British Medical Journal

1875 BMJ (Clinical Research Edition)  
April Io, I875.] THE BRI7ISRAMEDICAL 7OURNAL. 48I noid space between the outer and inner sheaths of the optic nerve, were mentioned and discussed. The conclusion was that Graefe's explanation is insufficient, as is that of Schwalbe-Schmidt, and that that of Benedikt is the least assailable, perhaps because the least demonstrable. Dr. H. D. Noyes said that the theory of extension of fluid from the brain was niot substantiated, but most necropsies showed fluid at the ocular but not at the
more » ... not at the cerebral end of the nerve. As the nerve approaches the eye, its circulation is increased by the accession of vessels, and around its entrance into the ball a vascular ring is formied. The nerve can only find room for expansion in a longitudinal direction. Caution is necessary in deducing cerebral conditions from examination of the ocular end of the optic nerve. Dr. R. H1. Derby thought that the unreliability of the ophthalmoscope in the diagnosis of cerebral hyperzemia or anmemia was conclusively proved. Dr. Knapp remarked that there was a distinction between two forms of choked disc: that from neuritis descendens, with inflammatory action in the nerve or sheath, and distinct elevation of the disc, and that where fluid existed between the layers of the optic sheath. Blood might sometimes ooze from the brain through the intervaginal space into the eye. He believed that, with few exceptions, neuro-retinitis pointed to cerebral disease. Dr. Dalton considered the absence of arterial pulse in the eye as a remarkable fact, and the pulsationi in the veins under abnormal conditions as still more incomprehensible. We might, perhaps, explain the non-pulsation of the arteries, but not that of the veins.
doi:10.1136/bmj.1.745.481 fatcat:jn6ccigq3ffsbp6a7hlqupydtq