"Regeneration" by Thomas Hunt Morgan is a scientific publication written in the early 20th century. The book explores the biological concept of regeneration across various organisms, examining both the mechanisms and implications of the ability of certain species to regenerate lost parts. Morgan, a prominent biologist, delves into the historical context of regeneration studies and critiques existing hypotheses, providing insights from experimental embryology and presenting new conclusions based on recent discoveries in the field. The opening of the work introduces the topic of regeneration through a historical lens, recounting early experiments by naturalists such as Abbé Trembley and Spallanzani, who notably observed the regeneration capabilities of hydras and earthworms, respectively. Morgan describes how these early studies generated interest in the phenomenon and set the stage for later research. He notes that regeneration is not only a fascinating biological process but is also influenced by environmental factors like temperature and food supply. Morgan emphasizes that understanding regeneration is crucial for comprehending broader biological principles and sets the groundwork for a deeper exploration of the internal mechanisms and external influences that contribute to regeneration in various species. (This is an automatically generated summary.)