THE HUMORS OF THE EYE. 205 



Capsule, is transparent, elastic, ^gVfr inch thick anteriorly, ^^ 7 inch pos- 

 teriorly ; has a layer of flat cells between its anterior portion and the lens, 

 which, after death, break down into a fluid, the Liquor Morgagni. 

 Zonula of Zinn, or Suspensory Ligament, connects the capsule with the 

 ciliary body. It is formed by a splitting of the 

 hyaloid membrane into two layers, one going 

 in front of the lens, the other behind. It is 

 shown exaggerated in the cut. 

 Canal of Petit, is a triangular space around the 

 circumference of the lens, formed by the sepa- 

 ration of the two portions of the suspensory 

 ligament (shown inflated in the cut). 

 Processus Zonulce, are small radiating folds o 

 the anterior surface of the suspensory ligament, which are received be- 

 tween the ciliary processes. 



Describe the Structure of the Crystalline Lens. It consists of flattened 

 hexagonal fibres, united laterally into lamellae, by serrated edges, and curving 

 around the borders of the organ. Its centre or Nucleus is unstratified, and 

 denser than the surrounding portion or Cortex. It is unorganized, having no 

 vessels or nerves, but receives its nutriment by imbibition from the uveal tract, 

 and possibly from the other humors of the eye. 



What is the Vitreous Humor ? The Vitreous Humor or Hyaloid Body 

 is an apparently structureless substance, of gelatinous consistence, consisting 

 of water with a little albumen and salts, and containing cells, nuclei, and con- 

 nective-tissue filaments. It has no vessels or nerves, and is situated in the 

 posterior chamber of the eye, behind the lens, which it supports, as also the 

 retina. The 



Canal of Stilling, Canal of Cloquel, or Hyaloid Canal, traverses the vit- 

 reous humor antero-posteriorly, being the channel for the transmission in 

 the foetus of the Hyaloid Artery to the membrana pupillaris. [See ante, 

 p. 202.] 



Hyaloid Fossa, a depression on the anterior surface of the vitreous, receiv- 

 ing the posterior convexity of the lens. 



What is the Hyaloid Membrane ? It is a delicate capsule investing the 



vitreous, and supposed to send delicate septa into the substance of that humor. It 



divides anteriorly into two layers, which enclose the Canal of Petit and the Lens, 



forming the suspensory ligament of the latter, or Zonula of Zinn. [See above.] 



The foregoing is the view of most anatomists, but some assert that this 



membrane is identical with the internal limiting membrane of the retina, 



extending only to the ora serrata. [Henle, Iwanoff, etc.] 



