Bateson's objections to the chromosome theory of heredity

Bateson was appointed fellow at St John's College, Cambridge, in 1887 and began to study the origins of variations that acted in natural selection. Rather than the gradual alterations postulated by Darwin as fuel for evolution, Bateson observed abrupt variations in plants, animals and humans. Such ‘discontinuous variation’ appeared to be rather frequent, and he felt it could provide the grist for the evolutionary development of new species over time. He summarized his work in an 1894 book, Materials for the Study of Evolution.Footnote ⁷

The rediscovery of Mendel's work on heredity in the summer of 1900 provided Bateson with a working theory for accurately predicting the results of breeding studies he had begun using plants and animals.Footnote ⁸ Mendel's laws required independent segregation of characters, but as early as 1902, Bateson began to uncover frequent examples of ‘coupling’, the co-segregation of particular hereditary characters in several plant species.Footnote ⁹ The British team raised the question of ‘our theories of chromosomes and their importance in the transmission of segregated characters’.Footnote ¹⁰

The American cytologist Edmund B. Wilson subsequently summarized recent studies linking chromosome segregation and heredity.Footnote ¹¹ In October 1905, he wrote to Bateson about his own investigation on chromosomes and sex determination in insects:

As he became an advocate for Mendelism in England after 1900, Bateson really defined this new branch of biological science. His innovative research studies at Cambridge attracted a group of young students who wanted to take his informal classes and then work with him on studies in plant and animal breeding. Very quickly the group confirmed that Mendel's laws worked well in predicting the outcome of most cross-breedings in both plants and animals. Bateson coined the word ‘genetics’ to summarize the work he was doing.Footnote ¹³ He wrote one of the first English textbooks on genetics, Mendel's Principles of Heredity,Footnote ¹⁴ and established the Journal of Genetics in 1910.Footnote ¹⁵

In August 1907 Bateson travelled to America and spoke before the International Zoological Congress. He agreed that the key to understanding genetics resided in the cell nucleus. ‘It is in cell division that almost all the phenomena of heredity and variation are accomplished’. It was certainly tempting to assume that herein lay the answer to genetics. ‘In the visible rearrangement of the chromosomes [in cell division], occurrences so tangible and striking are witnessed that the observer can hardly avoid exclaiming, “This is the essential process of heredity … or the chromosomes which I can watch and count must be the physical basis of hereditary likeness.”’ But Bateson would not accept such an easy solution. He noted that there was no connection between different characters inherited and visible differences in the size or shape of the chromosomes. No difference existed in the chromosomes of various differentiated tissues of the same organism either. There was also no correlation between the number of chromosomes and the evolutionary complexity of an organism. Only one ‘cytological’ difference had been consistently connected with a physical trait. Bateson agreed that the idiochromosome had something to do with sex determination in many different species. He predicted that the cytologist would someday join the breeder in ‘the attack on genetic problems’.Footnote ¹⁶

A centre for the study of chromosomes and genetics developed at Columbia University when T.H. Morgan joined E.B. Wilson there in 1908. Within two years, breeding and cytological data convinced Morgan that there had to be a connection between the segregation of hereditary elements and the chromosomes.Footnote ¹⁷ He concluded,

Correlation between physical alterations in a specific chromosome and both sex determination and sex-linked characters suggested the general conclusion that chromosomes were indeed the ‘locus of materials associated with the production of characters’.Footnote ¹⁹ Morgan now proposed an

Bateson was drawn into the discussion of chromosome theory again when he reviewed Morgan's book The Mechanism for Mendelian Heredity for several scientific journals. The work presented a model in which the hereditary factors were inherited in groups (linkage) and the number of linkage groups equalled the number of chromosomes in the germ cell. He recounted a model of the chromosomes with linear genetic factors, arranged like beads on a string. Recombination frequency, then, was a measure of linear distance between the genetic factors. Bateson thought this was ‘the great thesis of the book’. The material was certainly suggestive, but not convincing. Bateson noted,

This fact had convinced Bateson of at least one example of the proposed chromosome–heredity connection.

But Bateson listed a number of objections to accepting the Morgan theory. Linkage had only been observed in the fruit fly. The fact that crossing over apparently did not occur in the male fly seemed to be a considerable argument against accepting the theory. Bateson also wondered whether there was a real distinction ‘between the nature of heredity in plants and animals’. Bateson particularly disliked the materialistic assumptions of the CTH:

Bateson's objection to the CTH was therefore rational and argued that further scientific work was required to resolve these issues. Despite his research interest in other areas of inheritance and cellular development, Bateson continued to address issues of the CTH for the rest of his life.

Reasons for Bateson's objections

Two historians have already examined the question of Bateson's reluctance to readily accept the CTH. William Coleman thought that conservative opinions in the social and political realm inhibited Bateson from adapting to new ideas in genetics.Footnote ²² Conservatism offers personal and social stability by preservation of the status quo.Footnote ²³ When Bateson began his studies on Mendelian genetics after 1900, he was at the forefront of a whole new science. His work was ‘really interesting’, and he made many really ‘important discoveries’ that helped define the field. His enthusiasm and professional confidence increased as his colleagues recognized his valuable work. But having achieved professional credibility, Bateson later narrowed his professional milieu.Footnote ²⁴ His scientific eminence allowed him to follow his own interests with essentially unlimited resources for the rest of his life.Footnote ²⁵ Over time, however, continued research in one area can lead to professional obsolescence as other workers expand the scientific realm.Footnote ²⁶

Some observations indicate that most scientists do not seek innovation in their daily work at all. Normal science is pretty much like ‘puzzle solving’, collecting data from nature and testing whether it fits the predictions of the theories accepted collectively by scientists in that particular field.Footnote ²⁷ This style of science is exactly what Bateson wanted to perform after 1910. In his 1914 Presidential Address to the British Association for the Advancement of Science, Bateson noted that the great advances in science were made by ‘the sporadic birth of penetrative geniuses’. Such innovators as Mendel shone a light in the direction for subsequent research. Bateson noted then, ‘The journeymen follow after him, widening and clearing up, as we are doing along the track that Mendel found’.Footnote ²⁸

Because science is a collective enterprise, the legitimacy of a theory is not based solely on one person's opinion. Each scientist is enthusiastic about, and often passionately attached to, his own theory. Selective interpretation of new data may result in overconfidence in any one scientist's material.Footnote ²⁹ Resistance to altering one's accepted views may become quite intense and move beyond the logical extension of such paradigms. Professional status can also insulate a scientist from criticism by his colleagues. Prominent scientists may become arrogant, convinced that they possess superior distinction in their field of research. The work of such individuals may become less objective and can progress toward ‘incredulity’.Footnote ³⁰ Such was the fate of Bateson's work, which diverged from the mainstream of genetic research after 1910, and his reputation suffered as professional colleagues came to view his work as rather dubious.

Alan Cock believed that less philosophical and more practical issues affected Bateson's opinion of the CTH.Footnote ³¹ Bateson repeatedly commented that the lack of adequate experimental evidence was the reason why he could not agree with the theory, despite the fact that younger colleagues attempted to demonstrate the vast experimental evidence from both plants and animals that substantiated the CTH. Another reason Bateson declined to accept the new theory was because he had two alternatives of his own. The reduplication model for somatic segregation and Bateson's other idea on vibrations and forces in living cells that guided inheritance and embryonic development fascinated him throughout his scientific career. These notions were never formulated into specific questions that could be addressed with the experimental techniques of his day.

A dislike for microscopy was also cited as another reason why Bateson did not pursue the chromosome theory. Bateson's early research on vertebrate evolution involved extensive histological study of animal tissues. His first published papers on morphology appeared in the Quarterly Journal of Microscopical Science.Footnote ³² However, this work was completed before the technological advances that would allow more detailed visual study of the cell nucleus and chromosome behaviour during cell division.

During his years at Cambridge, Bateson repeatedly urged collaboration between the breeder and the cytologist to more completely understand cell division and genetic segregation.Footnote ³³ Over the years before the war, Wilson and Morgan offered to work with Bateson on cytological studies to expand the chromosome theory, but he declined and preferred to follow his own research interests.Footnote ³⁴ For years, Bateson was comfortable to continue his own breeding studies and paid little attention to suggestions that he also explore the cytological aspects of genetics.Footnote ³⁵ For a long time, he felt the cytological data appeared to be irrelevant to his own work.

Alan Cock postulated that Bateson just enjoyed the CTH controversy because he was an iconoclast. From his earliest days at Cambridge, Bateson was involved in campus controversies ranging from the location of a red mailbox to awarding degrees to women. Scientific controversies raged throughout his life. He argued about origins of plant species, the relationship of the biometric and Mendelian genetic theories, the CTH, the heredity of acquired characters, and, later in life, the veracity of alleged psychics in London.Footnote ³⁶ Bateson proudly accepted the label of sceptic and noted, ‘The term controversial is conveniently used by those who are wrong to apply to the persons who correct them’.Footnote ³⁷

Bateson also had strong antipathy for certain classes and individuals. Because of this fact, he often confused the message with the messenger. He believed that members of the English upper class were the elite in science and society and demonstrated a marked dislike for other scientists of working-class background. He tended to dismiss observations or theories made by the wrong kind of people. Bateson thought that Wilson was clearly of the right social group. He had studied in Europe, was fluent in six languages and also was an accomplished cellist.Footnote ³⁸ Bateson argued that such distinctions were natural, given the way the human race had evolved. In a letter to his mother, he observed,

He thought that social hierarchy was necessary if progress was to be made. If ‘the appropriate social context’ was present and maintained, it would allow the ‘qualities, potential and authority of the uncommon individual, the man of genius’ to develop.Footnote ⁴⁰

Reginald Ruggles Gates had been educated in Canada and the United States and discovered examples of synapsis and mutations in several plant species, substantiating the findings in Drosophila that supported the CTH.Footnote ⁴¹ Bateson was not very impressed with the work and called Gates ‘mean trash’.Footnote ⁴² Bateson did not approve of Morgan's social background either. Born in Kentucky, Morgan retained his homey lifestyle and often appeared rather ‘unkempt and disheveled’.Footnote ⁴³ The two men met during Bateson's 1907 trip to New York. The first impression was not very positive as Bateson noted to his wife, ‘Morgan is a thick head’.Footnote ⁴⁴ The dislike continued over the years and was rekindled in Bateson's 1921 visit to Columbia University. He recalled, ‘I have just the same impression that I got 14 years ago, that he is of no considerable account. His range is dreadfully small’.Footnote ⁴⁵ Bateson recorded as he was leaving New York, ‘I wish I really liked him, but I am quite sure I don't’.Footnote ⁴⁶

Subject and author indices of more than ten thousand manuscript items related to Bateson's life and work have become available online within the last decade.Footnote ⁴⁷ The current accessibility of documents unavailable to previous investigators justifies another attempt to further explicate Bateson's work on chromosomes and heredity.

Bateson's reluctant conversion

Bateson remained unconvinced that the experimental data existed to justify the chromosome model. ‘It is not quite satisfactory to invoke factors whose presence is manifested by a phenomenon … Circumstantial evidence is never good proof, but to have any validity it must come from more than one point’.Footnote ⁴⁸ His colleagues then attempted to demonstrate that, in fact, the theory was widely applicable. His former student Leonard Doncaster noted to Bateson that Hans von Winiwarter of Vienna had found an idiochromosome which was associated with sex-limited inheritance in the cat.Footnote ⁴⁹ J. Schmidt from Copenhagen told Bateson that sex-linked traits in fish also appeared to correlate with the sex chromosome.Footnote ⁵⁰ Richard Goldschmidt from Munich reported to Bateson that the X chromosome and sex inheritance were related in butterflies as well. Goldschmidt communicated these results, noting, ‘I hope that this summary account of the correlation between sex chromosomes and sex inheritance … will make a permanent impression on you’.Footnote ⁵¹ Bateson had noted, ‘As you may know I am always inclined to skepticism as to the chromosome being the only bearers of hereditary factors, and I will believe when I must’.Footnote ⁵² Goldschmidt replied, ‘I believe that the time is near when you will become a friend of chromosomes’.Footnote ⁵³ Erwin Baur reached a similar conclusion based on breeding studies done in the plant Antirrhinum. He noted to Bateson after the war that he had used Morgan's notions of chromosome mapping to define linkage groups containing forty-two genetic factors. Linkage ratios appeared to be constant. He wrote confidently, ‘As far as I can see, the facts are very similar to those in Drosophila, and that convinces me that in the main points, Morgan is correct’.Footnote ⁵⁴

Doncaster was also becoming more convinced by the work of the Drosophila group. He noted to Bateson,

Doncaster thought at this time that the union of microscopic and genetic study provided powerful evidence in favour of the chromosome theory. In his mind, ‘The regularity of Mendelian segregation is so universal that I think it must be correlated with some cytological regularity, and the chromosomes are the only known bodies that show this’.Footnote ⁵⁶ The chromosome theory not only made sense, but also accurately predicted experimental results. He concluded that ‘a theory which enables predictions to be made and verified cannot be lightly disregarded’.Footnote ⁵⁷

Reginald C. Punnett followed Bateson as professor of biology at Cambridge. In 1919, he noted to Bateson that sex linkage was evident in the begonia.Footnote ⁵⁸ He also applied the chromosome theory to breeding studies in the sweet pea. As early as 1917, his results showed that the pea cells each contained seven chromosomes and that the genetic factors in that species could be divided into seven linkage groups.Footnote ⁵⁹ R. Ruggles Gates had studied the chromosomes in more than fifty Oenothera, each containing a different number of chromosomes. Different morphological features appeared in each strain, implying that the genetic factors associated with the chromosomes produced visible somatic modifications.Footnote ⁶⁰ Subsequent studies by Gates on heredity and chromosome behaviour in lettuce also convinced him that the chromosome theory could be widely applied to many plants. He observed synapsis, the microscopic appearance of chromosome arms wrapping around each other in that species. Gates proposed that this was the physical correlate of the genetic phenomenon of crossing over.Footnote ⁶¹ Gates wondered why Bateson did not accept data from cytology and genetics on the soundness of the chromosome theory: ‘Why are you so loathe to accept the chromosome facts?’Footnote ⁶² Bateson replied that he felt that more data was needed to reach a conclusion on this matter. ‘When we have reached the point of knowing more than just facts, I do not loathe them, I rather like them’. Bateson stated that he would accept the validity of the chromosome theory when ‘it can be established by reasoning that is not circular and free from alternative and mutually independent hypotheses’.Footnote ⁶³ Gates was rather astounded at Bateson's reply. He noted,

Bateson finally admitted, ‘I shall not be very surprised if some connexion is proved to exist between the number of linkages and the number of chromosomes’.Footnote ⁶⁵

In late 1921 Bateson was invited to speak at the American Association for the Advancement of Science meeting in Toronto. He also planned to visit Morgan and his colleagues at Columbia University. They expected to present him with data that would convince him of the validity of the chromosome theory. Bateson considered this such a fundamental change in his view of the scientific world that he described it as almost a religious experience. Even before he left England, he noted to Julian Huxley in October that ‘great hopes of my conversion are entertained’.Footnote ⁶⁶ In New York, Calvin Bridges showed Bateson slides of normal and abnormal Drosophila chromosomes. Altered morphological characters could be associated with abnormal chromosome patterns in the fruit flies.Footnote ⁶⁷ Bateson noted that his ‘course of conversion was begun’. He had to conclude, ‘I see nothing but capitulation ahead as far as the general theory of chromosome responsibility is concerned’.Footnote ⁶⁸ He noted to his wife, ‘The chromosomes must be in some way connected with our transferable characters’, but ‘the details of the linkage theory strike me still as improbable’.Footnote ⁶⁹ He admitted, ‘I had to announce my conversion on the main point: that chromosomes are definitely associated with the transferable characters … much enthusiasm over this, of course, but as a candid man I don't see how any other view can be maintained’.Footnote ⁷⁰ He also recognized that the trip had changed his point of view. ‘I am heartily glad I came. I was drifting into an untenable position which would soon become ridiculous … Cytology is a real thing – far more important than I had supposed. We must try to get a cytologist’.Footnote ⁷¹

In his first lecture to the AAAS meeting, Bateson concluded that he had literally seen the light:

The union of heredity and microscopy implied that the ‘geneticist is the successor to the morphologist’. He thought that ‘biological science has returned to its rightful place, investigation of the structure and properties of the concrete and visible world’.Footnote ⁷³ In a second lecture to the Zoological Section of the association, Bateson outlined a model for heredity based on the available data. Clearly the chromosomes were the vehicles for the hereditary elements. Groups of elements, or genes, resided in specific chromosomes, as evidenced by their linkage, or cosegregation, during cell division. The genes on the chromosomes were arranged in a linear fashion. The relative distance between several loci could be calculated with this model. Bateson accepted the mechanism for heredity, but still had his doubts about whether crossing over and recombination were actual physical events. In summary, Bateson agreed that the chromosome theory ‘had proven to be an extraordinarily efficient symbolism … It has made a coherent sense, where before we had disconnected detail, and that is as fine a service as any theory could perform’.Footnote ⁷⁴

In fact, Bateson had already begun to bury some of his doubts and publicly accepted the major features of the chromosome theory even before he travelled to New York in December 1921. His notes for a lecture delivered a month before at the University of London described twelve linkage groups in Primula and seven linkage groups from Pisum among plants, while the fruit fly Drosophila had four linkage groups. He then discussed the mechanism postulated to construct a linkage map correlating hereditary factors and sex chromosomes from the fruit fly.Footnote ⁷⁵ Scientists sometimes discuss a theory with which they disagree merely because it has heuristic merit, but that is not the sense of Bateson's lecture notes.Footnote ⁷⁶ At Leicester he discussed linkage, the crossing-over theory of recombination, and the fact that non-disjunction – a physical, visible event seen cytologically – proved the gene and sex-chromosome correlation in Drosophila.Footnote ⁷⁷ He then explained the Primula linkage maps in lectures given at Birmingham and Leeds.Footnote ⁷⁸

A young colleague at the John Innes Institute asked Bateson about Morgan's work: ‘I suppose it is sound?’ Bateson replied, ‘Yes, I am afraid we have to admit it’.Footnote ⁷⁹ In a fit of pique, Bateson later admitted that he ‘hated it’ (the CTH), but supposed that ‘we have to accept it all now’.Footnote ⁸⁰ Bateson had to admit that ‘a great part of it – probably the main part is substantially true … The transferable characters, almost beyond question, are somehow associated to the chromosome. I don't like it, but I see no way of escape’.Footnote ⁸¹ Bateson defended the chromosome theory because there are

Whether the chromosome theory could elucidate questions of heredity and development would occupy Bateson for the rest of his life.

The chromosome theory is unsatisfactory

In 1910 Bateson left Cambridge University and became director of the John Innes Institute at Merton. He received a large rise in salary and essentially a free hand to pursue research in plant genetics.Footnote ⁸³ At this time, Bateson also received a letter from Morgan describing some interesting breeding results with the fruit fly. Morgan had found an unusual white-eyed variant fly and offered samples to Bateson so that he might begin his own study.Footnote ⁸⁴ Bateson declined the offer and proposed to study unusual genetic phenomena in plants, such as rogues, chimeras and variegated forms.Footnote ⁸⁵ In fact, he and Morgan had already discussed ‘differential cell division’ as a mechanism for producing the two different classes of germ cells. Such cell division might also occur in somatic cells and produce regional variations like variegated colour in plant leaves.Footnote ⁸⁶ Bateson and Reginald Punnett subsequently proposed a ‘reduplication’ model to explain Mendelian genetic ratios based on different planes of cell division at gametogenesis that would distribute the genetic elements into daughter cell nuclei. Bateson also observed, ‘Whereas some factors are continually transmitted in their entirety, others are liable to be broken up by what I regard as a process of quantitative fractionation occurring in the mechanical dissection of the events at certain critical cell divisions’.Footnote ⁸⁷ Because the cell contained many genetic factors which segregated mostly independently, they also suggested that some segregation could occur at cell divisions prior to those observed during meiosis. Bateson noted to Erwin Baur in 1911,

However, if such reduplication took place early in the embryonic development of one organ, and not in others, Bateson could not imagine how ‘the normal form of the plant remains unchanged’. Those genetic elements that segregated together had to be physically located in one part of the cell prior to formation of the division planes.Footnote ⁸⁹ Unequal segregation involving three characters appeared unlikely in any conceivable model.Footnote ⁹⁰ The model was imperfect, but, Bateson suggested, ‘In a problem of such extreme difficulty even improbable suggestions are worthy of consideration’.Footnote ⁹¹ Bateson subsequently observed that the theory was ‘admittedly a very crude conjecture’ of cell division,Footnote ⁹² and admitted that beyond a certain point ‘all speculation fails’.Footnote ⁹³ The phenomenon of genetic coupling or linkage had first been observed in plants, and Bateson wondered whether plants and animals employed fundamentally different mechanisms for cell division and genetic segregation.Footnote ⁹⁴

Morgan subsequently responded to Bateson's proposed reduplication model for segregation by pointing out that no evidence existed for such genetic phenomena except when the maternal and paternal chromosomes united at meiosis. He thought that his own chromosome theory was more powerful because it rested ‘on a mechanism that could be studied by actual observation’.Footnote ⁹⁵ Other scientists found Bateson's theory rather outlandish:

Morgan later observed the lack of experimental data to support the notion, and pointed out that the theory ‘has been given up by practically all students of developmental mechanics’.Footnote ⁹⁷ Bateson himself then admitted that the reduplication model was ‘far less attractive’ than the CTH and that no experimental data supported its suppositions on somatic segregation.Footnote ⁹⁸

But in fact Bateson was becoming aggravated by the continued interest in chromosomes and heredity. In 1914 Morgan asked Bateson to consider publishing a paper from the Columbia group in the Journal of Genetics. Bateson wondered whether the reason the paper had been sent to a British publication was to originate a discussion on this whole issue of chromosome theory. He replied to Morgan, ‘None of us is in the least likely to take up the matter, and we think that publication of the paper in the Journal of Genetics would merely look odd.’ Bateson summarized his own feelings by stating that ‘I am in no hurry to get into controversy on the subject’.Footnote ⁹⁹ He also worried that genetics had become a ‘chromosome obsession’ to the neglect of all the other aspects of heredity and development.Footnote ¹⁰⁰ He discussed the notion of chromosomes bearing the hereditary elements in a letter to his Danish colleague Carl H. Ostenfeld. He admitted, ‘Beginning with a thoroughly skeptical feeling, I have come around so far as to see that the suggestion is, to say the least, very attractive’.Footnote ¹⁰¹ But a year later, he had become disillusioned. He noted, ‘I get further and further away from the chromosome hypothesis of Morgan and his friends. Last year I did hesitate somewhat, but I can't apply it to the everyday facts of heredity at all’.Footnote ¹⁰² The CTH just did not seem to apply to Bateson's research work.

During the war years, Bateson continued plant-breeding studies at the John Innes in an attempt to support the reduplication theory of segregation. He observed rogues in Pisum and analysed the offspring separately grown from upper and lower pods. Standard-type plants generally grew from the lower-pod seeds, while rogue plants more commonly developed from higher-pod seeds. He concluded that there had to be ‘some process of somatic segregation which prevents the type elements from reaching the germ cells’.Footnote ¹⁰³ The inheritance of the rogue form did not follow Mendelian rules, suggesting that rogue gametes were given off by the plant sporadically, ‘not in accordance with any system that we can perceive’. Chromosome numbers in the type and rogue plants appeared to be identical.Footnote ¹⁰⁴ He also found that red flowers grew from a cutting taken from a pink-and-white-flowered Bouvardia. He argued that such chimeras could result from somatic segregation.Footnote ¹⁰⁵ Variegation in leaf colour of several plant types also suggested that genetic segregation had occurred within somatic tissues.Footnote ¹⁰⁶ But by 1920, Bateson admitted that he could not provide a mechanism to explain these findings. He noted that such ‘interpretations of this kind are inconsistent with all that we have learnt of genetic principle’. His staff did examine the plant cell chromosomes in some cases, and determined that they were not tetraploid.Footnote ¹⁰⁷ A study on the inheritance of male sterility in flax also generated more problems than it solved. Bateson noted, ‘On these questions we have as yet no sufficient evidence’ to provide a mechanism to explain the findings. He began to question if newer technology could be applicable. In 1921, he noted, ‘It would be interesting to see whether a cytological basis for these phenomena can be detected’.Footnote ¹⁰⁸

Reginald Gregory did examine the cytology and genetics of Primula. The standard plants had twenty-four chromosomes, but tetraploid lines were found with double that number. He studied both dominant and recessive characters that segregated in the tetraploid lines and concluded that these contained four genetic factors for each character instead of the usual two. Breeding studies showed ratios of characters in the offspring consistent with such tetraploid segregation. But Bateson was not convinced that the results shed light on the relationship between genetic factors and chromosomes. Although the offspring were consistent with such tetraploid segregation, the fact that duplication of the chromosomes had been accompanied by a duplication of genetic factors could suggest a definite connection between the two, or it might just reflect the ‘quadruple nature of the cell itself’.Footnote ¹⁰⁹ Gregory also suggested that Bateson employ a cytologist to count the chromosomes in the Primula lines and then attempt to further elucidate the supposed connection between chromosome number and hereditary factors.Footnote ¹¹⁰

In studies of transmission genetics, the chromosome theory provided the most accurate model for predicting results of crosses involving linked characters. But in the developmental genetic studies performed by the John Innes group, changes in chromosome constitution in the few examples they examined could not be associated with any of the phenomena being considered. In Bateson's mind, the relevance of the chromosome theory for his own work remained questionable. The theories of chromosome genetics and reduplication were hence incommensurable.Footnote ¹¹¹ A major hindrance to research success at the John Innes was the nature of problems chosen by Bateson for his team to investigate. An important task of a scientific administrator is to define research questions which both are significant and can be addressed by the personnel and techniques currently available.Footnote ¹¹² One staff member later recalled that the institute developed a reputation for attempting to solve research problems that were ‘impossibly difficult’.Footnote ¹¹³ The annual John Innes reports regularly summarized outlines of studies proposed, but not completed.Footnote ¹¹⁴

The quest for a more satisfying theory of inheritance

Successful scientific ideas must fulfil several criteria. They must be original, often simple, and functional, meaning that they can solve problems in the real world. They must have the ability to predict outcomes of subsequent experiments. Resolution of competing theories typically is accomplished by careful experimental design to measure the efficacy of one theory compared to another.Footnote ¹¹⁵ Bateson was a brilliant experimentalist in his work that defined the tenets of Mendelian genetics before 1910. But thereafter, his research programme at the John Innes faltered. He published many interesting observations on plant chimeras and variegation, but could explain few of the results by any known genetic mechanism. Limited chromosome counting added little to the research reports. In contrast, Morgan's group utilized both genetic breeding and cytology to demonstrate experimentally the many parallels between the behaviour of the Mendelian factors and the segregation of the chromosomes in Drosophila. They produced an ‘interfield’ theory of both synergy and predictive power that could be further evaluated experimentally.Footnote ¹¹⁶

Most biologists in the early twentieth century sought to demonstrate that biology was as much an experimental science as was chemistry or physics. They typically adapted operative mechanisms to their science, defining individual components of living systems. The characteristics of each component could then be measured and altered experimentally, and their properties explained in chemical and physical terms. Non-measurable fields or forces were rejected as non-scientific vitalism.Footnote ¹¹⁷

Bateson came from an empiricist background, but found the initial chromosome theory presented by Morgan too speculative and lacking in experimental validation. He also concluded that the theory implied a particulate basis for inheritance. Bateson preferred to think of inheritance in terms of force-field action rather than particle behaviour. He argued for a dynamic kinetic notion for both heredity and development.Footnote ¹¹⁸ His conception of forces acting on living systems did not imply vitalism, but rather demonstrated the use of borrowed terms from contemporary physics to define biological phenomena in a non-material scheme.Footnote ¹¹⁹ Bateson attempted to apply his scientific intuition to form analogies, utilizing concepts from other branches of sciences, as thought models to later construct scientific theories.Footnote ¹²⁰ Coleman observed that Bateson's premises would prove to be reasonably clear, ‘but [their] further development is desperately obscure, and [their] obstructions Bateson could not escape’.Footnote ¹²¹

The concept of kinetic forces acting in living systems was a current topic during Bateson's student days at Cambridge. As early as 1871, the London zoologist St George Jackson Mivart had suggested that vibratory forces produced the repetitive, symmetrical patterns of organs so characteristic of living things.Footnote ¹²² Michael Foster taught physiology courses at Cambridge and described the ‘living substance of the organised cell … as being in continuous and rapid molecular vibration’.Footnote ¹²³ T.H. Huxley mentored Foster and was one of the first biologists to draw the analogy between vortex whirlpools and living organisms. He further suggested that all matter was made of ‘aether’, and the ‘elementary units’ of such matter were permanent vortices. He proposed that such a conception could be treated mathematically to generate predictions which could then be tested experimentally.Footnote ¹²⁴ Huxley foreshadowed the notion that biology was an experimental science just as was chemistry or physics.

After 1850 there was increased acceptance in academic life of analogies between thought and material objects. James Clerk Maxwell was a Cambridge undergraduate when this tradition began to develop. He attempted to provide a mathematical model to explain the experimental observations made by the physicists of his day. He hoped that the model would eventually demonstrate a ‘profound natural relation’.Footnote ¹²⁵ During the 1860s Maxwell used such analogies to describe an electromagnetic field as an array of elastic vortex cells.Footnote ¹²⁶ Lord Kelvin subsequently showed that forces in such fields affected the component vortex atoms in mathematically predictable fashions. Such phenomena as alterations in sodium spectra could then be forecast and verified in the natural world.Footnote ¹²⁷ An entire generation of young Cambridge physicists laboured to refine the suggestions of Maxwell and to assess the accuracy of their formulations by performing physical experiments with light, heat and electricity.

Bateson absorbed this physics mentality from his contacts in the scientific world. Balfour Stewart, professor of physics in Owens College, Manchester, published a popular work, The Unseen Universe, that explained the concept of the vortex atoms to a broad audience.Footnote ¹²⁸ The author and the young Bateson were both early adherents of the Society for Psychical Research and may have encountered each other at society meetings in London.Footnote ¹²⁹ Joseph Larmor was appointed to the mathematics faculty at St John's College in 1885. He became close friends with Bateson when they served as officers of the Cambridge Philosophical Society during the 1890s.Footnote ¹³⁰ Over the next decade, Larmor further elaborated on the aether and vortex-atom model as the fundamental unit of matter.Footnote ¹³¹ He repeatedly designed physical experiments in order to test the theoretical constructs he had prepared.Footnote ¹³² The electromagnetic theory was dynamic and analysed the forces, waves, vibrations and vortices that produced the changes in nature. The stated goal of such a unified field theory was to be that

Larmor summarized the importance of such theories' relevance to reality: “The question is, as to which scheme of formulation gives as a whole the closest and most expressive representation of the complex of natural knowledge and affords the most promising clues to its further elaboration and extension.”Footnote ¹³⁴ Larmor and Bateson, then, would both agree that life was a matter of ‘motion and force’.Footnote ¹³⁵

Bateson first announced his interest in the connection between biology and forces when he wrote to his sister Anna in September 1891:

Another letter followed several days later. ‘I am still in great excitement about my “Undulatory hypothesis”. I am sure it will work … It makes me giddy to think of the things that may come out of it!’Footnote ¹³⁷ Bateson discussed the new idea with several Cambridge colleagues, including the botanist Francis Darwin, who was also thinking along similar lines and encouraged Bateson to make this theory a ‘feature’ for the book under way on variation.Footnote ¹³⁸

One month before Bateson's initial letter on the vibratory theory, Francis Darwin and Dorothea Pertz had presented a paper at the BAAS meeting in Cardiff on experiments to measure rhythmic vibrations in living plants. They concluded that this ‘repeating power may be the fundamental property of living matter which stretches from inheritance on one side to memory on the other’.Footnote ¹³⁹ The same individuals presented further work on this topic before the Cambridge Philosophical Society in 1900.Footnote ¹⁴⁰ The Innes Library contains no letters between Bateson, Darwin and Pertz on this matter, but Bateson was certainly familiar with their material on plant vibrations. Darwin and Pertz worked with Bateson's sister Anna at Cambridge, and Bateson studied the inheritance of flower petals with Pertz.Footnote ¹⁴¹

In an unpublished manuscript from this era, Bateson outlined a ‘simple mechanical view’ of the mode of occurrence of segmentation in plants and animals. He proposed that these represented internodal lines, or planes of maximum movement, reflecting vibrations in elastic, living protoplasm. He was considering not only large-organ segmentation such as petals or limbs, but also microscopic segmentation of the ovum and even the chromosomes. He noted that his paper might include ‘karyokinetic figures’, which represented symmetric cell division.Footnote ¹⁴² It is certainly possible in this case that Bateson was considering the development of his own chromosome theory for inheritance.

When Bateson completed the Materials book in 1894, he commented on the nature of the forces such a model proposed to produce significant diversity:

A figure later in the same work illustrated a mechanical model Bateson had prepared to show the relation of extra legs to the body in insect variants.Footnote ¹⁴⁴ In 1903, Bateson presented another model to explain axes and segmentation in plants based upon ‘rhythmical vibrations’.Footnote ¹⁴⁵

The vibratory theory languished for decades as Bateson busied himself with Mendelian genetics after 1900, but he continued to think about it. He noted to his wife in 1910, ‘My wave idea isn't difficult, for so far, it is a mere idea for an idea. It has no body or anything to take hold of – but as an idea for an idea, I think it is a good one’.Footnote ¹⁴⁶ As early as 1890, Bateson had heard Larmor discuss the mathematical analysis of ripple formation on the surface of liquids through which an electrical charge was passed.Footnote ¹⁴⁷ Bateson observed the formation of sand ripples himself. He wondered whether a viscous fluid passing in a thin layer over a plate could form ripples as well as any other model known. Authorities in this field thought that such ripples were the result of vortex formation.Footnote ¹⁴⁸ He then corresponded with the hydrologist Vaughn Cornish on wave action and the formation of harmonious ridges of sand.Footnote ¹⁴⁹ Bateson later formulated these speculations in the Silliman Lectures which were published in 1913. He proposed that segmented structures in living beings resulted from the action of mechanical forces, or ‘dividing waves’, that could be described in mathematical terms.Footnote ¹⁵⁰ He again used the analogy of wave action and sand ripples to represent the repeated pattern formation seen in living organisms. Uniform force produced a uniform series of ripples. Variations then occurred when the force fields were altered. The same thing could explain variations in nerves and digits observed in animals. But this ‘orderly force’ could not be explained by any known theory of the science of his day.Footnote ¹⁵¹

Bateson recalled another model from his student days at Cambridge with Michael Foster, who argued that ‘a living thing is a vortex of chemical and molecular change’. Organisms were therefore viewed as impermanent manifestations of material ‘flowing through a vortex’. The vortex was viewed as ‘life itself’, and could divide to form new vortices. The looping vortices then presented a ‘model representing several of the essential features of living beings’, including reproduction. Victorian artists and writers thought the vortex typified both perpetuity and change, and was not a static structure.Footnote ¹⁵² For Victorian scientists, the vortex provided a powerful analogy of biologic species, both functioning day-to-day and then transmitting essences to subsequent generations. Bateson was convinced that an understanding of the mechanics of cell division would greatly enhance knowledge of both heredity and development:

Bateson certainly did not deny that the genetic elements had some material form. He repeatedly tried to envisage a model that would incorporate the dynamic nature of cellular physiology. In 1920, he shared such an idea with Muriel Wheldale, a plant biochemist who had worked at the John Innes. He thought that the genes must be some sort of a ‘gel, probably with some fibrous material running through them. May not very sensible movement along very long axis take place?’ The notion that polymers were, in fact, long chains of covalently bonded atoms rather than mere clumps of gel had just been developed.Footnote ¹⁵⁴ As such, chemical action could produce physical movement along the course of the chromosome fibre. But again, Bateson did not develop the notion any further. ‘Don't trouble to write if my question is unanswerable’, he noted.Footnote ¹⁵⁵

The exploration of gels in living systems had been an active research topic at Cambridge for some time. One of Bateson's colleagues, William B. Hardy from Gonville and Caius College, had begun studying the biochemistry of the cytoplasm with cytological staining techniques which he reported to the Cambridge Philosophical Society in 1891.Footnote ¹⁵⁶ He then sought to apply concepts from colloidal chemistry to define the physical nature of cellular protoplasm.Footnote ¹⁵⁷ In 1908, Hardy presented the Croonian Lecture to the Royal Society on application of colloidal chemistry to the structure and function of individual proteins.Footnote ¹⁵⁸ Subsequent work by Benjamin Moore from the University of Liverpool revealed that colloids were in dynamic energy states. He proposed that this was ‘the primary source of the power appearing in the phenomena of vitality’. Changes in colloid structures then simulated changes exhibited in living organisms. Colloid evolved in the laboratory to resemble cell membranes, repetitive striated fibres and even ‘mitotic nuclear division figures’.Footnote ¹⁵⁹ One of the leading researchers in this field was Stéphane Leduc from the Ecole médecin de Nantes. Bateson's Austrian colleague Hans Przibram mentioned Leduc's work in a letter from 1910.Footnote ¹⁶⁰ The photomicrographs published by Leduc of colloidal precipitations appeared to show centrosomes, spindle fibres and chromosomes aligned for mitosis.Footnote ¹⁶¹ Leduc thought, ‘The experiments showed that diffusion is quite sufficient to produce organic karyokinesis, and that the only physical force required is that of osmotic pressure’.Footnote ¹⁶² Bateson acknowledged Leduc's work in the Silliman Lectures. He thought that this provided the best model of living organisms in which force in the colloidal gel in one direction could produce repetitive patterns like ripples in the sand generated by waves.Footnote ¹⁶³ That same year, Bateson asked Larmor if he had any ideas on how the intrinsic properties of such a gel allowed it to divide. He also wondered if there might be chemical differences in forces within a gel that resulted in segmentation of living parts.Footnote ¹⁶⁴

Bateson subsequently summarized his thoughts on the theory in the Sedgwick Memorial Lecture of 1917. He observed,

Two years before his death, Bateson presented a lecture on progress in biology at Birkbeck College in London. He summarized his thinking on cell dynamics and heredity as follows:

Not only heredity but also embryonic development appeared to be related to rhythm. Bateson explained to the Russian biologist V. Issajev, ‘For me, such organs repeated in series are strongly suggestive of wave motion … a force is emanating capable of setting up repetitions of rhythmical intervals which present true analogies with mechanical vibrations’.Footnote ¹⁶⁷

Early in 1922, Edmund B. Ford encountered Bateson, who had just returned from visiting the Drosophila group in New York. He asked Bateson what he now thought of the chromosome theory devised by Morgan. Bateson replied that he was convinced of the theory's truth, but complained, ‘All of my life's work has gone for nothing’.Footnote ¹⁶⁸ Bateson's dismay reflected not that he had failed to elucidate the chromosome theory himself, but rather that his attempts to define a broader field theory for genetics had been frustrated. Shortly thereafter, he prepared the Leidy Lecture that would summarize the goals of his own research career – that genetics comprised three parts: (1) experimental breeding, (2) cytology and (3) developmental mechanics (Entwicklungsmechanik). A precise understanding of organic evolution required careful attention to all three components.Footnote ¹⁶⁹ Bateson had cast a broad ‘attentional net’ through biology, chemistry and physics, hoping to recognize associations through his analogies and model-building schemes.Footnote ¹⁷⁰ But his limited training in mathematical and physical sciences hindered his efforts to formulate notions of vortices, waves or gels into plausible genetic hypotheses that could be experimentally tested.Footnote ¹⁷¹ Such proposals that could not be experimentally verified had no research potential and were viewed by most scientists as mere ‘metaphysical sentiments’.Footnote ¹⁷²

But Bateson was not satisfied to work only in the realm of experimental science. He was a dreamer and wished to look to the future for inspiration. Surely intuition and imagination might produce a glimmering result long before the technical means could be devised to analyse and prove a hypothesis via experimentation.Footnote ¹⁷³ Bateson noted to the mathematician Godfrey Hardy, ‘in physics or astronomy, as well as in biology, that it is only by the investigation of imaginary worlds that we can hope to advance our knowledge of the real one’.Footnote ¹⁷⁴ Bateson clearly believed that hypotheses should be examined experimentally. But that in itself was not sufficient to validate a theory. For him, an explanation that ‘satisfied’ had reached its ‘highest possible limit’.Footnote ¹⁷⁵ Bateson believed that the goal of scientific work was not merely the technical manipulation of nature, but rather the development of an aesthetic sensibility analogous to a work of art.Footnote ¹⁷⁶ Many scientists are driven to find laws of nature that bring order to a broad field of investigation, producing harmony and a sense of organization and beauty.Footnote ¹⁷⁷ Explanatory coherence then reflects the elegance and attractiveness of the theory.Footnote ¹⁷⁸ Albert Einstein also thought that any new theory had to be graceful, catching nature in action, as he put it. A theory that was truly beautiful provided every confidence that it was, in fact, correct.Footnote ¹⁷⁹

Bateson imagined a unified-field theorem to explain the developmental mechanics of the living world. He eventually recognized the usefulness of the chromosome theory in correlating the behaviour of genetic traits with segregation of the chromosomes, but that theory failed to address the broader questions he sought to answer. His epitaph would surely recall a life unfulfilled.