Aberrant Nerve Fibres in Human Development

Abstract

In the early years of this century debate concerning the development of nerve fibres became more intense. During the previous decade, following the developmental studies of His (1883, 1886) and the early embryological studies of Ramon y Cajal (1890), the neurone theory as proclaimed by Waldeyer in 1891 seemed assured of victory; but when, with Apáthy and Bethe, new technical developments diverted attention from the whole neurone to its apparent constituents, the neurofibrillae, the simple concept of the outgrowth of the nerve fibre became enmeshed in complexity. Methods for their impregnation with silver were soon elaborated (Bielschowsky, 1904; Ramon y Cajal, 1903), and Held (1907) affirmed that a network of neurofibrillae preceded the appearance of the definitive nerve process. This claim became associated with the much older views of Hensen (1864, 1876) that protoplasmic strands were the forerunners of the nerve fibres and constituted a ground plan for the later development of the peripheral nervous system.