his findings undermined vitalism. He developed an experimental test that later became standard: growing Elodea in water with light but varying other environmental factors and assessing gas bubbles generated (Weeves 1949:9). Dutrochet's studies were the best physiological investigations between 1804 and 1840, but they were not studied as carefully as they deserved (Sachs 1890:514). Von Mohl further clarified osmosis in plants (Reed 1942:177–178). In Prussia, agricultural chemists and related workers wanted to increase crop productivity. Berlin professor of chemistry Sigismund Friedrich Hermbstädt (1760–1833) published a three-volume chemistry textbook for his students in 1791, and then translated Lavoisier's Traité élémentaire de chimie (1789) into German (1792). He taught chemistry at the Berlin Medico-Surgical College and other institutions, but when Wilhelm Humboldt established the University of Berlin (now Humboldt University) in 1810, Hermbstädt became professor of technology, which included agricultural chemistry (Kerstein 1978). He had founded the Archive der Agriculturchemie in 1803 and published seven volumes before it ended in 1818. It published such illustrious authors as Saussure and Alexander von Humboldt. Hermbstädt also published in it his own experiments with different fertilizers for crops (Browne 1944:189–192). Studies on agricultural chemistry were also being conducted by agronomist Albrecht Daniel Thaer (1752–1828), who became head of the Institute for Agriculture in Möglin, wrote a four-volume treatise, Grundsätze der rationellen Landwirtschaft (Berlin, 1809–1812), and also taught at the University of Berlin, 1810–1818. Thaer's bibliography, which numbers each edition of his works and includes foreign translations, runs to 429 titles (Klemm and Meyer 1968:196–228). Agricultural chemist Heinrich Einhof (1778–1808) became professor of chemistry at Möglin, and he published analyses of plant products and humus in Archiv der Agriculturchemie (Browne 1944:178–183, Partington 1964:252). Thaer published Einhof's Grundriss der Chemie für Landwirthe 1808 soon after Einhof's death. Gustav S. Schübler (1787–1834) was the founder of soil physics (Browne 1944:225–231). He studied science and medicine at the Universities of Tübingen and Vienna, practiced medicine in Stuttgart, then taught at a new agricultural institute near Bern, Switzerland, 1812–1817, before returning to teach at Tübingen. His Grundsätze der Agricultur-chemie in näheraer Beziehung auf land- und forstwirthschaftliche Gewerbe (Fundamentals of Agricultural Chemistry with special reference to practical farming and forestry, 1830) devoted 170 pages to soils and fertilizers and 67 pages to analysis of plant products. His classification of soils was partly physical and partly chemical: quartz sand, sandy limestone, earthy gypsum, powdered calcium carbonate, potter's clay, loamy clay, humus, loam of cultivated fields. He also divided soils into heavy and light soils. Sachs discussed three works that synthesized plant physiology during the 1830s. The best was the first: Physiologie végétale (three volumes, over 1600 pages, 1832, German, 1833–1835) by Augustin-Pyramus de Candolle (1778–1841), who was discussed (regarding phytogeography) in Part 34 of this study (Egerton 2010:26–29). He was the most productive botanist of his time, and Physiologie végétale was the second part of his Cours de botanique. It proved to be more popular than the first part, Organographie végétale (two volumes, 888 pages, 1827), and the Royal Society of London awarded him a medal for it (Candolle 2004:440). Sachs (1890:515–516) grumbled that Candolle sometimes buried "points of fundamental importance under a huge mass of facts and statements from other writers" and he "went off on a tangent with his idea of the contractile spongiole at the root tip" (Reed:1942:176), which tip supposedly sucked up solutions. Candolle did understand that the escape of water vapor from plants was related to the number of stomata, and that sunlight accelerates transpiration (Reed 1942:189–190). Browne (1944:213) complained that "De Candolle's support of the humus theory [1832, III:1242–1243], because of the high standing of his authority, greatly delayed the acceptance of the mineral theory of plant nutrition." Browne (1944:213–214) also thought that de Candolle (1832, I:248–249) probably exaggerated the importance of root excretions as inhibitors of other plants, now called amensalism, the importance of which was still unclear in 1987 (Barbour et al. 1987:119). Candolle accepted a limited vitalism (Drouin 1994a, b). Karl S. Sprengel (1787–1859) was an agricultural chemist whose work Browne (1944:231–239) considered very important, but historians of botany have ignored him. He studied under the agronomist Thaer. Sprengel managed several large estates in Saxony and Silesia for seven years, then took an agricultural tour through Germany, The Netherlands, France, and Switzerland. He next studied and taught at Göttingen University until 1831, taught at Collegium Carolinum in Brunswick, 1831–1839, and finally opened an agricultural academy at Regenwald. He wrote numerous articles, which he later incorporated into five of his books, which Browne discussed. He was skeptical of the humus theory of plant enrichment and studied its content and possible role (Ihde 1964:421, Partington 1964:310, 312). He listed (1845) 15 elements that he considered essential for healthy plant growth—oxygen, carbon, hydrogen, nitrogen, sulfur, phosphorus, chlorine, potassium, sodium, calcium, magnesium, aluminum, silicon, iron, and manganese—and five elements that might be essential—fluorine, iodine, bromine, lithium, and copper. The first three came from the air, and the rest from the soil. He thought that either too little or too much of some elements could inhibit growth. He analyzed and compared productive and unproductive soils, an example of which Browne quoted (Browne 1944:234). He classified soils into 18 groups and fertilizers into 6 groups and provided analyses of 180 soils from different parts of the world. He emphasized that different plant species have different mineral and soil needs. Browne summarized Sprengel's significance (1944:237) Sprengel was thus recognized long before Liebig as a proposer of the doctrine of mineral fertilizers. Liebig (1862), always jealous of his own claims for this discovery, disputed this recognition on the basis of the great inaccuracy of Sprengel's analyses and also because he failed to distinguish between essential and unessential ash constituents. While this does not affect the priority of Sprengel's announcement, Liebig was perfectly correct in the main facts of his criticism. Figure 8Open in figure viewerPowerPoint (a) August Pyramus de Candolle. Trembley 1987:388. (b) Jean-Baptiste Boussingault. Carles 1954:154. Browne added that Liebig's analyses were not flawless either. The founding of agricultural experiment stations was an important addition to teaching agricultural sciences. Bossingault developed the first one in France, Lawes the second one in England, and others followed in Germany and the United States (Rossiter 1975, Finlay 1998). Jean-Baptiste Boussingault (1802–1887) was a Parisian who had a rudimentary early education, but his mother gave him the money to buy Louis Thenard's Traité de chimie (four volumes, 1813–1816), and he taught himself chemistry. He attended public lectures at the Collège de France and then studied at a mining school (as Humboldt had). He spent the years 1821–1832 in geological, mineralogical, and meteorological researches in the Andes (Aulie 1970a, b, McCosh 1984). He published 25 scientific papers while in South America, and afterwards published 20 more articles on South America. His posthumous Mémoires (five volumes, 1892–1903) discussed his life only into 1832, perhaps inspired by his patron and friend Humboldt's Personal Narrative. Boussingault, like Saussure, brought to physiology from the physical sciences a sophistication in experimentation that runs through his work (Ihde 1964:422–423, Partington 1964:340–341). After returning to France, he married on 7 January 1835, and then taught chemistry at Lyon for half a year. His wife and her brother had inherited an estate at Bechelbronn in Alsace, and he became fascinated by the challenge of applying science to agricultural improvements (Browne 1944:239–252). German plant physiologist Sachs (1890:449) claimed that Boussingault "pursued the path of pure induction as contrasted with Liebig's deductive mode of proceeding, [and] gradually improved the method of experimenting on vegetation," and French plant physiologist Carles (1954:155) judged Boussingault to be the greatest agronomist of the 1800s. A prominent English historian of agriculture (Russell 1937:13) agreed: "to Boussingault belongs the honor of having introduced the method by which the new agricultural science was to be developed," and their judgment is echoed by McCosh (1984:xiii). Theophrastos (c. 371–c. 287 B.C.) had reported that legumes, excepting chickpea, reinvigorated soil (Theophrastos 1916, II: Book 8, section 7, par. 2, pages 183–185; Theophrastos 1976–1990, II, Book 4, section 8, par. 2, page 273) and Pliny (AD 23–79) had reported that plowing under lupines enriches the soil (Plinius Secundus 1950, Book 17, ch. 6, pages 38–39). The Belgian practice of crop rotation was learned by Englishman Sir Richard Weston in 1644 and published in his Discours of Husbandrie (1650), but no one before Boussingault studied the practice scientifically (Russell 1966:37–38). He planned a series of crop rotations and studied this problem, 1836–1848, with special focus on where plants get nitrogen, in what form, and how it is assimilated (Aulie 1970b:422–445, McCosh 1984:68). He also compared the time taken by crops to mature at Bogata and Bechelbronn, measuring days between germination and maturation and also mean temperature. The several aspects of physiology, soils, and fertilizers that he studied are seen in his Économie rurale considérée dans ses rapports avec la chimie, la physique et la météorologie (two volumes, 1843–1844, second edition, 1851, German 1844, second edition, 1851, English 1845, Italian 1850). He was never satisfied with his understanding of the uptake and use of nitrogen by plants. Boussingault experimented on this by growing clover, peas, wheat, and oats in unfertilized soil and found that the clover and peas gained nitrogen, but the wheat and oats did not (1843–1844, I:82–83; cited from Browne 1944:244). The agricultural press flourished in the 1800s, in both Europe and the United States. The Cultivator, a monthly edited by Joseph Buell at Albany, New York, for the years 1838–1839 provides a sample for both Britain and America, since he quoted extensively from British periodicals. It included accounts of livestock as well as crops, but only the latter a