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Connections and Relations of the Lens. — The back of the 

 lens lies in a hollow in the front of the vitreous humour, 

 which is bounded by an extension of the hyaloid capsule 

 of this humour, which is so distinct from the posterior 

 lens-capsule that I should hardly have mentioned them 

 separately had this not been recently denied. It bends 

 inwards near the edge of the lens, and forms the posterior 

 wall of the space known as Petit's canal. The lens may be 

 removed in its entire capsule without destroying the in- 

 tegrity of this partition between the vitreous humour and 

 the lens-bed. But its chief support is the suspensory liga- 

 ment Avhich slings the lens to the ciliary processes. This 

 arises from the whole inner surface of the ciliary body, in 

 front of the ora retinae, from columnar epithelial-like bodies 

 resting on the pigmental epithelium, and it is attached in a 

 plaited manner to the capsule at the edge of the lens, 

 advancing slightly upon the front, and to a less extent on the 

 back of the lens. It is composed of fibres which chemically 

 resemble yellow elastic tissue. They are remarkable for 

 their hard, sharp outlines, and their clear fracture. They 

 break up near the lens into brushes of very fine fibrillse, the 

 interspaces between which are occuj^ied with delicate mem- 

 braniform expansions. Kolliker regards the elongated bodies 

 from which these fibres arise as special modifications of the 

 connective-tissue radial fibres of the retina, which are con- 

 tinued in front of the ora, the nervous retinal elements 

 ceasing at this boundary line. The place of the attachment 

 of the suspensory ligament to the lens varies within rather 

 large limits in different animals ; in birds and reptiles it is 

 nearer the front of the lens than in man. 



The Ciliary Muscle. — Let us now turn to the muscular 

 apparatus of accommodation. In the human eye, the ciHary 

 muscle is the active factor of accommodation. "When the 

 cornea and sclerotic are removed, a greyish ring is seen 

 behind the iris on the outward surface of the ciliary body. 

 It was considered ligamentous imtil Professors Briicke 

 and Bowman, nearly simultaneously, discovered its muscu- 

 larity. In mammalia the muscular tissue is unstriped. The 

 deepest bundles of muscular fibre, those which are in close 

 relation to the outer surface of the ciliary processes, are 

 very obliquely directed ; collectively they form a ring resem- 

 bling a sphincter, yet not completely separable from the 

 other muscular bundles. Attention was first drawn to these 

 fibres by the late H. MiJller, who conceived that, acting 

 through the intervening ciliary processes, they might com- 

 press the edge of the lens. 



