Chap, xxxviii.] THE VITREOUS BODY. 307 



which evidently carry the nutritious fluid for the lens- 

 fibres. 



431. (2) The vitreous body is a fluid substance 

 enclosed in a delicate hyaline capsule the membrana 

 hyaloidea. This membrane, at the margin of the 

 fossa patellaris of the vitreous body i.e., the fossa in 

 which the lens is lodged but without covering it, 

 passes as the zonula ciliaris, or zonula Zinnii, or 

 suspensory ligament of the lens, to the margin of the 

 latter, to which it is firmly adhering. So it adheres 

 also to the surface of the ciliary processes. The 

 zonula Zinnii is hyaline and firm, and is strengthened 

 by numbers of bundles of minute stiff fibrils. 



Between the suspensory ligament of the lens, the 

 margin of the lens and of the fossa patellaris is a 

 circular lymph space, called the canalis Petiti. 



Beneath the membrana hyaloidea are found iso- 

 lated nucleated granular-looking cells (the subhyaloid 

 cells of Ciaccio), possessed of amreboid movement 

 (Ivanoff). 



432. The substance of the corpus vitreum appears 

 differentiated by clefts, concentric in the peripheral, 

 radiating in the central, part (Briicke, Hannover, 

 Bowman, Ivanoff, Schwalbe). But these do not 

 contain any distinct membranous structures (Stilling, 

 Ivanoff, Schwalbe). 



The canalis hyaloideus, or canal of Stilling, extends 

 from the papilla nervi optici to the posterior capsule 

 of the lens, and is lined with a continuation of the 

 membrana hyaloidea. 



433. In the substance of the corpus vitreum occur 

 isolated nucleated cells ; they have amoeboid move- 

 ments, and some contain vacuoles, from commencing 

 degeneration. They are all identical with white 

 blood-corpuscles (Lieberkiihn, Schwalbe). 



Fine bundles of fibrils are occasionally seen in the 

 substance of the vitreous body. 



