DISEASE OF THE LACHRYMAL PASSAGES. 
253 
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 cite 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 consists in 
some tumefaction, partial or general, of the lining membrane, or 
arises from the effusion of lymph into the passages, or whether it 
is 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, be which it may of these three, 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 de- 
gree 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. 
Aug. 4 th y 184*1. — Having provided myself with three wax 
bougies of the smallest size made use of by surgeons, I had the 
horse cast, and his head extended and placed in a convenient 
position for operation upon the eye. An assistant firmly main- 
tained the eyelids apart, while I, choosing the inferior puncture — 
it being the larger and having the more direct passage — for 
operation, readily introduced into it a bougie ; but had pushed 
it no farther than into the lachrymal sac before it bent and be- 
came useless. Withdrawing this, I passed a second bougie, 
which, by dexterous manipulation and some force, I succeeded 
* “ English veterinarians have denied the existence of this sac : the best 
argument I cap offer of its presence is dissection — the same that has con- 
vinced myself.” For this, and further information on the subject, consult 
my “ Anatomy of the Horse,” at page 374. 
