Project Gutenberg 2011-08-27 Public domain in the USA. 91 Hertwig, Oscar 1849 1922 Hertwig, Oskar Hertwig, O. (Oscar) Hertwig, Wilhelm August Oskar Gertvig, O. (Oskar) Mitchell, P. Chalmers (Peter Chalmers), Sir 1864 1945 Mitchell, Peter Chalmers, Sir Präformation oder Epigenese? English The Biological Problem of Today: Preformation Or Epigenesis? The Basis of a Theory of Organic Development The Biological Problem of To-day: Preformation Or Epigenesis? The Basis of a Theory of Organic Development Produced by Bryan Ness, Josephine Paolucci and the Online Distributed Proofreading Team at http://www.pgdp.net. (This book was produced from scanned images of public domain material from the Google Print project.) "The Biological Problem of To-day: Preformation Or Epigenesis?" by Oscar Hertwig is a scientific treatise written in the late 19th century. This work delves into the biological debate concerning the nature of development, specifically examining two opposing theories: preformation, which posits that all characteristics of an organism are already present in a miniature form within the germ, and epigenesis, which suggests that development is a progressive formation from an initially unorganized state. Hertwig's exploration of these theories is informed by his expertise in embryology and cell biology. The opening of the book sets up the central question regarding whether embryonic development represents a preformed structure or an elaborative process shaped by environmental influences. Hertwig introduces the ideas of other biologists, particularly focusing on August Weismann's germplasm theory, which classifies hereditary material as distinct and stable while addressing the complexities of reproduction and differentiation. Through critical analysis, Hertwig aims to establish that true development relies on epigenesis, where the organism grows and develops through interactions with its surroundings, rather than merely revealing what was predetermined in the germ. The opening serves as a prelude to a deeper examination of the implications each theory carries for understanding heredity and the intricacies of life. (This is an automatically generated summary.) en Developmental biology Embryology Genetics QH Text Browsing: Science - General Browsing: Science - Genetics/Biology/Evolution 316609 316619 2024-09-15T15:04:35.886132 2023-09-16T08:22:26.055852 text/html text/html 312329 2011-08-27T16:34:44 text/html; charset=iso-8859-1 423219 2011-08-27T16:34:46 text/html; charset=iso-8859-1 application/zip 507972 2024-09-15T15:04:42.854090 application/epub+zip 509291 2024-09-15T15:04:37.886134 application/epub+zip 179149 2024-09-15T15:04:36.728114 application/epub+zip 751115 2024-09-15T15:04:46.314607 application/x-mobipocket-ebook 721482 2024-09-15T15:04:41.759137 application/x-mobipocket-ebook 301425 2022-09-17T05:46:00.419681 application/x-mobipocket-ebook 273561 273338 2024-09-15T15:04:35.182122 2023-09-16T08:22:25.400895 text/plain; charset=us-ascii text/plain 273249 2011-08-27T16:34:44 text/plain; charset=iso-8859-1 94279 2011-08-27T16:34:46 text/plain; charset=iso-8859-1 application/zip 273313 2011-08-27T16:34:44 text/plain; charset=us-ascii 94191 2011-08-27T16:34:46 text/plain; charset=us-ascii application/zip 21327 2024-09-15T15:04:46.455566 application/rdf+xml 24221 2024-09-15T15:04:37.102112 image/jpeg 4663 2024-09-15T15:04:36.914120 image/jpeg 500308 2024-09-15T15:04:35.925191 application/octet-stream application/zip Archives containing the RDF files for *all* our books can be downloaded at https://www.gutenberg.org/wiki/Gutenberg:Feeds#The_Complete_Project_Gutenberg_Catalog