Bone-marrow of the Guinea-pig as a Mesodermal Inductor in Implantation Experiments with Embryos of Triturus

Abstract

Marrow from the thigh-bone of the guinea-pig, treated in 70 per cent, alcohol, has been used as the inductor material in implantation experiments with gastrulae of Triturus. The inductor has induced mesodermal structures such as limb rudiments, notochords, pronephric tubules, and mesenchyme, and, in addition to these, proctodaea with anal openings. These last are regarded as secondary induction products of the induced mesoderm. The only suggestion of neural induction consisted of darkly staining cells, which may perhaps be regarded as neural. The results show that the mesoderm-inducing agent is independent of the agents inducing neural structures, and the ‘spinal’ agent earlier postulated can thus be further divided into components inducing mesoderm and inducing neural structures. The question as to what is the specific action, independent of the mesoderminducing agent, of the neural-inducing component in the previously established ‘spinal’ inductor, is discussed.