Thomas Hunt Morgan's 1901 exploration of regeneration traces the phenomenon across the animal kingdom, from the remarkable ability of hydras to rebuild themselves to the more limited regenerative powers of earthworms. Working at the frontier of experimental embryology, Morgan surveys what 19th-century naturalists had discovered about regeneration and subjects their conclusions to rigorous experimental scrutiny. He examines how factors like temperature, nutrition, and the mechanical conditions of injury influence whether and how an organism can replace lost parts. The book reveals a scientist thinking in real time about one of biology's deepest puzzles: how does a living thing know to rebuild exactly what was lost, and why can some creatures do it while others cannot? Morgan would later win the Nobel Prize for his genetic work, and this early volume shows his meticulous experimental mind already at work, questioning assumptions and building new frameworks for understanding development. For readers curious about the history of biology or the science of renewal, this text offers a window into how turn-of-the-century scientists grappled with regeneration's mysteries.
