Marcello Malpighi

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[b. Crevalcore (Italy), March 10, 1628, d. Rome, December 30, 1694]

A pioneer in the use of the recently invented microscope, Malpighi located the capillaries that carry blood from the arteries to the veins. He also identified sensory receptors (papillae) of the tongue and skin and capsules of the kidney and spleen. He showed that there is no such thing as black bile, which since ancient times had been believed to be one of the four humors (fluids) of the human body, together with yellow bile, blood, and phlegm.

The Italian microscopist Marcello Malpighi (1628-1694) was the first to see the capillaries and was a founder of histology, embryology, plant anatomy, and comparative anatomy.

On March 10, 1628, Marcello Malpighi was born at Crevalcore near Bologna. He attended the University of Bologna, where he graduated in philosophy and in medicine in 1653. Malpighi became a lecturer in logic at Bologna in 1655 but left in 1656 to be professor of theoretical medicine at Pisa. There he met Giovanni Borelli, a mathematician who had recently turned his attention to the analysis of movement in animals.

Malpighi returned to Bologna in 1659, where he was made extraordinary lecturer in theoretical medicine. Through Borelli's influence, Malpighi was elected to the first chair in medicine at Messina in 1662, but in 1666 he returned to Bologna to become professor of medicine, and he remained there for the next 25 years.

By 1667 Malpighi's work had already aroused the interest of the recently formed Royal Society in London, and one of its secretaries wrote to him suggesting that he communicate his results to the society. Malpighi responded favorably, and most of his later books were published in London. He was elected a foreign member of the Royal Society in 1668.

Malpighi was also a successful physician, and in 1691 he became the personal physician of Pope Innocent XII in Rome. Malpighi died on Nov. 29, 1694, in Rome.

Discovery of Capillaries

In September 1660 Malpighi began to study the structure of the lungs, and within nine months he had communicated the results of these studies in two letters to Borelli in Pisa, who published them under the title De pulmonibus observationes anatomicae (1661). Malpighi presented "a few little observations that might increase the things found out about the lungs." These observations included the first descriptions of the air sacs (pulmonary alveoli) in the lungs of a dog and of the pulmonary capillaries in the frog and tortoise.

Having convinced himself of the presence of direct connections between the arteries and veins in the lungs of the frog and the tortoise, Malpighi was prepared to speculate that the same was so in other animals: he was unable to see such anastomoses in the dog's lung, perhaps, because these "small vessels escape the senses on account of their smallness."

Histological Studies

The science of the study of the structure of tissues was established by the classical microscopists, and Malpighi's contributions were among the most important. He published four tracts in 1665. The first one described the presence of "red globules of fat" in the blood vessels of the mesentery of the hedgehog. This is one of the earliest descriptions of the red blood cell, although Malpighi did not realize the significance of his observation. In other tracts he described the papillae of the tongue and the skin and suggested that these may have a sensory function. The layer of cells in the skin now known as the Malpighian layer was also described. The last tract of 1665 concerned the general structure of the brain. Malpighi showed that the white matter consists of bundles of fibers which connect the brain with the spinal cord. He described the gray nuclei that occur in the white matter.

Malpighi's De viscerum structura execitatio anatomica (1666) gives a detailed and fairly accurate account of the structure of the liver, spleen, and kidney. Malpighi dissected the tissue under the microscope, and he identified small particulate masses or "lobules," resembling bunches of grapes, in the liver. Each lobule was composed of "tiny conglobate bodies like grape seeds" connected by central vessels. Having seen these lobules in the livers of several species, he concluded that the lobule was the fundamental hepatic unit. He believed that the lobules were supplied by fine blood vessels and that their function was secretory. Malpighi realized, therefore, that one function of the liver is as a gland and that the bile duct must be the passage through which the secreted material (bile) passes: the gall-bladder was, therefore, not the site of origin of bile. He was also able to prove in an animal experiment that the gallbladder is only a temporary store for bile on its way to the intestine. Malpighi speculated that bile might be useful in the process of digestion.

Although Malpighi was fond of describing many structures as "glands," he realized, from his study of the blood supply to the spleen, that this organ is not a gland but a contractile vascular organ. He was the first to describe the lymphatic bodies (Malpighian corpuscles) in the spleen.

Whereas other anatomists believed that the outermost part of the kidney was structureless, Malpighi showed that it is composed of many little wormlike vessels (the renal tubules) which he called "canaliculi." Although he could not demonstrate any continuity between the convoluted canaliculi and the straight tubules in the central mass of tissue (medulla), he predicted that such a continuity exists. Malpighi's description of how he discovered the glomeruli in the outer part of the kidney is vivid: "In all kidneys which up to this time I have been able to get, I have detected a number of very small glands [that is, Malpighian corpuscles, or glomeruli]. In order to see these glands, black fluid mixed with spirit of wine should be injected through the renal artery. And when the kidney is sectione…. one will see these same innumerable glands attached like apples to the blood vessels, the latter swollen with the black liquid and stretched out into the form of a beautiful tree." Malpighi realized that the "glands" were connected to the "extreme ends of the arteries" and to the veins but did not observe the true nature of the "glands," that is, that they are composed of a tuft of capillaries. He speculated that their function was to secrete the urine.

Malpighi's detailed description of the medulla of the kidney showed how the canaliculi converge on the pelvis and enter the ureter. In pathological specimens he observed the formation of kidney stones in the pelvis.

Insect Anatomy

Malpighi's memoir De bombyce (1669), on the silk-worm moth, was the first detailed account of the structure of an invertebrate. Prior to his study, it was still believed that such small creatures were devoid of internal organs, and he himself was surprised to find that the moth was just as complex as higher animals. He not only discovered the trachae and spiracles, the system of tubes and holes through which insects breathe, but also correctly guessed their function. He was the first to describe the nerve cord and ganglia, the silk glands, the multichambered heart, and the urinary tubules, which still bear his name.

Embryological Studies

With his microscope, Malpighi was able to study much earlier stages of the embryo than had hitherto been possible. His results were communicated to the Royal Society in two memoirs: De formatione pulli in ovo (1672) and De ovo incubato (1675), which placed embryological study on a firm basis of sound observation. He saw the heart within 30 hours of incubation and noticed that it began to beat before the blood reddened. He described the development of the dorsal folds, the brain, the mesoblastic somites, and structures which were later identified as gill arches. However, Malpighi believed that he had seen the form of an embryo in an unincubated egg. A possible explanation is that the egg, being 2 days old, had been "incubated" in the hot Italian August sun. This observation was used, not by Malpighi himself as much as by his followers, to support the doctrine of preformation, that is, that the whole adult was present in the egg and had only to be "unfolded" by a suitable stimulus.

Plant Anatomy

Some of Malpighi's most extensive writing, beautifully illustrated, is on plants. Malpighi and his contemporary Nehemiah Grew became the confounders of plant anatomy by their systematic studies on the microscopic structure of plants. Malpighi's book Anatome plantarum was published in two parts in 1675 and in 1679. His illustrations frequently show the plant cell with its wall, first described by Robert Hooke in 1665.

Malpighi's interest in the structure of plants began when he noticed the broken branch of a chestnut tree which had fine threads projecting from the surface. Upon examining these with his lens he was struck with their resemblance to the air tubes of insects. Although he wrongly concluded that they served the function of breathing, his enthusiasm for the study of plants had been awakened. His drawings of the stems of higher plants distinguished between the annular rings of the dicotyledon and the scattered bundles of the monocotyledon (the terms dicotyledon and monocotyledon were introduced in the early 18th century). He suggested that material required for growth of the plant was formed from the sap by the leaves, but the erroneous idea that the sap circulated, as blood did, was originated by other writers.

Malpighi's work on the development of plants is just as significant as that on the development of animals. He made drawings of the embryo sac and endosperm and gave a superb account of the germination of seeds in which he differentiated between those later called monocotyledons and dicotyledons. He was the first to describe tubercles on leguminous roots, and he showed that some galls contained a grub. He traced the grub back to an egg and onward to an insect, of which he illustrated the egg-laying apparatus.

Further Reading

Some biographical information on Malpighi is in Howard B. Adelmann, Marcello Malpighi and the Evolution of Embryology (1966), and in Circulation of the Blood: Men and Ideas, edited by Alfred P. Fishman and Dickinson W. Richards (1964). For background see Charles Singer, A History of Biology to about the Year 1900 (1931; 3d rev. ed. 1959).

Additional Sources

Malpighi, Marcello, The correspondence of Marcello Malpighi, Ithaca N.Y. Cornell University Press, 1975.

Bibliography

See study by D. B. Meli (2011).

Malpighi, Marcello (1628–1694), Italian physician and anatomist. Malpighi was born in Crevalcore, near Bologna, on 10 March 1628. He graduated in medicine and philosophy at the University of Bologna in 1653, and he taught logic at the same university until 1656, when he was called to the chair of theoretical medicine at the University of Pisa. Three years later he returned to Bologna, lecturing in theoretical and practical medicine. From 1662 to 1666 he held the chair of primary professor of medicine at the University of Messina. He then returned once more to Bologna, where he taught practical medicine until 1691, the year in which he moved to Rome in the capacity of chief physician to Pope Innocent XII. He died in Rome on 30 November 1694. These institutional settings are of a special importance in understanding his development as an anatomist, physician, and natural philosopher. Although he was trained at Bologna in the traditional course of scholastic disciplines, he also attended with other select students the private dissections and vivisections conducted by the university professor Bartolomeo Massari. In his time at Pisa he met Giovanni Alfonso Borelli (1608–1679), professor of mathematics there, and their ensuing collaboration was crucial in bringing Malpighi closer to corpuscularianism (the idea that the visible properties of matter derive from the interactions of minute particles of matter), to mechanical philosophy (the view that every natural phenomenon can be explained through matter and motion), and to Galileo's natural philosophy. In Messina he found a congenial environment for his investigations on marine animals and the sensory organs. Finally, from 1667, correspondence with Henry Oldenburg and the relationships that he established with the Royal Society brought Malpighi into closer contact with English experimental physiology.

Malpighi's works display a wide range of interests. In De Pulmonibus (On the lungs; Bologna, 1661), composed in the form of two letters addressed to Borelli, he announced his discovery of capillary circulation and gave a detailed account of the vesicular structure of the human lung. In Epistolae Anatomicae de Cerebro ac Lingua (Anatomical letters on the brain and the tongue; Bologna, 1665) and in De Externo Tactus Organo (The external organ of touch; Naples, 1665), he made his discovery of the sensory receptors of the tongue and cutaneous papillae part of a far-reaching project in neuroanatomical research. De Viscerum Structura (The structure of the internal organs; Bologna, 1666) and De Structura Glandularum Conglobatarum (The structure of the conglobate glands; London, 1689) present Malpighi's main theoretical view of the gland as the building block of the body's mechanical structure. In De Bombyce (On the silkworm; London, 1669) he investigated the anatomy of insects, and he gave an accurate description of the development of the chick in De Formatione Pulli in Ovo (The development of the chick in the egg; London, 1673), adding new evidence in support to the preformationist hypothesis, that is, the idea that the organism is already present and fully developed in the seed or egg. In Anatomes Plantarum (Anatomy of plants; London, 1679), Malpighi made use of the microscope and its related techniques in the study of animal and vegetable anatomy with great dexterity and profit. In De Polypo Cordis (On the polyp of the heart; 1666), he argued that the examination of pathological states, natural anomalies, and monstrosities could shed light on the normal functioning of organs and on the general processes of nature, thus laying the foundations for a research program centered on localizing the anatomical seats of disease.

From an anatomical point of view, Malpighi's work is a clear example of experimental investigation conducted in the wake of William Harvey's discovery of the circulation of the blood. Philosophically speaking, the main influence comes from Galileo's redefinition of matter, motion, and nature. Distancing himself from Descartes's extreme views on the mechanization of the body and the thorough identification of natural productivity with mechanical agency, Malpighi did not rule out the animate and sentient character of the body, and he emphasized the unattainability of perfection in the natural mechanics of living beings. Being both a theoretical anatomist and a physician—his Consultationes Medicinales (Medical consultations; Padua, 1713; Venice, 1747) are evidence of his clinical expertise—Malpighi represents the intriguing case of an early modern practitioner confronted with the need to harmonize theory (a new image of the body) and practice (the continuing success of traditional therapy) in the context of the new medical discourse.

Bibliography

Primary Sources

Malpighi, Marcello. The Correspondence of Marcello Malpighi. Edited by Howard Bernhardt Adelmann. Ithaca, N.Y., 1975.

——. Opera Omnia. London, 1686. Rept. New York, 1975.

——. Opera Posthuma. London, 1697, Amsterdam, 1698.

Secondary Sources

Adelmann, Howard Bernhardt. Marcello Malpighi and the Evolution of Embryology. Ithaca, N.Y., 1966.

Bertoloni Meli, Domenico, ed. Marcello Malpighi: Anatomist and Physician. Florence, 1997.

—GUIDO GIGLIONI

Marcello Malpighi.

Marcello Malpighi (10 March 1628 – 29 November 1694) was an Italian doctor, who gave his name to several physiological features, like the Malpighian tubule system.

Contents 1 Early years 2 Career 3 Research 4 Years in Rome 5 Memories of Malpighi in Bologna 6 Some of Malpighi's important works 7 Footnotes 8 Other References 9 External links

Early years

Malpighi was born on March 10, 1628 at Crevalcore near Bologna, Italy. The son of well-to-do parents, Malpighi was educated in his native city, entering the University of Bologna at the age of 17.^[1] In a posthumous work delivered and dedicated to the Royal Society in London in 1697, Malpighi says he completed his grammatical studies in 1645, at which point he began to apply himself to the study of Peripatetic Philosophy. He completed these studies about 1649, where at the persuasion of his mother Frances Natalis he began to study physics. When his parents and grandmother became ill, he returned to his family home near Bologna to care for them.

Career

In 1653, his father, mother, and grandmother being dead, Malpighi left his family villa and returned to the University of Bologna to study Anatomy. In 1656 he was made a reader at Bologna, and then a professor of physics at Pisa, where he began to abandon the disputative method of learning and apply himself to a more experimental method of research. Based on this research, he wrote some Dialogues against the Peripatetics and Galenists (those who followed the precepts of Galen), which were destroyed when his house burned down. Weary of philosophical disputation, in 1660, Malpighi returned to Bologna and dedicated himself to the study of anatomy. He subsequently discovered a new structure of the lungs which led him to several disputes with the learned medical men of the times. In 1662, he was made a professor of Physic at the Academy of Messina.^[2]

Retiring from university life to his villa in the country near Bologna in 1663, he worked as a physician while continuing to conduct experiments on the plants and insects he found on his estate. There he made discoveries of the structure of plants which he published in his Observations. At the end of the year 1666, Malpighi was invited by the Italian Senate to return to the public academy at Messina, which he did in 1667. Although he accepted temporary chairs at the universities of Pisa and Messina, throughout his life he continuously returned to Bologna to practice medicine, a city that repaid him by erecting a monument in his memory after his death.^[3]

In 1668, Malpighi received a letter from Mr. Oldenburg of the Royal Society in London, inviting him to correspond. Malpighi wrote his history of the silkworm in 1668, and sent the manuscript to Mr. Oldenburg. As a result, Malpighi was made a member of the Royal Society in 1669. In 1671, Malpighi’s Anatomy of Plants was published in London by the Royal Society, and he simultaneously wrote to Mr. Oldenburg, telling him of his recent discoveries regarding the lungs, fibers of the spleen and testicles, and several other discoveries involving the brain and sensory organs. He also shared more information regarding his research on plants. At that time, he related his disputes with some younger physicians who were strenuous supporters of the Galenic principles and opposed to all new discoveries. Following many other discoveries and publications, in 1691, Malpighi was uprooted from his beloved home in Bologna and summoned to Rome by Pope Innocent XII as papal physician, which position he held until his death three years later. He died of apoplexy in 1694.^[4]

Marcello Malpighi is buried in the church of the Santi Gregorio e Siro, in Bologna, where nowadays can be seen a marble monument to the scientist with an inscription in Latin remembering - among other things - his "SUMMUM INGENIUM / INTEGERRIMAM VITAM / FORTEM STRENUAMQUE MENTEM / AUDACEM SALUTARIS ARTIS AMOREM" (great genius, honest life, strong and tough mind, daring love for the medical art).

Research

Around the age of 38, and with a remarkable academic career behind him, Malpighi decided to dedicate his free time to anatomical studies.^[5] Although he conducted some of his studies using vivisection and others through the dissection of corpses, his most illustrative efforts appear to have been based on the use of the microscope. Because of this work, many microscopic anatomical structures are named after Malpighi, including a skin layer (Malpighi layer) and two different Malpighian corpuscles in the kidneys and the spleen, as well as the Malpighian tubules in the excretory system of insects.

See Timeline of microscope technology for more information.

Although a Dutch spectacle maker created the compound lens and inserted it in a microscope around the turn of the seventeenth century, and Galileo had applied the principle of the compound lens to the making of his microscope patented in 1609, its possibilities as a microscope had remained unexploited for half a century, until Robert Hooke improved the instrument. Following this, Marcello Malpighi, Hooke and two other early investigators associated with the Royal Society, Nehemiah Grew and Antoine van Leeuwenhoek were fortunate to have a virtually untried tool in their hands as they began their investigations.^[6]

Working on frogs and extrapolating to humans, Malpighi demonstrated the structure of the lungs, previously thought to be a homogeneous mass of flesh, and he offered an explanation for how air and blood mixed in the lungs.^[7] Malpighi also used the microscope for his studies of the skin, kidneys, and liver. For example, after he dissected a black male, Malpighi made some groundbreaking headway into the discovery of the origin of black skin. He found that the black pigment was associated with a layer of mucus just beneath the skin.

He was the first to see capillaries in animals, and he discovered the link between arteries and veins that had eluded William Harvey. He may have been the first person to see red blood cells under a microscope. His treatise 'De polypo cordis' (1666) was important for understanding blood composition, as well as how blood clots. In it, Malpighi described how the form of a blood clot differed in the right vs. the left sides of the heart.

The use of the microscope enabled Malpighi to discover that insects (particularly, the silk worm) do not use lungs to breathe, but small holes in their skin called tracheae. Malpighi also studied the anatomy of the brain and concluded that this organ is a gland. In terms of modern endocrinology this deduction is correct because the hypothalamus of the brain has long been recognized for its hormone-secreting capacity.

Because Malpighi had a wide knowledge of both plants and animals, he made contributions to the scientific study of both. The Royal Society in London published two volumes of his botanical and zoological works in 1675 and 1679. Another edition followed in 1687, and a supplementary volume in 1697.^[8] In his autobiography, Malpighi speaks of his Anatome Plantarum, decorated with the engravings of Robert White (1645–1703) as "the most elegant format in the whole literate world."^[9]

His study of plants led him to conclude that plants had tubules similar to those he saw in insects like the silk worm (using his microscope, he probably saw the stomata, through which plants exchange carbon dioxide with oxygen). Malpighi observed that when a ring-like portion of bark was removed on a trunk a swelling occurred in the tissues above the ring, and he correctly interpreted this as growth stimulated by food coming down from the leaves, and being blocked above the ring.

A talented sketch artist, Malpighi seems to have been the first author to have made detailed drawings of individual organs of flowers. In his Anatome plantarum, there is a longitudinal section of a flower of Nigella (his Melanthi, literally honey-flower) with details of the nectariferous organs. He adds that it is strange that nature has produced on the leaves of the flower shell-like organs in which honey is produced.^[10]

Malpighi had success in tracing the ontogeny of plant organs, and the serial development of the shoot owing to his instinct shaped in the sphere of animal embryology. He specialized in seedling development, and in 1679 he published a volume containing a series of exquisitely drawn and engraved images of the stages of development of Legumeninosae (beans) and Cucurbitae (squash, melons). Later he published material depicting the development of the date palm. The great Swedish botanist Linnaeus named the genus Malpighia in honor of Malpighi’s work with plants; Malpighia is the type genus for the Malpighiaceae, a family of tropical and subtropical flowering plants.

Because Malpighi was concerned with teratology (the scientific study of the visible conditions caused by the interruption or alteration of normal development) he expressed grave misgivings about the view of his contemporaries that the galls of trees and herbs gave birth to insects. He conjectured that the creatures in question arose from eggs previously laid in the plant tissue.^[11]

Malpighi’s investigations of the life cycle of plants and animals led him into the topic of reproduction. He created detailed drawings of his studies of chick embryo development, seed development in plants (such as the lemon tree) and the transformation of caterpillars into insects. His discoveries helped to illuminate philosophical arguments surrounding the topics of emboîtment, pre-existence, preformation, epigenesis, and metamorphosis.^[12]

Years in Rome

In 1691 Pope Innocent XII invited him to Rome as Papal physician. He taught medicine in the Papal Medical School and wrote a long treatise about his studies which he donated to the Royal Society of London.

Marcello Malpighi died of apoplexy (an old-fashioned term for a stroke or stroke-like symptoms) in Rome on September 30, 1694 at the age of 66. In accordance with his wishes, an autopsy was performed. The Royal Society published his studies in 1696.

Memories of Malpighi in Bologna

Malpighi's tomb in Bologna

Malpighi is buried in the church of the Santi Gregorio e Siro, in Bologna, where nowadays can be seen a marble monument to the scientist with an inscription in Latin remembering - among other things - his "SUMMUM INGENIUM / INTEGERRIMAM VITAM / FORTEM STRENUAMQUE MENTEM / AUDACEM SALUTARIS ARTIS AMOREM" (great genius, honest life, strong and tough mind, daring love for the medical art).

Some of Malpighi's important works

• Anatomia Plantarum, two volumes published in 1675 and 1679, an exhaustive study of botany published by the Royal Society.
• De viscerum structura exercitati
• De pulmonis epistolee
• De polypo cordis, 1666
• Dissertatio epistolica de formation pulli in ovo, 1673

Footnotes

1. ^ Murray Scott, Flora. The Botany of Marcello Malpighi, Doctor of Medicine. The Scientific Monthly. Volume 15, No. 6, pages 546-553
2. ^ Churchill, J. Marcelli Malpighii Philosophi et Medici Bononiensis e Regia Soc. Lone. Opera Posthuma Fig. aeneis illustrate quibus praefixa est ejusdem Vita a seipso Scripta Lond. Source: Philosophical Transactions (1683-1775), Vol. 19 (1695–1697), pp. 545-560. Published by the Royal Society 08/02/2011 09:28
3. ^ Pinto-Correia. The ovary of eve: egg and sperm in preformation. 1997 Pages 22-25
4. ^ Murray-Scott, 547
5. ^ Pinto-Correia, 23
6. ^ Bolam, Jeanne. ‘The botanical works of Nehemiah Grew’, F. R. S. (1641-1712); [Source: Notes and Records of the Royal Society of London, Vol.27. No. 2 (Feb 1973), pages 219-231]
7. ^ Bolam, Jeanne. ‘The botanical works of Nehemiah Grew’, F. R. S. (1641-1712); [Source: Notes and Records of the Royal Society of London, Vol.27. No. 2 (Feb 1973), pages 219-231]
8. ^ Arber, Agnes. Nehemiah Grew (1641-1712) and Marcello Malpighi (1628-1694): an essay in comparison. Isis Volume 34, No 1 pages 7-16.
9. ^ Arber, Agnes. Nehemiah Grew (1641-1712) and Marcello Malpighi (1628-1694): an essay in comparison. Isis Volume 34, No 1 pages 7-16
10. ^ Lorch, Jacob. The discovery of nectar and nectaries and its relation to views on flowers and insects. Isis. Volume 69, No. 4 pages 514-533
11. ^ Arber, Agnes. Nehemiah Grew (1641-1712) and Marcello Malpighi (1628-1694): an essay in comparison. Isis Volume 34, No 1 pages 7-16.
12. ^ Bowler, Peter. Preformation and pre-existence in the seventeenth century: a brief analysis.; The History of Biology. Volume 4, No.2, 221-244

Other References

Adelmann, Howard (1966) Marcello Malpighi and the Evolution of Embryology 5 vol., Cornell University Press, Ithaca, N.Y. OCLC 306783 Marcello Malpighi. (1685) De Externo Tactus Organo Anatomica Observatio (Naples, Italy: Aegidium Longum

External links

Wikimedia Commons has media related to: Marcello Malpighi

• Biography of Marcello Malpighi in the Encyclopaedia Britannica
• Some places and memories related to Marcello Malpighi
•  "Marcello Malpighi". Catholic Encyclopedia. New York: Robert Appleton Company. 1913. 

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Name	Malpighi, Marcello
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Date of birth	10 March 1628
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Date of death	29 November 1694
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