6
Transmutations and Disintegrations
Creation of life, alteration of species, mutation of genes: the connections between radium and life underwent profound transformations over the course of the first half of the twentieth century, with clear consequences in both the conceptual and experimental realms (shifts in the meaning of mutation, the forgetting of powerful discursive roots, and the shift from radium to other forms of ionizing radiation such as X-rays, among others). At first seemingly steady in the power of its metaphysical and metaphorical associations to produce new experimental systems and to condition the interpretation of their results, radium’s connections with life seem to have transmuted with every passing decade.
Transmutation, decay, disintegration—each of these metaphors seems apt in describing these ongoing reworkings of radium’s associations with life. Moreover, such transformations are arguably a consequence of the same historical processes at the intersection of metaphor, metaphysics, and experimental hermeneutics that permitted radium and life to become so closely and productively associated in the first place. Tracing these sets of transformations beyond Muller’s 1927 work, and beyond the shift in the meaning of mutation from organism to chromosome to gene, understandably leads us into an ever more complex muddle with each subsequent decade. This chapter explores the afterlife of these associations, as the ties that had once bound metaphor and experimental practice so tightly together transmuted into productive new experimental systems and approaches that had seemingly little to do directly with radium—decaying to mere discursive residues or nearly disappearing altogether. The recounting of such an increasingly refractory story seems to test the very limits of historical narrative. In other words, given a history of constant transmutation and ongoing decay that never quite reaches total disintegration, how does a story that defies endings end?
Rather than simply tracing a complicated story across experimental systems, investigators, and decades and wrapping it all up with a compelling and coherent empirical ending, a more reflexive approach would seek to use “radium” as a narrative conceit, a powerful metaphor, and an epistemological tool for the historian as it was for the scientist. Such an approach would take the metaphor of the half-life of the transmutations and disintegrations of the association between radium and life in a performative, and not merely descriptive, sense.1 It might even seek to question in the course of its own telling just how far any such narrative of a decay chain might reasonably extend until leadened with unworkable examples.
By tracing this asymptotic process of decay, and in coming to some points where one is no longer sure whether the historical evidence speaks to a still-extant connection—does radium really have anything to do with radiation genetics, with Max Delbrück, with Niels Bohr, or with any of the other scintillations touched on briefly in this chapter?—I hope to parallel in this chapter’s deconstruction of my historical narrative the same epistemological dynamics in the metaphysics of metaphor that were so profoundly at play in the construction of scientific knowledge detailed in the preceding chapters.
As the once pronounced clicking of the Geiger counter of historical narrative (Soddy! Burke! MacDougal! Gager! Blakeslee! Muller!) slowly merges back into background static, both the writing and the rewriting of the history of radium and the secret of life might thus prove to be a further unexpected transmutation, decay, and perhaps even disintegration of this once all-powerful association. Perhaps, then, as we trace here the shift away from radium and toward a more generalized radiobiology; Muller’s surprising later work with radium and the overlap he saw between his theories of the gene and other discourses of “organic radiation”; and the larger physicalist turn in the study of heredity in the 1930s and 1940s with the emergence of “radiation genetics” and “phage genetics,” we might more consciously be aware of the curious persistence of links between the realms of the radioactive and the living even as radium itself began to exit the historical scene. We might more consciously be aware, as well, of “the artificial transmutation of the meme.”
From Radium to Radiobiology
From its birth in a drafty laboratory at the hands of Marie Curie to worldwide acclaim, and from the foundation of radium institutes in various countries to an intense focus on the medicinal applications of radium, and up to the increasing realization that radium was not “just like fire,” but potentially even more dangerous, the role of radium shifted in later years from wonder element that could do no wrong to both tool and mixed blessing.2
Radium’s penetrating power was undoubtedly formidable, and questions about risks associated with its use grew over the decades with the publication of ever more stories of vials being lost on the Paris Métro or in the snow of Saskatoon (more than one hundred cases of lost radium were known by 1944, and only two-thirds of these were ever recovered),3 of the accidental ingestion of radium capsules by a woman in Philadelphia who needed an operation to remove them in 1929, and of the deaths of several of radium’s greatest promoters from overexposure (including Sabin Arnold von Sochocky and the millionaire playboy and radium tonic enthusiast Eben Byers). As historian Matthew Lavine has noted:
By the late 1920s, roughly the peak of the element’s availability on the medical and consumer marketplaces . . . patients had finally gained enough experience with the substance on an experiential basis for that familiarity to begin to breed contempt, or at least potential disillusionment . . . expectations could not be maintained in the face of the underwhelming reality of radium nostrums. Only because the laity had had actual contact with radioactive substances (or believed they had), could the experiences of Marie Curie, Eben Byers, and the dial painters start to gain a real foothold in the discourse.4
While radium “seeds” were still readily used in cancer treatments as late as 1924, in January 1925 one newspaper made reference to the increasing “roll of martyrs to science” killed by radium overexposure. The end of May brought news of the fate of the New Jersey dial painters: “New Radium Disease Found: Has Killed 5; Women Painting Watch Dials in a Jersey Factory the Victims, Doctor Says . . . Cancer Called Incurable; Trust in Radium Is Unjustified, New York Physician Asserts.” By 1932 one headline ran, “Death Stirs Action on Radium ‘Cures.’”5 While radium had been touted as a cure for cancer in the early years, signs of an ongoing dissociation of radium from life were already apparent to some observers by 1920:
Great attempts have, as we know, been made to cure Cancer with Radium; but as far as can be gathered up to the present Radium is certainly not a cure for the disease. All manner of different methods have been tried for curing it, but so far a practical and satisfactory cure for Cancer is not yet known. . . . The author is himself aware of two or three deaths which have been caused by the “Radium treatment,” and, furthermore, there have been indications that if “Radium” had not been resorted to life would probably have been prolonged.6
Moreover, failures that had previously been documented but generally overlooked—or interpreted as signs of radium’s life-giving power, like Gager’s own induction of a slew of morphological defects in his radium-treated plants—were becoming increasingly recognized with each passing decade: seeds whose vitality were “destroyed,” leaves losing chlorophyll, and guinea pigs succumbing to radium’s damaging rays.7
Radium continued to be used in laboratory work well into the late 1930s,8 but with other options becoming available, radium stocks seem to have been perceived as more and more risky with every passing year. As one letter Muller received noted, “A recent event has suggested that there may be some misapprehension on the part of those responsible for holding National Radium on loan from the Medical Research Council for research purposes, as to the correct procedure in cases where there is damage to the containers, with or without suspected leakage of radium.”9
Gager, however, clearly remained interested in using radium even as others had begun to move on to other sources of ionizing radiation. He wrote to a colleague, W. C. Curtis, at the University of Missouri, requesting further support for investigations with radium: “I would be very much interested in it if you will include radium with X-rays, so that the funds shall be in support of investigations of the effect of X-rays and rays of radium on plants and animals.” As Gager described his plan, he emphasized the central role radium had in his studies, in explicit distinction from X-rays: “My problem for future work is to continue the same kind of investigations as were reported in my 1927 paper (Gager & Blakeslee), which is an investigation of the effect of radium rays in modifying heredity and to study the cytology of egg and sperm cells that have been exposed to the rays.”10 Curtis responded, reassuring Gager that radium had been excluded only as an oversight: “I hasten to say that it has been our intention all along to include all radiations in our program. Perhaps my own interest in the X-rays has led me inadvertently to use language indicating such a limitation.”11 It was even specified in “Communication No. 2,” issued on March 8, 1928, “that ultra-violet, x-rays, and work with radium are all included” in the program designed to fund research on the “Effects of Radiations upon Organisms.”12
It was also at this time that the International X-Ray and Radium Protection Committee came to be organized, in July 1928. Although the equation of the biological effects of X-rays with those of radium was long-lived, it was a matter of decades before X-rays came to completely supplant radium in discussions of radiological protection: the committee was renamed the International Commission on Radiological Protection only in 1946. (This was the same year that the American Roentgen Ray Society and the Radiological Society of North America “combined their protection activities into a single committee.”) Some integration of the two forms of ionizing radiation had taken place earlier, however, as with the first institutionalization of the Advisory Committee on X-Ray and Radium Protection in early 1929, which published guides on X-ray protection in 1931.13
And even with his intense focus on and interest in the effects of X-rays, Muller himself had never really left radium behind (see chap. 5). Despite the loss of his radium in 1924, Muller was again in possession of some by early 1932, this time rented from the Radium Emanation Corporation. In the intervening years he had even suggested to other researchers that they investigate various genetic effects of radium.14 He continued to request and receive more radium sources into the late 1930s,15 and he continued highlighting the place of radium in his narrative explanations of mutation even years after his more prominent work with X-rays: mutations were “of an ultramicroscopic nature, such as the impact of a minute ray (for instance, from radium) on one of his genes.”16 Muller succeeded in getting radium from the Medical Research Council at least as late as 1938, and even in 1943, he wrote that he continued to value radium “because of the greater ease with which it can be used to give low intensities constantly over a long period, but that there is in fact no quantitative or qualitative difference between x-ray + radium effects, for a given total dose in r units.”17 And, as the old became new again, the Science Service reported just after noting Muller’s receipt of the Nobel Prize in 1946 that he “has added radium radiations to X-rays as weapons of genetic bombardment.”18
Others geneticists also continued experimenting with radium—at Woods Hole, at least—until a fund designated for such experiments ran out after 1940.19 Widespread use of radium was markedly on the downswing by the mid-1930s, however, and cost was a major—though not the only—factor. One source of funding for radiation biologists officially changed its policy to support more explicitly physical work with radiation instead. Within a few short years, for example, Blakeslee and his student John T. Buchholz could get no more funds from the Radiation Committee for their biological work.20
The broader trend was readily apparent. Expensive and increasingly more difficult to control than ever-improving X-ray technologies, radium no longer held pride of place. While Gager, Muller, and some others continued to use radium, X-rays began to dominate the scene. Blakeslee himself had begun to use X-rays, in addition to radium, in his collaborations with Buchholz, and he made use of various X-ray tubes while at Cold Spring Harbor throughout the 1930s, alongside Milislav Demerec.21 And Curtis reported to Gager in early 1928 that “Stadler is just installing an X-ray machine in the building next to ours.” The convenience of using X-ray machines over radium was clear to Curtis: “I shall be able to carry on my work with much greater convenience than in the past when I had to depend upon the machine at the hospital.”22 Running X-ray machines was not necessarily any easier or safer than using radium, however. One of the researchers at the Edinburgh Institute of Animal Genetics (where Muller worked for a time) had continued his experimentation with X-rays and radium up until 1938, and one of his coworkers noted that “the difficulty of regulating the x-ray dosage seems the greatest snag of all” in their experimentation. Following the arrival of a powerful new X-ray tube, he reported to Muller that the “workers don’t know how to operate it carefully.”23
In time, newer and ever-improving instrumentation “such as the van de Graaff generator, powerful linear accelerators, betatrons, synchrotrons and microtrons” made possible the production of other ionizing radiations well beyond the strength of ordinary X-rays.24 “Improved X-rays for Cancer Work,” proclaimed one headline: “Harvard Physicists to Use Deeply Penetrating Type in New Laboratory; Hope to Displace Radium.” The article beneath noted that “the trouble with the use of X-rays up to this time has been that they are not as penetrating as the so-called ‘gamma rays’ of radium.”25
Were X-rays the new radium? By 1928 W. D. Coolidge had commented that “Man, in his effort to equal the power of radium, is locking himself up in a lead-lined room, encaging himself within a cabinet of thick lead and submitting himself to the dangers of high electric currents such as he has never reached before.” One journalist noted that Coolidge “has succeeded, so far, in attaining only one-half the power that lies within a fraction of an ounce of radium—nature’s most remarkable element.”26 A popular novel written at the time of this transition to X-rays, Rudolf Brunngraber’s Radium (1936), spoke of one scientist who
implored electro-technicians and physicists throughout the world to perfect Röntgen apparatus, since Röntgenization was a fairly efficient substitute for irradiation. Surely it would be possible, he went on, to increase the tension of the gamma-rays in Röntgen tubes?
The perfection of the Röntgen tubes even played a significant role in the story’s plot:
Also, thought Francis, Pierre Cynac was the man with whom he himself, Francis, would come into conflict with his Röntgen tubes for contact-therapy and his short-wave-length apparatus for restoring health to diseased cells. Success in these domains would make radium superfluous, and therefore ruin Pierre’s schemes as radium king. . . . Life was a horrid muddle.27
: : :
But as nuclear physicists claimed the production of “artificial radium” by 1935, even the “most powerful rays” later produced with the invention of a million-volt “giant cancer tube” at Caltech were still said to be “equivalent to [the] entire world[’s] radium supply.”28 By 1948 other replacements for radium were on tap: “Atom-Bomb By-Product Promises to Replace Radium as Cancer Aid,” reported the New York Times, noting that the replacement—irradiated cobalt—was “a ‘virtually costless metal,’ promised in every way to be as effective as radium in the treatment of cancer, and far easier to use.”29 Indeed, by the 1950s, “the nearly entire focus of gamma rays from radium on plant growth would switch to cobalt-60,” especially in “gamma gardens.”30 And in reports on the “atom-smasher extraordinary” Ernest O. Lawrence of the University of California, Berkeley, the newspapers claimed that he had perfected “a new cyclotron which produces the most artificial radium-like rays in the world.”31 These varied novel means of producing powerful ionizing radiations ultimately contributed to a brave new world for radiobiology in the post–World War II context.32 As Spencer Weart has noted, “Isotopes became an invaluable tool for studying everything from physiology to the way heredity works. Much of the tremendous progress in biology and medicine since the 1950s would have been impossible without radioactivity. Tracer isotopes would unveil the secrets of life itself!” Indeed, as one CBS radio program announced: “When you get deeper and deeper into the secrets of life, you find them so fascinating you sometimes forget that the atom can kill.”33 While the Atomic Energy Commission would later commission Blakeslee to “study the effects of thermal neutrons and radiations from nuclear detonations and from a cyclotron in the production of chromosome and gene mutations by using the Datura material,” and would later team up with the USDA and over a dozen state agricultural experiment research stations to determine “whether radioactive material does indeed stimulate plant growth,” the Journal of Heredity was already reporting by 1946 that “there is no reason to believe that a whiff of atomic energy is calculated to improve human germ-plasm.”34 Indeed, the end of the USDA study “marked the end of an era for radium.”35
Transmutations: The Gene as Atom (of Radium)
Even as X-rays vied with radium as the preferred tool for biological experimentation in later decades, Muller continued to rely on radium not only as a mutagen, but also as an important conceptual tool, seeing radium and life as somehow intimately connected analogically, discursively, evolutionarily, mechanistically, and metaphysically. Even a decade after his epoch-making work, he continued to describe and analyze phenomena in terms that frequently glowed radioactive. Even as he turned to X-rays, agreed with the physicists’ equation of X-rays with γ-rays from radium, helped to establish the equivalence of these rays in their biological effect, and displaced the radium-based artificial transmutations of Gager and Blakeslee in the historiography, Muller went further than most in continuing to approach the questions of genetics through the language and frame of radioactivity—a testament to the endurance of the powerful associations between radium and life that had long served as his source of inspiration. Two particular areas of his research agenda following his 1927 work serve as good illustrations of this approach: his claims for a possible role for radium as an internal organic mutagen, and his proposed physicalist analysis of the “auto-attraction” of genes.
Following the artificial transmutation of the gene, Muller sought to find an explanation of observed natural mutation rates with reference to natural sources of radiation. As it turned out, ambient sources of radiation were seen to be insufficient (with the physicist L. Mott-Smith, Muller estimated that the amount of natural radiation was some 1,333 times too low; Nikolai Timoféeff-Ressovsky would later estimate that it was 462 times too low). After having discarded nearly every other possible environmental and cosmic source, Muller thus returned to his favored element to explain the discrepancy: “Practically, we should have left only highly radioactive substances like radium as possible sources of radiation competent to give the observed natural mutation rate.”36 And as he moved from a consideration of the mutation rate of genes—his atoms of life—to their very state of mutability, the term “half-life” crossed back again from radium to the realm of the living as he referred to the “half-life of the individual self-duplicating gene in Drosophila.”37 Atoms of life and living atoms now both had half-lives.
Similarly, while looking for a mechanism to explain purported cases of mass mutation and other mysteries of altered mutation rates—precisely the same sorts of issues that intrigued many Oenotherologists—Muller seriously considered speculations by Vladimir Vernadsky and others as to whether organisms might have evolved so as to be able to store radium and thereby preserve the ability to mutate. Organisms, in other words, might be viewed as condensers of radium.38 (Others at the time had similarly wondered “whether there is any relation between the power of radium concentration and the variation or evolution of the organism.”39) Muller explicitly excluded other radioactive elements such as uranium and thorium from consideration: only radium was powerful enough to begin to account for the effect.40
Muller thus continued to call on radium to explain some of the unaccounted-for phenomena of life not only in the individual organism (in inducing its own particular mutations), and not only in intriguing explanations of the stability and length of life of its genes, but also in considerations of an individual organism’s very capacity for mutation and evolution in the first place.41 Muller’s serious—if brief—consideration of whether organisms are condensers of radium and how this might explain evolutionary processes is an interesting transmutation of Burke’s earliest claims to have shown “that there is an element, a bio-element, possessing a vast store of potential properties, and of potential energy equivalent to biotic.”42 Recall that even Becquerel had made similar claims in 1925.
Time and again, Muller also insisted that advances in the study of heredity depended on cooperation between physicists and biologists, as it was “in the tiny particles of heredity—the genes—that the chief secrets of living matter as distinguished from lifeless are contained,” and it was by “understanding of the properties of the genes,” which were “most unique from the standpoint of physics,” that biologists and physicists together could “bridge the main gap between inanimate and animate.” Genes, these most remarkable entities on the border of life and nonlife—“so peculiar are these properties that physicists, when first confronted with them, often deny the possibility of their existence”—were the new radiobes. Understanding them might “throw light not only on the most fundamental questions of biology, but even on fundamental questions of physics as well.”43
Genes, as “the ultimate particles of heredity”—which even “probably constitute the ultimate particles of life itself”—also presented Muller with other mysteries he was keen to solve from a physical standpoint. Their manner of replication (or the mystery of their “autosynthesis,” as he termed it), was of interest, but first and foremost in Muller’s mind was solving the mystery of the nature of gene attraction in terms of what could be observed at the cytological level: the lining up and drawing near of homologous chromosomes during the process known as karyokinesis (the nature of nuclear fission was as of much interest to Muller as it had been to Burke).44 By 1936 Muller sought to explain this phenomenon of “auto-attraction” in terms of radiation. Not only did he theorize that the genes themselves “emanated” some kind of “radiation,” he argued that “under certain conditions, it becomes evident that each gene forms the center of a specific field of attractive force.”45 Though Muller claimed to “use the word radiation here only in the most general sense,” the discursive imprint of radium seems clear: Muller was literally talking about organic “radiations resulting in genic attractions,” about physical radiations as somehow emanating from the genes, in order to account for auto-attraction of homologous chromosomes during karyokinesis.46 He thought that the solution of this problem by physical means would do much to enlighten biologists as to the nature of the gene. But he reported that it had been difficult “to make quantitative studies, after the physicist’s fashion, of the nature of the force of gene attraction; studies of its variation of intensity with distance; of the effect of varying conditions upon it; of its direction; of its speed of propagation; of the possible interference with one another of the forces emanating from different genes; of its possible polarization, etc.”47 Muller even wondered whether a “Heisenbergian ‘principle of uncertainty’” was at the root of how “one tiny gene” with its own “ultramicroscopic determinism” could produce through “growth and development . . . a molar indeterminism” on which natural selection could act.48 Muller seemed open to the possibility that organisms could, in effect, mutate themselves.
Life spans, half-lives, and disintegrations, organisms as condensers of radium, radioactive auto-attraction, and references to Heisenbergian questions of determinism—Muller’s work suggests that a link between the realms of the radioactive and the living persisted in some respects at least well into the 1940s.49 But Muller was far from the only one whose work suggested that further transmutations were afoot. By 1933 some researchers even classified mutants along a “mutation spectrum” (using a word from the study of radiation) using Greek labels—α, β, γ—that exactly paralleled the three kinds of rays given off by radium.50
: : :
The novelist Rudolf Brunngraber had framed the matter aptly in his Radium: “What objection is there to the hypothesis that the tissues, live, dead, or dying, may emit such radiations? Heatless radiation accounts for the light of the glow-worm, the firefly, and the luminous deep-sea fishes. Why, then, should not animal cells give off other kinds of radiation?” After Rutherford and Bohr’s proof of elemental transmutation and the ways in which “we had come to conceive a universe in which matter was a figment of the imagination, in which matter was resolved into a gamut of undulations,” Brunngraber noted, “there was no longer any difficulty in conjecturing that the organic cell likewise must be an electrical system which emits and receives radiation.”51
Chief among these ideas of cells radiating rays in the 1930s was the purported discovery of “mitogenetic radiation”—a discovery that was entirely consonant with Muller’s other explorations into the idea of organisms as radium storage units, and which fascinated him. While N-rays had proved crucial on Burke’s path to radium and ultimately to radiobes, it was these later “M-rays” that most closely paralleled Muller’s own querying of physical radiations emanating from the genes in the 1930s, and which might themselves represent a further transmutation of the associations between radium and life.
First described in 1923 by Alexander Gurwitsch, a Russian cytologist, M-rays were thought to be especially noticeable in actively fissioning living tissue. Characterized first as “mitosis-stimulating radiation,” these oscillatory rays were not only produced by actively dividing tissues, but could also stimulate other tissues.52 A subcommittee of the National Research Council dedicated to mitogenetic radiation was established in 1928, just a year after Muller’s artificial transmutation of the gene, and Muller himself was intrigued by the phenomenon. Reflecting on some work by Altenburg, Muller had even speculated that “natural ultraviolet rays (‘mitogenetic rays’) produced by the chemical reactions occurring in organisms are responsible for some of the mutations that occur naturally.”53 Perhaps, he noted elsewhere, even the “structure of the radiation would be some sort of geometrical resemblance between the arrangement of parts in the gene and the arrangement of parts in a bundle of the radiation itself.”54 Radiation, the gene, and the organism were all held together in one atomic whirlpool by M-rays, just as an earlier generation had held life and light together with N-rays, and just as Crile and Lakhovsky in the wake of Burke had theorized about radiation produced by and emanating from living things.
Over the next few years, some six hundred papers confirming M-rays’ existence by two hundred authors from American and European laboratories were published in well-respected journals; reported observations reached a record level in 1935 before tapering off.55 One commentator in 1933 even directly associated mitogenetic rays with radioactivity:
In the face of such experimental evidence it is extraordinary that the existence of the Gurwitsch rays should be questioned. The remarkable thing about them is not that they have been discovered but that their presence was not suspected long ago. . . . The complexity of protoplasm is not in itself sufficient evidence of radioactivity, but it does leave one more ready to suspect it of being thus active.56
Despite its many defenders, however, mitogenetic radiation was one more radiation consigned to the dustbin of history, and the NRC subcommittee formed to study it disbanded by 1936.
Is the sputtering arrival of mitogenetic radiation another potential transmutation of the radium-life association? The answer to this question returns us to the full spectrum of possibilities relating metaphysics and metaphor to experiment. No longer clearly demonstrating an ontological connection, as Muller seemed to wish for, countless further provocative examples of an ongoing association of radioactivity with life can nevertheless be readily identified, suggesting that something more than mere metaphor is going on. One 1947 book, discussing the nature of radioactivity, described the protons and neutrons in the nucleus of the atom as “cells.”57 The authors of the Smyth Report on Atomic Energy for Military Purposes, published in 1945, concluded that the term “nuclear” still had “primarily a biological flavor” and opted for the term “atomic” instead (which was also “less likely to frighten off readers”).58 Even in 1957 one author referred to cells as “the transmuters of molecules” and described mitosis in terms of tissue having “the ability to make use of the chain reaction principle. . . . It may be said that normal tissues grow by means of a controlled chain reaction”—thus using Niels Bohr’s concept of the chain reaction in nuclear physics to describe the original biological process of fission.59 (“Fission” had itself been a biological term before it became a nuclear one.60) Even the association of cells with one another was sometimes described in atomic terms: “Far from being isolated, the cells live in close integration and create an atomic whirlpool.”61
Even as late as 1947, in a lecture he delivered at Oak Ridge, in which he also acknowledged having read Soddy in his youth, Muller remained explicit about the connections he saw between the world of atomic energy and the world of the gene:
It may also seem strange that people in my line of study, who have been concerned with the slowest moving and in a sense the most insidious forces in the world, should have anything to contribute which might be of interest in connection with the line of work dealt with here, which concerns the quickest, the most violent and spectacular of forces. . . . I [shall] try to give you an inkling of some of the ways of working of these peculiar, slow-moving forces which, unlike the violent destructive energies of the atomic chain reaction, have very gradually worked constructively and themselves, too, in a kind of chain reaction system, on the chemical level, so as to have finally brought into being, not dissolution, but the ultra-complicated organizations found in our own bodies and in those of all higher animals and plants.62
In short, the sheer conceptual productivity provided by this metaphorical overlap between the realms of the radioactive and the living clearly remained a major driver for Muller and for others for some years. In other instances, however, it seems evident that the terminology was simply convenient to retain, or somehow remained a compelling usage despite important points of disanalogy. As with the initial formation of a biologically inflected radioactive discourse in the early part of the century (see chap. 1), these later parallels were the results of deliberate choice, mere coincidence, and overdetermination alike.
No matter their individual plausibility, the sheer number of such examples and their widespread occurrence—even as experimental interests and concerns increasingly led many investigators farther afield from radium itself—might well be further evidence of the ongoing transmutations of the radium-life connection not only toward radioactive discursive residues, but also toward the continued use of radiation in understanding the atomic physics of the gene. “Already it is evident that the problem of the gene is the problem of the atom,” noted one science journalist in 1945, parroting Muller.63 Even cytogeneticist Cyril Darlington would write in 1933 that the gene is the “atom of inheritance” and that “we can assume without hesitation that an intra-molecular and therefore intragenic change precedes and conditions all more complicated kinds of change.”64 Others would soon pick up on this call for a more physicalist treatment of the gene.
Decay: The Target Theory, Light and Life, and the Atoms of Biology
Although Gager, Blakeslee, and even Muller for a time continued to use radium in their experiments and in their thoughts, the increasing instrumentalization of radiation—the movement away from a singular focus on the lifelike and life-relevant properties of radium and toward the use of X-rays as tools in the study of life—unquestionably moved many subsequent experimental systems further away from what had once been an all-encompassing association of radium with life. With the gene becoming the natural target and X-rays and other forms of ionizing radiation the increasingly obvious means for studying mutation, Muller’s success also inadvertently aided in the growth of the new field of “radiation genetics,” which sought to bring radiation ever closer to the secret of life in the genes.65 As mutation became a physicalized process, paralleling the materialization of the gene, and as new kinds of radiations proved easier or cheaper to use than radium itself, the field of radiation genetics, by drawing on earlier tropes that analogized the hereditary substance to an unstable element, signaled a shift from what was often a population genetic approach (dealing with the half-lives of genes in a population) to a more strictly biophysical and molecular approach. No longer merely genic, mutation was becoming molecular. And what had begun as the use of radiation to study the gene was transformed, in the hands of radiation geneticists, into the use of the gene to better understand the molecular effects of radiation.66
One outgrowth of this use of radiation and its effects on molecules to study genetics came to be known as the Treffertheorie, or “target theory”—a series of attempts to establish with ever greater precision the character of the genetic material and the size and nature of the genes, and to establish a quantitative relationship between the amount of ionizing radiation deployed and the amount of mutation produced.67 The target theory held that in many respects, the gene could be understood by analogizing it to an unstable element. In fact, the target theory’s attempts to ascertain the size of the gene by atomic bombardment bear at both first and second glances an uncanny resemblance to Rutherford’s earlier search for the atomic nucleus. The experimental practices of target theorists are thus arguably also among key further transmutations of the associations between radium and life.
The biophysicist Max Delbrück agreed with Muller that biological problems could be attacked most fruitfully with the tools of physics: “As we enter this new territory, we are rewarded at every step with new insights into the wonderful mechanics of the hereditary mechanism, for the exploration of which radiation has furnished a powerful tool.”68 According to William Summers, Delbrück “used evidence and concepts from target theory experiments to construct a model of mutation and then a theory of gene mutation and structure.” Angela Creager has also viewed Delbrück’s contributions as primarily theoretical: he “drew on quantum mechanics to interpret mutations in terms of shifts in atomic configuration from one stable energy state to another.”69 (Gunther Stent would later characterize this as a “quantum mechanical” model of the gene—a clear echo of Muller’s quantum understanding of evolution.70) The biophysicist Delbrück, geneticist Nikolai Timoféeff-Ressovsky, and physicist Karl Zimmer teamed up to explore how radiations might be used to better characterize the “gene molecule” and understand it from a quantum mechanical point of view. The end result of their collaboration was an important “green pamphlet” known familiarly among those in the new field as the Dreimännerwerk, or “Three-Man Paper,” of 1935.71
As Delbrück later recalled, “The major paper got a funeral first class. That means it was published in the Nachrichten der gelehrten Gesellschaft der Wissenschaften in Göttingen, which is read by absolutely nobody except when you send them a reprint.” The three men circulated reprints among the small community of interested geneticists and physicists, however.72 They concluded that
mutation was a “one-hit” process, a single ionization produced by a quantum of radiation within a certain sensitive region. They calculated the size of the sensitive region to be on the order of a large organic molecule. Although they were cautious about identifying this sensitive region with the gene itself, they argued from the target-theoretical analysis that the gene could be understood as a “group of atoms.”73
One of the (few) longer-term accomplishments of the target theory was thus the literal equation, long in the making, of genes with the atoms of physics.74
The target theory—and the rapid growth of radiation genetics as a whole—has often been viewed as a sort of imposition of physicalist methods on biology, or at least of physicists on biological questions, a topic with its own large literature.75 More specifically, Summers has carefully traced the ways in which specific ideas from “the atomic physics of Thomson and Rutherford” were applied to the study of the gene and how they “depended in the first instance on a conjunction of events and an individual with specific interests and knowledge”—reflecting a classic historiographical interest in compensating factors, interests, and the play of contingency.76 It may be equally useful, however, to view at least some of the development of radiation genetics and the target theory as later curious decay products of the once powerful associations between radium and life—later, having largely happened after Muller’s most compelling work, and curious, because while the constant reiterations of “physics” and “biology” (and the atoms of each) owe much to discursive modes established earlier, radium itself had by and large disappeared from consideration in the new radiation genetics. The initially powerful associations between radium and life not only transmuted, one might say, but also decayed.
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Viewed in this light, even Niels Bohr’s famous lecture “Light and Life” of 1932—delivered as the inaugural lecture of the International Congress of Light Therapists in the Rigsdag in Copenhagen—might be viewed as a further decay product.77 Bohr’s claim that perhaps there were new laws of physics to be discovered in the biological realm paralleled older, familiar claims that the discovery of radium necessitated the rethinking of the laws of physics.78
Moreover, his association of “light and life” was one that dated back well before Burke. Some commentators at the time even drew direct links from Muller’s work to Bohr’s lecture, stating that “there is a connection” between “fruit-fly eggs which have been genetically jolted by radiations” and Bohr’s “Light and Life.”79 (In 1935 Timoféeff-Ressovsky, Delbrück, and Muller met with Bohr at the Carlsberg Laboratory in Copenhagen specifically to discuss the nature of mutagenesis.80)
But while Burke’s work proved to be sensational and Muller’s bent was experimental, Bohr’s reworking was more thoroughly conceptual: “We are not dealing here with more or less vague analogies,” between light and life, Bohr said, echoing his many predecessors in sounding a note of caution about metaphors. Rather, the concern was “with an investigation of the conditions for the proper use of our conceptual means of expression.”81 And because living things are constantly in flux, Bohr argued, the application of mechanical or quantum ideas from physics to the analysis of life is difficult: “This fundamental difference between physical and biological research implies that no well-defined limit can be drawn for the applicability of physical ideas to the problem of life. . . . This apparent limitation of the analogy in question is rooted in the very definitions of the words . . . which are ultimately a matter of convenience.”82
Bohr held that the analysis of words was important to understanding the nature of the claim that could be made for a particular association between physics and biology. In so doing, he was only the most recent exemplar of investigators into the relationship between radiation and life for whom words were central, including Soddy (“words would not come . . . as though propelled by some outside force I heard myself utter unbelievable words”), one of Burke’s critics (“Put in this way the whole matter resolves itself into a question of words”), de Vries (“the instability seems to be a constant quality, although the words themselves are at first sight, contradictory”), Blakeslee (“We all feel a difference in meaning between the words mutant and mutation”), and Muller (“Mutation and Transmutation—the two key words processes stones of our rainbow bridges to power!”) When dealing with the borderlands between radiation and life, words mattered as much as things for Bohr, as they did for his predecessors. Perhaps Muller’s emendations to his description of mutation and transmutation say it all: beginning as mere words and metaphors, then functioning as processes and experiments, they end as “stones” in a metaphor of another kind.
Bohr also suggested that biology, like physics, has an irreducible aspect known as the quantum, but that this quantum is not the mutant, the cell, or the gene (as Muller would have it), but the very “secret of life” itself. This “secret of life” was always inherent in our knowledge of the living world, a residue that could never be “explained away.” The quantum of life, Bohr suggested, was not waiting to be found inherent in some entity, but lay rather in our considerations of what would make it so. Was radium alive? Were radiobes examples of primitive life? Were chromosomes truly the determiners of heredity? Were genes more properly conceived of as the ultimate basis of life? Debates over the precise status of each of these entities in the field of life could now be superseded through better consideration of the meaning of “life.” Framed in such reflexive ways, this epistemological twist in Bohr’s “Light and Life” might be productively viewed less as an intrusion of physicalist thought into biology than as an ever more distant decaying residue of radium and life. Bohr’s twist suggests that the “secret of life” is not “out there,” waiting to be empirically discovered using the radium of the moment. Rather, a new and different mode of investigation and analysis—suggesting a new way of narrating and analyzing this complex history of transmutations—would call less for a “just the facts” narrative with an unproblematic recounting from empirical sources than for a reflexive narrative reconceptualizing what counts as “proper” evidence and reasoning, and challenging the very presumptions of historical narrative itself. These sorts of deliberately artificial transmutations of the meme might be central to alternative ways of telling the history of the complex reworkings of “radium and life.” Perhaps, just as Morgan and Muller had to doubt radium’s mutagenicity in order to make their own advances into the nature of induced mutation, the historian should reflexively seek to doubt his own compelling narrative and deconstruct its own interweavings of metaphors, metaphysics, and modes of historical reasoning (a possibility explored further in the Conclusion).
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Bohr’s contemporaries found more concrete insights in his lecture. Sitting in the audience in Copenhagen was the young Max Delbrück: “I was interested—well, anybody who was at all interested in quantum mechanics couldn’t help but be fascinated.”83 Delbrück found inspiration in Bohr’s lecture to search for an analog of the physicist’s notion of complementarity in the biological realm—even if that meant a new principle that was in some way unpredictable. As Lily Kay has noted, “Bohr inspired Delbrück to explore biology—the ‘secret of life’ as he put it.”84 Once an assistant to Lise Meitner in the laboratory that had produced the first artificial fission, Delbrück envisioned numerous interconnections between biology and atomic physics—indeed, he chose to work with Meitner from 1932 to 1937 largely because of the proximity of her laboratory to the Kaiser Wilhelm Institutes for Biology (“I thought it would be a good opportunity for me to pal around with biologists”). Bohr’s speech, Delbrück noted, “was sufficiently intriguing for me . . . to decide to look more deeply specifically into the relation of atomic physics and biology.”85
As Delbrück would later remark in 1944, “Perhaps we are approaching a similar phase in biology” to that in “physics around 1890,” just before “the discoveries of radioactivity, of X-rays, and of the electron.” He continued, “It would seem that the principles of atomic physics will have a large share in the construction of this ‘modern biology.’” He even referred to “the atomic theory of biology, i.e., genetics.” This reference was intended as more than mere rhetoric or analogy: where Bohr was vague, Delbrück wanted “to find out just how far atomic physics does carry us in the understanding of the phenomena of the living cell.” In so doing, he was asking new versions of some very old questions: Were there atoms of life?86 And just what was the relationship between the half-living atom and those atoms of life?
While Muller had tentatively proposed in 1922 that bacteriophage—a virus that infects bacteria—“would give an utterly new angle from which to attack the gene problem,” it was up to Delbrück to lead the field of “phage genetics.” (Delbrück, along with Salvador Luria and Alfred Hershey, “dominated this nascent phase of molecular genetics.”)87 Delbrück recalled his first discovery of bacteriophage-induced plaques in the lawn of bacteria on Carl Lindegren’s petri dishes as a “simple experiment on something like atoms in biology.”88 But a colleague remembered Delbrück exclaiming upon seeing the plaques, “Oh, my God, you have atoms in biology. I’m going to work on that.”89
No mere passing fancy or simple descriptive technique, these “atoms in biology” inspired Delbrück to draw connections between the atomic theories of physics and a quantum understanding of genetics (the so-called “atomic theory of biology”) as he used ionizing radiation to produce mutations to better study the physical nature of the gene. Erwin Schrödinger, the son of a botanist, drew further on Delbrück’s work with Timoféeff-Ressovsky to happily equate de Vries’s mutation theory with the quantum. Schrödinger’s famous What is Life? (1944) is a paean to the idea of the hereditary unit as an atomic structure; he claimed in 1945 that “in the light of present knowledge the mechanism of heredity is closely related to, nay, founded on, the very basis of quantum theory.”90 But as Schrödinger suggested, the reduction of genetic fundamentals either to the phage system or to a basic code-script—rather than the more complicated systems of heredity in Oenothera, Datura, and other higher organisms with admittedly much more complex hereditary mechanisms at levels above the gene—also meant further reductions in the meaning and phenomena of mutation.
But even Luria’s later discovery that phage could be both inactivated and reactivated by irradiation—with radiation now not only causing damaging gene mutations, as Muller had established, but also able to re-induce some of the characteristics of life—may serve as yet another far-removed residue of the association between radium and life. And Delbrück’s later characterization of the discovery of the structure of DNA also suggests ongoing resonances: “Very remarkable things are happening in biology,” he wrote to Bohr, after learning about the discovery in a letter from James Watson. “I think that Jim Watson has made a discovery which may rival that of Rutherford in 1911.”91 Perhaps, then, even the ascription of the “secret of life” to DNA—refracted through Delbrück’s “riddle of life”—is another product in the decay chain of radium and life.92
Orthogonal to traditional narrative progressions from target theory and radiation genetics to Bohr’s “Light and Life,” and from Delbrück’s talk of “atoms in biology” to the “secret of life,” these brief scintillations suggest an alternative historical narrative of ever-sporting associations between radium and life over decades and across subfields.93 But if these varied cases seem increasingly less compelling or tangential than the chapters that preceded them—if something has seemingly decayed in the association of radium and life from Muller to Bohr and Delbrück—still further disintegrations are yet to come.
Disintegration
In the aftermath of Muller’s work, genes continued to be strongly associated with the atoms of biology. Gager’s General Botany of 1926, for example, reported that “most mutants are exceedingly stable . . . the genes of the vinegar fly, Drosophila, indicate a minimum stability on the average for each gene comparable to that of radium atoms, which have a so-called ‘mean life’ of about 2000 years.”94 Yet points of disintegration began to emerge. By 1936 Muller had calculated the life span of a gene to be of a different order of magnitude than that of an atom of radium—on the order of 100,000 years.95 And despite the curiosities of the background levels of radioactivity in living matter, by 1959 Muller was able to remark that “the genetic material, unlike protoplasmic constituents, is not subject to flux: that is, the atoms within it remain there permanently, without turnover.”96 What had been an intra-atomic connection to life was rapidly becoming merely extra-atomic chemistry. Even radium’s use as a central metaphor was eclipsed by Muller’s increasing use of alternative tropes, such as the older trope of the fire of metabolism.97
Nor was radium, or radiation in any form, still necessary for the production of mutants. Charlotte Auerbach discovered alternative mutagens in mustard gas in 1943, and by 1937 Blakeslee and others had already begun to use the chemical colchicine in efforts at what they called “genetics engineering.”98 In light of the chromosomal evolutionary engineering first pioneered by Blakeslee, Barbara McClintock began to construct maize stocks that could, through their own dynamics, produce random mutations. The discovery was as shocking to McClintock and her contemporaries as Muller’s and Blakeslee’s had been to theirs. (McClintock reported she was “astounded. . . . It had gone wild. The genome had gone wild.”99) As Nathaniel Comfort has noted, not only did McClintock’s technique involve a thoroughgoing and contested reconsideration of the nature of mutation,100 but her use of the breakage-fusion-bridge cycle for producing mutation was positioned to replace the use of X-rays, casting them aside as “expensive and dangerous”—just like radium before them.101
As the effects of radiation increasingly came to be seen as fundamentally different from (and more damaging than) the diverse new ways in which mutations could be spontaneously induced in organisms, the role of ionizing radiations in the study of heredity became much less clear. Even as X-rays replaced radium on many fronts as tools of “extraordinary nicety,” as Muller had put it, a fuller understanding of mutational processes meant that they were increasingly viewed as potentially misleading tools: Muller and Stadler disagreed repeatedly over whether the mutations induced by X-rays were the same as those occurring naturally.102 And as X-rays, unlike radium, were without a “natural” analogy to life to fall back on for discursive comfort, more such contestations rapidly emerged. Even Delbrück would note by 1949 that “it may turn out that certain features of the living cell, including perhaps even replication, stand in a mutually exclusive relationship to the strict application of quantum mechanics, and that a new conceptual language has to be developed to embrace this situation.”103
The connections between radium and life were thus, in some respects, disintegrating. Disanalogies between radiation and life had, of course, always been present. But with the development of novel experimental systems that increasingly technologized and instrumentalized the uses of radiation, and with the reduction of the basis of life to the gene in the view of many geneticists, the significance of these disanalogies became easier to discern. And these disanalogies were combined with changes in understandings of the nature of various forms of radiation, advances in X-ray technologies, and fully instrumentalized experimental techniques in radiation genetics that needed no further metaphorical justifications, thereby challenging the earlier connections once so obvious to Soddy, Burke, and their contemporaries, and even to Muller. The once obvious truth that radium had curious properties reminiscent of, ontologically similar to, and perhaps even generative of life became increasingly difficult to see by midcentury as ever more complicated understandings of the genic nature of mutation dovetailed with rising concerns about the uses of radium and popular notions of radiation as life-stealing rather than life-bearing.
In fact, germs of decay—such as the idea that radium could be detrimental to life, rather than stimulating or otherwise positive in its effects—were already present in the earliest literature on radium, from early visions of the potential inherent dangers of its untapped but unlimited power for misuse to understandings of radioactive decay as a kind of backward evolution from the more complex to the less complex.104 Disanalogies had always been present: radium didn’t really reproduce, and even the view of its daughter elements (decay products that were not the same as the original radium) as “mutants” seems to have strained the analogy too much for contemporaries to offer more than the first outlines of such an account. Soddy eventually came to blame radium for his infertility. And even Muller’s search for the sterile products of irradiation can be seen as marking an important disintegration of the association of radium and life. Unlike Morgan’s avoidance of sterile mutants (seen as noise obscuring the signal he was trying to detect, and therefore not a factor in his discoveries), and unlike Gager and Blakeslee’s search for possible new species of Datura (which they clearly found), Muller’s complicated techniques for calculating mutation frequency in Drosophila relied centrally on the identification of lethality itself—dead flies—as revealers of mutations, the observable evidence for his carefully designed tests. Neither dead flies nor X-rays (recall Frau Roentgen) would be the most obvious candidates for an ongoing association with life. Even as Muller’s radioactive metaphysics increasingly construed the gene as something akin to an atom of radium and placed it at the center of all evolutionary change, the seeds of decay were already present.
Finally, as the “secret of matter” was to be found in the atomic nucleus, it stood to reason for Muller, as for many others, that the “secret of life” might reside in the biological nucleus, and that radium and its daughters might be the means to get there. “Whatever the secret of the gene’s ability to reproduce itself and its mutation may consist in,” Muller noted in 1950, “it seems today clearer than ever . . . that this is also the most fundamental secret of life itself.”105 But just as the biological claimants for the role of “secret of life” continued to shift over the years—from animalcule, organic molecule, or monad in earlier times to cell, chromosome, and gene, as told in these pages—so, too, did the physical claimants to act most intensely or instructively on them. Therefore, even as the shift from radium to other forms of ionizing radiation provided for multitudes of new experimental possibilities and for the emergence of the new fields of radiation genetics and radiobiology, the once familiar associations of radium with life continued to disintegrate as experimental setups and tools strained any immediately obvious connection between the two. As experimental productivity and epistemically helpful framings parted ways, such associations became increasingly unrecognizable by midcentury, and radium came to seem to have almost nothing to do with the secret of life at all.
Various other developments contributed to this destabilization, of course, and further transmutations, processes of decay, and disintegrations continued apace over the span of decades and across contexts. A general belief in radiation hormesis (the stimulating effects of radiation), so much a part of the early twentieth-century association between radium and life, began to go out of fashion by the 1940s.106 Moreover, the rise of an instrumentalized radiation genetics, as well as larger cultural contexts in which the hydrogen bomb became the ultimate symbol of radioactive contamination and concern, led to a dawning “radiophobia.”107 The association of radiation and life, brought into being at a certain moment, the product of a particular reach and lifetime, was now also accompanied by world-historical events. By 1951 one book—Our Atomic Heritage—could even declare plainly in one chapter subtitle, “Radiations equal mutations,” and in the next, “Mutations are not good.”108
Dovetailing with the multitude of other concerns and events by the 1950s, radium’s associations with life continued to disintegrate. Muller’s own mutagenic studies with radium and X-rays contributed prominently to the concept of radiation-induced hereditary damage; his work brought concerns regarding the lack of a minimum threshold below which no mutational damage could be expected and introduced the concept of “our load of mutations” to a wider audience in 1949.109 This view of the effects of radiation as lethal, damaging, and generally “bad”—Muller’s rallying cry throughout the 1940s and beyond as he conducted further experiments—was the opposite of the widespread conception of mutation as profitable and life-enhancing held by most biologists in the first decade of the century: the shift from “Our Lady of Radium” to “Our Load of Mutations” was clear. In a Cold War battle for the planet in which the threat of exposure and of radioactive fallout were ever present, such concerns were more than merely biological. And so mutations themselves—once the high goal of experimental evolutionary efforts at Cold Spring Harbor and elsewhere—came to be routinely seen by geneticists as detrimental in nature, rather than the desirable new means for the production of agricultural superstars they had once been.
Although echoes of the radium-life connection continue to turn up in the most unexpected of places,110 as is only appropriate for an association with a half-life, the overall trend was clear: by midcentury, radium—and by extension, radioactivity and ionizing radiation more broadly—had by and large transmuted. Now rarely seen to be helping to unveil the secret of life, radiation became increasingly associated with fears of cumulative and irreversible genetic damage, contamination, and death.111
Transmutations, decay, and disintegrations! Are radium and life the same thing? Or were they taken to be such, and how did that change over time? Were genes the atoms of life, the radium of the cell—or was it chromosomes, or viruses? Or “the quantum”? And why are these particular cases mentioned and others not? Why weaken the richly detailed and coherent narratives of the case studies in the previous three chapters with such a seeming smorgasbord of increasingly less compelling cases? Just what is going on here?
By midcentury, this proliferation of narratives, of possibilities, of likely descendants and dubiously relevant cases—only a few of which have been traced here—all becomes terribly confusing within the confines of one synoptic historical narrative. Just so much is to be expected in a historical narrative that takes transmutation and decay seriously as immanent tools of analysis and seeks to perform the same sorts of multiplicities and confusions and to raise the same sorts of hints and doubts that its actors themselves clearly grappled with by midcentury. Perhaps Brunngraber captured it best in his novel Radium (1936):
“Radioactivity and life are one and the same thing.”
“Maybe, maybe,” replied George in a dubious tone. . . . “I’m sorry,” he said, “but my mind is growing somewhat confused.”112
(That, indeed, is somewhat the point.)