Physico-Chemical Experiments on the Amphibian Organiser

Abstract

THE process of induction by organisers, discovered during the last twelve years by Spemann and his collaborators, is now recognised to be among the most important morphogenetic factors in early embryonic development. The exact nature, therefore, of the organising influence exerted by the dorsal lip of the blastopore on surrounding regions, is a subject of peculiar interest. Recent experiments^1,2,3,4 have given strong support to the view that induction is due to a definite chemical substance, since the organiser tissue can be narcotised, crushed, dried, frozen, or boiled, without loss of its inductive power. Holtfreter⁵, indeed, has shown that regions of the newt embryo, such as the ventral ectoderm, which do not normally possess inductive power, acquire it after being boiled.