Dissection of Eye of the Ox, 267 



attached to its outer border, en route to reach the Lens capsule). 

 Such an interval does exist, and is known as the Canal of Petit. 



At this point in the dissection we have then three concen- 

 tric rings apparent in front of the eye ; in the centre, the Lens 

 and its capsule ; immediately external to, and placed around 

 the lens capsule comes the transparent, membranous, suspen- 

 sory ligament of the Lens, and, next, the cut edge of the 

 Betina, of which the anterior termination (ora serrata) was 

 removed in a previous dissection. 



The Student should now cut across the thin membranous 

 capsule in which the crystalline Lens is enclosed, and with- 

 draw the Lens (which is a transparent double convex body) from 

 its seat in a hollow on the front of the Yitreous body to which 

 it is inseparably united. 



The Lens should be dried, or hardened by immersion in 

 spirit*, or boiled f in a test tube until it becomes opaque, and 

 then split with a knife, by which it may be demonstrated to 

 consist of a whole series of concentric laminae, arranged one 

 within another, like those in an onion, which may be separately 

 detached from one another. Under the microscope each layer 

 may be teased out with needles and seen to be constructed of 

 minute parallel fibres : and in the Lens of the Ox, now 

 under consideration, these fibres in some parts of the Lens 

 will be seen to be irregularl}'- serrated at ' their edges ; but 

 this is not the case in every layer, nor in the same layer in all 

 subjects. 



The Yitreous body will be seen to fill four-fifths of the space 

 within the coats of the eyeball, and reaches forwards external to 

 the circumference of the Lens, nearly to the Iris : but is slightly 

 hollowed in front to receive the Lens. In looking to the 



* Or Chromic Acid. 



t The water in which the Lens has heen hoiledwill he opaque ^^ith Globulin. 

 It will bring out the Fibres better if 1 per cent, of Sulpburic Acid be added, 

 and the boiling be continued for five or ten minutes. 



