An elementary compendium of physiology : for the use of students / by F. Magendie ; translated from the French with copious notes, tables, and illustrations, by E. Milligan.

  • Magendie, François, 1783-1855.
Date:
1829
Catalogue details

Licence: Public Domain Mark

Credit: An elementary compendium of physiology : for the use of students / by F. Magendie ; translated from the French with copious notes, tables, and illustrations, by E. Milligan. Source: Wellcome Collection.

Provider: This material has been provided by University of Bristol Library. The original may be consulted at University of Bristol Library.

    86/710 (page 36)
    Retina. Vessels and nerves of the eye. Optie nerve. According' to the latest researches upon the anatomy of the iris, it appears certain that the membrane is muscular,8 and that it is composed of two layers of fibres, the one external, radiated, which dilates the pupil, the other circular, concentric, which shuts the opening. The external circular fibres appear to be supported by a species of ring, which each of the radiated fibres contribute to form, and in which they slide, during the alternate contractions and relaxations of the pupil. The iris receives vessels and ciliary nerves, the latter from two sources ; the ophthalmic ganglion, and the nasal branch of the fifth pair. Between the choroid and the hyaloid there exists a membrane essentially nervous. This membrane, known by the name of the retina, is almost transparent; it presents a slight opacity, and a tint feebly inclining to lilac ; it is composed of the expansion of filaments which compose the optic nerve. M. llibes does not consider it as such ; he thinks that it forms a particular membrane, in which the branches of the optic nerve are distributed. He then establishes an analogy between the retina and the other mem- branes. The retina presents, about two lines outwardly from the entrance of the optic nerve, a yellow spot, Tache jaune, and beside it a number of folds. These appearances are found only in man, in apes, and in some reptiles.15 The eye receives a great number of vessels, the ciliary ar- teries and veins; and many nerves, the greater part of which come from the ophthalmic ganglion. Optic Nerve. This nerve preserves the communication between the brain and the eye. It does not come from the optic thalamus, as many ana- tomists imagine ;b it originates—1st, from the anterior part of the corpora quadrigemina ; 2d, from the corpus geniculatum exter- num, a prominence which is seen a little before, and without these tubercles; 3d, and lastly, from the lamina of grey substance placed between the adhesion of the optic nerves at the mamillary eminences, and which is known by the name of tuber cinereum. The two opposite nerves approach each other, and appear to join upon the superior aspect of the body of the sphenoid bone. There have been many endeavours made to determine if they cross