Physico-chemical experiments on the amphibian organizer

Abstract

Induction of medullary plate cells or of neural tubes occurred after the implantation of the following materials into the blastocoele of the early gastrula (Triton taeniatus and T. alpestris) : cell-free, centrifuged material from neurulae; pieces of uncleaved eggs first centrifuged and then coagulated in boiling water; ether and petrol-ether extracts of neurulae, using pure triglycerides as vehicles for the oily extracts; the unsaponifiable portion of an ether extract of amphibian embryos; fresh liver from adult newts; and ether extracts of adult newt viscera. No induction could be obtained with the triglycerides used as vehicles for the extracts, or from the triglycerides alone or combined with egg-albumen, cholesterol, tri-hydroxyoestrin, calciferol, or coconut oil. Fresh liver from adult newts gave a much greater % of inductions than the ether or petrol-ether extracts. It is concluded that the organizer is probably a chemical substance soluble in ether and petrol-ether.