DEVELOPMENT OF THE MENINGES

Abstract

In 1926, we (Harvey and Burr¹) presented experimental evidence supporting a hypothesis of the senior author that the pia-arachnoid membrane is a structure which developmentally is an analog of the sheath of Schwann of the peripheral nerve and is a derivative of the neural crest. Harvey Cushing² has called attention to the fact that Oberling,³ in 1922, advanced a similar hypothesis based on histopathologic studies. The experiments reported by us (Harvey and Burr) consisted in transplantations of the nervous system of Amblystoma, carried out with and without neural crest. The results of those experiments indicated clearly that when the nervous system was transplanted without neural crest no cellular investment could be found interposed between the brain and the surrounding mesenchyme. Portions of the neural tube which were transplanted with neural crest gave clear evidence of the presence of a definitive cell layer, immediately surrounding the nervous system,