J D Bernal

by Andrew Brown

  During the four years between the first and second editions, Khrushchev’s denunciation of Stalin at the twentieth congress of the Soviet communist party meant that party followers world-wide had to revise their outlooks. This adjustment was taken seriously by British communists, who also had to come to terms with events in Hungary. As part of the cosmetic repairs, Beria (the despicable chief of the NKVD who was executed within months of Stalin’s death) soon had his name expunged from official Soviet history, being replaced by an entry on the Bering Sea. Bernal was visited at Birkbeck by N.V. Belov, an old friend, who was Professor of Crystallography at Gorki University. Bernal brought Belov to his office to meet some of his younger colleagues. Belov’s eye was caught by the Soviet encyclopaedia that Sage had on his shelves. Reaching for the volume containing BE, Belov remarked, ‘There have been some changes.’ Turning the pages, he smiled and said ‘Ah, Bernal, he is still all right!’6

  By 1965, when the third edition of Science in History appeared, Sage had to rewrite the chapters on ‘Science in our time’ to reflect the revolution in molecular biology, the rapid developments in electronics and computing, and the advent of the Space Age. An optimistic tone prevailed, based on the past successes of science which he hoped would now be brought to the peoples emerging from colonial rule. Yet he was concerned that the benefits of science were unevenly spread, and that there was still widespread hunger in the world because underdeveloped countries depended on subsistence agriculture, without access to modern techniques or chemical fertilizers. In his new preface, Sage wrote:

  Actually the differences between the standards of living of the peoples in the developed and the under-developed world is not yet diminishing: it is increasing in a way that seems bound to lead to a crisis, and there is always the danger that a crisis of this sort might itself set off a first world nuclear war. This crisis can and must be avoided, but it can be avoided only by the efforts of the peoples themselves of all countries. For that they must get the necessary education and find the capital to build themselves a scientific and industrial complex which can provide for their needs.7

  Just three years later, when the final, illustrated, edition came out, his mood was much more pessimistic. Far from beginning to narrow, he saw the gap between rich and poor nations widening even more.

  While science is playing a larger and larger part in the advanced industrial countries, it is stagnant or even receding in those parts of the world which contain the bulk of its population. The effect of this is to bring about for the first time the possibility that humanity will extinguish itself by war or famine. Science, as it is now being used, contributes to making such a horrifying prospect not only possible but almost certain, and up till now there has been little evidence of factors that will cause this process to reverse. This vast prospect of Nemesis, however imminent, has caused little alarm and produced virtually no efforts to deal with it. It would seem that there is a universal tacit conspiracy to avoid thinking about it by those responsible for creating the situation in the advanced countries, and the victims’ complaints are met with indifference and repression.8

  These words were written at the height of the Vietnam War, and Bernal placed most of the blame for science losing its way in the world on the USA. With their calm discussions of ‘megadeaths’ and ‘overkill’, the ‘men of Big Science are being reduced to the worst kind of savage imaginable. Moreover, behind them lies a population whose values have been mentally corrupted by the policy and ideology of anti-communism.’9 There was a second Industrial Revolution at hand that was based largely on electronics and automation, and a few American corporations were threatening to gain control of the global economy by their mastery of these developments. He could not see how this American infiltration could be arrested, especially by the ‘old capitalist powers, such as England, France and Germany… on account of their small size and outdated methods’.10

  It is now evident that the real source of wealth lies no longer in raw materials, the labour force or machines, but in having a scientific, educated, technological manpower base. Education has become the real wealth of the new age.11

  How much more difficult it would be for countries of the Third World to establish their own autonomous industries. The post-colonial countries were in a race against the onset of famine; while they might receive some genuine aid from the socialist countries, Bernal thought that ideally they ‘should rely on their own resources of materials and men. In other words, they will have to pull themselves up by their own boot-straps’.12

  The sweep of Science in History was tremendous, and Sage realized that he had to compromise on the depth of his scholarship if the book was to be coherent. It grew from a single tome of 867 pages in 1954 to four volumes of 1,328 pages in the fourth edition, published in 1968. There remained one prehistoric question that was so intriguing he explored it separately – the origin of life. His first serious consideration of the topic came in the 1947 Guthrie lecture, referred to in the last chapter. In 1946, he had visited Princeton and talked to Einstein about the underlying unity, in terms of its biochemical processes, of life on Earth. As a result of their discussion, Sage came to the view that ‘life involved another element, logically different from those occurring in physics at that time, by no means a mystical one, but an element of history. The phenomena of biology must be… contingent on events. In consequence, the unity of life is part of the history of life and, consequently, is involved in its origin’.13

  The origin of life was a subject that had been opened up in the nineteenth century by Darwin, Pasteur and Thomas Huxley, but which remained essentially speculative and not the province of any particular branch of science. In other words, it was perfect for Sage. Claiming to be fully aware of his own inadequacy, he listed the attributes necessary to make any headway on the problem: the researcher would need ‘to be at the same time a competent mathematician, physicist, and experienced organic chemist, he should have a very extensive knowledge of geology, geophysics and geochemistry and, besides all this, be absolutely at home in all biological disciplines’.14 Other than Sage, J.B.S. Haldane was probably the scientist who came closest to satisfying these qualities, and it was he who had made a notable contribution to the subject in 1929. In a short article, he considered how a chemical environment might have arisen that would be conducive to the origin of life, and his essential thesis was encapsulated in three sentences: ‘When ultraviolet light acts on a mixture of water, carbon dioxide and ammonia,’ he wrote, ‘a vast variety of organic substances are made, including sugars, and apparently some of the materials from which proteins are built up… Before the origin of life they must have accumulated until the primitive oceans reached the consistency of hot, dilute, soup… The first living or half-living things were probably large molecules synthesized under the influence of the Sun’s radiation, and only capable of reproduction in the particularly favourable medium in which they originated’.15

  Although Haldane did not know it at the time, some similar ideas had been published in the USSR in 1924 by a botanist and biochemist named Alexander Oparin. Oparin proposed the evolution of complex carbon and nitrogen compounds in the Earth’s primitive ocean, and further suggested that it was possible that those organic compounds then aggregated together into larger molecules, eventually forming gels.16 In his original pamphlet, Oparin had assumed that oxygen was present in the Earth’s primitive atmosphere, whereas Haldane thought there was ‘little or no oxygen’ (but plenty of carbon dioxide and ammonia) so that ‘the chemically active ultra-violet rays from the Sun were not, as they are now, mainly stopped by ozone (a modified form of oxygen) in the upper atmosphere, and oxygen itself lower down’.17 Oparin later agreed that the primordial atmosphere lacked elemental oxygen. Such a reducing atmosphere would stabilize organic (carbon-rich) compounds and also meant that the first organisms would depend on fermentation for their energy metabolism.

  In his Guthrie lecture, Bernal underpinned his ideas with two kinds of scientific data – �
��the geochemistry and physico-chemistry of the cooling planet, and the organic chemical composition common to all existing living organisms.’ He viewed the process of life developing as ‘a play divided into a prologue and three acts’.

  The prologue introduces the scene on the surface of the primitive earth, and the first group of actors of an entirely inorganic kind which must start the play. The first act deals with the accumulation of chemical substances and the appearance of a stable process of conversion between them, which we call life; the second with the almost equally important stabilization of that process and its freeing from energy dependence on anything but sunlight. It is a stage of photosynthesis and of the reappearance of molecular oxygen and respiration. The third act is that of the development of specific organisms, cells, animals and plants, from these beginnings. All we have hitherto studied in biology is really summed up in the last few lines of this act, and from this and the stage set we have to infer the rest of the play.18

  Bernal had one major reservation about the Oparin–Haldane hypothesis that the evolution of organic molecules into proto-proteins and other building blocks of living organisms took place in the primordial soup of the ocean. He was worried about the problem of extreme dilution – how would the simple molecules, perhaps containing one carbon atom, ever come together with a dozen or more similar molecules in such a vast setting to form a complex aggregate? While there might be some concentration in pools and lagoons, he had a novel theory:

  It has occurred to me, however, that a much more favourable condition for concentration, and one which must certainly have taken place on a very large scale, is that of adsorption in fine clay deposits, marine and freshwater.19

  The role of clay appeared plausible to Sage on the general grounds that ‘there is probably today more living matter, that is protein, in the soil and in the estuarine and sea-bed clays than above the surface or in the waters’. There were also new specific experimental findings to bolster his theory. Electron microscopy had revealed that fine-grained clay comprised thin sheets of aluminium silicate that gave ‘an enormous effective adsorptive surface’. What was more, there was chemical evidence that a wide variety of organic compounds were preferentially adsorbed on such surfaces in an orderly way so that relatively high concentrations could be achieved. The regular arrangement of molecules as they attached to the clay surface would encourage chemical interactions: the ‘simpler molecular compounds could be made to undergo complex polymerization, polymerization to such an extent that the macromolecules produced might be able to exist in a colloid form even without the clay, and become… enzymes in their turn’.20

  Clay was not the only material on which Bernal thought adsorption of carbon-based molecules might have occurred. In his mind, quartz was another potential scaffolding for macromolecules, and it had an additional attraction over clay: it was a mineral with handedness – its crystals have either a right-handed or a left-handed twist. Reminding his audience that Pasteur had shown that living organisms characteristically do not contain mirrorimage molecules, whereas ‘normal chemical processes produce right-handed and left-handed molecules with equal facility’, Bernal suggested that the twist of the quartz crystal would restrict macromolecular assembly to molecules of the same handedness. The asymmetry of life was a fundamental point in Haldane’s theory too, for he wrote:

  It is probable that all organisms now alive are descended from one ancestor, for the following reason. Most of our structural molecules are asymmetrical, as shown by the fact that they rotate the plane of polarized light, and often from asymmetrical crystals. But of the two possible types of any such molecule, related to one another like a right and left boot, only one is found throughout living nature… There is nothing, so far as we can see, in the nature of things to prevent the existence of looking-glass organisms built from molecules which are, so to say, the mirror-images of those in our own bodies… If life had originated independently on several occasions, such organisms would probably exist. As they do not, this event probably occurred only once, or, more probably, the descendents of the first living organism rapidly evolved far enough to overwhelm any later competitors when these arrived on the scene.21

  When The Physical Basis of Life was published, Bernal included an appendix given over to critical comments made by Pirie, in a letter after the original Guthrie lecture appeared. Pirie was put out that these private remarks should appear in public – not because he did not stand by his arguments, but because he was concerned they were carelessly expressed. When he saw the book, Pirie wrote to Sage complaining that he had written his observations in a hurry and may have been ‘tight’ at the time. He went on: ‘Continually I complain, in political fields, that you write thoughtlessly with errors of phrasing’,22 and now Sage was making him inadvertently guilty of the same lapses of style. Pirie23 had a deep love for the English language and often contributed to the Oxford English Dictionary.* Pirie closed his letter with a threat: ‘If you publish this letter I will sue you’! Unabashed, Sage sent the following reply:

  Dear Bill,

  It never occurred to me that you were tight, or, even if you were, you could ever have forgotten yourself so far as not to express yourself in perfect English!… I should have asked you and I am very sorry now that I did not because you might have produced longer and even more controversial comments.

  As we have seen, Pirie took some revenge in his review, ‘Vital blarney’. He used the review to amplify one of his major reservations about Bernal’s thesis.

  The framer of a hypothesis, or speculation, about the origin of life labours under the difficulty, not only that he does not know what raw material he has to work with, but also that he does not know what types of substance he must arrange to have synthesized. Professor Bernal assumes that, in the beginning, proteins were essential. He assumes this partly because they are components of some living organisms now, and partly on the authority of Engels. I have already argued against the dogma that proteins are essential, but the dogma dies hard and the case may be argued further.

  The statement that all living organisms contain protein is unproven; fewer than 0.1 per cent of the present-day species have been examined for protein, not many more have even been shown to contain nitrogen. It may well be that all present-day species do contain proteins; this will demonstrate that protein-based mechanisms have proved more efficient than others and in the course of 2,000 million years of evolution have ousted them. Present-day conditions tell us nothing about the qualities necessary or desirable at the beginning.24

  The debate, laced with personal barbs, was too good to be allowed to rest, and the editors of New Biology asked Sage for a rejoinder to ‘Vital blarney’. Bernal restricted the banter, which by now had a distinct edge, to his opening paragraph:

  One of these days I will see a review by N.W. Pirie of a scientific work of which he thoroughly approves. It will no doubt be a study by an expert in the field which explores, very precisely and with every reasonable precaution, a circumscribed subject and expresses the result in an orderly way with due allowance for any possible foreseen or unforeseen error. It will certainly never be anything I write. To be criticized by Pirie therefore does not surprise me and is no mark of distinction. However, in his delight in castigating the impudence of anyone – not even a biochemist – who pretends to knowledge about the origin of something that does not exist, he has allowed himself to express opinions of his own of an extravagance of scepticism that far exceeds anything he charges against me, and it is these rather than his criticisms of my efforts that require to be answered. The burden of Pirie’s review was that firstly I had said nothing new, or even nearly new, for what I had said had been better said fifty to a hundred years ago, further, insofar as I had said anything else it was unproven or wrong, and lastly, that not being a professional biochemist I had no right to say anything at all on the subject.25

  It seemed to Bernal that Pirie’s objection to speculative inquiry into the origin of life on the basis ‘
You cannot be right because you do not know enough’ was an attempt to obstruct the progress of science. In Bernal’s mind, the question had moved from the one that confronted the Victorians like Huxley – whether life originated from a previous inorganic state – to the question of how it did so. He did not deride the Victorians ideas – indeed he quoted a newly discovered passage written by Charles Darwin in 1871 that seemed to anticipate the Oparin–Haldane hypothesis with its discussion of a ‘proteine compound’ emerging from ‘some warm little pond, with all sorts of ammonia and phosphoric salts, light, heat, electricity etc., present’. In The Physical Basis of Life, Sage was merely trying to chart a process by which organic material could have arisen from inorganic compounds that was in keeping with the modern laws of biochemistry, geochemistry and physics. He made no claim that this was the only way life could have started, but thought it was ‘churlish and self-defeating to disparage what we know and to refuse to try to put facts in a reasonable order because we do not know all of them to start with’.26

  At about the time Bernal was writing these words, a graduate chemistry student at the University of Chicago, Stanley L. Miller, set out to replicate the primordial environment in a simple laboratory experiment.27 He was inspired to carry out the experiment by his supervisor, Harold Urey, a Nobel Laureate in chemistry, who had lately become interested in the origin of life and had reached the conclusion that the prebiotic atmosphere would have been a reducing one, conducive to the synthesis of organic molecules. Miller set up a closed apparatus of tubes and flasks, in which he boiled water (the ocean) and circulated the resultant water vapour with reducing gases (ammonia, hydrogen and methane thought to have existed in the primitive atmosphere) past an electrical discharge or spark (to represent lightning). After the first twenty-four hours of circulation, the water became ‘noticeably pink’ and ‘by the end of the week the solution was deep red’. When this primordial tomato soup was analysed, it was found to contain at least two amino acids, glycine and alanine, in surprisingly large (milligram) quantities. As Haldane would have predicted, the amino acids in Miller’s flask were equally distributed into the left- and right-handed forms; the exclusive presence of the L form in living organisms remained to be explained.