Minute Structure of the Inner Surface of an Embryonic Central Nervous System

Abstract

F. SAUER¹, referring to mitosis in the neural tube, wrote: “The attachment of the neural tube cells to each other at the surface bordering the lumen appears to play an important part in the mechanics of the development of the neural tube”. Having been preceded in general conception by other authors^2–4, he stated that elements of neural epithelium were attached to each other at the surface bordering the lumen by a terminal bar net, and that there was “no internal limiting membrane other than the cytoplasmic membrane of cells”. In spite of this statement, the old conception of His⁵ describing the internal limiting membrane as a felt-work of fibrils into which passed the cytoplasmic fibrils of the spongioblasts had been generally accepted. Later on, Sauer's suggestion was revived by further authors^6–11; but none of them elaborated the minute structure of internal limiting membrane or considered its possible significance in ontogenesis.