Encyclopedia Entry on Nineteenth-century Science and Religion

Paul Jerome Croce

SCIENCE AND RELIGION

essay in the Encyclopedia of American Cultural and Intellectual History (Scribner's, 1999) for the section on Antebellum, Civil War, and Reconstruction: 1838-1877

The strained relationship between science and religion in the middle of the nineteenth century presented Americans with one of their first challenges in diversity. During the first half of the century, all human knowledge was widely regarded as comfortably integrated, and the social overlap of scientists and religious thinkers along with the harmony of reflections about nature and the divine were powerful glues at the core of this synthesis. However, by the end of the century, scientific inquiry developed theoretical justifications and institutional structures separate from religious realms. The bloom of intellectual and cultural diversity that emerged in the wake of these independent inquiries (both to support science and then in reaction to it), and that have exploded in the twentieth century, began with the breakup of harmony between science and religion from the 1830s to the 1870s. This fissure was the modern precursor of the contemporary split between the "two cultures," as C. P. Snow famously called the humanities and the sciences in the twentieth century, and the motherload of our modern pluralism.

The introduction of Darwinism and the widespread influence of evolutionary theories after the 1859 publication of The Origin of Species set the terms of debate about science and religion in the ensuing decades. Despite a widespread perception of the warfare of science and religion generated by the theory of species development based on natural selection, the conflict motif was actually only one major view among many in the 1860s and 1870s. At least as important as the irreligious scientific naturalism of Darwinism was the probabilistic nature of his hypothesis and his method of inquiry. And on both fronts--the content and the methods of Darwinism--its revolutionary impact developed force because of gradual changes in science as practiced over the preceding decades.

There have been two major interpretations of the relation of science and religion in the nineteenth century. The traditional view, emerging even at the time, was that the two fields were at war with each other, with enlightened, rational science vanquishing obscurantist religion. The dramatic clarity of John William Draper, History of the Conflict between Religion and Science (1874) and Andrew Dickson White, A History of the Warfare of Science with Theology in Christendom (1896) was so forceful that it still shapes popular views as the folk wisdom of our culture concerning science and religion. A recent revisionist trend, however, emphasizes that many scientists retained their religious beliefs and that many religious believers welcomed new scientific theories; this more recent view expands the separation between science and religion into a spectrum. Although there were a fair number of scientific boosters and religious traditionalists on either end who hoped--or we might even say, hoped and prayed--for the warfare motif to justify their own polarized position, the conventional wisdom now maintains that a general harmony prevailed between science and religion at least until the early twentieth century. And yet that harmony was often hard won, and it went through two major phases.

Until about 1860, science and religion were widely perceived to be in harmony, although the increasingly separate practices of science and religion made reconciliation of their insights more and more difficult. After 1860, tensions between science and religion increased, with a few intellectuals trumpeting the change and most striving mightily to retain the harmony. Meanwhile, changes in the methods of science suggested new paths to reconciliation of science and religion through their mutual uncertainty. These remained as hints, unrecognized by most, but gathering force for further development in the twentieth century.

The nineteenth-century emphasis on harmony between science and religion was in some ways a response to the Enlightenment. The most radical, anti-clerical phases of the intellectual movement to expand the influence of human reason never gained much of a foothold in America. More Americans sympathized with the Scottish Common Sense phase of the Enlightenment, which emphasized trust in the untutored natural ability of the human mind and heart to discover the true and the good, and which encouraged the moderate belief that science and urbanity could support the more humble drives for religion and morality. What Henry May has called the Didactic Enlightenment encouraged inquiry into the natural world on the model of Francis Bacon's empiricism, which emphasized fact-gathering and caution in proposing theories. Proponents of the didactic perspective treated the facts of nature as evidence for the designing hand of the divine following the natural theology of William Paley. By the early nineteenth century, religious leaders, although aware of the radically anti-religious potential in the Enlightenment, found they could reverse its secular thrust by actually enlisting science to support religion. Boasting about the "altered tone of science," Lewis Green, minister and president of Hampden-Sydney College, said in 1842, "The whole spirit of physical investigation has been revolutionized in the present century; and ... the stupid Atheistic Materialism of the last century, has almost totally disappeared."

The religious enthusiasm for science coincided with more secular attitudes because science was also welcomed as a source of patriotic pride and a tool for economic growth. New knowledge of the natural world flooded in with the reports of travel and settlement in the west, and technological innovations helped to spark America's great economic growth. Throughout this period, however, science had only a minimum of institutional infrastructure with the founding of the American Journal of Science and Arts in 1819 and a few scientific schools (notably Rensselaer Institute, Troy, NY, founded in 1824; Yale's Sheffield Scientific School, 1846; and Harvard's Lawrence Scientific School, 1847). By contrast schools and departments for the training of young scientists flourished after 1860, spurred by the demands of the Civil War and of industrial growth in the ensuing years. More common in the earlier period were the local scientific and natural history societies and lyceums, which were havens for serious but amateur scientific inquiries by professional men with scientific curiosity. With the gender specializations of the time, woman gravitated toward the writing of children's primers, scientific illustrations, and popularizations, and these often served as scientists' first enthusiastic steps in their fields. Religion's place in this form of science was wary and watchful, curious but not overtly critical.

With the growth of scientific knowledge and the first pressures toward specialization, the local societies proved inadequate by the 1840s. National organizations, including the Smithsonian Institution and the American Association for the Advancement of Science, established professional standards, encouraged research presentations and publications, and in general promoted the "increase and diffusion" of scientific knowledge as the Smithsonian charter put it. The government, most notably the Coast Survey (whose name changed to the Coast and Geodetic Survey in 1878) employed one third of ante-bellum scientists. In addition, colleges added prominent scientists to their faculty. For example, Harvard hired the prolific and influential botanist Asa Gray in 1842 and persuaded the Swiss geologist and zoologist Louis Agassiz to move across the Atlantic in 1848. Although very different personally and their contrasting approaches to science would take them to opposite sides of the debate over Darwinism, they were both deeply religious and shared the view that scientific research offered no threat to religious belief.

Meanwhile, evangelical religion of the time did not resist science, but instead was either indifferent or quietly supportive of the design argument. Charles Grandison Finney, for example, said flatly that "studying science is studying the works of God." Nature understood by science provided evidence for Christianity, which contributed to the public authority of Christian churches. And non-scientific intellectuals, such as the Transcendentalists, the diverse followers of Emanuel Swedenborg's spiritual philosophy, and other romantic thinkers, following Ralph Waldo Emerson's maxim that "every natural fact is a symbol of some spiritual fact," assumed that investigation of the natural world would support religious insight. These romantic thinkers were in the vanguard of a revolution against Baconian science, and its complement in religion, natural theology, which looked to the orderly empirical facts of nature for proof of the divine. But while their German-inspired idealism was philosophically opposite to empiricism, it reinforced the same theme of harmony between science and religion, albeit on different terms. In place of emphasizing factual evidence, romantic thinking effectively domesticated the harsh proofs of science by proposing that the complicated results of scientific pursuit were actually part of the wonders of the natural world and the awesome workings of the divine. Henry David Thoreau represented another stream of romanticism in his blending empiricism and idealism, which linked science and religion through his spiritual but factual natural history investigations, conducted in the spirit of German polymath scientist Alexander von Humboldt's empirical naturalism.

For all their disagreements, practitioners of science and religious adherents, empiricists and idealists shared the conviction that scientific work would not conflict with the essential truths of religion. Aware that some still "kept distrustful eyes on science," mineralogist and geologist James Dwight Dana was confident that it would bring "new revelations of profound truths direct from God's works." Theologian James Henley Thornwell said, "Geology and the Bible must kiss and embrace each other, and ... [t]he earth can never turn traitor to its God."

Religious leaders were generally even more enthusiastic than scientists about science's support of religion. For scientists, religious connections were becoming more like rhetorical ornaments placed at the introduction and conclusion of scientific addresses. Their religious beliefs, while personally welcome, were becoming increasingly irrelevant to the actual work of scientific research. For example, Gray heard Agassiz lecture on his triumphal visit to the United States the year before he was hired at Harvard, and noted that the pious zoologist's "references to the Creator were so natural and unconstrained as to show that they were never brought in for effect." Although he was a strong religious believer, he could not accept religious references applied just for pious show.

The ebbing away from religion came gradually, and when antireligious conclusions were made explicit in the 1840s, most scientists readily defended religion's harmony with their fields of inquiry. In 1844, Englishman Robert Chambers argued for the evolutionary change of species in The Vestiges of Creation. He published it anonymously in rightful expectation of hostility for its purely material explanations. The book's reception gave Darwin himself caution about publishing his more thorough and persuasive account of species development.

Just as scientific investigations were conducted without reference to science, so too did religious believers become more distant from science. The increasingly privatized religion of the heart in the early to middle nineteenth century was the culmination of the Reformation assault on the institutional church, the eighteenth-century evangelical impulse, and the special challenges of churches in the New World where religious believers generally worked through voluntary organizations, but resisted the more formal hierarchies of European culture. Sentimentalized religion, with close ties to the feminization of the middle-class, was not overtly antagonistic to science, but left little reason for a religious interest in science; on the contrary, it suggested a strict separation of science and sentiment, echoing the separate spheres of men and women. Although religious believers tacitly assumed scientific support of religious belief, most simply ignored the insights of science and paid little attention to its gradual steps away from religion.

Although average believers were moved by private feelings and religious sentiments, religious intellectuals and church leaders worried more about their connection to science. They noticed the growth of scientific knowledge, recalled the more radical phases of the Enlightenment, and felt moved to reconcile science with traditional doctrine. Intellectuals at Princeton or New Haven, for example, had more motivation than the typical churchgoer to connect their religion to the hopes for harmony that science might be able to offer. Their apologetics offered a twist on an old intellectual tradition in the Western world. In place of arguing for the compatibility of science and religion based on unquestioning faith in divine existence and providential governance of the world, mid-nineteenth-century intellectuals were so aware of fundamental doubts that they felt they could no longer rely on assumptions of faith, but instead searched anxiously for scientific proofs of religion. Their quest for a faith with scientific certainty dovetailed with the passionate assurances then appearing in other parts of American religion and culture, including the millennial zeal of revivalists, the earnest creation of new religions, and the fierce call for manifest destiny.

Darwin's theory of species development through natural selection and the enthusiasm for professional and nonreligious science that came in its wake, brought the religious leaders' worst fears to life. Building the argument for species change on the analogy with selective breeding of domesticated species and supporting it with an abundant array of facts from the burgeoning sciences of botany, embryology, geography, geology, morphology, physiology, and zoology, Darwin's theory presented a fundamental challenge to the conventional wisdom about harmony between science and religion. First, the presentation was wholly naturalistic, without a place for the divine or even any religious flourishes; second, with the struggle for existence as the engine of change, Darwinism implied a world without mercy and morality; and third, the central hypothesis was presented as a plausible explanation but not a proof. The theory of natural selection operated in a different conceptual universe from the urge to find proof for religion in the benign facts of nature.

In the context of the earlier generation's commitment to certainty, Darwin's theory of natural selection was both religious and scientific heresy. With its attention to constant change and minute variations within species pools, the scientific "heresy" produced new paths for research spurring investigation into vast eons of time, exploration of broad expanses of geography, and close attention to details in individual creatures. In suggesting and justifying large amounts of new inquiry into nature, Darwinism reinforced trends toward professionalization and specialization in the sciences.

Although Darwinism was greeted with some spirited scientific resistance, most notably from Louis Agassiz, and was honored more in general as evolutionism than for its particular arguments, its success coincided with a great upsurge of institution-building in higher education. By the 1870s, some of the leading colleges took the first steps along these lines: chemist Charles Eliot became president of Harvard in 1869 and emphasized scientific training as part of the buildup of a strong masculine character in preparation for cultural leadership; and after training at Yale's Scientific School and serving as president of the University of California, Daniel Coit Gilman in 1876 became president of the Johns Hopkins University, which pioneered by prioritizing research, especially in science, instead of undergraduate education. Even outside universities, science became a point of widespread public curiosity and respect by the 1870s, as evidenced by the publication of Appleton's Journal "for scientific news" (from 1867) and Popular Science Monthly (from 1872), the creation of scientific columns in Harper's (from 1869) and Galaxy (from 1871), and the addition of the word "science" to the subtitle of the Atlantic.

Religious figures were slower to respond to Darwinism. Taking heart from the scientific opponents to Darwinism during the 1860s, many religious leaders treated it as a tempest in a scientific teapot. Applying the logic of the previous generation in reverse, they assumed that any theory that did not reinforce religious belief must not be good science. In addition, although the Civil War promoted institution building in science, it inhibited serious reflection on science and its implications.

By 1870, with evolutionism entrenched in scientific circles, religious thinkers finally turned their attention to the theological implications of the "transmutation hypothesis." Only at this point did religions even begin to separate in response to Darwinism, on paths that have become the polarized mainstays of twentieth-century American religion. Comparing Darwin's hypotheses with the ideal of Baconian empiricism and also horrified with the purely naturalistic amorality of the theory, conservatives rejected Darwinism on scientific and religious grounds. For example, the Episcopal clergyman and University of Pennsylvania Provost Daniel Goodwin wrote scathingly that the "theory and all its possibilities are no better proof than the dream of an inebriate or the visions of a madman."

Asa Gray took the lead for a blending of Darwinism and religion. Not concerned with the naturalistic displacement of God from Providential action and primary causes, he retained a picture of the divine as a mysterious reclusive force, like a hidden, forceful wind behind all worldly action; "natural selection is not the wind," Gray argued, "but the rudder which ... shapes the course." These religious words from a scientist supported liberal theologians such as Henry Ward Beecher and James Woodrow who presented evolution as God's approach to the creation and governance of the world. This religious school of thought aligned with late nineteenth-century professional scientists who, while geology and physics provided no clear evidence for the fabulous time spans required for the operation of natural selection, and before the reinforcement of the theory of natural selection with genetic science in the twentieth century, were more likely to endorse evolutionism without Darwinism. For scientists and liberal theologians, evolution was a way of comprehending progress in nature and society, and it was often construed as a form of Lamarckian inheritance of acquired characteristics. American Neo-Lamarckians depicted evolution on a shorter time span and with more optimistic opportunities for voluntary improvement than were allowed with the chance mutation and inheritance mechanisms of Darwinism.

Most supporters of evolution treated innovations in science, including Darwinism, as fully authoritative or even certain. After all, science had the prestige of professional status, and it was associated with the marvelous technological innovations that thrilled the average citizen. But scientists themselves increasingly treated their theories as Darwin did: as hypotheses. Darwin himself wrote in a letter to fellow scientist Gray, that he sought throughout his theory "to establish a point as a probability by induction and to apply it as hypotheses to other parts and see whether it will solve them."

Two young students of science at Harvard in the 1860s, Charles Sanders Peirce and William James, noticed this core of uncertainty beneath the social confidence of science. As early as 1868, James wrote that Darwin's theory "at best helps to accumulate a probability," but he recognized that "the great value of the hypothesis [is] in setting naturalists to work.... It is doubtless provisional, but none the less serviceable for that." And in 1877, Peirce wrote with more logical precision that Darwinism is a result of the "statistical method applied to biology" because "Darwin, while unable to say what the operation of variation and natural selection in any individual case will be, demonstrates that in the long run they will, or would adapt animals to their circumstances." Out of their youthful discussions about the nature and methods of science, especially Darwinism, in the 1860s and 1870s, Peirce and James developed the theory of pragmatism, although it did not take on that name publicly until 1898. Before it was a name, pragmatism grew in the shadow of Darwinism, from a recognition of the uncertain and therefore hypothetical and constructed but also useful nature of science; and in the context of mid-nineteenth-century debates about the relation of science and religion, pragmatism emerged as a new way to reconcile science and religion. While it avoided the early-nineteenth-century expectation of harmony between the two fields based on their mutual certainty, pragmatism inaugurated a tradition that embraced modern science and drew parallels between its methods and the character of religious belief--based on their mutual uncertainty.

In the early nineteenth century, scientific and religious truths were usually presented in terms of proof and certainty. However, by the end of the century, propositions in these fields had fewer universal assurances: hypotheses qualified the expression of scientific theories; liberal religious commentators used the language of metaphor and ambiguity; and conservatives held on to the methods of the earlier generation. During the middle of the century, not only did the practice of science and religion reach a fundamental separation, but also the seeds were planted for the liberal-conservative split in religious views of science over the question of how much certainty was required to sustain belief. And so, the warfare of science and religion was not wholly inaccurate, but rather it was a polemical, popularized exaggeration of a very real trend. Meanwhile, professional students of science and religion embraced the uncertainty of steady inquiry and ambivalence in each field, while most of the public was still eager for scientific proof and religious assurance. This fraying of the culture over fundamental truths broke the edifice of consensus in nineteenth-century American culture and cracked the expectation of uniformities in thought and culture. And into breach created by the changing relations of science and religion, countless other intellectual and cultural diversities followed.

Sidebar on Louis Agassiz (1807-1873)

Louis Agassiz was a professor of natural history at Neuchâtel in Switzerland when the Lowell Institute invited him to Boston. His spotting of glacial action on first arriving in America set the tone for his quarter century of enthusiastic leadership of American science: "I sprang on shore and ... was met by the familiar signs, the polished surfaces, the furrows and scratches, the line engravings of the glacier ... and I became convinced ... that here also this great agent had been at work."

In 1846, Agassiz was already world famous for his vast knowledge and encyclopedic classification of fish (his special expertise) and the whole animal kingdom, and for his theory of glacial action during an ancient ice age. His special appeal in America, where his lectures were even hawked on street corners, was his idealistic, religious approach to science. Glaciers were "God's great plough" clearing landscapes to make room for special creations, and as Ralph Waldo Emerson said, "he made anatomy popular by the aid of an idea"--the conviction that the whole natural world was organized by divine plan.

Agassiz's theory of special creation made him an odd bedfellow with Southern pro-slavery advocates when he theorized that blacks were created separately from whites. He maintained his loyalties to his adopted city, however, and was a vigorous Unionist during the Civil War. Darwin's theory of natural selection clashed directly with his theories of glacial action and the fixity of species in their current terrain. However, his enthusiasm inspired nonscientific amateurs and a whole generation of late-nineteenth-century scientists--many of whom, such as Joseph LeConte, blended his idealism with evolutionism in the development of American Neo-Lamarckianism. Agassiz himself, however, resisted the tide of scientific opinion and firmly rejected Darwinism and evolutionism for the rest of his life.

Sidebar on Cholera Epidemics: Divine Punishment or Natural Disaster?

After 1817, cholera became a global disease, spreading from local pockets in the Far East, first to Persia and Russia, and then across Europe to the Americas and the rest of the world. It was an unwelcome stowaway with the vast migrations of people in the nineteenth century and improvements in the transportation and marketing of goods. Urban centers, with their large concentrations of people, but not yet with public health standards or even much order in public works, were fallow fields for the epidemics that swept in periodically through the century. And it was a reaper not only grim, but also swift and lurid, turning it victims cold and darkened, with painful cramps and thorough dehydration--all in the span of as little as one day. Before the isolation of the organism causing cholera, Vibrio comma, by the German physiologist Robert Koch in 1883, the disease was wholly mysterious and terrifying, and it inspired a broad range of religious and scientific explanations.

In 1832, 1849, and 1866, the United States suffered three major outbreaks of cholera, and as historian Charles Rosenberg points out, the cultural responses to the disease serve as a microcosm of secularizing trends over these decades. One minister, in "A Sermon Preached August 3, 1832, A Day Set Apart in the City of New-York for Public Fasting, Humiliation and Prayer ..." regarded cholera as a "scourge, a rod in the hand of God." Although liberals objected to this stern talk, they retained a place for the divine in their explanations, even if they assumed that God operated exclusively through secondary laws.

The argument about natural laws controlling even God's will gained still more adherents by 1849. Spiritual and physical concerns about the spread of the disease mingled, for example, in a New Bedford newspaper editorial: "Prayer, without at the same time forsaking sin and doing right, is an utter mockery, and deserves a curse. We must now cleanse and purify ourselves." There was growing concern, as the president of the Wisconsin State Medical Society lamented, about human "ignorance of the nature and the character of the pestilence." Distinct impressions were forming that concentrations of filth and unwashed food contributed to the spread of cholera, but efforts to combat the disease, whether from religious or scientific circles, were utterly powerless. This contributed not only to secularization, but also to skepticism about the medical profession and to the growth of nonmainstream medical systems, especially hydropathy and homeopathy, which were gererally more successful than "regular practitioners" in combatting the disease.

When the scourge returned in 1866, there was still no cure, but there was some hope for prevention of its spread. The medical profession, bolstered by the organization of the Sanitary Commission during the Civil War and reinforced by scientific studies of contamination in food and water supplies, set up Boards of Health, first in New York, for the reform of public health in the degraded urban centers. There was now almost no public mention of religion in relation to cholera, except those who, like one Methodist preacher, proposed that he could not minister to "the souls of man ... while their bodies are thus crowded and packed in such filthy abodes." This shows the eagerness during this era to enlist mankind in God's work, and yet there is no assumption of divine Providence guiding the course of the world.

In thirty-four years, cholera had shifted in the public imagination from a spiritual crisis to a social problem.

Bibliography

Books:

Bozeman, Theodore Dwight Protestants in an Age of Science: The Baconian Ideal and Antebellum American Religious Thought. Chapel Hill: University of North Carolina Press, 1977.

Bruce, Robert V. The Launching of Modern American Science, 1846-1876. New York: Alfred A. Knopf, 1987.

Burnham, John C. How Superstition Won and Science Lost: Popularizing Science and Health in the United States. New Brunswick: Rutgers University Press, 1987.

Cashdollar, Charles D. The Transformation of Theology, 1830-1890: Positivism and Protestant Thought in Britain and America. Princeton: Princeton University Press, 1989.

Conser, Walter H., Jr. God and the Natural World: Religion and Science in Antebellum America. Columbia: University of South Carolina Press, 1993.

Croce, Paul Jerome Science and Religion in the Era of William James, Volume One: Eclipse of Certainty, 1820-1880. Chapel Hill: University of North Carolina Press, 1995.

Cummings, Sherwood Mark Twain and Science: Adventures of a Mind. Baton Rouge: Louisiana State University Press, 1988.

Daniels, George H. American Science in the Age of Jackson. New York: Columbia University Press, 1968.

Dupree, A. Hunter Asa Gray: American Botanist, Friend of Darwin. Baltimore: Johns Hopkins University Press, 1988.

Fleming, Donald John William Draper and the Religion of Science. Philadelphai: University of Pennsylvania Press, 1950.

Hawkins, Hugh Between Harvard and America: The Educational Leadership of Charles W. Eliot. New York: Oxford University Press, 1972.

Hovenkamp, Herbert Science and Religion in America, 1800-1860. Philadelphia: University of Pennsylvania Press, 1978.

Hull, David L. Darwin and His Critics: The Reception of Darwin's Theory of Evolution by the Scientific Community. Chicago: University of Chicago Press, 1973.

Kohlstedt, Sally Gregory The Formation of the American Scientific Community. Urbana: University of Illinois Press, 1976.

Kucklick, Bruce Churchmen and Philosophers: From Jonathan Edwards to John Dewey. New Haven: Yale University Press, 1985.

May, Henry The Enlightenment in America. New York: Oxford University Press, 1976.

Moore, James R. The Post-Darwinian Controversies: A Study of the Protestant Struggle to Come to Terms with Darwin in Great Britain and America, 1870-1900. New York: Cambridge University Press, 1979.

Rabinowitz, Richard The Spiritual Self in Everyday Life: The Transformation of Personal Religious Experience in Nineteenth-Century New England. Boston: Northeastern University Press, 1989.

Rosenberg, Charles The Cholera Years: The United States in 1832, 1849, and 1866. Chicago: University of Chicago Press, 1987.

Stevenson, Louise Scholarly Means to Evangelical Ends: The New Haven Scholars and the Transformation of Higher Learning in America, 1830-1890. Baltimore: John Hopkins University Press, 1986

Turner, James Without God, Without Creed: The Origins of Unbelief in America. Baltimore: John Hopkins University Press, 1985.

Snow, C. P. The Two Cultures and the Scientific Revolution [The Rede Lecture, 1959]. New York: Cambridge University Press, 1961.

Edited Collections:

Lindberg, David C., and Ronald L. Numbers God and Nature: Historical Essays on the Encounter Between Christianity and Science. Berkeley: University of California Press, 1986.

Oleson, Alexandra, and Sanborn Brown, eds. The Pursuit of Knowledge in the Early Republic: American Scientific and Learned Societies from Colonial Times to the Civil War. Baltimore: Johns Hopkins University Press, 1976.

Article:

Kohlstedt, Sally Gregory "Parlors, Primers, and Public Schooling: Education for Science in Nineteenth-Century America." Isis 81, no. 308 (1990), 425-45.

Illustrations

Louis Agassiz, late in life, portrait by A. Tonrel, Boston: in possession of the Hunt Institute for Botanical Documentation, Carnegie Mellon Univeristy

Asa Gray, 1865: in possession of the Archives of the Library of the Gray Herbarium, Harvard University