VISION 179 



(c) Carefully separate from the eyeball all connective and adipose 

 tissue. 



(3) Remove the retractor muscle of the ox-eye in process of dis- 

 section, taking care not to sever any important bloodvessels or 

 nerves. 



(a) Locate and describe the venae vorticosce. How many are 

 there? 



(6) Find the anterior ciliary arteries. How many can be found? 



Describe their relation to the tendons of insertion of the recti 

 muscles. What tissues do they supply? 



(c) Find the two long ciliary arteries. 



(d) Locate and enumerate the short posterior ciliary arteries. 



(e) Dissect out the ciliary nerves. What tissue do they supply? 



(4) Let one member of the division dissect, for demonstration, the 

 orbital muscles of a dog, cat, or rabbit. To facilitate the dissection 

 fix the animal with dorsum up, and remove with bone forceps the 

 upper and outer walls of the orbit. 



(5) Let one member of the division inject, with carmine or ver- 

 milion mass, the internal carotid of a dog, cat, or rabbit, and dissect 

 out for demonstration the ocular branches of the ophthalmic artery. 



II. DISSECTION OF THE EYEBALL. 



Appliances. The eyes, already partly dissected, which have been 

 kept in an ice-chest. Let one man make an anterior and another 

 a posterior dissection. 



Dissection. 1. Anterior Dissection. Fix the eye to the board, 

 cornea upward, pinning out the dissected muscles as guys. 



(1) Describe the cornea as seen from the front. Does the radius 

 of curvature of the lateral meridian seem to be the same as that 

 of the vertical meridian? With heavy scissors remove the cornea, 

 leaving a margin of one-sixteenth inch anterior to its junction with 

 the iris. 



Examine the cut surface of the cornea with a lens. 



(2) Through the elliptical opening thus made examine the iris as 

 to texture, etc. 



(3) Holding the margin of the cornea with strong forceps, carefully 

 dissect the sclerotic coat from the choroid for about one-eighth of 

 an inch posterior to the angle of the anterior chamber. Locate four 

 points in the margin from which the incisions may be made antero- 

 posteriorly between the insertions of the recti muscles. From the 

 points located make the incisions posteriorly as far as the equator of 

 the eyeball. Dissect each flap from the underlying choroid; remove 

 the pins which fix the recti muscles, and through traction draw the 

 flaps back; fix. 



