Archives containing the RDF files for *all* our books can be downloaded at https://book.klll.cc/wiki/Gutenberg:Feeds#The_Complete_Project_Gutenberg_Catalog Project Gutenberg 2011-08-27 Public domain in the USA. 470 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.) Reading ease score: 45.7 (College-level). Difficult to read. en Developmental biology Embryology Genetics QH Text Category: Science - Biology 316720 2025-08-15T07:02:09.435618 text/html 312329 2011-08-27T16:34:44 text/html 537229 2025-08-15T07:02:17.949533 application/epub+zip 538301 2025-08-15T07:02:13.291538 application/epub+zip 167998 2025-08-15T07:02:11.838541 application/epub+zip 796536 2025-08-15T07:02:21.284487 application/x-mobipocket-ebook 766959 2025-08-15T07:02:16.847502 application/x-mobipocket-ebook 301425 2022-09-17T05:46:00.419681 application/x-mobipocket-ebook 273561 2025-08-15T07:02:08.819579 text/plain; charset=us-ascii 273249 2011-08-27T16:34:44 text/plain; charset=us-ascii 273313 2011-08-27T16:34:44 text/plain; charset=us-ascii 21895 2025-08-15T07:02:21.423491 application/rdf+xml 24471 2025-08-15T07:02:12.373534 image/jpeg 4694 2025-08-15T07:02:12.108547 image/jpeg 94279 2011-08-27T16:34:46 application/octet-stream application/zip 423219 2011-08-27T16:34:46 application/octet-stream application/zip 94191 2011-08-27T16:34:46 application/octet-stream application/zip 527273 2025-08-15T07:02:09.472588 application/octet-stream application/zip en.wikipedia en.wikipedia