Experiments on Embryonic Induction

Abstract

The communication describes two cases of induction by pieces of the chick primitive streak grafted into the embryonic shield of the rabbit (7½ days after copulation, long primitive streak stage) and discusses the technical difficulties raised by such experiments. The results show that the ectoderm of the rabbit at this stage possesses the capacity of reacting to an inducing stimulus by the formation of neural plate (i.e. is "competent" (Waddington, 1932) to form neural plate), and thus make it probable that the embryonic development of the mammals is influenced by factors similar to those which have become familiar in the Amphibia and birds. They are also a demonstration of the lack of species specificity of the inducing agents involved in embryonic organisers.