This dissertation on late Enlightenment poetics and the history of the biomedical sciences unfolds a lapsed possibility near the historical beginnings of the division of labor between literary and scientific representation. Against the pressure, then and now, to treat the culture of science as context or antithesis to literary production, I recover a countervailing epistemology that cast poetry as a privileged technique of empirical inquiry: a knowledgeable practice whose figurative work brought it closer to, not farther from, the physical nature of things.In his late life science, Morphology, Goethe mischievously re-signified "objectivity" to mean an observer's vulnerability to transformation by the objects under view: "every new object, well seen, opens up a new organ in us." Such a gesture at once opens the scene of experiment to the agency of objects, and shifts biology's question from the life force within beings, to the metamorphic relations between them. From Wordsworth's call for a "science of the feelings," to Blake's for a "sweet Science," and Goethe's for a "tender Empiricism," my project argues for a series of late Enlightenment attempts to re-invent empiricist methodology - and to do so with the resources of verse and figure. These revisionary poetic sciences, I argue, challenged early biological and aesthetic protocols to countenance the mutual, material influence between the subjects and objects of experiment; to represent `bare' sensation as itself vulnerable to social and rhetorical transformation; and to position vulnerability - to impression, influence, and decay - as central, not inimical, to life.I show that writers from James Thomson and Erasmus Darwin to Percy Shelley retrieved Lucretius's classical materialism as a model for describing bodies (textual and animal) as porous assemblages, shaped by losses and incorporations of what is not self, and not immediately present. In Lucretius's De Rerum Natura, all things, decaying in time, scatter fine atomic husks from their bodies: simulacra, figurae, imagines. Here `figures' are fractions of the real estranged from their sources, and all bodies, not just poets or their language, produce them. Such an epistemology afforded poetry a strong claim upon the real, and proved particularly fit to connect the epochal interest in living bodies to the period's new sense of its own historicity. Poets deployed Lucretius's atomist imaginary in order to make historical experience palpable as what Wordsworth called an "atmosphere of sensation." The material tropes they mobilized to do so, I argue, have been unrecognizable through the symbol-allegory paradigm that controls most rhetorical readings of romanticism.Such a view of the period's philosophy of life differs from a more frequent argument, whereby romantic poetics and early biology converge in the ideal of organism or artwork as self-sufficient whole, "both cause and effect of itself" - and the ideal of life or imagination as the "power" productive of such wholes. This Kantian and Coleridgean ideal of "organic form," I argue, has overshadowed our critical understanding of what the late Enlightenment poetics of life might have sought to do. Working through the tense collaboration between the Poet and the Man of Science in Wordsworth's 1800 "Preface" to Lyrical Ballads and in Blake's notion of "sweet Science" (The Four Zoas,1797), my introduction extracts two critical lenses - "matter figures back," and "atmospheres of sensation" - with which to discern the rival epistemology described in the dissertation's four body chapters. In chapters that center on, and move outward from, Goethe's poetic biology (1-2) and Shelley's "poetry of life" (3- 4) I show how a neglected strain of materialist natural curiosity sought to uncouple professionalizing biology and subject-centered aesthetics from their rhetoric of agency, autonomy, and power.In my first chapter, "Composite Life," I translate previously unavailable pieces from Goethe's microscopy logs (1785-6) and On Morphology periodicals (1817-24) as emblematic of the broader contemporary interest in studying living beings as composite, rather than organic forms. Here, each "seeming individual" is as a "being-complex," a fractious "assemblage of independent beings." Morphology, moreover, redirects biological inquiry from the question of new life (generation) around which the discipline had coalesced, to the biology and poetics of decomposition and senescence - or, as Goethe names one essay, "Going to Dust, Vapor, Droplets." What, this essay begins to ask, might life look like from the perspective of the non-reproductive, but communicative, effluvia that mediate between beings? What arts of discomposure would be adequate to this view? Focusing on an experiment in which a cut mushroom "draws" its own image in spores, I argue for the credibility in the period of non-human acts of representation: that is, for material (neo-Lucretian) images that emanate not just from agents, but from things.My second chapter, "Thinking Like an Object, Contra-Kant" concerns the aesthetic and poetic stakes of the experimental method Goethe calls "tender Empiricism," an approach to composite life that I read as a sly critique of Kant's durable accounts of aesthetics and organism. From Goethe's perspective, Kant's celebrated epistemological modesty - his concern that a man not "presumptuously ... tack a whim ... to the objects" (Goethe's paraphrase) - screens a more significant hubris: the presumption that a person could produce whims without objects and a sensing body; and, more basically, that what is important about a subject is the way in which he is not a natural object. Re- valuing the passive quality of tenderness as an epistemic virtue, Goethe experiments in "objectively active thinking," permitting the way the self is (also) an object to re-enter natural and aesthetic philosophy. The chapter culminates in a re-reading of the didactic poem Dauer im Wechsel ["Durance in Change"] from the perspective of objective figuration, centering on a neo-Lucretian simulacrum that, I argue, Paul de Man consequentially mistook for a symbol.In Chapter Three I move from Goethe's poetic morphology to Shelley's "poetry of life." "Growing Old Together: Composite Physiognomy in The Triumph of Life" examines the way Shelley's Triumph revives Lucretian corporeality in order to rebuke the markedly triumphalist rhetoric of both contemporary vitalist physiology and post-Waterloo historiography. Offering a new account of the face-giving trope of prosopopeia in the poem, I argue that Shelley mobilizes Lucretian simulacra in order to think through the way personal bodies produce and integrate passages of historical time. Representing aging faces as mutable registers of the "living air" of a post-Napoleonic interval, The Triumph depicts senescence as the unintended work of multitudes, pressing towards a biology and epistemology of transience that holds rhetorical, vital, and historical materialisms together.In Chapter Four, "The Natural History of Violence: Atomist Pre-Histories for Shelley's The Mask of Anarchy," I continue the increasingly historical trajectory of the dissertation's materialism by turning to Shelley's poetic representation of the 1819 "Peterloo Massacre." Here, I attempt to put the dissertation's valuation of epistemological "sweetness" and "tenderness" to the test of an event in which subjects' vulnerabilities were tragically violated. Focusing on the The Mask's preoccupation with the way wrongly spilled blood enters geological and meteorological cycles, I argue that the poem, which Shelley called "wholly political," is also a form of natural history. I recruit Erasmus Darwin, William Cowper, and James Thomson as well as Walter Benjamin to argue for a didactic natural historical mode in which a poem speaks polemically for bloodstained materials that do not, in themselves, disclose their provenance. In this way I suggest that, despite its reputation, pre-Darwinian natural history - and especially its poetry - is anything but a-historical or a-political. In the dissertation's Coda, "Marx's Sensuous Science" I pick up this materialist current at the start of the historical materialism more familiar to present-day critics: Karl Marx's doctoral dissertation on classical atomisms. I link Marx's reception of Lucretius to the idea of natural history that emerges in his "Economic and Philosophical Manuscripts of 1844," which paraphrase Goethe on tender empiricism, and argue (like Blake, Wordsworth, and Shelley) that any sensation-based science needs to countenance the senses' susceptibility to historical re-configuration. The Manuscripts strain, very much in the tradition my chapters lay out, towards what Marx calls a "sensuous science." Like Goethe and Shelley, Marx presses past the biology of organicism in order to adumbrate "man's inorganic body," a body neither contemporaneous nor coincident with itself and whose life is traversed by and contingent upon innumerable others. In the Coda I take this cue to compare Marxian and neo-Lucretian ideology critique, asking how the embodied impressionability valued in "tender," "sweet," and "sensuous" sciences may run, but may also outrun, the risk Marx named "reification."