DISEASE OV THE LACHRYMAL PASSAGES. 155 



within the puncta, no doubt, on occasions, it becomes so through its 

 whole course. The common seat of obstruction — so far as our 

 very limited observations warrant an opinion — appears to be the 

 superior part of the ductus ad nasum ; or it may, according to 

 D'Arboval, be the lachrymal sac*. "In the first part of its 

 course" — I quote from my ' Anatomy of the Horse' — " the duct 

 diminishes a little in its caliber; from about the middle, how- 

 ever, it begins to enlarge again, and soon after acquires its former 

 diameter." This will account for the usual seat of obstruction. 

 What the nature of the obstruction is — whether it consist in 

 some tumefaction, partial or general, of the lining membrane, or 

 arise from the effusion of lymph iijto the passages, or whether it 

 be the effect, simply, of concretion and lodgment of secretion, 

 natural or altered in condition, it may not be in our power pre- 

 cisely to determine, although a pretty conclusive inference may 

 generally be drawn from due consideration of the circumstances 

 of the case : let it, however, consist in which it may of these 

 three pathological conditions, it will not materially alter our views 

 of treatment; which, as far as my own practice has gone, will 

 probably be best elucidated by the following detail : — 



An aged cream-coloured Hanoverian horse, that had in his 

 younger and better days been honourably employed in drawing 

 the king's state carriage, was brought to me for being troubled 

 with " watery eyes," producing ophthalmic irritation, and tumidity 

 and soreness of the conjunctival membrane, with nebulous opacity 

 of the cornea, and intolerance of light to such a degree that the 

 eyes, especially one, were all but closed. Another ill consequence 

 of this overflow of the tears out of their natural channel was, 

 destruction of the hair and excoriation and soreness of the cheek 

 below the eye. This horse had — the same as all his peculiar 

 breed have — eyes of the Albino description : whether such eyes 

 manifest any particular susceptibility to disorder of this kind I 

 cannot say. 



* English veterinarians have denied the existence of this sac : the best 

 argument I can offer of its presence is dissection — the same that has con- 

 vinced myself. For a description of it, as it exists in horses, consult my 

 "Anatomy of the Horse," page 374. 



