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[631] HELMHOLTZ HELMHOLTZ [631]
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[631] HELMHOLTZ HELMHOLTZ
example of something science could never accomplish because the impulse moved so quickly over so short a path. In 1852, however, Helmholtz stimulated a nerve connected to a frog muscle, stimulating it first near the muscle, then farther away. He managed to measure the added time required for the muscle to respond in the latter case. He was even a mathematician of parts, doing work in the non-Euclidean geome try that had been devised by Riemann [670],
But he is best known for his contri butions to physics and in particular for his treatment of the conservation of en ergy, something to which he was led by his studies of muscle action. (He was the first to show that animal heat was pro duced chiefly by contracting muscle and that an acid—which we now know to be lactic acid—was formed in the working muscle.)
Mayer [587] had announced the con cept of the conservation of energy in 1842, but Helmholtz in 1847 (indepen dently) did so in much greater detail and in more specific fashion, so that he has usually been given the credit, although nowadays the tendency is to divide the credit more or less equally at least three ways among Helmholtz, Mayer, and Joule [613]. Like the others, Helmholtz had difficulties getting his paper printed and finally published it in pamphlet form. Helmholtz used the notion of the con servation of energy to oppose the vi talists. If there were a “vital force,” he said, in living organisms but not in the inanimate universe, then the conser vation of energy would not hold for or ganisms, and they could then be perpet ual motion machines—which they were not.
In 1854 Helmholtz considered the pos sible sources of solar energy. The only source that seemed reasonable at the time was gravitation, as Mayer had ear lier pointed out. The nebular hypothesis of Laplace [347] had the sun begin as a vast nebula that gradually contracted. Well, the kinetic energy of the particles falling toward the sun’s center could be converted into radiation and that could account for solar energy over long pe riods of time. But not long enough. From the amount of radiation energy emitted by the sun, Helmholtz calculated the rate of contraction and then, working backward in time, fixed the period when the sun must have been so voluminous as to in clude the earth’s orbit in its body. By this calculation, the maximum length of time that the earth could have existed was 25 million years. Like Kelvin’s [652] calculation of the maximum time re quired for the cooling of the earth, this gave geologists far too little time for their own theories. Both Kelvin and Helmholtz were misled by ignorance of radioactivity and nuclear energy, and Helmholtz died just a few years too soon to learn his error. Nevertheless this misconception proved useful in one way. It drove some biolo gists such as Nageli [598] and Kolliker [600] to conceive of evolution as pro ceeding by sudden jumps, thus permit ting the squeezing of the entire process into the drastically shortened period al lowed by Helmholtz and Kelvin. A generation later De Vries [792] was to develop the theory of mutations out of this and would in this way add the final major touch to Darwin’s [554] theory of evolution by natural selection. Helmholtz began important work that was concluded by others. He was inter ested in the work of Maxwell [692] on electromagnetic radiation and introduced the problem of locating the radiation well beyond the visible spectrum to his student Hertz [873], whereupon Hertz triumphantly proved the case. Helmholtz also reasoned that atoms and groups of atoms moving through a solution during electrolysis must carry with them “atoms of electricity.” This foreshadowed the work of Arrhenius [894]. To be sure, Helmholtz, despite his ex cellence and versatility, had his short comings. Even the sun has spots, and Helmholtz, it seems, was a poor lecturer. During his return from a lecture tour in the United States, one of his fainting spells caused him to fall. He suffered a 412 [632] VIRCHOW
VIRCHOW [632] concussion, never recovered, and died eight weeks later. [632] VIRCHOW, Rudolph Carl (fihr'- khoh) German pathologist Born: Schivelbein, Pomerania (now Swidwin, Poland), October 13, 1821
Virchow (the son of a small mer chant), like Schwann [563], Kölliker [600], Du Bois-Reymond [611], Helm holtz [631], and Henle [557], studied under J. P. Müller [522]. He obtained his medical degree at the University of Berlin in 1843. He was a man of strong convictions and an even stronger social conscience. As a young surgeon he was the first to describe leukemia (in 1845), but he also showed too pronounced a sympathy for the revolutionaries that were threatening the stability of the ultraconservative Prussian government in 1848. While in vestigating a typhus epidemic in Silesia that year he denounced social conditions scathingly and fought on the side of the revolutionaries in the disorders that broke out at this time. He lost his university position in con sequence. This was not entirely a bad thing, for it forced Virchow into semire tirement and steered him into thoughtful consideration of the microscopic struc ture of diseased tissues. (He quickly obtained, in 1849, a new professorial post, in any case. It was at Würzburg, in the more liberal atmo sphere of Bavaria.) By the time he returned to Berlin as a professor of pathological anatomy, in 1856, he had worked out his notions in detail. In a book published in 1858 he demonstrated quite conclusively that the cell theory extended to diseased tissue too. He showed that the cells of diseased tissue were descended from normal cells of ordinary tissue. There was no sudden break or discontinuity signifying the dis ease, but a smooth development of ab normality. Thus he brought the study of disease down to a more fundamental level than the tissues of Bichat [400] and became the founder of cellular pathol ogy. This permitted molecular biologists a century later to bring the study of dis ease down to the still more fundamental level of the molecules within the cell. In 1860 Virchow epitomized his no tion of the cell theory by a pithy Latin remark that can be translated as “All cells arise from cells.” It was the final knitting together of the cell theory of Schwann and Schleiden [538] and had implicit in it the repudiation of sponta neous generation, a repudiation that Pas teur [642] was about to translate into ex perimental terms. Virchow, however, refused to accept Pasteur’s germ theory of disease. Per haps the effect of a germ, in causing a tissue to become diseased, seemed too discontinuous to him. He viewed disease as a civil war between cells, an outbreak of anarchy in the well-ordered cellular society that made up the organism, and not as an invasion from outside. (Of course, as we now know, there are dis eases of both varieties, Pasteur’s and Virchow’s.) In any case, Virchow found himself part of a rapidly shrinking minority in his views on the germ theory and his re action was to leave biology and to throw himself into anthropological and archeo logical research. He was involved in the excavation of Troy, for instance. His an thropological studies convinced him that there were no such things as “superior races.”
His medical experience had helped re vive (if they needed reviving) the liberal notions of his youth, for in studying poverty-stricken areas he was appalled by the influence of social backwardness on health. He took the position that it was useless to try to treat sick people until one treated a sick society. He went into politics, was on the Berlin city coun cil in 1859, got himself elected to the Prussian Parliament in 1862, and to the Reichstag itself (after the unification of Germany) in 1880. As one of the leaders of the small German Liberal Party, which vigorously opposed Bis marck, he so irritated that statesman that Bismarck challenged him to a duel in
[633] CLAUSIUS
CLAUSIUS [633] 1865. Virchow contemptuously refused to accept this medieval solution to non medieval problems. Virchow was no socialist, however, and was one of the German biologists who strongly rejected Darwin’s [554] theory of evolution, partly because he considered it “socialist.” As a Reichstag member he voted for a law that banned the teaching of Darwin’s theory in the schools.
But Bismarck moved in the direction of social reform (to draw the teeth of the gathering opposition) and the edge of Virchow’s liberalism gradually blunted with age so that eventually he was un seated by a Social Democrat. Virchow, however, remained active in Berlin city politics and was instrumental in pushing through important improvements in such matters as water supply and the sewage system. (Such improvements were as im portant in their way in putting an end to the epidemics that had always plagued Europe as were the studies arising out of Pasteur’s germ theory, so in a sense Virchow got a little of his own back.) [633] CLAUSIUS, Rudolf Julius Em manuel (klow'zee-oos) German physicist
Koszalin, Poland), January 2, 1822
Clausius, the son of a schoolmaster, studied at the University of Berlin and obtained his doctorate at Halle in 1847. He accepted a professorial position at Zürich in 1855 and at Würzburg in 1867. Clausius was primarily a theoretical physicist. He did not make his name by conducting experiments but by applying mathematics to the construction of theories that explained the observations and experiments of others. He was one of those who contributed to the working out of the kinetic theory of gases, a proj ect completed by Maxwell [692] and Boltzmann [769]. He also proposed theories concerning the passage of elec tric current through solutions, being the first to suggest that the current might pull molecules apart (dissociation) into electrically charged fragments. This no tion was not accepted by others at the time and it was only Arrhenius [894] a generation later who managed, with difficulty, to put it across. Clausius’ most fruitful work came in 1850 in connection with the views of Carnot [497] and the suggestions of Kel vin [652] as to the continual degradation of energy. Clausius discovered that if he took the ratio of the heat content of a system and its absolute temperature, this ratio would always increase in any pro cess taking place in a closed system. (A closed system is one that loses no energy to the outside world and gains no energy from it.) With perfect efficiency, which is never realized in the real world, of course, the ratio would remain constant, but it would never, under any circum stances, decrease. Clausius eventually (in 1865) called this ratio entropy for no clear etymo logical reason. In 1850, at which time he was a professor in Berlin, he sent a com munication to the Berlin Academy of Sciences to the effect that entropy always increased, never decreased. This was equivalent to Kelvin’s notion of energy degradation, and entropy was a measure of the extent to which energy could be converted into work; the higher the entropy, the less the quantity of en ergy for such conversion. Clausius ex pressed all this so clearly that he is usu ally considered the discoverer of this sec ond law of thermodynamics. This inevi table increase of entropy is a general ization second in importance in the field of energy-interconversions only to the first law, that of the conservation of en ergy. (Oddly enough Clausius was one of those who attacked Helmholtz’s [631] enunciation of the first law in the early 1850s.)
The only true closed system in actual practice is the universe as a whole and so the picture arose of a universe in which entropy is steadily rising and the availability of energy for conversion into work steadily falling. Eventually the deg radation would be complete, entropy would be at a maximum, and nothing 414 [634] SCHLIEM ANN LENOIR
would exist but a universe at complete temperature equilibrium. There would be no more heat flow, no more change, no more time, in fact. This dramatic picture of the end of all things has been called “the heat-death of the universe." It was a scientific analog of the Last Judgment but its validity is less certain now than it was a century ago. Though the laws of thermo dynamics stand as firmly as ever, cosmol- ogists are far less certain that the laws, as deduced in this small segment of the universe, necessarily apply to the uni verse as a whole and there is a certain willingness to suspend judgment on the matter of the heat-death. By 1869 Clausius was professor of physics at the University of Bonn, a po sition he held for the rest of his life. In 1870 he organized a volunteer ambu lance corps of Bonn students for service in the Franco-Prussian war and was wounded while leading it—a wound from which he never fully recovered. This is an example of the manner in which the scientific internationalism of the Napoleonic era had withered into chauvinism. As another example, Clau sius never hesitated to engage in vitriolic controversies with British scientists in a determined drive to see to it that Ger man scientists got their full share of credit in all scientific advances.
mahn)
German archaeologist Born: Neu Buckow, Mecklen burg-Schwerin, January 6, 1822 Died: Naples, Italy, December 26, 1890 Schliemann, the son of a minister, was caught up in the story of Troy when he was only seven, when he had seen a pic ture of Troy in flames in a history book he had received as a Christmas present. Un able to afford much of an education, he became a grocer’s apprentice at fourteen, then a cabin boy, an office boy, and a bookkeeper. But he had a flair for lan guages, learned thirteen of them, includ ing Russian and Greek (both ancient and modern), and his dream drove him. In 1846 he established an indigo business in Russia and it prospered. He traveled to the United States in 1850, went to California, became an American citizen, continued to prosper, and finally had enough money to do what he had wanted to do all along—go to Asia Minor and find Troy. He went at this with single-minded de termination, being guided by the geo graphical references in the Iliad and without the great care that archaeologists have learned to exercise in their excava tions since his time. Nevertheless, he chose the right spot and uncovered a series of ancient cities built one on top of the other, obtained various fascinating artifacts, much of it in gold, and in 1873 announced that one of those cities was Homer’s Troy. Later, he dug at the site of Mycenae, which had been Agamemnon’s capital, and again found valuable artifacts, which he described in 1878. Although Schliemann was not the first archaeologist, he made it popular. His findings were sensational, rang through the world, and were the beginning of ar chaeology in its modern sense. [635] LENOIR, Jean Joseph Etienne (luh-nwahr') Belgian-French inventor Born: Mussy-la-Ville, Belgium, January 12, 1822 Died: Varenne-St. Hilaire (Seine), France, August 4, 1900 Lenoir, who moved to France from his native Belgium in 1838, was self-edu cated; he taught himself chemistry and put his ingenuity to work in devising a number of inventions. He is best known, however, for his invention in 1859 of the first workable internal combustion en gine.
For the previous century and a half the steam engines devised by men such as Savery [236] and Watt [316] had made use of heat outside the cylinder. The steam formed by the heat then entered the cylinder and moved the piston.
[636] GALTON
GALTON [636] It had occurred to a number of men that a mixture of some inflammable gas with air could be made to explode within the cylinder and that the energy of com bustion would then move the piston directly. In fact Carnot [497] had discussed such a device in his book on heat in 1824. (The difficulty was that the fuel would have to be a gas or at worst an easily vaporized liquid fuel. Such fuels were not really available in large quantity until the petroleum re sources of the world were slowly devel oped in the latter half of the nineteenth century.) If such an internal combustion engine could be developed it would be much smaller than a steam engine, and much more readily set into motion (since a gas-air mixture will explode at the touch of a spark, while the initial boiling of water over a coal fire is a slow process). Lenoir was the first to design and build an internal combustion engine that worked, using illuminating gas as the fuel. In 1860 he hitched it up to a small conveyance, which became the first “horseless carriage” to be run by such an engine. (There had been earlier horseless carriages that had been run by ordinary steam engines.) Lenoir also built a boat powered by such an engine. He sold some 300 of these engines in five years. The Lenoir engine was very wasteful of fuel, however, and the development of a practical automobile had to wait a gen eration, during which time Otto [694] made the necessary improvements in the internal combustion engine. Lenoir, despite his inventions and the fact that he was recognized in his own lifetime, died poor. [636] GALTON, Sir Francis English anthropologist
1822
Died: Haslemere, Surrey, Janu ary 17, 1911 Galton, bom to a wealthy family, was a child prodigy. Tutored by one of his sisters, he could read before he was three and was studying Latin at four. He was first cousin to the far more famous Dar win [554], a fact that is irrelevant but that works against him, for he is always compared to Darwin to his own disad vantage. Galton was merely a good sci entist, whereas Darwin was a great one. Gabon’s life falls into three segments, in each of which he did very useful work. He underwent initial training as a physician (he graduated from Cam bridge in 1844), but when his father died, Galton became financially indepen dent and promptly abandoned his stud ies. Instead, he spent the late 1840s trav eling through Africa. He wrote books on his experiences as an explorer in 1853 and 1855 and, in 1853, entered into what was to prove a long and happy (though childless) marriage. He then turned his hand to meteor ology and in 1863 wrote a book called
the modem technique of weather mapping. It was he who invented the term anticyclone, signifying the pressure highs, which usually bring fair, calm weather, as opposed to the pressure lows, which bring storms. And, on a much more mundane level, he invented the high-pitched whistle that dogs can hear but humans cannot. When Darwin’s Origin of Species came out in 1859 Galton could not help but feel the tug of the biological sci ences. In consequence, the last half of his life was spent on anthropology and in particular in the study of heredity. It was his misfortune that the dis coveries of Mendel [638] were not made known to the scientific world, and so the proper basis for genetics did not exist in Gabon’s time. Thus, Galton believed (as Darwin did) that characteristics would blend when individuals of different types were mated, so that the offspring would represent an intermediate state. Mendel had shown this was not so, a fact Dar win was never to know. Gabon, how ever, was to live long enough to see Mendel’s accomplishments brought to light once more by De Vries [792]. Nevertheless, Galton made important advances in the study of heredity. He was the first to stress the importance of
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