| Description | Slide shows two microscopic photographs of an axolotl (salamander) embryo with grafted epidermis from triton (newt) and a triton with a grafted epidermis from an axolotl.
Pictures are labelled 'A' and 'B'. 'A' has the labels 'n', 's', and 'g'.
Title below images reads 'Fig. 85 - The formation or non-formation of a given structure depends not only on the presence of an inductive or formative stimulus (organiser), but also on local specific factors, intrinsic to the fields. Triton taeniatus normally develops a balancer, the axolotl does not. Nevertheless, a piece of gut-roof of axolotl grafted into an embryo of triton can induce the balancer field of the latter to develop supernumerary balancers, A. Conversely, B, a piece of trunk epidermis of triton grafted onto the head of an axolotl embryo, gives rise to a balancer (left side of photograph), while no balancer is formed from the normal axolotl epidermis on the other side. The axolotl therefore possesses the necessary formative stimulus for balancer formation, but its epidermis fails to react to it. g. grafted axolotl tissue; n. normal balancer ; s, supernumerary balancer. (From Mangold, Naturwiss. XIX, 1931.)' |