FIBRES OF THE LENS. 



735 



The fibres of the lens are somewhat flattened threads, about 3-^^th of an 

 inch wide, and are directed over the edge of the lens from the planes on one 

 surface to those on the other. In their course between the opposite surfaces, 

 no fibre passes from pole to pole, but the fibres beginning in the pole or 

 centre of one surface terminate in the end of a plane on the opposite sur- 

 face, and vice versa ; the intervening fibres passing to their corresponding 

 places between. Some of the superficial fibres possess transparent nuclei, at 

 nearly regular intervals. In the more superficial fibres of the growing lens 

 the nuclei occupy very regularly the equatorial part. At their ends, 

 where the fibres meet the planes, they are soft and indistinct ; and at the 



Fig. 486. MAGNIFIED VIEW OF THE FIBRES 

 OF THE CRYSTALLINE LENS. 



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 (from Kolliker). C, 

 longitudinal view of a few of the fibres from 

 the equatorial region of the human lens 

 (from Henle). ^ The most of the fibres 

 are seen edgeways, and, towards 1, present the 

 swellings and nuclei of the "nuclear zone ;" 

 at 2, the flattened sides of two fibres are 



middle part, where they are placed 

 on the margin of the lens, they are 

 widest and best marked. The fibres 

 are six-sided prisms, flattened in the 

 plane of the lamina in which they lie. 

 The edges are bevelled and sinuous ; 

 they are very regularly toothed at the 

 edges in fishes and some other animals 



Fig. 487. 



Fig. 486. 



Fig. 487. CELLS CONNECTING THE LENS WITH 

 ITS CAPSULE (from Bowman). 



for more perfect junction with those in the same plane ; but in man and 

 mammals, the edge is only slightly jagged or irregularly serrated. 



Changes in the lens by age. In the foetus, the lens is nearly spherical : it 

 has a slightly reddish colour, is not perfectly transparent, and is softer, and 

 more readily broken down than at a more advanced age. 



