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141 [221] LEEUWENHOEK LEEUWENHOEK
The fame of his architecture has com pletely obscured the fact that Wren was one of the coterie of scientists who made Restoration England a brilliant spot in the history of science. He was a charter member of the Royal Society and rose to its presidency in 1681. He was a nota ble geometer, having studied mathemat ics under Oughtred [172]. He lectured in astronomy, first at Gresham College, then at Oxford, and was one of those whose speculations on the nature of gravity laid the groundwork for New ton’s [231] work. Wren is buried in St. Paul’s and on the commemorative tablet is one of the best-known epitaphs in history: “Si mon- umentum requiris, circumspice” (“If you would see his monument, look about you”). [221] LEEUWENHOEK, Anton van (lay'ven-hook) Dutch biologist and microscopist Born: Delft, October 24, 1632 Died: Delft, August 26, 1723 Of all the seventeenth-century micros- copists, Leeuwenhoek was the most re markable. He was not the first, for Mal pighi [214] preceded him. Nor were his microscopes marking the way of the fu ture, for Hooke [223] was developing a compound microscope, one made up of more than one lens, and this was the true path of advancement. However, Hooke’s compound microscopes, with their still imperfect lenses, were quite limited in their clarity and powers of magnification. Leeuwenhoek, on the other hand, retained the simple micro scope based on a single lens ground with such delicacy and perfection that they could magnify up to nearly two hundred times. They were tiny and short-focus, some being no larger than the head of a pin, but through them Leeuwenhoek saw what no other man in his century could. He had had little schooling. His father, a basketmaker, died when young Leeu wenhoek was sixteen and the youngster became a clerk in a dry-goods store in Amsterdam, then opened a drapery shop of his own in Delft. As a sinecure he was appointed janitor at the Delft City Hall, a position he held for the rest of his life. His business and his appointment kept him comfortably off, and he lived only for his hobby, grinding lenses. This had begun because drapers used magnifying glasses to inspect cloth and Leeuwen hoek wanted to see more and better. He began feeding his mania (which is what it became) in 1674. In his lifetime he ground a total of 419 lenses, many of which were focused on some perma nently mounted object and through some of which no man other than himself looked. He worked alone and since he could read only Dutch, he could see the illustrations but could not read the writ ings of the great contemporary micros- copists such as Hooke and Malpighi. Leeuwenhoek, with a passion for peering at the small, looked at every thing from tooth scrapings to ditch water. He noted the fine structure of muscle, skin, hair, and ivory. He also re ported a great deal of accurate detail on the development of tiny insects. He found tiny creatures parasitic on fleas and inspired the English author Jonathan Swift to write a famous quatrain: So naturalists observe, a flea Has smaller fleas that on him prey; And these have smaller still to bite ’em; And so proceed ad infinitum. Leeuwenhoek was the first to discover the one-celled animals now called pro tozoa and in 1677 opened up a whole world of living organisms as alive as the elephant and whale yet compressing all that life into a space too small to see without mechanical help. He observed human capillaries and red blood cells with more care and detail than had the original discoverers, Malpighi and Swam merdam [224], and was the first to de scribe spermatozoa. He reported this last discovery rather nervously, fearing it might be considered obscene. Beginning in 1673 he wrote volumi nously to the British Royal Society, in Dutch, with his letters sometimes long enough to be respectable pamphlets. The Society received the communications from this unknown Dutchman with con siderable reservations. However, in 1677 142 [222] BECHER
BECHER [222] Hooke built microscopes according to Leeuwenhoek’s specifications and con firmed the Dutchman’s observations. Leeuwenhoek sent twenty-six of his tiny microscopes to the Society so that members could see for themselves. In 1680 the Royal Society elected the Dutch draper to membership—and did so unanimously. In all he sent 375 communications to the Royal Society (to whose attention his work had been brought by Graaf [228]) and 27 to the French Academy of Science (to which he was elected in 1680).
His discoveries were dramatic enough to make him world-famous. The Dutch East India Company sent him Asian in sects to put under his lenses. The queen of England paid him a visit, as did Frederick I of Prussia and Peter the Great, tsar of all the Russias, when he was visiting the Netherlands “incognito” to learn shipbuilding. It was in 1683 that Leeuwenhoek made his most remarkable discovery. He described structures that could only be bacteria. These tiny things were just at the limit of what his lenses could make out. In fact, no one else was to see bac teria again for over a century. Leeuwenhoek continued true to his passion and his hobby almost to the end of his long life of ninety years, cared for always by a devoted daughter, his sole surviving child. He was little interested in anything but observing and describing, but in that he was unexcelled. After his death, a number of his microscopes were sent to the Royal Society, in accordance with his last will. He competes with Malpighi for the title of father of microscopy. Even though Malpighi preceded him in time, Leeuwenhoek did more to dramatize and popularize the field. [222] BECHER, Johann Joachim (bekh'er) German chemist Born: Speyer, Palatinate, May 6, 1635
Died: London, England, October 1682
Becher was the son of a Lutheran minister who had become impoverished in the Thirty Years’ War. The necessity of helping to support his family slowed his education. Becher was a curious mixture of sense and nonsense. He was a successful physi cian, serving as court physician at Mainz in Germany in 1666. (Germany at the time was broken up into several hundred independent political units so that there was room for many court physicians.) He was also an economist with intelli gent notions concerning the regulation of trade, notions which got him into trouble with conservative merchants who con sidered any change subversive. As eco nomic adviser to Holy Roman Emperor Leopold I, he suggested a Rhine-Danube canal, cutting across from headwaters to headwaters, to facilitate trade between Austria and the Netherlands. He was also convinced that transmu tation was possible and tried to turn the sands of the Danube into gold. His fail ure, though not quite as dangerous to personal safety as Alhazen’s [85] had been, was dangerous enough. At least, he felt it wise to leave Austria, first for the Netherlands and then for England. In a book published in 1669 he tried to adapt the alchemical elements to the growing chemical knowledge of the sev enteenth century. To do so he divided solids into three kinds of earth. One of these he called terra pinguis (“fatty earth”), and saw this as a principle of inflammability, like the alchemical sul fur. His notions on the behavior of this principle were to be refined into the phlogiston theory by his follower Stahl [241] a generation later. Among his more immediately practi cal suggestions was one to the effect that sugar was necessary for fermentation and another that coal be distilled to ob tain tar. There is a statement attributed to Becher that goes as follows: “The chem ists are a strange class of mortals, im pelled by an almost insane impulse to seek their pleasure among smoke and vapor, soot and flame, poisons and pov erty, yet among all these evils I seem to 143 [223] HOOKE
HOOKE [223] live so sweetly, that may I die if I would change places with the Persian King.” Surely, with appropriate changes in phrasing, this is applicable to all those who find in the attainment of knowledge the greatest good. [223] HOOKE, Robert English physicist
July 18, 1635 Died: London, March 3, 1703 Hooke, the son of a clergyman, was a sickly youngster, scarred by smallpox, who showed himself an infant prodigy in mechanics and who managed to get into Oxford in 1653. There he supported himself by waiting on tables, and ap parently never got over the humiliation. At Oxford he attracted the attention of Robert Boyle [212], with whom he got his start. The association was one of mu tual advantage for it was Hooke’s me chanical skill that made a success of Boyle’s air pump. Hooke became a member of the Royal Society in 1663 and was secretary from 1677 to 1683. Moreover, from 1662 to the end of his life he held the post of “curator of experiments” to the Society. This post, the only paid one in the Soci ety, gave him a kind of bureaucratic power he never hesitated to use against those he conceived to be his enemies. He was on the one hand a most inge nious and capable experimenter in al most every field of science, and on the other a nasty, argumentative individual, antisocial, miserly, and quarrelsome. Since he investigated in a wide variety of fields, he frequently claimed (with some justice) that he had anticipated the more thorough and perfected ideas of others. His malignant pleasure in controversy could rarely be matched by others. He fought with Huygens [215], for instance, but his particular prey was the tran scendent genius (but moral coward) Isaac Newton [231], whom he more than once reduced to distraction and finally drove to nervous breakdown. In theory Hooke half accomplished much. He worked out an imperfect wave theory of light (which contradicted Newton and anticipated Huygens); he worked out an imperfect theory of gravi tation (which anticipated Newton); he speculated on steam engines, toward which the work of Papin [235], Savery [236], and Newcomen [243] was point ing. He speculated on the atomic compo sition of matter, anticipating Dalton [389].
He ventured into astronomy, too, and in 1664 discovered Gamma Arietis to be a double star. Only Riccioli [185] pre ceded him in the discovery of such ob jects. Hooke suggested, too, that earth quakes were caused by the cooling and contracting of the earth and that Jupiter rotated on its axis. His concrete accomplishments were in two fields: physics and biology. In phys ics he studied the action of springs and in 1678 enunciated what is now called Hooke’s law. This states that the force tending to restore a spring (or any elas tic system) to its equilibrium position is proportional to the distance by which it is displaced from that equilibrium posi tion. Earlier he had discovered that spi ral springs will expand and contract about an equilibrium position in equal periods regardless of the length of the in- and-out swing. It was this discovery of what we now call the hairspring that made small and accurate timepieces pos sible and, by eliminating the bulky pen dulum, led ultimately to wristwatches and ship’s chronometers. In the field of biology Hooke was one of the most eminent microscopists. In 1665 he published a book, Micrographia, written in English rather than Latin. In it are to be found some of the most beautiful drawings of microscopic obser vations ever made. His studies of micro scopic fossils led him to speculate on evolutionary development. His studies of insects are unrivaled by anyone but Swammerdam [224] and he studied feathers and fish scales with an eye to beauty as well as to accuracy. At least some of the figures were supposedly drawn by Wren [220], the famous archi tect. The discovery for which Hooke is best remembered, however, is that of the 144 [224] SWAMMERDAM STENO
porous structure of cork. Under the mi croscope, a thin sliver of cork was found to be composed of a finely serried pat tern of tiny rectangular holes. These Hooke called cells. The name was a good one when applied to empty struc tures for it is used to signify a small room. These cells turned out to be the dead remnants of structures that in life are filled with a complex fluid. Living struc tures retained the name of cells, how ever, and Hooke’s word has become as important to biology, thanks to the in sight of Schleiden [538] and Schwann [563] a century and a half later, as Democritus’ [20] word “atom” has be come to chemistry and physics. Shortly after the publication of Micro graphie London burned down in the Great Fire of 1666. Hooke was busily engaged in rebuilding projects and never returned to his microscopy. [224] SWAMMERDAM, Jan (svahm'- er-dahm)
Dutch naturalist Born: Amsterdam, February 12, 1637
Died: Amsterdam, February 17, 1680
Swammerdam was the son of a phar macist whose hobby was a museum of curiosities. Young Swammerdam helped his father and acquired a devouring in terest in natural history. He studied med icine at Leiden University, where Steno [225] and Graaf [228] were fellow stu dents. He obtained his medical degree in 1667 but never practiced, preferring in stead to engage in microscopy. His father, who had originally in tended him for the priesthood, cut off support, but that did not stop Swammer dam’s work, although he allowed himself to become sickly and undernourished. He spent the last half of his short life in fits of melancholia, weakened by ma laria, and devoted to a religious cult. In the useful portion of his life he collected some three thousand species of insects and produced excellent studies of insect microanatomy. Some of his figures are as good as anything produced after his time, and he may be considered the founder of modern entomology. He showed that muscles changed shape but not volume, thus demonstrating that they did not contract through an influx of an imal spirits by way of the nerves—one of Galen’s [65] notions. He also demon strated the detail of the reproductive or gans of insects, which tended to support Redi’s [211] disproof of their sponta neous generation. The discovery for which Swammer dam is most famous is that of the red blood corpuscle, which, we now know, is the oxygen-carrying structure of the blood. He announced this discovery in 1658, when he had barely reached his majority. His work was largely neglected until it was resurrected a half century later by Boerhaave [248]. [225] STENO, Nicolaus (stay'noh) Danish anatomist and geologist
1638
Died: Schwerin, Germany, De cember 5, 1686 Steno is the Latinized form of the Danish name Stensen, and the change is but a symptom of a more general one. Steno, the son of a well-to-do goldsmith, was brought up a Lutheran and trained as a physician, obtaining his medical de gree from Leiden in 1664. Eventually he became court physician to the Grand Duke Ferdinand II [193] of Tuscany. The change from Lutheran Denmark to Roman Catholic Italy resulted in a per sonal conversion to Catholicism and in that faith Steno rose to the position of bishop in 1677, after which, like Pascal [207] and Swammerdam [224], he aban doned science for religion. Steno’s most important concrete dis coveries were in anatomy. He recognized that muscles are composed of fibrils and described the duct of the parotid gland (the salivary gland located near the angle of the jaw)—still called the duct of Steno. Also he demonstrated the exis tence of the pineal gland in animals other than man. In a way this was an
[226] GREGORY
DENIS [227] embarrassing discovery, since he was a follower of the philosophy of Descartes [183] and his discovery of nonhuman pineals knocked out an important por tion of the Cartesian system of physiol ogy. Steno made a promising beginning in a completely different field. Fossils (a name invented by Agricola [132] to rep resent anything dug out of the earth) were still a geological mystery. Many of them resembled living things in every de tail (and, in fact, the word “fossil” is now applied only to these objects) and an explanation was needed. The easiest explanations for the religion-centered medieval mind were that these fossils were deceiving products of the devils, or “practice-creations” of God before he buckled down to the real business of cre ation, or the remains of animals drowned in Noah’s Flood. Steno, however, re verted to the speculations of a few Greek philosophers and suggested that they were ancient animals who had lived normal lives and in death were petrified, a point in which his contemporary Hooke [223] agreed with him. No super natural forces were brought into the ex planation. Steno also described rock strata in anticipation of William Smith [395] and held that tilted strata were originally horizontal. Steno also set forth what is now called the first law of crystallography: that the crystals of a specific substance have fixed characteristic angles at which the faces, however distorted they themselves may be, always meet. [226] GREGORY, James Scottish mathematician and as tronomer
November 1638 Died: Edinburgh, late October 1675
Gregory, the son of a minister, gradu ated from Marischal College in Aber deen. In 1663 he published the design of a perfectly good reflecting telescope. An attempt to have it constructed ended in failure, however, largely because the art of grinding glass into accurate curves had not yet been perfected, and Newton [231] constructed his, of somewhat dif ferent design, first. Gregory was an ardent astronomical observer and went blind, supposedly through the eyestrain involved in peering through his telescopes. He died young but lived to see Hooke [223], Newton’s inveterate enemy, build a reflecting tele scope of the Gregorian variety and pre sent it to the Royal Society. In mathematics Gregory was the first to study systematically the convergent series. (The word “convergent” in this connection is drawn from the lenses with which Gregory was accustomed to work.) Such a series has a finite sum al though it is made up of an infinite num ber of members (which, to be sure, steadily decrease in size). This broke the back of “Achilles and the Tortoise,” the twenty-one-century-old paradox of Zeno [16]. [227] DENIS, Jean Baptiste (duh-nee') French physician Born: Paris, 1640 Died: Paris, October 3, 1704 Denis was the son of one of the engi neers working for Louis XTV at Ver sailles. He himself may have studied medicine at the University of Mont pellier.
The establishment of the circulation of the blood by Harvey [174] had set off new interest in anything related to blood. In particular the question arose as to whether blood could be transferred from one organism to another and whether blood from a healthy organism might not be beneficial to one that was sick. Richard Lower [219], for instance, at tempted the transfer of blood from one dog to another. Denis, on hearing of this work, was the first to involve human beings in such transfusion. On June 15, 1667, he trans fused the blood of a lamb (about twelve ounces’ worth) into an ailing young man, who seemed much the better for it.
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