Experiments on Embryonic Induction: Part II. Experiments on Coagulated Organisers in the Chick Available to Purchase

The experiments to be described in this section were begun in October, 1931, but no successful experiments were performed until the end of 1932. A short note on the results obtained was published in Nature (Waddington, 1933 b). In the meantime, Bautzmann, Holtfreter, Spemann and Mangold (1932) had shown that in the Amphibia coagulated organisers are still able to exert the inductive capacities which they possess in the living state. This work followed on the earlier experiments of Marx (1931) who obtained inductions with narcotised organisers, and Spemann (1931 a) who found that the inductive capacity is retained when the organiser tissue is subjected to crushing. The same type of investigation into the nature of the inducing agent in the amphibian organiser has now been carried still further by Spemann, Fischer & Wehmeier (1933), Holtfreter (1933 a and b) and Waddington, Needham & Needham (1933 a and b), all of whom have prepared cell-free organising extracts. The last-named authors have been able to show that the active substance is ether-soluble, but Fischer & Wehmeier (1933) claim that the substance is glycogen.