XXXII.—The Continuity of the Vertebrate Nervous System: Studies on Lepidosiren paradoxa

Abstract

As is well known, one of the chief problems relating to the vertebrate nervous system is the question of its continuity or discontinuity both in the adult and in the embryo. The upholders of the latter theory believe that the neurones of the adult are not in continuity but only come into close contact by means of the synapses, while in the embryo the young nerve grows out through the tissues with a free end, and only secondarily unites with its particular end-organ. Much experimental, physiological, and pathological evidence has been brought forward in support of this view, and its upholders include most of the neurologists of the day, whose knowledge, however, relates chiefly to the higher vertebrates and who have made no, or at most very little, detailed study of the phenomena presented by the more primitive forms.