CHAP. ni.J 



SIGHT. 



860 



it will distend the cavity and render the suspensory ligament 

 tense. But since the suspensory ligament passes obliquely for- 

 wards, all round, from the ciliary processes to the front of the 

 lens, tension of the ligament will tend to flatten the lens, altering 

 its shape but not its bulk. 



The choroid, of which the ciliary processes form the forward 

 continuation, is loosely attached to the sclerotic along the line 

 of the lamina fusca and suprachoroideal membrane ; the one can 

 to a certain extent be slipped backwards and forwards beneath 

 the other. 



sp.clu 



FIG. 145. DIAGRAM OF THE CILIARY MUSCLE AS SEEN IN A VERTICAL RADIAL 

 SECTION OF THE CILIARY REGION. 



E.cj. epithelium of the conjunctiva, d.cj. dermis of the conjunctiva. Scl. Scle- 

 rotic, sp.ch. suprachoroidal layer. Ch. Choroid. p.e. pars ciliaris retinae and 

 pigment epithelium represented as one layer. C.P. Ciliary processes. /. Iris. 

 ag.h. anterior chamber. E.p. ligamentum pectinatum. c. S. canal of Schlemm, 

 and x tissue to inside of it. 



l.c.m. longitudinal, and c.c.m. circular ciliary muscle, y bundles of the longi- 

 tudinal muscle cut across as they are taking a circular direction. 



The (longitudinal) ciliary muscle (Fig. 145) is attached on 

 the one hand to the junction of the sclerotic and cornea, and on the 

 other hand to the front part of the choroid. If we suppose the 

 former to be a fixed point, the contraction of the muscle would 

 pull the moveable choroid and ciliary processes somewhat for- 

 ward. But the pulling forward of these structures would slacken 

 the suspensory ligament by bringing its ciliary attachment more 

 forward. And a slackening of the suspensory ligament by reliev- 

 ing the pressure on the elastic lens would allow the front surface 

 to become more convex. This is shewn diagrummatically in 

 Fig. 146, one-half of which, the left half, is intended to repre- 

 sent the eye directed towards distant objects, while the other 



