Download or read book The Effect of External Influences upon Development written by August Weismann and published by DigiCat. This book was released on 2022-08-10 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this lecture, the author points out that Nägeli's perspective on the evolution of the organic world has always struck him as surprising. He assumed that it had arisen from inherent internal forces and that external influences had only played a secondary and unimportant role, improving and modifying but not determining. This astute thinker stated unequivocally that, in his opinion, the course of development would have resulted in roughly the same outcome even if life conditions had remained unchanged since the beginning.