From the creation of half-living microbes in the test tube to charting the earliest histories of genetic engineering, Radium and the Secret of Life highlights previously unknown interconnections between the history of the early radioactive sciences and the sciences of heredity. Equating the transmutation of radium with the biological transmutation of living species, biologists saw in metabolism and mutation properties that reminded them of the new element. These initially provocative metaphoric links between radium and life proved remarkably productive and ultimately led to key biological insights into the origin of life, the nature of heredity, and the structure of the gene. Radium and the Secret of Life recovers a forgotten history of the connections between radioactivity and the life sciences that existed long before the dawn of molecular biology.
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Radium and the Secret of Life
By Luis A. Campos
The University of Chicago PressCopyright © 2015 The University of Chicago
All rights reserved.
The Birth of Living Radium
While uranium and thorium had already been known for decades, and while their newfound radioactivity catapulted them to greater prominence at the end of the nineteenth century, it was only with Marie Curie's discoveries of polonium and especially of radium, and with Ernest Rutherford and Frederick Soddy's subsequent theory of radioactive decay, that the new science of radioactivity took off—and with it an intense new culture of fascination with radium. The turn of the century saw the birth of a metaphorical (and sometimes more than metaphorical) understanding of "living radium."
For an age when chemistry and physics were thought to be closing in on the last few secrets of nature, the back-to-back discoveries of X-rays and of radioactivity came as a complete surprise. Curie's famed discovery had followed immediately after Wilhelm Roentgen's initial discovery of the penetrating power of X-rays in 1896 and Henri Becquerel's accidental discovery of the radioactive properties of uranium shortly thereafter. Dredging through tons of Joachimstal pitchblende to obtain the smallest fraction of radium in 1898, Curie had found with radium the radioactive element par excellence, some millions of times more radioactive than uranium. Incredibly rare and precious, even in minuscule amounts radium dazzled, glowing in the dark and shooting off rays in a seemingly endless blast of energy that came from nowhere in particular. As Rutherford later recounted, "The name radium was a very happy inspiration of the discoverers, for this substance in the pure state possesses the property of radio-activity to an astonishing degree." In comparison, Roentgen's and Becquerel's discoveries had made nowhere near the impact on the public. When Curie finally succeeded in isolating radium in a pure state in 1902, granting incontrovertible proof of its elemental status, radium was already well on the way to becoming the all-powerful and wondrous new element that could do everything—and that soon enough could do no wrong.
The peculiar connection between the phenomena of radioactivity and the properties of and discourses surrounding life first began to emerge in those earliest days of the science of radioactivity with Ernest Rutherford and Frederick Soddy's discovery that radioactivity, in fact, indicated the transmutation of the elements. Elements were supposed to be the fundamental building blocks of the physical world, the basic level of atomic composition of all things. "Atomic" literally meant that which could not be subdivided. A substance that had all the hallmarks of an element, that fit an empty spot on the periodic table, and yet came apart, spontaneously, was—prior to the discovery of radioactivity—almost inconceivable. "Elements" simply did not permit subdivision. The discovery of the transmutation of atomic species proved to be nearly as problematic a revelation for Rutherford and Soddy as the transmutation of biological species had once been for Darwin.
For all its mythical status, Rutherford and Soddy's legendary collaboration lasted only a year and a half. Beginning in 1901, when they both found themselves at McGill University—Rutherford an established professor of physics, Soddy an up-and-coming young chemist—their "local and intense" collaboration resulted in the production of nine papers, the last of which, "Radioactive Change," appeared in May 1903 and presented their theory in its final form. Their famed collaboration not only brought forth the first solidified account of elemental transmutation—the "disintegration theory of radioactive transformation"—but also served to explain many of the other radioactive properties of the radioelements and to advance the idea of an evolutionary history of the universe told by its elements.
The experimentum crucis that led to the birth of the disintegration theory of radioactive substances took place in April 1902, when Rutherford and Soddy observed thorium X spontaneously changing within the confines of their laboratory setup into the noble gas argon. Soddy, though no alchemical adept, had nevertheless always been interested in the connections, historical and otherwise, between alchemy and chemistry and had even lectured on alchemy in his course on the history of chemistry: "I made that goal [of transmutation] quite clear," he said. The appearance of alchemical transmutation before his very eyes, however, was almost "too devastatingly simple." He recalled himself "standing there transfixed as though stunned by the colossal import of the thing."
I remember when I interpreted my first experiment I could not wait to tell Rutherford, but words would not come. I could feel my heart throbbing, and as though propelled by some outside force I heard myself utter unbelievable words: "Rutherford, this is transmutation!"
Rutherford, "in his breezy manner," is said to have shouted back: "For Mike's sake, Soddy, don't call it transmutation. They'll have our heads off as alchemists."
Soddy, however, remained transfixed by the idea of elemental transmutation. Once disparaging of earlier attempts at alchemical transmutation, he now found himself converted. In short order, he publicly declaimed in a lecture at McGill that "alchemy must be regarded as the true beginning of the science of chemistry." Accordingly, he said, transmutation "is, as it has always been, the real goal of the chemist." From doubtful practicing chemist-cum-historian of alchemy to firm adherent, Soddy came completely around and found himself "entirely engrossed" in interpreting his newfound transmutation:
The atoms were disintegrating, so disposing of the chemists' cherished theories of its immutability. I began to consider the state of the disintegrated atom. Was it now a smaller atom of the same element? By its integration would it have assumed another character, become another element? By further possible emissions would it further disintegrate and if so, at what rate? How long would such a disintegrating atom live? Since it seemed obvious that most of the atoms in the element would at some time be suffering disintegration it followed that the element would be composed of atoms in various stages of disintegration.
Soddy recollected Rutherford afterward "taking me to task because people were saying that what we were saying was tantamount to 'transmutation,' and I had to convince him that it was transmutation and put him au fait with the chemical evidence to confute anyone who disputed it." Transmutation still smacked too much of the alchemical for a respectable scientific report, however, and in the first published account of their discoveries in April 1902, the word "transmutation" was replaced with the more benign "transformation." Yet the excitement of their alchemical discovery still bubbled beneath the surface: in an effort to get their first paper published in the Transactions of the Chemical Society, Rutherford had written privately to Sir William Crookes, saying that "although of course it is not advisable to put the case too bluntly to a chemical society, I believe that in the radio-active elements we have a process of disintegration or transmutation steadily going on which is the source of the energy dissipated in radioactivity." Nevertheless, the shift to "transformation" as the term of choice was rapid—by September of that same year, Rutherford and Soddy reported in the Philosophical Magazine that radioactivity was "a manifestation of sub-atomic chemical change" and, as such, "the radioactive elements must be undergoing spontaneous transformation." From here on out, a distinction emerged between rather more scientific references to "disintegration" and "transformation" and what were clearly more popular references to "transmutation"—although Soddy continued to blur the lines from time to time.
With their different disciplinary interests, it was only natural that Rutherford and Soddy would pursue different paths after their discovery. Rutherford, the physicist with "a most radiating smile," focused on further experimentation aimed at discovering the nature of the α-particles produced in moments of radioactive transformation. Soddy, the chemist, focused more on the chemical implications of the new discovery and looked for further proof of transmutation. While Rutherford remained at McGill until leaving for Manchester in 1907, Soddy had already transferred to William Ramsay's laboratory at Cambridge by 1903. Soddy found his first samples of radium by chance one day in April of that year as he walked "past a store [Isenthal's] on Mortimer Street off Upper Regent Street" in London. A sign in the window read: "Pure radium compounds on sale here." At a time when radium was available only "by favour of the Curies," as Soddy recalled, this was an exceptional find: "Here it was to be bought in a London shop at some eight shillings a milligram of pure radium bromide," the product of a German production firm (Geisel of the Chinin Fabrik of Brunswick) that had begun to manufacture radium compounds on a commercial basis.
The final proof of transmutation thus came in Ramsay's laboratory with the production of helium from the radium sample on April 27, 1903. The result of Ramsay and Soddy's collaboration, one commentator noted, was nothing less than "the chemical sensation of the summer of 1903." The presentation of the proof of transmutation at the annual meeting of the British Association for the Advancement of Science in Southport in 1903 came at a time when Lord Kelvin was still espousing the idea that it was the ether that carried energy to radioactive substances, rather than seeing such energy as something inexplicably inherent in the atom. By 1903, however, general agreement was beginning to fall in favor of the Rutherford-Soddy account of radioactive transformation. The only significant holdouts against the theory of radioactive transformation in the British context, it turns out, were Kelvin and Henry E. Armstrong. Armstrong attacked the disintegration theory, "which assumes that nature has endowed radium alone of all the elements with incurable suicidal monomania," but both men were largely silenced after Rutherford's presentation. The physics of the new phenomenon of radioactivity was beginning to come together. The broader cultural and biological import of radium, however, was just beginning.
"Physics Stark Mad in Metaphysics"
"In pre-radium days," W. Hanna Thomson remarked in his popular 1909 What Is Physical Life? Its Origin and Nature, "we took the diverse chemical elements for granted, with vague speculations as to their possible evolution from some primitive kind of stuff out of which the fabric of the world has been spun." But the discovery of radioactivity, he went on, "has made it certain that one element can be evolved from another, or, in other cases, legitimately thought of as evolved from another, by the addition or separation of certain components." Whether or not Thomson's description of the phenomena of radioactivity is technically accurate, what is certain is that the work of Rutherford and Soddy took what had previously been a merely suggestive connection between the processes of cosmic and biological evolution and linked the two much more closely. From Robert Chambers's all-encompassing Vestiges of the Natural History of Creation of 1844 (which continued to outsell Darwin's Origin even years after the latter's publication in 1859) to the work of Herbert Spencer and others, many in the nineteenth century readily viewed evolution as a simultaneously cosmic and biological process. While elements in everyday experience may have been stable, the idea that elements—much like living things—at some point in the history of the cosmos underwent an evolutionary process was considered only mildly far-fetched and not entirely beyond reasoned imagination. Astrophysicist Norman Lockyer's 1900 book Inorganic Evolution is perhaps the most notable indicator of the idea being already "in the air" just prior to Rutherford and Soddy's work. It was only following their proof of transmutation, however, that these earliest evolutionary links between the radioactive and the living could, and did, become much more closely and provocatively established.
Given these preexisting traditions that linked cosmic with biological evolution, Rutherford and Soddy's new quasi-alchemical talk of the "transmutation" of the elements could not help but resonate with talk of biological transmutation. Elemental transmutation seemed to imply cosmic evolution of some sort, just as biological transmutation implied biological evolution. Radioactivity and life were thus linked not only from the dawn of research into radioactivity, but from the very dawn of time. As such, the terms of the one could be applied with ease to the other—which is precisely what Soddy proceeded to do.
In his Wilde lecture of February 23, 1904, "The Evolution of Matter as Revealed by the Radio-Active Elements," Soddy remarked at greater length on the nature of the relationship between the process of radioactive change, the "evolution of the elements," and cosmic evolution more generally, conjecturing whether one could ever "regard the universe ... [as] proceeding through continuous cycles of evolution" and discussing the period of average life for the first time. To an observer getting only a glimpse into a vast cosmic process of evolution "going on for indefinite ages," he wrote, the currently recognized "atoms of the periodic law" were probably only a subset of the original constitution of the universe and its "parent-element[s]." These elements as we now know them were, Soddy wagered, but "the forms with longest life, which exist to-day because they have survived a long process of evolution in which those physically unfit have disappeared." Or, as he elsewhere characterized cosmic history, "Matter has passed to its present position of apparent immutability by a long process of natural selection. The elements known to the chemist are stable because they exist and have survived. On the other hand, it is now possible to examine some excessively unstable forms of matter," or, in other words, the radioactive elements. The radioactive elements—uranium, thorium, and radium, and by no mere coincidence the three heaviest elements in the periodic table thus far—were for Soddy "transition forms" or "elementary forms of matter physically unfitted to survive, but which are brought within our powers of knowledge because they constitute the temporary halting places through which matter is passing in a scheme of slow continuous evolution from the heavier to the lighter forms." As Soddy said in his annual summary of the year's findings for the British Chemical Society, "We have here the introduction into chemistry of a conception analogous to that of evolution in the biological sciences."
The choice of language is striking: not only was there a kind of cosmic evolution taking place—by natural selection, no less—but atoms were said to have parents, to have lives, to survive. ("Its simple existence is eloquent of its fitness to survive," Soddy wrote.) As Rutherford wrote to Jacques Loeb in 1907, "I'm feeling very fit and hard at work examining the recent evidence of the parentage of radium—latest report still uncertain though no doubt this is a productive parent." Parents, grandparents, and even great-grandparents all made an appearance in Soddy's thinking: "Radioactive children frequently resemble their great-grandparents with such complete fidelity that no known means of separating them by chemical analysis exists." (Even Marie Curie would refer in her 1911 Nobel lecture to "the atom of radium [that] gives birth to a train of atoms of smaller and smaller weights.")
Rutherford and Soddy needed a term to describe these species of unstable atoms transmuting their way from one element to another, a term that highlighted these kinds of particular and as yet unsung connections between the animate and inanimate that would grant the inorganic a particular kind of half-living status. The name they settled on was deliberately evocative of one of the most basic of living processes: these radioelements were to be called metabolons.
Excerpted from Radium and the Secret of Life by Luis A. Campos. Copyright © 2015 The University of Chicago. Excerpted by permission of The University of Chicago Press.
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Table of ContentsContents Introduction 1. The Birth of Living Radium 2. Radium and the Origin of Life 3. Radium and the Mutation Theory 4. Radium Genetics 5. The Gene Irradiated 6. Transmutations and Disintegrations Conclusion: The Secret of Life Acknowledgments Notes Bibliography Index