An outline of the embryology of the eye : with illustrations from original pen-drawings by the author / by Ward A. Holden.

  • Holden, Ward A. (Ward Andrews)
Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: An outline of the embryology of the eye : with illustrations from original pen-drawings by the author / by Ward A. Holden. Source: Wellcome Collection.

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    tissue passes through it into the cavity of the secondary vesicle. Previously a small quan- tity of mesoblastic tissue has been carried in with the lens and takes part in the formation of its va£cu]ar__sheat but a greater quantity of mesoblastic tissue passes through the in- ferior cleft and forms the vitreous, which is an almost structureless substance containing blood-vessels. The vessels entering first at the posterior extremity of the cleft divide into two systems of branches, one of which runs forward in the vitreous near the wall of the cavity, and another runs to the posterior pole of the lens where it breaks up into in- numerable twigs which lie in the vascular sheath of the lens. The cleft in the optic stalk closes about these mesoblastic vessels and they come to lie in the centre of the optic papilla, the branches which run in the vitreous being obliterated before birth. As soon as the secondary optic vesicle is formed, its two layers begin to differentiate,