STRUCTURE OF THE LENS AND VITREOUS HUMOUR 227 



in transverse section they appear prismatic (B). Many of the superficial 

 fibres are nucleated (c), the lens-fibres having originally been developed 

 by the elongation of epithelium-cells. 



FIG. 265. FIBRES OF THE CRYSTALLINE LENS. (350 diameters.) 



A, longitudinal view of the fibres of the lens from the ox, showing the serrated edges. B, 

 transverse section of the fibres of the lens from the human eye. C, longitudinal view of 

 a few of the fibres from the equatorial region of the human lens. Most of the fibres in 

 C are seen edgeways, and, towards 1, present the swellings and nuclei of the 'nuclear 

 zone ; ' at 2, the flattened sides of two fibres are seen. 



The vitreous humour is composed of soft gelatinous tissue, appa- 

 rently structureless when examined in the fresh condition, but contain- 

 ing a few scattered amoeboid cells, the processes of which are often long 

 and varicose, and the cell-bodies distended by large vacuoles. The 

 hyaloid membrane, which invests the vitreous humour, is homogeneous 

 and structureless except in the region of the ciliary processes, where it is 

 fibrous in structure, forming the zonule of Zinn and spreading out into 

 the suspensory ligament of the lens. 



Q2 



