304 THE DOG IN DISEASE. 



The gland of Harder is placed in connection with it, 

 and secretes a protective oily matter. 



It is important to remember the conjunctwa^ a mucous 

 membrane extending over the front of the ball, reflected 

 on the inside of the eyelids, and terminating at their edges. 

 It is very thin and transparent over the cornea. 



Fig. 24.— Eye partially Dissected (after Sappey). 

 1. optic nerve ; 2, 3, 4, sclerotic dissected back so as to uncover the choroid coat ; 

 5, cornea, divided and folded back with sclerotic coat ; 6, canal of Schlemm ; 

 7, external surface of choroid, traversed by one of the long ciliary arteries and 

 by ciliary nerves ; 8, central vessel, into which the vasa vorticosa empty ; 9, 10, 

 choroid zone ; 11, ciliary nerves ; 12, long ciliary artery ; 13, anterior cihary 

 arteries ; 14, iris ; 15, vascular circle of iris ; 16, pupil. 



While it is possible that any part of the eye may be 

 the seat of disease, affections of certain regions are very 

 uncommon, and it would serve but little purpose to give a 

 complete account of all the diseases of the eye that have 

 occurred at any time. 



The eyelids, eyebrows, eyelashes, lachrymal apparatus, 



