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

Levander (1938) has shown that an alcohol extract prepared from bone can, when injected into rabbit muscle, induce there cartilage and bone cells. This observation has been confirmed by several investigators (Annersten, 1940; Bertelsen, 1944; Lacroix, 1945; Levander, 1949; Willestaedt, Levander & Hult, 1950). Of these, Bertelsen has shown in addition that not only is an extract prepared from bone proper active, but also that an extract prepared from bonemarrow is even more active. In addition to the authors mentioned above, Schreiber (1950) has lately dealt with the problem. He has assumed, on good grounds, that the agent inducing bone and cartilaginous tissue in the experiments mentioned above is similar, as regards its chemical nature, to the ‘spinal’ inducing agent in my experiments (Toivonen, 1940, 1949 a and b, 1950). This assumption of Schreiber's has prompted me to investigate experimentally the inducing action of bone-marrow when implanted into the gastrula of Triturus.