ERNST MAYR, KARL JORDAN, AND THE HISTORY OF SYSTEMATICSplanet.uwc.ac.za/nisl/Biodiversity/pdf/Hist...

0073-2753/05/4301-0001/$10.00 © 2005 Science History Publications Ltd

Hist. Sci., xliii (2005)

ERNST MAYR, KARL JORDAN, AND THE HISTORY OF SYSTEMATICS

Kristin JohnsonArizona State University

INTRODUCTION

A few weeks before his ninety-fourth birthday the entomologist Karl Jordan was surprised to receive the draft of a brief biography of himself. Until then he had not known that the Royal Entomological Society of London planned a special volume in his honour, an event unique in the society’s history. The contributors ranged from the Hon. Miriam Rothschild, the naturalist-niece of Jordan’s former employer, the late Lord Walter Rothschild, to one of the central architects of the evolutionary synthesis, Ernst Mayr. Richard Goldschmidt, Mayr’s sometime opponent in evolutionary theory, also contributed a letter of appreciation, as did Julian Huxley. Various specialists on fl eas, weevils, beetles, butterfl ies, and moths, who had found in Jordan an ideal example of the “museum entomologist”, described his contributions to their special-ties. For the scientifi c part of the Festschrift, contributors wrote on subjects of special interest to Jordan, including zoogeography, taxonomic revisions, identifi cation keys, and detailed morphological studies.

In Mayr’s contribution, an historical essay entitled “Karl Jordan’s contributions to current concepts in systematics and evolution”, he described Jordan as “one of the great biological thinkers of our time”.1 Mayr obviously found in Jordan an ideal hero for his campaign to raise the status of systematics, emphasize the importance of evolution to systematic work, and convince his fellow biologists of the importance of the biological species concept. Mayr credited Jordan, along with E. B. Poulton, with the fi rst clear defi nition of the biological species concept, and wrote that after Jordan’s discussions of the concept in 1896 and 1905 no substantial progress had been made in the literature for three decades.2 He also argued that systematics as practised at Rothschild’s Museum, and Jordan’s writings in particular, provided crucial components in the understanding of species as interbreeding populations rather than static mor-phological types, critical for the evolutionary synthesis of the 1930s and ’40s.3 Mayr wrote that some biologists would be wise to read Jordan’s writings, fi fty years after they had been composed, and he has continued to cite Jordan among those “ naturalist-systematists” who contributed to the modern synthetic theory of evolution.

History has served as an important tool for systematists committed to redefi ning their fi eld and emphasizing certain methods, priorities, and intents as the life sciences changed around them.4 Recent work on commemorative narratives and the creation of historical heroes by scientists demonstrates the important role that historical nar-ratives play in the legitimization of disciplinary research programs and trajectories.5 Mayr’s historical writings, unsurprisingly given his tireless efforts for both systematics

2 · KRISTIN JOHNSON

and evolutionary biology, are no exception. But historians have also highlighted the tendency of such narratives to remove historical fi gures from their own context and to redefi ne the past and its participants by modern terms and values.

Although Mayr’s essay was an extremely knowledgeable assessment of Jordan’s scientifi c work, it is important to note that it was also fi rmly tied to his desire to make both systematics and certain concepts central to biology. When Mayr was asked to contribute his analysis of Jordan’s scientifi c work, he was deeply involved in build-ing the evolutionary synthesis and its new organizations. He was also engaged in an intense debate over the biological species concept, the use of subspecies and of trinomials, and the respective roles systematists and geneticists had played in creat-ing the evolutionary synthesis. This essay examines how and why Jordan was useful to Mayr in these battles. Then, by combining Mayr’s analysis of Jordan’s concep-tual work with attention to the context and community in which Jordan originally worked, this essay provides a case study of the importance of including analysis of the institutional and disciplinary contexts in which concepts are produced and used. Indeed, the context-bound fate of the research program Jordan outlined, based on concepts Mayr later praised, illustrates some reasons why Mayr was still having to engage in defences of these concepts long after Jordan had supposedly proved them so useful.

I begin with a brief biography of Karl Jordan, followed by a description of some of his writings on geographical variation and species concepts. The point of this section is to focus on some of the important practices, constraints and contemporary inspirations of Jordan’s work not brought out in Mayr’s essay. Focusing on tracing the history of concepts in systematics and biology more generally, Mayr tended to leave such factors out of his historical essays, and as a result often removed workers like Jordan from their collections, naturalist networks, and distinct methodological and social contexts. I argue that despite Mayr’s efforts to raise the status of system-atics in his historical writings and elsewhere, his focus on concepts to the exclusion of institutional, methodological, and disciplinary aspects of systematists’ lives has often tended to reinforce the old bias against seeing systematics, and museums, as important in the history of science.6 We need to examine both the practice and the broader context in which naturalists work in order to understand the history and fate of the very concepts that have been so central to Mayr’s own scientifi c life, and provide better analysis of the strengths and weaknesses of different ways of doing systematics given the contexts in which systematists work. Doing so is particularly important because it highlights the diversity among naturalists’ methods, aims, and obligations, diversity that often played a profound role in naturalists’ ability to accomplish certain types of research. Mayr has repeatedly argued that the work of systematists between 1890 and 1930 led to concepts critical to the evolutionary synthesis, especially the understanding of species as populations, and he continues to use Jordan as an example.7 But Jordan’s story also has important things to tell us about the constraints placed on naturalists by their diverse views, methods, and institutional homes, as well as the changing world within which they work.

MAYR, JORDAN, AND SYSTEMATICS · 3

KARL JORDAN, SPECIES-MAKER

After obtaining degrees in zoology and botany at Göttingen, Heinrich Ernst Karl Jordan (1861–1959) came to the Rothschild Museum in Hertfordshire, England, in 1893 to work as entomological curator for Walter Rothschild’s growing collection.8 Jordan’s fi rst task was to determine and arrange Rothschild’s 300,000 beetles of 60,000 species, a feat he accomplished within a year. In 1894, when Rothschild suddenly decided to sell his beetles and concentrate on butterfl ies, Jordan began the meticulous work required for a planned “Revision of the Papilios” of the world. At a time when even systematists belittled the description of new species, naturalists understood revisions to be important contributions to the study of the natural world. The goal of a revision was to identify previously described species and to delimit species and their respective varieties, to clarify synonymy, and to place species in their correct genera. Well aware of the name-calling other biologists launched at his specialty, Jordan occasionally referred to such revisions as the work of “us species-makers”, but the sarcasm belied his strong belief in the importance of such work. He was an ardent defender of both the drudgery and detail required of species descriptions, monographs, and revisions. Jordan insisted that even if all the systematist could do, as the geneticist William Bateson once said, was keep his species separate, there was still a biological point to “species-making”. He argued that although the describer of a new form may be indifferent to the factors that had caused the modifi cation leading to that form, “his very act of describing it as a member of a chain of allied forms inhabiting each a different district connects a new modifi cation with the environment where it was found, and thus the describer adduces a causation”.9 He also insisted that in order for such modifi cations to be connected with the environment, the facts focused on by systematists had to include detailed locality data and large series of specimens, and that their nomenclature must emphasize geographical variation.

Rothschild’s museum became known for its large series of specimens of single species, amassed by Rothschild and his curators in order to determine the limits of variation for the purposes of their revisions. They emphasized the importance of detailed locality labels and departed from many systematists in their use of trinomi-als, a third name for geographical varieties, or subspecies. For Jordan, Rothschild’s curator of birds Ernst Hartert, and Rothschild himself, the use of subspecies was based on the assumption that geographical variation was central to the origin of species and must be the focus of systematic study.10

Though occasionally defended on the grounds that trinomials highlighted incipient species, usually the theoretical underpinnings of naming subspecies remained implicit. This was in part a refl ection of the prevailing methodological framework of natural history at the time that held fact-gathering to be the primary role of naturalists, and discouraged explicit references to evolutionary theory in natural history journals.11 But, eventually, faced with criticisms from both ornithologists and entomologists, Jordan composed cogent defences of the description of subspecies in the introduc-tions to the various Revisions issued by the Rothschild Museum. Whereas previous entomologists had described localized variations as distinct species, Rothschild and


Jordan relegated such forms to the status of subspecies if, aided by the museum’s large series, they found that the variation observed within such localities intergraded imperceptibly, forming a “continuous bridge” from one form to another. They did so on the grounds that (in Jordan’s words) “it is impossible to understand the rela-tionship of closely allied species without a knowledge of the varieties, and when one neglects the latter, one neglects also the most striking facts which can serve to explain the origin of species”.12 Notably, Jordan also defended the description of subspecies on the grounds that the use of trinomials removed much of the arbitrary nature of systematists’ work. He insisted that entomologists’ usual practice of leaving the question of whether a form was a variety or species, and what kind of variety if the former, to individual opinion led to an “arbitrariness in scientifi c research” not to be suffered. It was “a degradation of systematic work against which we earnestly protest”. To counter the arbitrary practice of describing some varieties and not others, Jordan insisted the systematist must carefully describe any difference that existed for a respective district as a subspecies.13

Given this emphasis, as Jordan set to work curating Rothschild’s collection of beetles and butterfl ies, one of his primary tasks was to decide whether variations observed within a species represented important geographical variation or some other type of variation. Faced with the need to determine whether a form was a variety or species, and what kind of variety, some Lepidopterists increasingly relied on the detailed examination of the genital armature on the assumption that a difference in the genitalia meant a form was a separate species. But upon examining long series of specimens for the purpose of Rothschild’s Revisions, Jordan realised that differ-ences in the genitalia could be both specifi c or varietal, just the same as any other characters used in descriptions. Further, Jordan found that geographical differences within forms usually correlated with variation in the genitalia, while individual vari-ation and discontinuous variation such as polymorphism did not. “Geographically separate races”, Jordan concluded, “are entirely different from aberrations, seasonal forms, and forms of dimorphic species that occur in the same locality”.14 He believed he had thus found fi rm proof “geographical variation is the beginning of the ramifi ca-tion of one species into more”.15 Rothschild and Jordan used this conclusion in all their subsequent work, emphasizing in their 1903 “Revision of the Sphingidae”, for example, that “Geographical variation leads to a multiplication of the species; non-geographical variation at the highest to polymorphism”.16 Given this conclusion, all Hartert, Rothschild and Jordan’s emphasis on good locality data, trinomial nomen-clature, and the detailed study of geographical variation made scientifi c sense. They could now insist that “the study of localized varieties is of the greatest importance in respect to the theory of evolution”. And further, since the degree of divergency, or geographical polymorphism, was often so minute that it would escape even a skilled eye “but for a carefully working systematist having drawn attention to it”, the naming of subspecies was all important to this study.17

As he paid close attention to the controversies among the self-described “biolo-gists” debating the origin of species in the 1890s, Jordan realized that what he had


found within the drawers of Rothschild’s museum while working on the revisions provided more than a defence of focusing on geographical variation; for his fi nd-ings directly contradicted some of the theories of speciation being put forth by more philosophically-inclined naturalists like George Romanes, Alfred Russel Wallace, and William Bateson. In contrast to Darwin’s claim that species and varieties differ only in degree not kind, Georges Romanes argued, for example, that species and varieties represented inherently distinct entities. Differences between varieties are non-essential variations in anatomy, he claimed, while the differences between species occurred within the sexual organs. Romanes then concluded that species arose from the selection of variations in the sexual organs, while varieties arose from the selec-tion of non-sexual differences. This “observation” was a basic premise of his theory of physiological selection, namely that speciation occurred through the selection of variation in the genitalia without geographical isolation.18 In contrast, in examining specimens for the Revision, Jordan had found that variation in the sexual organs occurred in similar ways among geographical varieties and species; the difference was one of quantity rather than quality, just as Darwin had said.

In a paper entitled “On mechanical selection and other problems”, published in the Rothschild Museum’s journal, Novitates zoologicae, in 1896, Jordan discussed the implications for his fi ndings based on museum work for the claims of the philo-sophical naturalists. Each proponent of the different theories of how species change had to begin with a defi nition of species. Jordan argued that most of the defi nitions in vogue were directly contradicted by what had been found in nature by systematists, and that naturalists were therefore making profound errors in their search for the process of speciation. Romanes’s theory that speciation could occur within the same locality furnished an excellent example. Romanes argued that only species exhibit hereditary distinguishing characters, but according to Jordan varieties did so as well. Similarly, Theodor Eimer held that only species were physiologically isolated, but sometimes so were varieties. And Alfred Russel Wallace defi ned species as possess-ing adaptive differences, but so, too, did varieties. The data in the museum directly contradicted the assumptions on which these naturalists had erected their criteria of difference for the purposes of theorizing.

There was something else at stake as well, for as Jordan pointed out:

The consequence of accepting a defi nition of the term ‘species’, which does not exclude every kind of variety (varieties as opposed to species) leads naturally to the conclusion that there is no real distinction between species and varieties, and that it is purely conventional whether we call a form species or variety, an opinion by no means rarely met with even amongst us species-makers.19

Jordan argued that anyone who truly accepted evolution must, however, in accept-ing that species diverge, at least silently accept that species are those branches of an evolutionary tree that cannot re-converge. Therefore it should be possible to differentiate species from those forms that were at a lower degree of development and which could reconverge. Jordan insisted that the chief criterion of what defi nes


a species, then, must be the impossibility of fusion following divergence from an ancestor.20 Jordan’s defi nition countered the claims of Romanes, Eimer, and Wallace, each premised on the assumption that the processes producing varieties and species were different. But his defi nition also countered Darwin’s claim, used by systematists and biologists alike, and unwittingly one of the most damning criticisms of museum work, that no real distinction existed between species and varieties. Jordan argued that the same process produced geographical varieties and species, but that there was a point at which the systematist could determine a distinction between these entities, and describe them as such. This point occurred when populations previously capable of interbreeding could no longer reconverge.

In an ideal world in which the systematist could carry out breeding experiments on every form of interest, Jordan’s defi nition provided a non-arbitrary standard through which to distinguish species from varieties: the criterion of interbreeding. Slightly different forms that could interbreed were geographical representatives of the same species. But even Rothschild had never had the space, time, or resources for breed-ing insects. What role could a large collection of dead specimens play, then, given such a defi nition? Jordan had no illusions regarding the ability of museum-workers to come consistently to defi nite decisions on whether a form was a species or a vari-ety based on the defi nition he put forth. A systematist, he wrote, could never prove with certainty from the specimens alone “whether the distinguishing morphological characters they exhibit are of specifi c value or not”. Jordan explained:

The actual proof of specifi c distinctness the systematist as such cannot bring; we species-makers do, in fact, not pretend, at least many of us do not, that in every case the form which we pronounce to be a species really is a species; we work, or ought to work, with the mental reservation that the specifi c distinctness of our species novae deduced from morphological differences will be corroborated by biology (in the widest sense).21

This agnostic stance regarding practice was, however, quite different from the belief that systematists’ determinations of species versus varieties refl ected no real-ity in nature or that they were arbitrary. Given the admission that systematists could not always come to accurate determinations, Jordan believed that they could reach a “probably correct” conclusion in the museum with two additional aids. Systematists must proceed by (1) taking into account the way divergence comes about, and (2) using the comparison of characters of such forms as have been tested to be specifi -cally distinct.22 In arguing that systematists must take into account how divergence comes about, Jordan took a defi nite stance, to a certain point, on the various debates concerning the process of speciation. In contrast to those who argued that speciation could occur within a single locality, Jordan insisted that geographical isolation was necessary for the divergence of species, on the basis of his observation that genital variation correlated only with geographic variation. Well aware that naturalists such as Moritz Wagner and John T. Gulick had been called to task for holding that speciation could develop entirely from geographical isolation, Jordan clearly stated


that some additional transmutative factor was also needed, but felt any comments on whether such factors might be orthogenetic, selectionist, or Lamarckian would be premature.23

In examining forms, the systematist had to determine whether isolation had pro-vided the requisite amount of divergence for two forms to have become incapable of interbreeding. And this was where Jordan’s second requirement for systematists to arrive at accurate conclusions arose. Though breeding experiments could not be done for all forms, some had been done, and these could provide points of comparison. One had to make a judgement whether the observed variation seemed more or less similar to that in known cases of different species. This determination-by-analogy required the use of many characteristics, careful comparative work, and large series of specimens. For, as Jordan explained: “In interpreting these facts of characters pre-sented by the individuals ... one starts with the assumption that what has been found to be true in the necessarily limited number of specimens investigated, holds good also in the vast multitude of individuals not compared.” The possibility of error with this method could be decreased by the comparison of a large material of individuals. “How large it should be”, Jordan and Rothschild constantly warned, “nobody can predict”. But of one thing they were certain: “To ascertain the extent of variation of the chief classifi catory unit, the species, the material can never be too extensive.”24 In order to determine what variation was geographical, the systematist was obligated to examine many organs, species, and individuals. As a result, “fi nality, even if the classifi cation is restricted to a small group of beings, entails such an enormous expenditure of energy that it can be approached only gradually in the course of time by continued co-operation between the various lines of research”.25

Jordan was well aware that the tedious work this goal entailed did not raise the status of systematists in the eyes of other scientists. But he insisted that the sys-tematist who followed these guidelines was extremely useful, both as a recorder of facts and, indeed, as the most able of all workers to interpret these facts. “Although nowadays the recorder of facts, the diagnosticist, does not rank high in science”, he noted, “every theory in Natural History depends especially on the correctness of the facts furnished by the diagnosticist; when that record lacks correctness the theory based upon it must break down”. He insisted that the biologist August Weismann, for example, could not be faulted for a theory he had formed based on a classifi cation that Lepidopterists had created on the basis of inadequate knowledge of the forms classifi ed. The blame “is much more on the side of the systematists” who based clas-sifi cation on a single character. “We learn from this illustration fi rst that diagnostic work is the true basis of evolutionistic theories and hence of the highest importance, and secondly that the record of facts must be exact.”26 Zoologists required careful, accurate revisions and monographs that set forth the facts upon which generaliza-tions could then proceed.

Jordan’s steadfast focus on the specimens in the museum, and the particular types of scientifi c practice he had developed to deal with them, refl ected his belief that the institutions, methods, and research program of natural history were still valuable.


Jordan spoke on the species problem, he would later say, “as a zoologist who has spent the larger part of his life battling in a museum with the species problem in its great variety”.27 Battling was an appropriate metaphor, for though he believed he had found a non-arbitrary species defi nition, Jordan recognized that the criteria of breeding did not lead to defi nite systematics, a point critics of systematics continued to belabour. In the United States the geneticist Thomas Hunt Morgan most famously ridiculed the work of modern systematists for their arbitrary species defi nitions and subjective classifi cations. The ichthyologist and naturalist David Starr Jordan admonished Morgan that “No modern taxonomist regards species as ‘arbitrary col-lections of individuals assembled for purposes of classifi cation’. Many species are obscured for lack of material or lack of accuracy in published accounts. This is not Nature’s fault. Charge it up to the weakness of humanity”.28 Karl Jordan believed the answer to this “weakness of humanity” could be found in a research program based on the examination of as many facts, individuals, and species as possible. He outlined a method of systematic research, including the use of analogy, long series of specimens, meticulous detail, and a broad range of characters, that compensated for the disadvantages of museum work given his defi nition of species and the need to differentiate (and provide names for) geographical variation. That Jordan’s methods could produce extraordinary results is evident from the fact the revisions that resulted from his and Rothschild’s meticulous work were done so well, that they awe modern entomologists and are still used to this day.

SOME PROBLEMS WITH “SPECIES-MAKING”

Jordan believed he had developed a research program that would allow systematists to make, if not always accurate, at least non-arbitrary decisions about species boundaries, and to differentiate between geographical and non-geographical variation. Inspiring other entomologists to follow suit, however, was another matter. Those who used the networks, journals, and disciplinary epithets of entomology often pursued their subject for varied reasons and in many different ways. And even those who praised the Rothschild and Jordan revisions could not always take up the calls for long series and detailed morphological examination that Jordan insisted good determinations and classifi cation required. Although the Lepidopterist G. F. Hampson admitted that he saw the value of full descriptions of subspecies under separate headings, for example, he excused himself from doing so on the grounds that he was limited as to space by his employers at the India Offi ce and had to economize in every way.29 Four decades later, entomologists often excused themselves from using terms like ‘subspecies’ on the grounds that so little was known about insects. E. D. Ball wrote:

If we knew our bugs one half as well as the bird men do their birds we might talk intelligently on sub-species, geographical races, varieties, etc., but in the present condition of entomology, with the overwhelming amount of unworked material, the large areas from which no material has ever been taken, and especially in groups where food plants may be the major factor in changing the character of


the insect, we are not in position to make these discriminations, therefore most writers have contented themselves with designating varieties.30

Time and the limitations of available collections, Ball explained, prevented ento-mologists from following Rothschild and Jordan’s methods, even if they wished to. Others paid no heed to Jordan’s more detailed arguments on theoretical grounds for distinguishing between geographical and non-geographical variation and using trino-mials. The British Museum (Natural History) entomologist A. G. Butler argued against Rothschild and Jordan’s practice of providing a trinomial name for subspecies in the 1920s on the grounds such work would lower the status of systematics: “There was some excuse for Ornithologists, with whom new species are rarities, if they desired to distinguish themselves ... to separate every slight phase of a species (even if only arbitrarily separable from its next neighbours into which it intergraded imperceptibly) under a trinomial abomination; but Entomologists, to whom good new species come still in abundance, have no excuse for such frivolity.”31 Few entomologists possessed resources comparable to Rothschild’s with which to amass collections according to the ideal laid down by Jordan. When Jordan criticized the classifi cation of swal-lowtail butterfl ies upon which Theodor Eimer had based an orthogenetic theory of evolution, Eimer had sarcastically replied that “even grave mistakes may innocently occur to somebody who is not in a position to have such collections at his disposal as Mr. Rothschild”.32 To make matters worse, many entomologists still worked in the 1930s under the assumption that a limited number of specimens of each species was perfectly adequate for the description of new forms, or that observation of the “outer-wear” of specimens was good enough for their purposes. In 1935 the ento-mologist Van Duzee could still insist that if he could not determine a species without dissection of the genitalia, “it can stay put just where it was”.33 If natural history was to contribute to the grand aim it had given itself of fi nding the order in nature, it also had to bring its own house in order. Indeed, it was with these challenges in mind that Jordan organized the fi rst International Congress of Entomology in 1910.

The fate of the detailed methods and aims Jordan outlined depended not only on convincing other entomologists of their importance. His methods also relied on the persistence of the context in which large natural history collections could be amassed and systematists could communicate freely. Jordan outlined how to do good systemat-ics during the Rothschild Museum’s “golden age”, when Rothschild had hundreds of collectors sending him material from all over the globe. Jordan had tied the use of a species concept based on interbreeding and the description and naming of subspecies explicitly and tightly to the availability of large collections. This research program depended on fi nancial resources, networks of correspondents, and a stable environ-ment for specimen accumulation and exchange. Jordan had always found drawing conclusions from the material in Rothschild’s Museum, even when it surpassed all other collections, diffi cult. As years passed, even he could not maintain the ideal he had outlined. Walter Rothschild’s allowance was reined in by his parents after he was involved in a fi nancial and social scandal in 1908, and the First World War destroyed — temporarily for some nations, and permanently for others — much of


the natural history trade upon which the Rothschild Museum depended. The war also focused entomological endeavour on applied concerns, drawing resources and prestige away from systematics for its own sake. As the world changed around them, entomologists and particularly those in museums were expected to provide an iden-tifi cation service to their applied fellows, work-loads that often prevented the more profound work required of Jordanian systematics. During the depression, William Schaus, of the Smithsonian, reported that he could no longer pay attention to varie-ties and aberrations and was allowing them to accumulate.34 As biology in general became both more reductionist and theory-based, the cataloguing tradition in which systematics had formed became increasingly side-lined from the central and most prestigious realms of the life sciences, losing both funding and man-power. All of these changes profoundly infl uenced Jordan’s and his colleagues’ ability to amass the series and fi nd the time to complete the detailed comparisons of many individuals necessary to use his defi nition of species and differentiate between geographical and non-geographical variation in practice.

JORDAN AND MAYR’S EARLY EXCHANGES

As a young ornithologist Mayr fi rst visited Tring on the advice of Erwin Stresemann in 1927, to be, as he described, “indoctrinated” by Hartert in how to collect for the museum as part of the Rothschild and Whitney expeditions to the South Pacifi c. Though he found Hartert to be great fun, he recalls that Jordan seemed the more interesting of the two curators. But as Hartert’s guest, he had less opportunity to talk with Jordan at length, and had no conversations regarding systematics in general with him.35 When Mayr returned from his expeditions, and Hartert retired from the museum in 1931, there was talk that Mayr would be hired in his place. But in 1932 Rothschild was forced to sell his entire bird collection to pay off debts. The American Museum of Natural History were the buyers, and when Mayr was hired by this museum he soon found himself in charge of the Rothschild birds when they arrived in New York.

A decade later, as war raged in Europe and Tring was crowded with military personnel and refugees from London and abroad, Mayr sent Jordan inquiries about the systematics of Lymantria and Siphonaptera. He explained to Jordan that he was formulating arguments against Richard Goldschmidt’s recently published The mate-rial basis of evolution. Goldschmidt had argued against the idea that subspecies are incipient species. “He (Goldschmidt) believes that species originate through revolutionary reorganizations of the germ plasm”, Mayr wrote, “and not through small mutative changes in geographical isolation”. Mayr explained that he wished to bring out the weakness of Goldschmidt’s conclusions using his own material. But the United States had no specialist in Lymantria, and so he listed his questions regarding the systematics and geographical distribution of the group in the hopes Jordan could help.36

Jordan took a break from his by then considerable administrative and war-time responsibilities to respond to this ornithologist across the sea. In replying to Mayr,


Jordan wrote that he was glad to hear the war was not interfering too much with work in the United States, in contrast to the situation in Britain.37 He apologized for being unable to answer Mayr’s questions regarding the Lymantria, for the collections of this family had all been moved to London. Besides, the man working through the British Museum’s collection of the family was engrossed in war work and had not yet studied the genitalia “necessary for sound systematics”. He had not seen Gold-schmidt’s book but offered his view that it sounded as if Goldschmidt interpreted his discoveries in the same way as William Bateson, “being entirely on a wrong track”. Bateson, Jordan explained, had argued that large-scale mutations determined the path of evolution. Jordan recommended that Mayr read an article by K. Mather in Nature, quoting to one of the deans of the evolutionary synthesis Mather’s words that modern geneticists realized increasingly that small variations are the material of evolution. “It is a pity that men like Goldschmidt have not studied the systematics of a family of mammals, birds, or insects before they entered on a discussion of the basis of evolution”, Jordan wrote. “The geographical variation is so general that it is quite unscientifi c to neglect the factors involved.” If the material had still been at Tring, Jordan wrote, “I should certainly, for my own satisfaction, test Goldschmidt’s systematics; but without the collection I am hopeless”.38 In acknowledging Jordan’s letter, Mayr wrote that he agreed entirely with Jordan’s view that locality was crucial in the differentiation of species, and informed him that he planned to set these ideas down fully in a forthcoming book entitled Systematics and the origin of species.39

When Mayr’s book was published in 1942, Jordan was eighty-one years old, and for almost fi ve years had been an “unoffi cial worker” for the Natural History Museum following Walter Rothschild’s death and the bequeathment of his entomological collection to the nation. Now, amid his work for the war effort, he was swamped by requests to identify and describe specimens coming in from applied entomologists, the tedious diplomatic and library work of the International Commission on Zoo-logical Nomenclature (ICZN), and maintaining the Rothschild Museum for visiting scientists. The natural history agents through which Rothschild had built his collec-tion were gone, and the colonial network of collectors was rapidly disappearing. As Jordan warned his correspondents intent on compiling collections, natural history as a business was relatively defunct.40 As for the British museum, it preferred to hire young men to whom they did not have to pay too much. “This sort of administration of a museum for RESEARCH”, Jordan noted to Charles D. Radford, “appears to me very queer”.41 Jordan’s good friend N. D. Riley, the head of the Entomological Department, had long-since complained that he rarely was able to handle a “bug” or do any work on the collections. “I am a kind of glorifi ed offi ce boy”, he confessed.42 Later entomologists defended the fact that Riley had never produced a “great Jordanian revision” of a large group of insects during his years at the museum on the grounds that as the head of the entomological department he was constantly at the mercy of departmental administration.43 As director of the Tring Museum after 1931, Jordan had similar diffi culties. “I wish matters would straighten soon”, he lamented to his friend Miles Moss in 1938, as he struggled to deal with the administration of all sorts


of details after Rothschild’s death, “and allow me to go on with research work”.44

“If the war had not broken out”, Jordan explained to Mayr, “Tring Park might be by now property of the British Museum and gradually be developed into a centre for biological research; the Park would be ideal for new institutes. Well, that was my hope”.45 The lack of adequate sites for thorough systematics concerned him, and had been one of the main reasons for his plans for the museum grounds. To his good friend Miles Moss, Jordan explained that “zoology requires research institutes now, since the Zoology of the Universities has practically been replaced by genetics”.46

JORDAN AS A SYNTHESIS HERO

As Jordan composed these laments to his friends, Mayr’s Systematics and the origin of species began what one historian called his “fi erce campaign, with notable success, to raise the status of systematic biology”, particularly in view of the rapid rise of genetics.47 Central to this endeavour was the foundation of an international journal, Evolution, which Mayr edited from its foundation in 1947 to 1949, and in which he wished systematists to play a central role. For too long, Mayr felt, experimental biologists had held the view that taxonomists were not biologists.48 “I feel we tax-onomists have a real obligation”, he wrote in his solicitations from systematists to contribute, “to tell the geneticists something about our most signifi cant researches”. A month later he wrote:

We must impress on general biologists that taxonomic work is not merely a clerk’s job but real, genuine biology [and] we must impress on them that it yields results that are inaccessible to any other branch of biology. I think we have made a good beginning and taxonomy enjoys a greater prestige now than it had for a generation or more. We have to keep at it to improve our position, otherwise we will slide back again.49

Cain has described how the evolutionary synthesis was not only about agreeing on important concepts. It also involved rearranging community rules, cultivating a new research culture, emphasizing certain criteria for legitimacy, creating new social networks, and reforming communication patterns. During the decade following the publication of his 1942 book, Mayr worked to promote evolution in systematics, foster certain research styles, and emphasize certain solutions to research problems.50 As Mayr soon found, history could play an important role in organizing and defi ning this new community as well.

In late 1953, a few months after his move from the American Museum of Natural History to Harvard University, Mayr received a letter from Harry Clench of the Carnegie Museum asking whether the idea of a Festschrift for Jordan appealed to him, and if it did, would he consider writing a paper on the zoogeography of the East Indies and “also perhaps part of the analysis of his contribution to Biology — say in the fi eld of systematics?” “It has seemed to me that very inadequate recognition has been given publicly of Karl Jordan’s worth”, Clench wrote. “Certainly he has not been by-passed, but it is still true that more honors are due him than have ever


been bestowed.” He added that had Jordan been a nuclear physicist “it would have been a different matter!”.51 It was a telling refl ection of systematists’ (as well as morphologists’ and biogeographers’) conviction of their low status within the hier-archy of sciences.

Mayr replied with enthusiasm. “I am all in favor of a Festschrift for Jordan”, he wrote. “He is still alive and in good health, but I believe he is well over 90 and we must hustle if this is to come out in his lifetime.”52 Swamped with deadlines, Mayr warned Clench that he would not be able to start on a paper until July, but then hoped that he “might analyze some portion of the Papuan region zoogeographically” as well as compose an essay tentatively titled “Jordan’s contributions toward the develop-ment of modern systematics”.53 He had read Jordan’s “famous 1896 paper” before, but that summer Mayr began reading through the rest of Jordan’s early papers in preparation for his essay.54

Meanwhile, Mayr not only continued to be involved in building the evolutionary synthesis, in its new organizations, and in defending its primary concepts. He was also engaged in controversies with paleontologists and philosophers over the reality of species, and in an intensifying debate over the use of subspecies and of trinomials in the journal Systematic zoology. The debate over the reality of species had begun with a collection of papers in Evolution entitled “The species concept: A discus-sion”. B. Burma had argued that ‘species’ have only a subjective existence: “Species and subspecies are the units with which the taxonomist deals, but they are merely convenient labels for arbitrary groupings and have only a minimum of biological meaning.”55 Mayr replied forcefully, with the experience of a naturalist, that the gap between what he called a non-dimensional species (the biological species) “is well defi ned and has objective reality” in a local fauna. In multi-dimensional situations, such as an analysis of allopatric forms (geographically separate forms that might be geographical variations rather than species), an inference had to be made on the basis of the “objective species of the non-dimensional species”. “The subjectivity of this expanded species concept”, Mayr wrote, “by no means invalidates the species concept per se”.56

But Mayr’s (and Jordan’s) practical response to the analysis of allopatric forms was also under fi re. A few months after Clench asked Mayr’s advice regarding the Jordan volume, the ornithologist Richard Meinertzhagen had written with word that Dr K. H. Voous of the Zöologisch Museum in Amsterdam had given a talk at the British Ornithologists’ Club “aimed at torpedoing the trinomial system”, without giving an alternative way to express geographical variation.57 Mayr replied that he was quite aware of the movement to do away with trinomials. He suggested Meinertzhagen read a recent article by Edward O. Wilson and William L. Brown in the Journal of systematic zoology. “Of course they go much too far”, he wrote, “but it shows which way the wind blows”.58 Among other criticisms of the subspecies concept, Wilson and Brown had pointed out that “the development of the entire theory of geographical speciation has been dominated in large part by ornithological leadership”, that many of the ornithological revisions concerned had been based on few characters, and


that they did not “remotely approach in morphological detail those published on some other groups of animals”. Given these problems, they lamented the fact that the subspecies had obtained formal taxonomic status within the rules of the ICZN. They cited Mayr’s own confessed frustration with systematists’ inconsistent use of the trinomial, and argued that workers needed to analyse trends of variation rather than “expending their energy on the describing and naming of trifl ing subspecies”. Nature was too complex to be bound by nomenclatural rules based on the presumed nature of geographic variation, museums usually did not possess enough material adequately to assess such variation, and in any case the modern taxonomist had enough to do.59

Mayr replied to Wilson and Brown’s critique of trinomials in the following volume of the journal. He acknowledged the widespread dissatisfaction with the subspecies concept and its application in zoology, but noted that their criticisms were by no means new; “similar statements can be found in the zoological literature of the last fi fty years”. He believed that most of these critics wrongly assumed that subspecies were meant to be as objective as species, and he countered that to get rid of the sub-species as a category because of complexity and diffi culty would simply be throwing the baby out with the bathwater.60

As these debates over some of the central tenets and practices of his own work commanded his attention and energy, Mayr began his essay on Jordan. As his Sys-tematics and the origin of species from the viewpoint of a zoologist demonstrates, Mayr knew the literature of systematics extraordinarily well, but he was obviously astonished and impressed by what he read, even having known Jordan’s 1896 paper “On mechanical selection” and a 1938 paper entitled “Where subspecies meet” (the only one of Jordan’s papers he cited in Systematics). He soon wrote to David Lack that he was astonished at the “maturity of [Jordan’s] viewpoint as put down in papers published between 1895 and 1910. There is no doubt that he was, in his thinking, far ahead of the contemporary geneticists”.61 Mayr described to, ironically enough, Richard Goldschmidt how he had found the experience of reading Jordan’s papers published in the 1890s and during the fi rst decade of the twentieth century “most enlightening, but also most shocking”. “Shocking”, he explained, “because Jordan was so far ahead of his contemporaries, particularly the early Mendelians who seemed to have absolutely no understanding of natural populations”.62 Perhaps more importantly, Jordan was far ahead of some of Mayr’s own contemporaries. Reading Jordan’s 1896 paper again, and many of his other papers for the fi rst time, Mayr found clear refuta-tions of some of the central challenges that were still being made to the biological species concept and the use of subspecies. The fact that Jordan’s refutations were based on some of the most careful systematics ever done, and by an entomologist in the face of complaints that ornithologists had ruled systematics for too long, only helped Mayr’s argument.

The essay for the Jordan Festschrift that resulted is a homage, fi rst, to Jordan. Second, it was a tribute to systematics based on certain concepts and practices. And third, it was a critique of those who still did not understand the importance of


systematics to biology and evolutionary theory. As a tribute, Mayr described Jordan’s most important work, including “several major treatises which have since become classics”, namely Rothschild and Jordan’s revisions of various families of butterfl ies and moths of 1895, 1903 and 1906. Mayr focused primarily, however, on Jordan’s more “philosophical” papers: “On mechanical selection and other problems” of 1896 and “Der Gegensatz zwischen geographischer und nicht-geographischer Variation” of 1905 (published in Zeitschrift für Wissenschaft Zoologie). Mayr pointed out that while reading these contributions to the debates over the mode of speciation, the existence of natural selection, and the meaning of mimicry and of polymorphism, “one is fi lled with admiration bordering on awe when one compares Jordan’s discus-sions with those of most of his contemporaries”.63

As a tribute to certain practices, the essay defi nes what Mayr believes counts as good, “biological” systematics, by emphasizing that Jordan’s greatest papers were devoted to the implications of certain types of variation for evolution. He pointed out that “many contemporary taxonomists might learn from what Jordan said in 1905” regarding the importance of studying the variation of taxonomic characters within local populations, rather than in single individuals. He explained how Jordan had understood the importance of and campaigned steadily for the use of the subspecies concept, and worked to clarify for his fellow entomologists the differences between subspecies, varieties, and aberrations. Most importantly, Jordan had examined the problem of the species concept with clarity and precision. “In order to understand and evaluate Jordan’s own viewpoint”, Mayr wrote, “it will be necessary to outline the current status of this problem”. He noted that it was evident from the fact that the controversy still continued, that a full understanding of the species problem had not been reached, citing as an example the recent exchange with Burma. Mayr blamed such misunderstandings on the presence of three distinct species concepts; the typo-logical-morphological, the non-dimensional (biological), and the multi-dimensional. Mayr then reviewed Jordan’s demolition of the typological-morphological concept of species in detail. Next, he summarized his investigation of the biological, non-dimensional species concept, which defi nes species in the same locality based on reproductive isolation, and pointed out that Jordan had correctly argued for the objec-tivity of this latter species concept. Although this concept had been used by previous naturalists, Mayr writes that “in all my search through the literature I have not found a single statement by any other author which indicates an understanding equal to that of Jordan. He was the fi rst to point out the completely objective nature of the species concept as a measure of relationship in a non-dimensional situation”. Jordan had clearly stated this concept’s importance to the study of evolution. “If it had not been ignored by so many taxonomists and non-taxonomists since that time”, Mayr noted, “we could have saved ourselves much useless argument”.64 Jordan had also elegantly explained that the multi-dimensional species concept, which defi ned grouping of populations from different localities, while more subjective, was ultimately based on non-arbitrary criteria. His adoption of the polytypic species and its application to natural populations through careful analysis of allopatric populations, avoiding the


presumption that isolated populations must be described as species, represented a profound clarifi cation in systematic work that could not be over-estimated.

Finally, in a section entitled “Jordan’s biological philosophy”, Mayr lauded Jordan’s belief in the importance of systematics in biology and the application of evolution to taxonomy. “There have always been two kinds of taxonomists”, Mayr began, “those for whom species of animals and plants are like postage stamps to be collected or described merely for the sake of rarity or novelty, and those others for whom systematics is an important branch of biology. Jordan has always included himself enthusiastically in the latter camp”. Mayr quoted at length Jordan’s statements regarding the importance of systematics, for example: “There are even biologists of fame who, in their misguided wisdom, scoff at systematics and look down upon this kind of work as more or less fruitless.... I take the opportunity ... of stating emphati-cally that sound systematics are the only safe basis upon which can be built up sound theories as to evolution of the diversifi ed world of live beings.” Jordan’s 1905 paper, Mayr noted, was full of examples of how classifi cation based on presumed relation-ships had led to “considerable improvement in the distributional picture and to a better understanding of biological phenomena”. This tribute not only defi ned what counted as important concepts, but also portrayed the good systematist as far more than a “species-maker”. Mayr emphasized that, though he worked with insects as study material, “Jordan has been at all times, fi rst and foremost a biologist”.65

Mayr’s contribution to the 1955 Festschrift was one of his earliest published writ-ings on the history of biology,66 and many of the well-known historical themes he would later develop in detail appear, including the importance of defi ning concepts in resolving controversies and the rift between those who worked with natural popula-tions and laboratory biologists. Indeed, Mayr explained Jordan’s lack of renown as due to the fact he worked “with a material (natural populations) and with methods (non-experimental) that were unpopular among laboratory biologists of his time”, an excuse that fi ts well with his subsequent narratives regarding the evolutionary synthesis.67 Mayr’s famous dichotomy between typological and population thinking was also included. He began his discussion of Jordan’s appreciation of the meaning of variability by noting, for example, that “one of the most revolutionary changes of concept in biology has been the replacement of typological thinking by thinking in terms of populations”.68

AN EXAMPLE TO PROVE THE GENETICISTS’ HISTORIES WRONG

Mayr points out that geneticists’ claims that the synthesis had resulted from their own work to bring population thinking into taxonomy inspired his campaign to highlight the work of naturalists, particularly his fellow systematists, in the development of the modern theory of evolution.69 Jordan was a perfect example. To illustrate how far ahead Jordan was in his thinking compared to the geneticists, Mayr described in detail his role in confi rming geographic speciation. Jordan provided clear refutation of De Vries’s theory, Mayr notes, when he determined that in no ‘sports’ was there any correlation with difference in the genital organs, a proof ignored by the Mendelians.


He had come to a complete disproof of sympatric speciation “merely through the study of incipient speciation and by an astonishingly lucid and logical analysis of the speciation process”. Mayr had not found in the entire genetic literature a single discussion of species as penetrating as that of Jordan.70

In his correspondence after the Festschrift appeared, Mayr emphasized his delight in having been able to prove the geneticists’ histories wrong. As Jordan’s colleagues in London read the essay (“It is the best of the contributions”, Elwood Zimmerman wrote, “and it is very much appreciated”71), Mayr wrote to Miriam Rothschild that he had been happy to analyse Jordan’s work, for it had given him the opportunity

to correct the rather distorted history of the biology of that period. According to some of the experimental biologists it is genetics which has discovered all we know on speciation. Anyone reading my quotations from Dr. Jordan’s papers will learn that the truth is different.72

Mayr wrote to Jordan a few days later that writing the essay had given him “the welcome opportunity to point out that the taxonomists, around the turn of the cen-tury, were well ahead of the geneticists in their understanding of species and species formation”. He continued:

The meteoric rise of genetics since that time has tended to conceal this important situation, to the detriment of the prestige of systematics. It is merely stating the truth if I tell you that I was astonished how modern much of your writing appears. It has been a great pleasure to be able to tell you that and to bring it to the atten-tion of our colleagues. Systematics has been a neglected and sometimes almost despised branch of biology during recent decades, but I notice that things have changed recently. Both in your country and mine there has been a new awareness of the importance of systematics and with it increased support. I feel that much new and important information is still to be discovered.73

Mayr was at least trying his best to make sure systematics was obtaining a new awareness and support. As Mayr’s manuscript was being read in Tring and in London, he was continuing his campaign to improve the status of systematics, not only intel-lectually on the grounds of its important conceptual contributions, but organizationally as well. In February of 1955 he wrote to Dr Theodore Just of the Chicago Natural History Museum to enlist him in his newly established “Committee on Systematic Biology” within the Divisional Committee on Biology and Medical Sciences of the National Science Foundation. “Like most workers in the fi eld of systematic biology”, Mayr wrote, “you have probably wondered sometimes where this fi eld is going, whether the emphasis in the fi eld is in the right place, whether it is properly supported, and what should be done about getting the right people in the fi eld and see that they are properly trained”.74 Mayr devoted his time and energy to making sure the fi eld was going in the right direction, and to ensuring that other biologists paid attention. Jordan served him well, here, too. The year after the Festschrift appeared, Mayr again used Jordan in his campaign to place systematists at the centre of evo-lutionary biology, both historically and institutionally. He nominated Jordan as a


Foreign Member of the National Academy of Sciences, citing how he deserved the title of “the father of the new systematics”, and that his contributions to the theory of evolution towered over those of his contemporaries. “Jordan was so far ahead of his times in his thinking”, Mayr concluded, in an attempt to explain the lateness of the nomination (Jordan was ninety-fi ve at the time), “that it required nearly forty years before his greatness was truly appreciated”.75 When this nomination seemed to have been blocked, Mayr campaigned for Jordan to be elected for Foreign Honorary Membership of the American Academy of Arts and Sciences, despite the fact, he noted, “that he is now in his 97th year”. This meant, he wrote to the Committee on Membership,

that some of our members, particularly the experimental biologists, will have never heard his name, while others may have the reaction: ‘Why wasn’t he elected 40 years ago?’ In the full realization of these two probable reactions I have joined in nominating Jordan because in my opinion he is one of the few really great zoologists of all time. I am thoroughly familiar with the scientifi c achievement of seven of the eight scientists nominated in Sections 2 and 3 for Foreign Hon-orary Membership, and it can be stated without a moment’s hesitation that not one of them, not even Burnet, towers over his contemporaries as Jordan did in the years 1890–1910 which were his years of peak productivity. At that time he did not receive as much recognition as he deserved because his fi ndings were diametrically opposed to the saltationist and anti-selectionist views of Bateson and DeVries, who dominated the evolutionary scene at that period.76

Again, Mayr emphasized that although Jordan was an entomologist, and most of his life work had been devoted to the classifi cation of Lepidoptera, fl eas and certain groups of beetles, he had been a “broadly interested biologist at all times”. Mayr cited the Festschrift essay as evidence, noting “what a far reaching infl uence Jordan had on our modern thinking through his classical publications on the species concept, on speciation, on the difference between individual and geographic variation, on the laws of biogeography, and on mimicry”.77 This time, Mayr succeded, and soon received word that Jordan’s election to the AAAS, on Mayr’s recommendation and coming as it did just prior to his death, “was probably almost the last bit of pleasure” Jordan had.78

Mayr continued to cite Jordan’s 1896 and 1905 papers in subsequent writings on species concepts, in particular as a contrast to those who regarded species as arbitrary divisions, or who remained “typological thinkers”. He repeatedly directed readers to his own 1955 essay describing Jordan’s contributions as evidence that the biologi-cal species concept came from systematics rather than genetics.79 And he noted that the division between typological and populational thinkers was still visible in 1957, “even though most geneticists, under the leadership of Dobzhansky, Huxley, Ford, and others, have swung into Jordan’s camp”.80 He also repeatedly used Jordan as an example of how “the naturalists” maintained the central place of natural selection (despite ample evidence to the contrary in Jordan’s papers).81


As described by Mayr, Jordan provided a perfect example of Mayr’s claim that naturalists’ (a term he used interchangeably with systematists’) knowledge and expe-rience had been central to the synthesis. And the implications of this centrality were clear from Mayr’s defence of analysing the history of biology. As he continued to emphasize the important role of naturalists in his famous “Where are we” essay, a direct response to geneticists’ claims that they had been responsible for the synthe-sis, Mayr cited his 1955 essay on Jordan when stating: “It is of more than historical signifi cance that population thinking came into genetics from systematics and not the reverse.” An historical analysis of respective contributions to the synthesis is important, Mayr argued, “not for purely historical reasons or to establish priorities for prestige reasons, but because the planning of future work will be helped by a clear recognition of the potential contributions that can be made by the various col-laborating branches of biology”.82

Mayr also wrote that he found such historical studies fascinating, particularly “to determine where they advanced our understanding and where they ‘missed the boat’ and why”.83 Ironically, the 1955 essay commemorating Jordan’s contributions to sys-tematic and evolution came very close to being written by someone Mayr defi nitely thought had “missed the boat”: Richard Goldschmidt. When Miriam Rothschild had asked Goldschmidt to contribute to the volume, he had originally, “remembering Jordan’s early work”, thought of a similar plan to Mayr’s. But his own library had been sold when he had retired, and as he was not “able now to climb around library shelves, etc.”, he had asked to send a personal letter rather than a contribution.84 It is safe to say that had the essay on Jordan’s contributions to systematics and evolution been written by Goldschmidt, it would have looked quite different. As the example of Mayr and Jordan’s brief exchange in 1942 shows, Mayr had been frustrated for years by Goldschmidt’s continual denial of the evolutionary signifi cance of geographical variation.85 Just a year before they were asked to write essays on Jordan, Mayr and Goldschmidt had both been visiting professors at the University of Washington. “I am afraid the poor students must have been confused getting such diametrically opposed views on evolution in alternating lectures”, Mayr wrote. “Goldschmidt and I got along famously, but scientifi cally we remained as far apart as ever.”86 This did not mean, however, that Mayr did not value Goldschmidt’s opinion about Jordan’s work. While preparing his essay, Mayr asked Goldschmidt’s advice on the early period of systematics.87 Goldschmidt replied to Mayr that he knew of no entomologist “who got as far as Jordan”.88 Mayr and Goldschmidt could agree on certain things. Both believed Jordan was much more than an “entomologist”, as commonly understood. Mayr insisted Jordan was a great biologist. In his own letter of appreciation, Gold-schmidt was quick to point out that he saw in Jordan, not an entomologist, but “a great zoologist and naturalist”. 89

Goldschmidt also noted that he had read Jordan’s basic work in Lepidoptera, “a knowledge which ten years later (1909–1912) encouraged me to start the genetic analysis of the subspecifi c categories in order to explore their evolutionary signifi -cance. Thus you infl uenced an important phase of my work without knowing it”.90


This is one of the few testimonies we have of any direct infl uence of Jordan’s writings, despite Mayr’s claim that Jordan’s “infl uence on entomologists and taxonomists in general cannot be exaggerated”.91 Another is that E. B. Poulton used Jordan’s 1896 essay in his own work on species, acknowledging his “indebtedness to the author of this learned and valuable paper”.92 But, given the fact that Goldschmidt came to such diametrically opposed views on speciation based on work inspired by Jordan, Mayr’s claims regarding Jordan’s contributions relied less on tracing clear lines of infl uence than the desire to point out how Jordan’s data and writings should be read and defi ning what counted as important concepts.

Jordan’s cogent analysis of geographical variation and his emphasis on the objective nature of species served Mayr well in his campaign to emphasize the importance of naturalists to the evolutionary synthesis, in contrast to what he saw as the over-stated claims of the geneticists. The essay gave him the opportunity to emphasize those concepts he saw as central contributions made by naturalists, including population thinking and the biological species concept. In these contests regarding the history and role of the new systematics, one fi nds Mayr, the historian of ideas, being formed. Indeed, Mayr informed Goldschmidt during this exchange regarding the Jordan essay that he was working on a book that would trace the concepts of the new systematics toward their origin.93

THE CHALLENGE OF COMPLETING “JORDANIAN REVISIONS”

Over the following fi ve decades (and counting), Mayr has composed his histories of biology with the explicit warning that what interests him is the history of ideas. His focus on concepts refl ects in turn his belief that the synthesis was delayed by a division in the conceptual worlds of naturalists and experimentalists that could be broken down into a number of dichotomies, including an interest in proximate versus ultimate causes and working in multidimensional systems versus non-dimensional ones. In his analyses of the conceptual confusion delaying the synthesis, Mayr has brought attention to geneticists’ lack of distinction between geographical varieties and other forms of variation on the grounds that their conceptual framework did not allow for such distinctions. The recognition of such distinctions was “not possible until the biological species concept had been adopted and population thinking had permeated biology”.94 As for systematists who ignored such distinctions, that simply showed their typological thinking.

However, the fate of Jordan’s research program and the responses of systematists to his ideals, discussed earlier, illustrates that there was much more involved in deter-mining naturalists’ response to both the biological species concept and the practice of describing subspecies than their typological or populational conceptual frameworks. Even the debate Mayr engaged in over the use of subspecies and trinomials as he wrote for Jordan’s Festschrift illustrates the important role both a changed context and a diverse community played in determining the ability of naturalists to pursue Jordan’s concepts in practice, no matter how valuable they may have been in theory. Wilson and Brown had defended many of the main tenets of Mayr’s work, including


his interbreeding criterion for species as both objective and useful. But they had obviously found the application of a formal taxonomic category, the trinomial, to geographical races problematic.

Specialists in many less well-worked groups [they wrote], and especially those where insuffi cient time and material are available for detailed analysis of geo-graphical variation, have all but forgotten the early claims of subjectivity for the race, and have come to regard it as a concrete geographical population capable of being recognized by one or a few ‘diagnostic’ characters most accessible for study in preserved material.95

Taxonomists seemed to have forgotten, they warned, “the great complexities and dis-parities revealed in racial patterns by some really thorough analyses of geographical variation made in the past”. They noted Mayr’s own cogent warnings regarding the use of trinomials, but pointed out that these had been ignored. “From our experience in the literature”, they concluded, “we are convinced that the subspecies concept is the most critical and disorderly area of modern systematic theory”.96

Over the following issues of the journal Systematic zoology, others joined their voices to Wilson and Brown’s anti-subspecies comments. William Gosline found their paper “a refreshing relief” after trying to live with the trinomial system for years. He had no quarrel with the subspecies as a zoological concept, and believed the adoption of trinomial nomenclature had “been instrumental in demonstrating the tremendous part that geography plays in speciation”. But as a rule-bound system that attempted to cover a range of heterogeneous phenomenon, he thought trinomials would not only lower the status of the systematist even further but turn him into “an intergrade between a philologist and an attorney”.97 Curtis W. Sabrosky contributed to the discussion the results of a study he had done a few years earlier on the “actual practices” of entomological authors. He had surveyed the use of trinomials within 750 North American journals since 1890 and found that, among other inconsisten-cies, 50% of subspecies had been described from only one locality, “not harmoniz-ing well with defi nitions involving such features as ‘adjoining range’ or zone of intergradation”.98

Theodore H. Hubbell, of the Museum of Zoology at the University of Michigan, abandoned scientifi c arguments to try and explain some of the sources of this prob-lem. Entomology was made up of highly trained biologists, competent self-taught amateurs, workaday taxonomists whose main job was to get on with morphologi-cally-based description and naming, and dilettante collectors. “Obviously it is not likely”, he pointed out, “that entomologists, so diverse in background, viewpoint, and objectives, will ever fully agree on how to treat subspecifi c entities”. In addition, many of those who worked to name the “estimated one to several million species of insects still undescribed” continued to work with small numbers of specimens with few localities, and were thus unable to deal properly with geographical variation. Entomological taxonomy at the subspecifi c level, he explained, “is in a chaotic state as compared to the situation in most vertebrate groups”. The diversity among ento-mologists combined with that in the insect world to create lists “fi lled with arrays


of ... nominal ‘subspecies,’ formed unintentionally, the actual status of which is unknown”. It was only a revision based on adequate collections that could remedy this situation. “Such a revision”, Hubbell noted, “may not be forthcoming for years or for generations”.99 Indeed, the museum entomologists whose job it was to complete such revisions increasingly found themselves too over-burdened with administrative work and requests for identifi cations from applied entomologists to carry out the more basic work of revisions.

These critics did not argue, then, that the research program outlined by Jordan, and championed by Mayr, was inherently useless, but that, given the available information in collections and naturalists’ varied ways, the practice of naming subspecies proved circumstantially inadequate. Pressed by other obligations, with limited material, and faced with the need to make some sort of determinations, the original appreciation of the complexity of distinguishing between different types of varieties had been lost by too many naturalists. Entomologists in particular used the so-called “new systematics” on collections that still suffered from too little material, and they were thus unable to deal properly with geographical variation. Indeed, Hubbell had tried to explain the perspective of the entomologist to Mayr in early 1954, after Mayr asked him why he had called certain allopatric populations of Mycotrupes beetles separate species rather than subspecies.100 Hubbell replied that their differing opin-ions regarding the question of species versus subspecies “refl ects a difference in our respective philosophies that is, in turn, probably traceable to the difference in the systematic situation confronting ornithologists and entomologists”.101 Hubbell did not wish to rid systematics of the use of subspecies. That year he had written, following a defence of the place of the subspecies in systematics, that “the subspecies is most useful as a synthesizing concept, much less useful in analysis, and that its useful-ness is, at least in part, a function of the completeness of the available data”.102 But he worked too closely with entomologists and entomological collections to obscure the serious limitations placed on the day-to-day use of some of the central tenets of “Jordanian” systematics.

The challenges faced by those attempting to describe subspecies does not reduce the importance of the underlying concepts such practices refl ected, nor the very infl uential and important role Jordanian systematics (whether through Jordan, but most likely through Mayr) played in considerably clarifying, ordering, and refi ning systematists’ understanding of geographical variation and focusing their attention on populations. This cannot be over-stated. Systematists have continued to use the subspecies both as a concept and as a taxonomic category.103 Indeed, entomologists argued that trinomials were no longer needed as a formalistic device controlled by ICZN rules, partly on the grounds that good systematists now studied geographic variation, whether they used trinomials or not. Each entomologist should be able to make geographic variation explicit in terms of the context of his research, it was argued, rather than for the sake of nomenclature.

When entomologists had time and material, it had become a given that work must proceed along the lines codifi ed by Jordan. But the description of subspecies based


on inadequate grounds created a disjunction between the taxonomic practice Jordan had outlined and the ideal concepts upon which his methods were based. Given such a situation, some entomologists wished to get rid of a nomenclatural practice legislated by international rules in favour of a pragmatic adjustment to reality, the diversity of entomologists, and the complexity of nature. One hundred years after Jordan’s call for entomologists to use large amounts of material to compare forms using a number of characteristics over a wide geographical range, entomologists continue their warnings that many subspecies are biologically unsubstantiated and that butterfl y taxonomists, at least, have failed “for the most part to examine variation across the range of a species so as to assess effectively discontinuous variation”.104 Mayr’s optimistic pronouncements that Jordan had proved critics of subspecies wrong, and that therefore they should be described, refl ected the ideal pursued at Rothschild’s museum, but an ideal that in practice proved elusive, and especially within the changing context of institutional support and availability of specimens for entomology, extremely diffi cult.

In the interests of defending concepts, Mayr ignored some of the most important sources of diffi culty for the acceptance and usefulness of the very concepts for which he campaigned in writing his histories. Focusing on conceptual change thus obscures one of the important factors in the fate of the research program outlined based upon Jordan’s concepts, namely the call for more facts in order to make sure the cabinets of specimens that surrounded naturalists provided as large a sample of nature as pos-sible. Understanding how Jordan’s concepts returned him to specifi c practices in the museum is critical to understanding the effectiveness of a species concept based on interbreeding and the usefulness of named subspecies in entomology. In histories of the biological species concept, the collection of series of specimens has often been cited as a crucial development in the move toward the view of species as populations. But the role of that concept in returning the naturalist to long series in practice has not been equally emphasized, despite its important implications for a research program based on the concept. The loss of this relationship between Jordan’s species concept and large series has occurred in part because a focus on the history of concepts leads from one concept to another (or, in the case of the evolutionary synthesis, a synthesis of concepts); a focus on the history of ideas generally has not led the historian from the examination of concepts back to scientifi c practice.105 Mayr’s useful analysis of the development of species concepts must be combined with the practical and disciplinary constraints within which entomologists work to understand how and why important conceptual developments have or have not infl uenced biology, and to help understand some of the factors involved in continuing debates over species concepts and taxonomic practice.106

SYSTEMATICS, SYNTHESIS, AND THE HISTORY OF SCIENCE

Upon receiving notice of the special volume of the Transactions of the Entomological Society of London, Jordan wrote that he felt the honour very deeply. Ever concerned with completing the foundational work of biology, he said he much regretted that he


had not been able to fi nish his comprehensive revision of the Anthribidae: “I hope I shall live long enough to do so.”107 A few months later, Miriam Rothschild wrote to Mayr to tell him Jordan’s opinion of his essay.

I thought you would be pleased to know that yesterday Dr. Jordan read your paper in manuscript, and was delighted with it. He asked me to thank you very much for all the nice things you said about him. I think you would have been very much amused to have seen Dr. Jordan’s reactions; when he fi nished reading he laid down the paper and exclaimed: ‘Well, Mayr has read my papers!!!’ He then added: ‘But he is too kind — he only refers to those in which I was right!’108

Mayr’s writings on the history of biology have inspired analysis, criticism and praise.109 Sloan points out that it is important to keep in mind that Mayr has prima-rily engaged in the history of science as a tool for concept analysis and clarifi cation. This motive, Sloan argues, while not “an attempt to recover and relive the past on its own terms with the empathy sought in historicist approaches”, must also not be simply dismissed as whiggish or illegitimate, keeping in mind Mayr’s own intent and context.110 Mayr has also defended his narratives, particularly what he calls “devel-opmental history”, or the analytical study of the past in view of the present. Mayr writes that “what a scientist is most interested in when doing historical studies is to illuminate or reconstruct the pathway of the currently prevailing ideas of science”.111 Most importantly, Mayr insists that most of the great controversies in the history of evolutionary biology “were due to a failure to make precise defi nitions, and to develop clear-cut concepts”, rather than the discovery of new facts.112

Mayr’s focus upon concepts also has a strategic advantage in portraying natural-ists as relatively unifi ed, and thus better placed to defend their activities as part of a community characterized by consensus. The narratives written of the evolutionary synthesis have often been recognized as manoeuvres in response to the relative status of parts of modern biology, and such histories are often formed, as Greene writes, by the polemical position of authors with respect to issues confronting biologists in their own day.113 The compromise account of the synthesis that emerged from Mayr’s and others’ writings in the 1980s was that the synthesis occurred through the combination of the experimental work of geneticists with the population thinking of naturalist-systematists.114 As we have seen, to construct this narrative Mayr char-acterized the response of the naturalist-systematists to both nature and evolutionary theory as distinct from that of geneticists and experimental zoologists. More gener-ally, and taking a cue from this conceptual narrative, the narrative of the history of biology as a whole was subsequently based on the tension between naturalist and experimentalist-thinking.115

In view of Mayr’s efforts to recover the role of the naturalist tradition in biology after 1953, Chung notes that “it makes sense for Mayr to stress the ‘unity’ within the naturalist camp”.116 Mayr allows that describing the role of systematists in the evolutionary synthesis is diffi cult owing to the enormous diversity among them, but he focuses upon differences in their conceptual views of nature based on a typological


versus a population view of species (what he calls stamp-collectors versus naturalist-systematists) to characterize their differences.117 From this dichotomy, the analysis of conceptual issues that divide naturalist-systematists from either experimentalists or geneticists can then proceed. This was despite the fact that Mayr was as familiar as anyone with the disunity among naturalists (evident from his participation in symposium after symposium intent on encouraging and instilling unity!). But the fate of Jordan’s own research program shows that Mayr’s narrative implies more unity among the “naturalist-systematists” than has ever been possible, for numerous rea-sons. So-called typological species concepts have at most been only one of a number of problems that have faced conscientious systematists intent on doing good work. The diversity of organisms of study, institutions of support, changing methodologi-cal constraints, views regarding nomenclature, and day-to-day demands of research among systematists have also been profoundly important in determining naturalists’ responses to conceptual change. This diversity within the naturalist tradition — so often obscured in evolutionary synthesis narratives — would profoundly infl uence the fate of the research programs and practices associated with the biological species concept and the detailed examination of geographical variation.

Mayr has done more than any naturalist in recent times to reinstate the history of systematics within the history of biology.118 But his failure to give more detailed consideration to the role of both practice and diversity among naturalists in the his-tory of systematics in favour of concepts and unity among naturalists has created characterizations of natural history that obscure central elements of the naturalist endeavour. As most systematists left theory implicit, Mayr tended to leave practice implicit (outside of his important works on how to do taxonomy). This led to the ironic situation in which his defence of systematics removed important workers like Jordan from their empirical surroundings, their collections, networks, and the distinct contexts, both methodological and social, within which their concepts were formed. The result is that much of the naturalist tradition is left out of the history of biology, even when great systematists, like Ernst Mayr, are included. While praising Mayr as a biologist, Michael Ruse, for example, dismissed Mayr’s experience of cataloguing the Rothschild collection as the curation “of rich men’s hobbies”. Ruse explained Mayr’s decision to move to Harvard as follows: “He had — he has — too much energy, too much sense of self-worth, too much ambition for science, to spend his life putting a bunch of bird skins in the right order.”119 Such a statement, however, loses the empirical basis and context through which books like Mayr’s Systematics and the origin of species were written.120 Ruse does note that Mayr’s “deep, deep knowledge of avian systematics and biogeography” allowed him to write this book.121 But it is important to emphasize that this knowledge was closely related to “putting a bunch of bird skins in the right order”, and the problems associated with the latter are the very stuff of evolution.

Of course, Mayr himself defends both museums and systematists against such characterizations and has often acknowledged the huge empirical foundation upon which his conceptual work is based. Indeed, he dedicated Systematics and the origin


of species to “the army of taxonomists who have unselfi shly devoted their lives to the task of describing and classifying the animals of the world”.122 In his scientifi c writings, it is very clear that the constraints on practice, the limits on available mate-rial, and other factors beyond the population or typological thinking of systematists help determine both the development of and responses to concepts. While noting that systematics was in a more diffi cult position than most other sciences, Mayr admitted that

it seems as if all the conclusions and generalized laws derived from a study of taxonomic material were dependent to a very high degree on the nature of this material and the background of the student. The result is that — partly from the variety of the material, too — we have an almost unlimited diversity of opinion

on the most important issues in systematics.123 Combined with this diversity in approach and material, was the limited amount of time and resources for systematic work. “The trouble with us taxonomists”, he wrote a few years later, “is that we are so busy with all sorts of jobs that we don’t get around to doing research, and when we do we usually don’t have enough leisure to produce a good, all-around biological paper but have to be satisfi ed more or less with taxonomic revision”.124 He under-stood as well as anyone that incorporating the concept of biological species into the all-important taxonomic monographs was often extremely diffi cult due to a lack of material.125 He also recognized that some of the most vociferous opponents of the concept included museum and herbarium taxonomists who had to assign specimens to species, and did not understand how to infer reproductive isolation.126 In the 1990s he attempted to address their concerns by describing specifi c procedures of inference.127 He also outlined “a rather elaborate” methodology for describing subspecies in order to counteract the somewhat indiscriminate descriptive practices of naturalists who had adopted the use of trinomials.128 But Mayr’s historical writings, the works of an author engaged in the analysis and defence of concepts, hide much of this practical knowledge. Adding these factors to the historical narratives of systematics may help us understand why, at least as Mayr sees it, the concepts proposed as alternatives to that of biological species are “merely operational prescriptions for the demarcation of species taxa” and why “most of the criticisms of the Biological Species Concept seem to be caused by a disappointment of the critic that the Biological Species Concept is not a set of instructions for the demarcation of species taxa”.129

Upon learning of Jordan’s death in January of 1959, Mayr wrote that this marked the end of a period in Systematic Zoology.130 Indeed, in retrospect, this was more true than Mayr suspected. For within two years of Jordan’s death some of the central tenets of “Jordanian” — and “Mayrian” — systematics were facing even more aggressive criticism than those led by Wilson and Brown. Soon, the debate over trinomials gave way to the more serious issue of whether the biological species concept to which Mayr had tied the use of subspecies so tightly should be used at all, as well as heated arguments over the proper methods, priorities, assumptions, and goals of systemat-ics.131 Some have complained that many of the debates since the 1960s over species


concepts tend to take refuge in the philosophical.132 I would argue that one of the reasons for this is that often the historical analysis of species concepts has ignored the role that the material needs and priorities of the museum taxonomist has played in whether concepts have been adopted or not.

For the purpose of tracing scientifi c concepts, descriptions like Mayr’s of what scientists have found most useful and enduring in Jordan’s work are helpful. But Jordan provides a perfect example of how, as with all sciences, the development of natural history “is not adequately conveyed by a conceptual history of the theories in the life sciences”.133 A focus on concepts tends to leave out explicit discussions of the implications of concepts for practice and the constraints placed on concept usage by naturalists’ varied contexts and intents, including the changing availability of the very specimens for which concepts are meant to provide order. It also ignores the fact that paying close attention to the complexity and diversity within the naturalist tradition is critical in view of the role of this diversity in determining the ability of participants to carry out certain research programs and develop standardized practices through which to study nature.134 It is not surprising that naturalists constitute an extremely diverse community of scientists. That this diversity had profound implications for the ability of naturalists to develop research programs, create robust knowledge, and convince other scientists that natural history, systematics, and museums deserved both respect and resources, illustrates the important role practice and context plays in the history of disciplines and their central ideas. The naturalist tradition is a complex part of the scientifi c enterprise, and historians of science have only begun to address the ways in which this tradition can add to our understanding of the scientifi c enter-prise. Examining the complex factors involved in systematics not only has important implications for investigating how theory has or has not infl uenced the practice of naturalists. It also directs our attention to how including the role of world events, social and economic changes, the shifting nature of support for museums, and the burden of administrative duties in scientists’ lives add to our understanding of this fascinating realm of the scientifi c endeavour.

ACKNOWLEDGEMENTS

I would like to thank Erik Ellis, Paul Farber, William Husband, Rob Iliffe, Mark Largent, Robert Nye, and Mary Jo Nye for their comments on either drafts of this paper or the dissertation upon which it is based. The Dibner Institute for the History of Science and Technology and a National Science Foundation Dissertation Improve-ment Grant SES-0218289 provided support for this research. Walter Bock and Ernst Mayr kindly took the time to read and comment on the paper. While we must agree to disagree regarding some of my conclusions, I am very grateful to them for their candid criticisms and advice.

REFERENCES

1. Ernst Mayr’s essay appeared as “Karl Jordan’s contributions to current concepts in systematics and evolution”, Transactions of the Royal Entomological Society of London, cvii (1955), 45–66, and


was reprinted in Mayr, Evolution and the diversity of life: Selected essays (Cambridge, MA, 1976) and, along with two of Jordan’s papers, in Keir B. Sterling (ed.), Contributions to American systematics (New York, 1974). For biographical information on Jordan see Miriam Rothschild, “Karl Jordan: A biography”, Transactions of the Royal Entomological Society of London, cvii (1955), 1–14; idem, Dear Lord Rothschild (Glenside, PN, 1983); N. D. Riley, “Heinrich Ernst Karl Jordan”, Biographical memoirs of Fellows of the Royal Society, 1960, 107–33; and “H. E. K. Jordan”, in E. T. Williams and H. M. Palmer (eds), Dictionary of national biography 1951–1960 (Oxford, 1971), 560–2. The “Jordan” volume is the 1955 issue of the Transactions of the Royal Entomological Society of London.

2. Mayr repeats the claim that Jordan and Poulton deserve credit for the clear defi nition of the biological species concept in Ernst Mayr, “The contribution of birds to evolutionary theory”, Acta XIX: Congressus Internationalis Ornithologici, ii (1988), 2718–23, p. 2720, and The growth of biological thought: Diversity, evolution and inheritance (Cambridge, MA, 1982), 272.

3. The word ‘synthesis’ to describe the developments in evolutionary theory in the 1930s and ’40s, namely a reaffi rmation of the role of natural selection operating upon small variations in producing evolutionary change, was fi rst used by Julian Huxley in 1942 in his book Evolution: The modern synthesis (London, 1942). Recent historical analyses of the synthesis period include: Joseph Allen Cain, “Common problems and cooperative solutions: Organizational activity in evolutionary studies, 1936–1947”, Isis, lxxxiv (1993), 1–25; idem, “Ernst Mayr as community architect: Launching the Society for the Study of Evolution and the journal Evolution”, Biology and philosophy, ix (1994), 387–427; Jonathan Harwood, “Geneticists and the evolutionary synthesis in inter-war Germany”, Annals of science, xlii (1985), 279–301; idem, “Metaphysical foundations of the evolutionary synthesis: A historiographical note”, Journal of the history of biology, xxvii (1994), 1–20; Vassiliki Betty Smocovitis, “Unifying biology: The evolutionary synthesis and evolutionary biology”, Journal of the history of biology, xxv (1992), 1–65; idem, “Organizing evolution: Founding the Society for the Study of Evolution (1939–1950)”, Journal of the history of biology, xxvii (1994), 241–309; and idem, Unifying biology: The evolutionary synthesis and evolutionary biology (Princeton, 1995).

4. Mary P. Winsor, “Cain on Linnaeus: The scientist-historian as unanalysed entity”, Studies in history and philosophy of biological and biomedical sciences, xxxii (2001), 239–54; and Keith Vernon, “Desperately seeking status: Evolutionary systematics and the taxonomists’ search for respectability, 1940–1960”, The British journal for the history of science, xxvi (1993), 207–27.

5. See Pnina G. Abir-Am, “Essay review: How scientists view their heroes. Some remarks on the mechanism of myth construction”, Journal of the history of biology, xv (1982), 281–315; Pnina G. Abir-Am and Clark A. Elliott (eds), Commemorative practices in science: Historical perspectives on the politics of collective memory (Osiris, xiv (1999)); and Bernadette Bensaude-Vincent, “Between history and memory: Centennial and bicentennial images of Lavoisier”, Isis, lxxxvii (1996), 481–99.

6. For exceptional studies that examine the history of systematics on its own terms see Joel Hagen, “Experimentalists and naturalists in twentieth-century botany: Experimental taxonomy, 1920–1950”, Journal of the history of biology, xvii (1984), 249–70; idem, “Ecologists and taxonomists: Divergent traditions in twentieth-century plant geography”, Journal of the history of biology, xix (1986), 197–214; and idem, “Naturalists, molecular biologists, and the challenges of molecular evolution”, Journal of the history of biology, xxxii (1999), 321–41.

7. See Ernst Mayr, “Where are we?”, Cold Spring Harbor symposia on quantitative biology, xxiv (1959), 1–14. Also see his “The recent historiography of genetics”, Journal of the history of biology, vi (1973), 125–54; The growth of biological thought: Diversity, evolution and inheritance (Cambridge, MA, 1982); and his contributions to Ernst Mayr and William Provine,


The evolutionary synthesis: Perspectives on the unifi cation of biology (Cambridge, MA, 1980), and the preface to the 1998 edition.

8. The museum’s public gallery is now known as the Walter Rothschild Zoological Museum, and the grounds now house the Natural History Museum (NHM), London’s ornithological collection. The museum was variously known as “Rothschild’s Museum” and the “Tring Museum”. Records are currently held as the Tring Museum Correspondence at the NHM Archives.

9. Karl Jordan, “The President’s Address”, Proceedings of the Royal Entomological Society of London, iv (1930), 128–42, p. 140.

10. On Hartert and the work of ornithologists studying subspecies more generally, including Mayr, see Erwin Stresemann, Ornithology: From Aristotle to the present (Cambridge, MA, 1975); J. H. Haffer, “Die Seebohm-Hartert-‘Schule’ der europäischen Ornithologie”, Journal für Ornithologie, cxxxv (1994), 37–54; and idem, “The history of species concepts and species limits in ornithology”, Bulletin of the British Ornithologists’ Club centenary supplement, cxii (1992), 107–58. On trinomials in ornithology in the United States, see Mark Barrow, A passion for birds (Princeton, NJ, 1998).

11. See, for example, Frederick Burkhardt, “England and Scotland: The learned societies”, in T. F. Glick (ed.), The comparative reception of Darwinism (Austin, 1974), 32–74.

12. Karl Jordan, “Notes in and Introduction to: W. Rothschild, ‘A Revision of the Papilios of the eastern hemisphere, exclusive of Africa’”, Novitates zoologicae, ii (1895), 167–463, pp. 180–1.

13. Walter Rothschild and Karl Jordan, “Lepidoptera collected by Oscar Neumann”, Novitates zoologicae, x (1903), 491–542, p. 496.

14. Karl Jordan, “An examination of the classifi catory and some other results of Eimer’s researches on eastern Papilios”, Novitates zoologicae, v (1898), 435–55, p. 454.

15. Rothschild and Jordan, “Lepidoptera collected by Oscar Neumann” (ref. 13), 499.

16. Walter Rothschild and Karl Jordan, “A Revision of the Lepidopterous family Sphingidae”, Novitates zoologicae, ix (1903), Supplement, p. xlii, their italics.

17. Karl Jordan, “On mechanical selection and other problems”, Novitates zoologicae, iii (1896), 426–525, pp. 446 and 449.

18. On Romanes see John E. Lesch, “The role of isolation in evolution: George J. Romanes and John T. Gulick”, Isis, lxvi (1975), 483–503.

19. Jordan, “On mechanical selection” (ref. 17), 427, 428 and 441.

20. Ibid., 442 and 436.

21. Ibid., 450–1.

22. Ibid., 442.

23. On these debates see Peter Bowler, The eclipse of Darwinism: Anti-Darwinian evolution theories in the decades around 1900 (Baltimore, 1983).

24. Rothschild and Jordan, “A revision of the Sphingidae” (ref. 16), pp. i, xxix, and xxix.

25. Ibid., p. xxx.

26. Jordan, “On mechanical selection” (ref. 17), 451.

27. Karl Jordan, “The species problem as seen by a systematist”, Proceedings of the Linnean Society of London, cl (1938), 241–7, p. 241.

28. From a letter dated 28 March 1923 quoted in Garland E. Allen, Thomas Hunt Morgan: The man and his science (Princeton, 1978), 313.

29. G. F. Hampson to W. Rothschild, 8 October 1894, Tring Museum Correspondence (TM) 1/7/13, Natural History Museum (NHM) Archives.

30. E. D. Ball to E. Van Duzee, 1 September 1927, E. D. Ball Papers, Box 4, SIA 7121, Smithsonian Institution, Washington, D.C.

31. A. G. Butler to F. A. Dixey, 26 May 1917, Dixey Correspondence, Hope Library Archives, Oxford


University Museum of Natural History. Butler was seventy-three at the time.

32. Jordan, “An examination” (ref. 14), 445.

33. Edward Van Duzee to E. D. Ball, 17 August 1935, E. D. Ball Papers, Box 3, SIA 7121.

34. William Schaus to A. J. T. Janse, 1928, William Schaus Papers, Box 6, SIA RU007100.

35. Ernst Mayr, pers. com., November 2003.

36. Ernst Mayr to Karl Jordan, 11 March 1942, TM, Karl Jordan Correspondence (KJC) #5, NHM Archives.

37. Karl Jordan to Ernst Mayr, 29 April 1942, KJC #3, NHM Archives.


39. Ernst Mayr to Karl Jordan, 25 March 1942, KJC #3, NHM Archives.

40. Karl Jordan to Franz Steinicke, 27 January 1947, KJC #5, NHM Archives (translation).

41. Karl Jordan to Charles D. Radford, 17 December 1947, KJC #5, NHM Archives.

42. N. D. Riley to William Schaus, 4 June 1933, Schaus Papers, Box 10, SIA RU007100.

43. Michael A. Salmon, The Aurelian legacy: British butterfl ies and their collectors (Berkeley, 2000), 219.

44. Karl Jordan to Miles Moss, 13 February 1938, MSS MILES C 7:7, NHM Entomology Library.


46. Karl Jordan to Miles Moss, 4 May 1942, MSS MILES C 7:7, NHM Entomology Library.

47. Mary P. Winsor, Reading the shape of nature: Comparative zoology at the Agassiz Museum (Chicago, 1991), p. xiii.

48. Cain, “Ernst Mayr as community architect” (ref. 3), 416 and 417.

49. Ernst Mayr to Waldo Schmitt, 17 February 1948 and 9 March 1948, quoted in Cain, “Ernst Mayr as community architect” (ref. 3), 418.

50. Cain, “Ernst Mayr as community architect” (ref. 3), 419.

51. Harry Clench to Ernst Mayr, 21 December 1953, HUG(FP) 74.7, Box 2, Folder 531, Harvard University (HU) Archives.

52. Ernst Mayr to Harry Clench, 4 January 1954, HUG(FP) 74.7, Box 2, Folder 531, HU Archives.

53. Ernst Mayr to Harry Clench, 11 March 1954, HUG(FP) 74.7, Box 3, Folder 572, HU Archives. Title from Ernst Mayr to Eugene Munroe, 22 April 1954, HUG(FP) 74.7, Box 2, Folder 563, HU Archives.

54. Ernst Mayr to Harry Clench, 11 March 1954, HUG(FP) 74.7, Box 3, Folder 572, HU Archives.

55. B. Burma, “The species concept: A semantic review”, Evolution, iii (1949), 369–70, p. 370.

56. Ernst Mayr, “The species concept: Semantics versus semantics”, Evolution, iii (1949), 371–2.

57. Richard Meinertzhagen to Ernst Mayr, 16 February 1954, HUG(FP) 74.7, Box 2, Folder 540, HU Archives.

58. Ernst Mayr to Richard Meinertzhagen, 23 February 1954, HUG(FP) 74.7, Box 2, Folder 540, HU Archives.

59. E. O. Wilson and W. L. Brown, Jr, “The subspecies concept and its taxonomic application”, Systematic zoology, ii (1953), 97–111, pp. 106 and 108.

60. Ernst Mayr, “Notes on nomenclature and classifi cation”, Systematic zoology, iii (1954), 86–89.

61. Ernst Mayr to David Lack, 24 November 1954, HUG(FP) 74.7, Box 3, Folder 577, HU Archives.

62. Ernst Mayr to Richard Goldschmidt, 19 October 1954, HUG(FP) 74.7, Box 3, Folder 575, HU Archives.

63. Mayr, “Karl Jordan’s contributions” (ref. 1), 46.

64. Ibid., 50–53.

65. Ibid., 45.

66. For his previous historical work see Ernst Mayr, “Bernard Altum and the territory theory”,


Proceedings of the Linnaean Society of New York, xlv/xlvi (1935), 24–38, and “The naturalist in Leidy’s time and today”, Proceedings of the Academy of Natural Sciences of Philadelphia, xcviii (1946), 271–6.

67. Mayr, “Karl Jordan’s contributions” (ref. 1), 57.

68. Chung has described how Mayr’s use of a distinction between population and typological thinking was fi rst formulated in his 1955 essay on Jordan. See Carl Chung, “On the origin of the typological/population distinction in Ernst Mayr’s changing views of species, 1942–1959”, Studies in history and philosophy of biological and biomedical sciences, xxxiv (2003), 277–96.

69. Ernst Mayr, pers. com., November 2003.

70. Mayr, “Karl Jordan’s contributions” (ref. 1), 59 and 62.

71. Elwood Zimmerman to Ernst Mayr, 6 February 1955, HUG(FP) 74.7, Box 3, Folder 600, HU Archives.

72. Ernst Mayr to Miriam Rothschild, 21 March 1955, HUG(FP) 74.7, Box 3, Folder 596, HU Archives.

73. Ernst Mayr to Karl Jordan, 23 March 1955, HUG(FP) 74.7, Box 3, Folder 591, HU Archives.

74. Ernst Mayr to Theodore Just, 10 February 1955, HUG(FP) 74.7, Box 3, Folder 591, HU Archives.

75. Ernst Mayr to Detlev Bronk, NAS, 25 February 1956, HUG(FP) 74.7, Box 4, Folder 625, HU Archives.

76. Ernst Mayr to Kirtley F. Mather, 4 March 1958, HUG(FP) 74.7, Box 2, Folder 688, HU Archives.

77. Ernst Mayr to Kirtley F. Mather, 4 March 1958, HUG(FP) 74.7, Box 2, Folder 688, HU Archives.

78. Harry Hopkins to Ernst Mayr, 13 January, 1959, HU(FP) 74.7, Box 6, Folder 715, HU Archives.

79. Ernst Mayr, “Diffi culties and importance of the biological species concept”, in Ernst Mayr (ed.), The species problem (New York, 1974), 371–87, p. 371.

80. Ernst Mayr, “Species concepts and defi nitions”, American Association for the Advancement of Science, Publication no. 50 (1957), 1–22, p. 5.

81. Mayr, “Recent historiography of genetics” (ref. 7), 149. William Provine has pointed out that Mayr has often not given enough attention to naturalists’ non-adaptionist theories. See his “The development of Wright’s theory of evolution: Systematics, adaptation, and drift”, in Marjorie Greene (ed.), Dimensions of Darwinism (Cambridge and New York, 1983), 43–70.

82. Mayr, “Where are we?” (ref. 7), 3.

83. Ernst Mayr, “Isolation as an evolutionary factor”, Proceedings of the American Philosophical Society, ciii (1959), 221–30, p. 221.

84. Richard Goldschmidt to Ernst Mayr, undated, HUG(FP) 74.7, Box 3, Folder 575, HU Archives.

85. For example, Ernst Mayr to David Lack, 26 August 1941, HUG(FP) 74.7, Box 2, Folder 81, HU Archives.

86. Ernst Mayr to John Moore (Department of Zoology, University of Sydney), 15 February 1953, HUG(FP) 74.7, Box 1, Folder 499, HU Archives.

87. Ernst Mayr to Richard Goldschmidt (Department of Zoology, University of California, Berkeley), 14 September 1954, HUG(FP) 74.7, Box 2, Folder 558, HU Archives.

88. Richard Goldschmidt to Ernst Mayr, undated, HUG(FP) 74.7, Box 3, Folder 575, HU Archives.

89. Richard Goldschmidt, “Letter to Dr. Jordan”, Transactions of the Royal Entomological Society of London, 1955, 13–14, p. 13.

90. Ibid.

91. Mayr, “Karl Jordan’s contribution” (ref. 1), 45.

92. E. B. Poulton, “What is a species?”, Proceedings of the Entomological Society of London, 1904, pp. lxxvii–cxvi, p. ci.


93. Ernst Mayr to Richard Goldschmidt, 19 October 1954, HUG(FP) 74.7, Box 3, Folder 575, HU Archives.

94. Mayr, “Recent historiography of genetics” (ref. 7), 128.

95. Wilson and Brown, “The subspecies concept” (ref. 59), 99. Mallet notes that this paper “was enormously infl uential on systematics in the USA, and generations of systematists trained at Harvard and Cornell, where Wilson and Brown worked, and their own many intellectual descendants, and their students’ students in turn, have eschewed the practice of naming subspecies”. James Mallet, “Subspecies, semispecies, superspecies”, in S. Levin et al. (eds), Encyclopedia of biodiversity (New York, 2001), v, 523–6. Bock, by contrast, insists Wilson and Brown’s paper had little infl uence on systematists (Walter Bock, pers. com. 10 October 2004).

96. Wilson and Brown, “The subspecies concept” (ref. 59), 101.

97. William A. Gosline, “Further thoughts on subspecies and trinomials”, Systematic zoology, iii (1954), 92–94.

98. Curtis W. Sabrosky, “Postscript to a survey of infraspecifi c categories”, Systematic zoology, iv (1955), 141–2, p. 142. See “Entomological usage of subspecifi c names”, Entomological news, li (1940), 159–64 for his original survey.

99. Theodore H. Hubbell, “Entomology: The naming of geographically variant populations, or what is all the shooting about?”, Systematic zoology, iii (1954), 113–21, p. 114.

100. Ernst Mayr to Theodore H. Hubbell, 9 February 1954, HUG(FP) 74.7, Box 2, Folder 536, HU Archives.

101. Theodore H. Hubbell to Ernst Mayr, 17 February 1954, HUG(FP) 74.7, Box 2, Folder 531, HU Archives.

102. The discussion regarding subspecies, the use of trinomials, and infraspecifi c variation in general, continued into the following volumes of Systematic zoology, including defences by Andrew Starrett, Herbert M. Smith, Fred N. White, and S. Durrant. Arguments for trinomials and subspecies, with the recognition that such terms had come to mean different things depending on the class of organisms under consideration, were offered by J. W. Tilden, “Certain comments on the subspecies problem”, Systematic zoology, x (1961), 17–23, and others. Earlier commentaries can be found in Carl Otto Rosendahl, “The problem of subspecifi c categories”, American journal of botany, xxxvi (1949), 24–27.

103. For a more recent discussion among ornithologists regarding the usefulness or otherwise of subspecies, see the discussion “Forum: Avian subspecies in the 1980s”, in the 1982 issue of The auk.

104. Martin R. Honey and Malcolm J. Scoble, “Linnaeus’s butterfl ies (Lepidoptera: Papilionoidea and Hesperioidea)”, Zoological journal of the Linnean Society, cxxxii (2001), 277–399.

105. See Paul Lawrence Farber, “Theories for the birds: An inquiry into the signifi cance of the theory of evolution for the history of systematics”, in Margaret Osler and Paul Lawrence Farber (eds), Religion, science, and worldview: Essays in honor of Richard S. Westfall (Cambridge, 1985), 321–39.

106. I should emphasize that whether entomologists’ arguments against naming subspecies were valid or not is irrelevant to my argument that their concerns illustrate how non-conceptual factors have infl uenced what work was done. For an argument that the consideration of systematics practice should have no bearing on the value of the biological species concept, and that the latter can be assessed only through a consideration of its role within evolutionary theory, see Walter Bock, “Species: The concept, category and taxon”, Journal of zoological systematics and evolutionary research, xlii (2004), 178–90.

107. Karl Jordan to N. D. Riley, 12 December 1954, DF306/9, NHM Archives.

108. Miriam Rothschild to Ernst Mayr, 2 March 1955, HUG(FP) 74.7, Box 3, Folder 596, HU Archives.


109. See John C. Greene, “From Aristotle to Darwin: Refl ections on Ernst Mayr’s interpretation in The Growth of Biological Thought”, Journal of the history of biology, xxv (1992), 257–84; and Thomas Junker, “Factors shaping Ernst Mayr’s concepts in the history of biology”, Journal of the history of biology, xxix (1996), 29–77. Various perspectives are also given in the numerous reviews of The growth of biological thought, discussed in Michael Ruse, “Admayration”, Quarterly review of biology, lx (1985), 183–92. For critiques of Mayr’s description of pre-Darwinian systematics as typological, see Paul Lawrence Farber, “A historical perspective on the impact of the type concept on insect systematics”, Annual review of entomology, xxiii (1978), 91–99; idem, “The type concept in zoology during the fi rst half of the nineteenth century”, Journal of the history of biology, ix (1976), 93–119; Peter F. Stevens, “Why do we name organisms? Some reminders from the past”, Taxon, li (2002), 11–26; and Mary P. Winsor, “Non-essentialist methods in pre-Darwinian taxonomy”, Biology and philosophy, viii (2003), 387–400.

110. Phillip R. Sloan, “Essay review: Ernst Mayr on the history of biology”, Journal of the history of biology, xviii (1985), 145–53, pp. 146–7. Also see Richard W. Burkhardt, Jr, “Ernst Mayr: Biologist-historian”, Biology and philosophy, ix (1994), 359–71 on Mayr’s use of history “to illuminate and advance a contemporary biological issue” (p. 362). Burkhardt also takes Mayr to task, in the case of his analysis of Lamarck, for not refl ecting more on the role of Lamarck’s practice as a cabinet naturalist in infl uencing his theoretical judgements (p. 365). Also see John Beatty, “The proximate/ultimate distinction in the multiple careers of Ernst Mayr”, Biology and philosophy, ix (1994), 333–56.

111. Ernst Mayr, “When is historiography Whiggish?”, Journal of the history of ideas, li (1990), 301–9, p. 305.

112. Mayr, “The recent historiography of genetics” (ref. 7), 128.

113. Greene, “From Aristotle to Darwin” (ref. 109).

114. Essays in Mayr and Provine (eds), The evolutionary synthesis (ref. 7); William B. Provine, The origins of theoretical population genetics (Chicago, 1971); “Francis B. Sumner and the evolutionary synthesis”, Journal of the history of biology, iii (1979), 211–40; and idem, “The role of mathematical population geneticists in the evolutionary synthesis of the 1930s and 1940s”, Studies in the history of biology, ii (1978), 167–92. Mayr restates his synthesis story in “What was the evolutionary synthesis?”, Trends in ecology and evolution, viii (1992), 31–34, and, most recently, in “80 years of watching the evolutionary scenery”, Science, cccv (2004), 46–47.

115. Garland E. Allen, Life science in the twentieth century (New York, 1975), and “Naturalists and experimentalists: The genotype and the phenotype”, Studies in the history of biology, iii (1979), 179–209. See also David Magnus, “Theory, practice, and epistemology in the development of species concepts”, Studies in history and philosophy of science, xxvii (1996), 521–45. Since the early eighties, historians have usefully qualifi ed this experimentalist–naturalist dichotomy in various ways. Most recently see Mark A. Largent, “Bionomics: Vernon Lyman Kellogg and the defense of Darwinism”, Journal of the history of biology, xxxii (1999), 465–88; and Alison Kraft and Samuel J. M. M. Alberti, “‘Equal though different’: Laboratories, museums, and the institutional development of biology in late-Victorian northern England”, Studies in history and philosophy of biological and biomedical sciences, xxxiv (2003), 203–36.

116. Chung, “On the origin of the typological/population distinction” (ref. 68), 292. Chung examines how Mayr’s 1955 paper accomplished this by establishing a new major contrast between the typological species concept on the one hand and the two biological concepts (the non-dimensional species concept of the old naturalists, and the multidimensional one of the new) on the other, and so unifi ed what had been in fact disparate concepts of species.

117. Ernst Mayr, “Systematics: The role of systematics in the evolutionary synthesis”, in Mayr and Provine, The evolutionary synthesis (ref. 7), 123–36, p. 123.

118. For additional important studies on the history of systematics, see the works by Haffer (ref. 10),


Hagen (ref. 6), and Farber (refs 105 and 109) cited above, and: Mary P. Winsor, Starfi sh, jellyfi sh and the order of life (New Haven, 1976); idem, “Louis Agassiz and the species question”, Studies in history of biology, iii (1979), 89–117; idem, “The impact of Darwinism upon the Linnaean enterprise, with special reference to the work of T. H. Huxley”, in John Weinstock (ed.), Contemporary perspectives on Linneaus (New York, 1985), 55–84; idem, Reading the shape of nature (ref. 47); and Pamela M. Henson, “Evolution and taxonomy: John Henry Comstock’s research school in evolutionary entomology at Cornell University, 1874–1930”, Ph.D. dissertation, University of Maryland, 1990.

119. Michael Ruse. “Booknotes”, Biology and philosophy, ix (1994), 429–35, p. 430.

120. By contrast, Cain points out that Mayr’s fi rsthand knowledge about intraspecifi c and geographic variation also arose from his research in the “excellent collections at the American Museum” (Cain, “Common problems and cooperative solutions” (ref. 3), 19). Walter Bock also provides a detailed analysis of how Mayr’s 1942 book and his subsequent theoretical work cannot be understood without taking into account the empirical foundation of this work, namely, to curate and study the huge collections at the American Museum of Natural History. See Walter J. Bock, “Ernst Mayr, naturalist: His contributions to systematics and evolution”, Biology and philosophy, ix (1994), 267–327.

121. Ruse, “Booknotes” (ref. 119), 433.

122. Ernst Mayr, Systematics and the origin of species from the viewpoint of a zoologist (New York, 1942), p. xii.

123. Ibid., 4.

124. Ernst Mayr to Waldo Schmitt, 9 March 1948, quoted in Cain, “Ernst Mayr as community architect” (ref. 3), 418.

125. For example, see Mayr, “Diffi culties and importance of the biological species concept” (ref. 79).

126. Ernst Mayr, “Fifty years of progress in research on species and speciation”, Proceedings of the California Academy of Sciences, xlviii (1993), 131–40, pp. 133–4.

127. See Ernst Mayr and P. D. Ashlock, Principles of systematic zoology, 2nd edn (New York, 1991), 100–5.

128. Ernst Mayr, “Of what use are subspecies?”, The auk, xcix (1982), 593–5, p. 594.

129. Ernst Mayr, “A defense of the biological species concept”, in Quentin D. Wheeler and Rudolf Meier (eds), Species concepts and phylogenetic theory: A debate (New York, 2000), 161–6, p. 161. Stevens notes that this tension between the extrapolation from the biological species concept to taxonomic species pervades Mayr’s work, and that subspecies nomenclature was justifi ed on evolutionary, rather than pragmatic, grounds. Peter F. Stevens, “Species: Historical perspectives”, in Evelyn Fox Keller and Elisabeth A. Lloyd (eds), Keywords in evolutionary biology (Cambridge, MA, 1992), 302–11, p. 306.

130. Ernst Mayr to Harry Hopkins, 28 January 1959, HUG(FP) 74.7, Box 6, Folder 715, HU Archives.

131. See Paul Ehrlich, “Has the biological species concept outlived its usefulness?”, Systematic zoology, x (1961), 167–76. Mayr notes, however, that Ehrlich later became a strong supporter of the biological species concept (Ernst Mayr, pers. com., 8 August 2004). On the debates over systematics see Part I of David Hull, Science as process: An evolutionary account of the social and conceptual development of science (Chicago, 1988) and the works by Hagen (ref. 6) and Vernon (ref. 4). The latter notes that one of the problems inspiring numerical taxonomists was that data on breeding structure and geographic distribution necessary for evidence of evolutionary relationships were usually unknown, and that the primary evidence was therefore still morphological resemblance. See Keith Vernon, “The founding of numerical taxonomy”, The British journal for the history of science, xxi (1988), 143–59, p. 146.

132. Coyne claims that much of the anti-biological species concept literature “leaves the solid ground of biology for the marshy hinterlands of philosophy”. See Jerry A. Coyne, “Ernst Mayr and the


origin of species”, Evolution, xlviii (1994), 19–30, p. 22.

133. Paul Lawrence Farber, Discovering birds: The emergence of ornithology as a scientifi c discipline: 1760–1850 (Baltimore, 1997; originally published London, 1982), p. x, and Farber, “Theories for the birds” (ref. 105). Also see Winsor, “The impact of Darwinism” (ref. 118), 84.

134. For a manifesto to including variation as an analytical category in the historiography of the life sciences on several levels, both organismal and cultural, see Gerald L. Geison and Manfred D. Laubichler, “The varied lives of organisms: Variation in the historiography of the biological sciences”, Studies in history and philosophy of biological and biomedical sciences, xxxii (2001), 1–29.

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