SUMMARY OF THE ANATOMY OF THE GLOBE OF THE EYE. 783 



adult, the vitreous humor being then entirely without blood-vessels. The vitreous humor 

 is divided into compartments formed by delicate membranes radiating from the point of 

 penetration of the optic nerve to the anterior boundary where the hyaloid membrane 

 is in contact with the capsule of the lens. In this way, the humor is divided up, some- 

 thing like the half of an orange, by about one hundred and eighty membranous processes 

 of extreme delicacy, which do not interfere with its transparency. 



Summary of the Anatomy of the Globe of the Eye. 



In this summary, we propose simply to show the relations of the various parts, giving 

 at the same time a brief statement of their physiological importance, in connection with 



11-41. -\ . \\C 



Cod 



R. 



FIG. 250. Section of the human eye, copied from Helmholts and slightly modified. 



Fig. 250, which represents a section of the human eye and shows the relations of its 

 various coats, humors, etc. 



The eyeball is nearly spherical in its posterior five-sixths, its anterior sixth being 

 formed of the segment of a smaller sphere, which is slightly projecting. In its posterior 

 five-sixths, it presents the following coats, indicated in the figure: 



S. The sclerotic ; a dense, fibrous membrane, chiefly for the protection of the more 

 delicate structures of the globe, and giving attachment to the muscles which move the 

 eyeball. Attached to the sclerotic, are the tendons of R, R, the recti muscles. 



Cor. The cornea; a transparent structure, forming the anterior, projecting sixth of 

 the globe ; dense and resisting, allowing, however, the passage of light ; covered, on its 

 convex surface, with several layers of transparent epithelial cells. 



Clio. The choroid coat, lining the sclerotic and extending only as far forward as the 

 cornea ; connected with the sclerotic by loose connective tissue, in which ramify blood- 

 vessels and nerves, and presenting an external, vascular layer and an internal pigmentary 

 layer, which latter gives its characteristic dark-brown color. 



C. P., C. P. The ciliary processes; peculiar folds of the choroid, which form its ante- 

 rior border, and which embrace the folds of the suspensory ligament of the lens. 



