Following Aristotle’s and William Harvey’s exciting observations of the first form of the heart beating into life in the newborn, Samuel Taylor Coleridge used this imagery of the punctum saliens pulsing into life to convey an emerging existence or form ‘leaping’ from one level of being into another. This chapter explores how the embryological theory of the punctum saliens became related, in Coleridge’s thought, to dynamical idealist theories of matter arising from opposed physical forces to become a metaphysical principle. These idealist theories of matter developed through Cambridge Platonism, Leibnizian dynamics, German transcendental and absolute idealism, and British romanticism. They viewed energies in life and mind in circulation, like the blood in Harvey’s theory of the beating heart. Coleridge co-opted the embryological punctum saliens for his metaphysics of the emergence of forms from one level of organization, or even from one hypostasis of being, to another. This essay charts the concept of the punctum saliens from Aristotle’s observations to Harvey’s theory of circulation, then to Coleridge’s metaphysics of matter and emergence, drawing from Gottfried Wilhelm Leibniz’s and Immanuel Kant’s dynamical theories of matter. The chapter illuminates not only an important strand in the history of scientific and philosophical ideas but also some notable poetry from the late eighteenth century, Coleridge’s ‘The Rime of the Ancient Mariner’ (1798) and George Canning and John Hookham Frere’s ‘The Loves of Triangles’ (April–May 1798), a parody in the Anti-Jacobin periodical that curiously admired what it ostensibly lampooned, mimicking Erasmus Darwin’s The Loves of Plants and Coleridge’s ‘The Eolian Harp’