Useful though these biometric methods were to become, another fruitful line of enquiry was beginning in the United States. The mutations first described in plants by de Vries, and then recognised elsewhere by Bateson, were to be tackled really seriously by one of Lankester’s marine biology acquaintances, one who took delight in the switch from qualitative to quantitative outlooks. Thomas Hunt Morgan (1866-1945) was to win a Nobel Prize for his “discoveries concerning the role played by the chromosome in heredity” particularly in fruit flies. Although the penny that dropped on Bateson’s train journey in 1900 was heard clearly by Morgan, it took until 1933 for the Prize to be awarded and full public approval to be granted.

When Morgan was a student at Woods Hole Marine Biological Laboratory in Massachusetts he had been interested in the embryology of sea spiders, to find out whether they were crustaceans or arachnids. But when he followed the footsteps of Lankester in 1894 to the marine laboratory in Naples, he became more interested in the chemical and physical changes that happened as the little creatures developed. From then on, TH Morgan saw no need for natural selection and believed that species had no reality in the flow of nature. “It appears that new species are born; they are not made by Darwinian methods, and the theory of natural selection has nothing to do with the origin of species, but with the survival of already formed ones.”  To him, a “naturalist” was the opposite of a “scientist” and biology could be explained in terms of physics and chemistry. This was despite him knowing very little of either and at the same time insisting that “genetics can be studied without any reference to evolution”. These were purist views, typical of the way an enthusiast supports a new idea if only to get it across. But they also showed the power of reduction to the smallest detail and the growing popularity of the quantitative approach.

Morgan’s view was a restatement of the old supporters of Lamarck who thought that selection could not create but only reject. They failed to see that it was through this rejection that new forms are created and it was to be three decades later that Morgan’s students realised this. They agreed that evolution worked at many levels, whether it was with the mathematics of molecules and populations of organisms, with the physics and chemistry of genes, the chemistry of physiology and with the influence of different environments. By change at any of these levels, biodiversity came from the splitting of lineages, by speciation, and that gave discontinuity in nature. But it was mutations that mattered most to Morgan because he thought they created new species immediately, despite the environment. They also occurred in single genes and would become extinct only if the change was harmful for all individuals.

From 1904 Morgan moved to New York aiming to find the commonly suspected patterns of change that seemed to be continuously passing from one generation to another. By then the talk of Mendel’s ratios validating the role of sudden mutations gave him new hope and he started to look for evidence of what might be in control of these hereditary characters. That was when he started to work with fruit flies, which were easy to use in his laboratory, or the ‘fly room’ as he called it.

This was more than just a room, rather a very well-organised and well-led group of enthusiasts who were in at the beginning of experimental genetics. Drosophila flies were cheap, quick and easy to breed in milk bottles, and the features they inherited showed up very noticeably. They also had just four very large chromosomes that showed changes in shape and colour in different parts, ideal for examining chromosomal events during the sexual and asexual cycles of cell division, how they related to the structural features of the adult. Mutations came easily and bred true as variously coloured eyes, striped bodies, wings of different shapes and such like. But these techniques were going to need thousands of experiments before any trends emerged and even then the data were not going to be easy to analyse and interpret. Like the processes they were monitoring the experiments needed to be fully controlled and monitored.

In 1907 Bateson visited Yale and set out his post-Mendelian statement about genetics and evolution. He fought for the slow and gradual recombinations that Mendel’s work had described and for which he had proposed the word “genetics” two years earlier. But there was still no evidence that any particles on the chromosomes or anywhere else were the agents of inheritance. Bateson kept quiet then about his thoughts on the train in 1900 when he also remembered another article by a German cytologist Theodor Boveri. That was about structures inside the cell nuclei of sea urchin embryos, structures the author had called chromosomes. Could the recombined ratios, he wondered, come from a re-sorting of particles on these chromosomes during sexual reproduction, both in peas and sea urchins?

Bateson preferred to think that vibrations were the more likely agent: “In Mendelian analysis we have now, it is true, something comparable with the clue of chemistry, but there is little prospect of penetrating the obscurity which envelops the mechanical aspect of our phenomena.” Inheritance must be transmitted by a force from physics, vibration. “Patterns mechanically produced are of many and very diverse kinds. One of the most familiar examples, and one presenting some especially striking analogies to organic patterns, is that provided by the ripples of a mackerel sky, or those made in a flat sandy beach by the wind or the ebbing tide.”

It came as no surprise that Bateson and Morgan were very different kinds of people, and they did not get on. Morgan looked a bit like Weldon with a droopy moustache, and he had a casual and laid-back southern outlook on life. Bateson thought Morgan “rough”, “of no considerable account” and “dreadfully small” and even reported to his wife that “TH Morgan is a thickhead”. At first, in 1907, about the only thing they had in common was that chromosomes were not of much significance in genetics.

Both men had nothing to say about natural selection or Darwin or the link between his ideas and Mendel’s ratios of inheritance. Instead, based as much on envy as on reason, Bateson gave Morgan, and the audience at Yale, his own eccentric idea, but with no new evidence. Instead, because he couldn’t leave his vibration theory alone, he could only offer a sad and weak attempt to get the idea across. “I think we are entitled to the inference that in the formation of patterns in animals and plants mechanical forces are operating which ought to be, and will prove to be, capable of mathematical analysis.”

Bateson left America without changing anyone’s mind about the cause of evolution, let alone his own. Many of the different ways of explaining evolution were still possibilities though they all had different levels of support and very few people could appreciate how each idea might fit into the whole picture of a living system. There was some support for vibrations, and evidence for degeneration, a case for eugenics and mutation as well as for Darwin’s more gradual theory of natural selection. Without evidence from genetics, geological dating, biogeography, migration or ecology, no single theory or investigator stood out as the most acceptable. There was still all to play for in the game of trying to understand how life worked. Although new disciplines had begun in the four decades since the Origin was published, none had given any major new advance. What little seemed acceptable was split up, all in bits.

One thing was for sure, the way to understand Mendel’s results was going to be through some quantitative assessment, and Lankester organised a series of monthly dinners at his club to help find a way through. On such occasions there was a lot of talk about the biometric work coming from Galton’s laboratory and how it might inform those hoping for selective human breeding. Two mathematicians in the group, Whitehead and Russell, were preparing to work on their monumental Principia Mathematica, and they wanted to link Lankester’s descriptive biology to their own quantitative methods, but it was going to be difficult at first. 

Bertrand Russell (1872-1970) was best placed to link these topical issues because he was one of the few people who could understand both languages. As a philosopher with mathematical skills, he was in the right place at the right time. Together with Whitehead he advocated three requirements to explain the history of life: a concept of infinity, the flexibility of choice, and the desire to reduce explanations to the smallest component. This rigorous and optimistic programme was raising the stakes of biologists, pushing qualitative description to one side and claiming biometricians as heroes.

Even Lankester appreciated that this was the way things were going and was pleased to explain that the new methods relied on descriptive data. And all around in science there was a shortage of data; numbers were highly sought after and soon there were plenty of non-scientists interested in mathematics solely as a mental exercise. This was summed up by one presentation in Cambridge that attracted a large audience when Bertrand Russell teamed up with TS Eliot reciting the value of pi for ten minutes. There was then a period of meditation before they continued with another hundred or more decimal places of the constant’s value. It was going to be important for biologists to keep mathematics under control.

What the old brigade of Wallace and Lankester saw as being even more difficult than describing life by equations was the link these mathematicians, outsiders to their classical biology, had with their philosopher friends in Vienna. It was the group that Rudolf Carnap was to lead for the next two decades and which at this early stage became known as the First Vienna Circle. These men met at the Cafe Central and had a very clear vision of where philosophy was going. They saw all knowledge coming together as a single language of science, becoming more and more precise and leading to a single truth, one Law of Life being verifiable by experiments and taken further by mathematical modelling.

Russell was never an inside member of this group and later went out of his way to distance himself, despite the excellent credentials that his three explanation of life gave him for membership. Instead, he experienced an incident that his Principia Mathematica could not account for and which would have been rejected as irrelevant by the First Vienna Circle. It was from a simple incident of seeing the pain felt by a lonely woman as she was growing old, all alone. “Having for years cared only for exactness and analysis, I found myself filled with semi-mystical feelings about beauty …. to find some philosophy which should make human life endurable.”

By then, measuring was seen to be an essential part of the scientific routine and few young biologists were sympathetic to Russell’s feelings about the old lady’s values of life: instead they searched for other explanations. One such person was in the same city of Vienna at the same time as the philosophers, Paul Kammerer (1880-1926), an experimental zoologist. He wanted to prove Lamarkian theories of evolution by breeding reptiles such as toads and salamanders. Kammerer’s first experiments involved breeding midwife toads in warm water and after several new generations he noticed the growth of black nuptial pads on the males’ feet to keep grip on the female.

Other toad species also had these pads, and Kammerer explained them all as adaptations to the slippery conditions. This didn’t prove or disprove Lamarck, but it did help understand something about toad life-styles. Usually the males could grip their mate easily and didn’t slip on dry land, but in the moist conditions of Kammerer’s experiments they kept sliding around. The question people were asking was whether the pads came from the expression of an existing trait, inherited from a line of ancestral species that also mated in water, or whether the pads were from a new mutation. Kammerer himself was unsure of the answer when he began this work in 1906 and didn’t come to favour the explanation that they were from rapid mutations until after the war.

With the measured scientist and philosophers at the Cafe Central and experimentalists like Kammerer, Vienna was hardening into a place of scientific rigour for the twentieth century. Not least of importance was an ear-nose-and-throat doctor, Wilhelm Fliess, who also reckoned to have helped turn biology into a science describable by mathematics. For more than ten years he had gathered data from cyclical body patterns such as 28 day menstruation and an associated periodicity of 23 days. He compared these to times of nasal bleeding, and even dates of birth and death and concocted an arithmetic formula to account for many other bodily functions as well. Fliess’s best friend was Sigmund Freud who entrusted his own nose to Fliess’s surgery, despite another patient nearly dying from similar treatment. The surgery was thought to be a cure for Freud’s arrhythmic heart beat and was regarded as a great success. It was also at the time of Freud’s entrance into life science, when he began to link human psychology to evolutionary biology.

(Rudolph Carnap)               (Central Cafe, Viena)                                           (Freud and Fliess 1895)

Francis Galton had already been thinking about this other ghost of Darwin, how study of the mammalian mind might fit in with evolutionary mechanisms. To open up his enquiries he began to subject some of the results from his Anthropometric Laboratory to his first statistical methods of analysis. He had the height measurements of thousands of parents and their children and plotted them out in different ways. Not surprisingly, taller parents tended to have taller children, but the children were rarely taller than the parents. Equally, shorter parents had only slighter shorter children. There was a tendency to revert back towards the average.

This way of measuring association between any two like-with-like variables, such as heights of parents with heights of children, helped Galton find a standard that he applied to other closely comparable data. Two variables are often closely associated for correlations as well as regressions, similarities as well as differences. They formed the basis of much more sophisticated biometric applications, weather forecasts, economic indicators and even public opinion polls. But in all cases the quality of the prediction was no better than the quality of the data used in the first place.