![]() In this way Roux was able after taking a frog's egg, pricking and destroying one of its two blastomeres, to obtain half an embryo from the other. This would show what each part was capable of by itself, while at the same time showing how far the developmental processes depending on them were dependent on or independent of each other. ![]() The first experiments consisted in separating the individual parts of the embryo from each other and culturing them in isolation. These questions, various answers to which constitute the theories of preformation or epigenesis, were lifted out of the realm of speculation up into that of an exact science when first Wilhelm Roux and then Hans Driesch used experimental methods in their research into development. How does that harmonious interlocking of separate processes come about which makes up the complete process of development? Do they go on side by side independently of each other (by "self-differentiation", Roux), but from the very beginning so in equilibrium that they form the highly complicated end product of the complete organism, or is their influence on each other one of mutual stimulation, advancement or limitation? The experiments which finally led to the discovery of the phenomena which are now designated as "organizer-effect" were prompted by a question which actually goes back to the beginnings of developmental mechanics, indeed to the beginnings of the history of evolution in general. Hans Spemann's 1924 paper " Induction of Embryonic Primordia by Implantation of Organizers from a Different Species" The Organizer-Effect in Embryonic Development Links: Gastrulation | Frog Development | Week 3 | Historic - Manual of Human Embryology | Wilhelm Rouxįrog Links: Frog Development | 2009 Student Project | 1897 Development of the Frog's Egg | Hans Spemann | Wilhelm Roux | 1921 Early Frog Development | 1951 Rana pipiens Development | Rana pipiens Images | Frog Glossary | John Gurdon | Category:Frog | Animal DevelopmentĮmbryologists: William Hunter | Wilhelm Roux | Caspar Wolff | Wilhelm His | Oscar Hertwig | Julius Kollmann | Hans Spemann | Francis Balfour | Charles Minot | Ambrosius Hubrecht | Charles Bardeen | Franz Keibel | Franklin Mall | Florence Sabin | George Streeter | George Corner | James Hill | Jan Florian | Thomas Bryce | Thomas Morgan | Ernest Frazer | Francisco Orts-Llorca | José Doménech Mateu | Frederic Lewis | Arthur Meyer | Robert Meyer | Erich Blechschmidt | Klaus Hinrichsen | Hideo Nishimura | Arthur Hertig | John Rock | Viktor Hamburger | Mary Lyon | Nicole Le Douarin | Robert Winston | Fabiola Müller | Ronan O'Rahilly | Robert Edwards | John Gurdon | Shinya Yamanaka | Embryology History | Category:People Later in 1988 he wrote the book "The Heritage of Experimental Embryology: Hans Spemann and the Organizer". Viktor Hamburger was a graduate student in Spemann’s department at Freiburg during the years that the organizer graft experiments were being performed. Below is the transcript from his Nobel Lecture 1935. Spemann received the 1935 Nobel Prize in Physiology or Medicine "for his discovery of the organizer effect in embryonic development". The same region in birds it is known as "Hensen's node" named for Victor Hensen (1835 – 1924) and is also known generally as the primitive node or knot. This region was also called the "Spemann's organiser". Hans Spemann (1869 - 1941) was a German embryologist who worked extensively on amphibian development and was the discoverer of the organiser region (or primitive node) the controller of gastrulation (1924).
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