["Circular bands" on the casts of the microcirculatory bed of the human heart in ontogenesis (data from scanning electron microscopy of corrosive casts)].

: Pieces of the wall obtained from the anterior cerebral bladder of human embryos at the age of 8-10 weeks can survive in the spinal cord of mature animals. In the transplant, unlike the normal embryonal histogenesis, neuroepithelial cells make groups of rosellas. The differentiation process of cells of the human nervous tissue transplant can be followed in the rat spinal cord without any immune suppression up to the end of the 2d month of development. During the 3d month the transplant neuroblasts perish as a result of the immune reaction.