i<:.\.\.Mi. \.\Ti<>.\ oh' mi-: i-:\i:i \.\LL 



the lens measures nine millimetres across, and about four millimet res bet ween its 

 pules. On each surface a series of line, sinuous, grey lines can be seen radiating 

 from the pole towards the equator, called resjiect ively the anterior and poMerior 

 Stellate figures. The lines observable on the posterior are always so placed a to 

 lie intermediate \\itli those on the anterior surface, so that on vie\\ inu them tlinnit/ll 

 tin' li/ix they occupy a position corresponding to the intervals between the line s on 

 the anterior surfaie. The lens-capsule is comparatively brittle, and can be readily 

 cut through when scraped with a sharp-pointed instrument: on doing so Un- 

 divided edge.s curl outwards, away from the lenticular siibManee. When removed 

 from its capsule, the outer portion of the lens is found to be soft and glutinous, but 

 its Mibstance gets progressively (inner as we approach the centre. This harder 

 central part is known as the nucleus, and the surrounding softer matter as cortex. 

 The cortical part shows a tendency to peel off in successive layers. It consists of 



FIG. 728. SEMI-DIAORAMMATIC HOHIZONTAL SECTION THROUGH EYEBALL AND OPTIC 

 NKHVB. (After Elfinger. Reduced and altered.) 



CORNEAL EPITHELIUM 

 CORNEA 



ANTERIOR AQUEOUS CHAMBER 

 IFUS 



POSTERIOR AQUEOUS 

 CHAMBER 



ZON'JLAR SPACE 

 (CANAL OF PETIT) 



CANAL OF 8CHLEMU 

 Ciliary muaole 



CONJUNCTIVA 



Internal rectus 

 muscle 



RETIXA 



Central retinal rcsseJs 

 OPTIC NERVE- 



mBSTANCB 

 riAL .VA7.- 1 /;-..///,,( Til 



SCLEROTIC 



/ rylrT- 

 intlhi lit/ Tenon'* 



and 

 loote tusve) 



I) I '/:. I /. XKIi I 'i:-*URA Til 



long fibres, the ends of which meet in front and behind at the anterior and posterior 

 stellate figures. 



Histologically the capsule is not in imnfediate contact with the cortex over the front surface 

 of the lens, a single layer of cells intervening, called the subcapsular epithelium. 



The zonula ciliaris or suspensory ligament of the lens is formed by a thick- 

 ening of the anterior part of a membrane enclosing the vitreous, strengthened by 

 numerous fibres derived from the folds of the ciliary region. Its chief attachments 

 to the lens-capsule are a little in front of and behind the equator, and the space 

 included between the most anterior and most posterior divisions of the ligament 

 is termed the zonular space (canal of Petit). This space is bridged across by fine 

 intermediate suspensory fibres, and is occupied by fluid. 



The vitreous humour is a transparent, colourless, jelly-like mass, enclosed in a 

 delicate, clear, structureless membrane, called the hijnloid membrane. This latter 

 is closely applied to the back of the posterior lens-capsule and of the suspensory 

 ligament, and to the inner surface of the pars ciliaris retina', retina proper, and 

 optic papilla. Although possessing some degree of firmness, the vitreous humour 

 contains quite 98 per cent, of water, and has no definite structure. Membranes 



