STKICTUEE OF THE LACHRYMAL DUCT. 553 



"Watery eye may also result from tumefaction of the eyelids, 

 occasioning not only an increased secretion of tears, but a 

 diminution in the size of the punda lachrymalis, increased 

 secretion of tears from the lodgment of an irritant in the eye, 

 and from a catarrhal or other inflammation of it. 



" The common seat of stricture of lachrymal duct appears to 

 be at its superior part, and it is best treated by syringing with 

 cold water from the punda lachrymalis downwards, or it may be 

 necessary to dilate it with a suitable hougie" — (Peecivall.) 



PARASITES. 



Worm in the eye is unknown in this country, but is met 

 with in India, and sometimes in Canada. The best account 

 of this parasitic disease that I have seen is contained in a 

 letter from Mr. Charles Percivall, dated June 24th, 1825. ^ 

 He says — " In low humid situations in India, where fogs are 

 prevalent, or where there is stagnant water, especially after an 

 unusually wet season, woj^m in the eye is a very common occur- 

 rence. It is also seen in otlier parts during the cold months, 

 from the beginning of October to the latter end of February, and 

 particularly during the continuance of an easterly wind. The 

 symptoms seem to be conjunctivitis, the cornea obscured by 

 ' nebulous effusion,' the eyehds closed, and intolerance to light. 

 On close inspection a small white worm can be discerned float- 

 ing in the aqueous humour, at one time rising to the superior, 

 at another sinking to the bottom of the chamber." 



The method of treatment is by " puncturing the cornea at its 

 upper and outer margin, and allowing the parasite to escape with 

 the aqueous humour. This spot is selected for the operation 

 because the cornea is here least dense ; and the upper instead of 

 the lower margin, because the aqueous humour, which gradually 

 re-forms, will be less likely to again escape whilst the wound is 

 healing, than if the incision had been made at the lower part." 



The best instrument is a sharp-pointed scalpel, which should 

 be pushed flatwise through the cornea, as near to its junction 

 with the sclerotica as possible, making an oblique opening under 

 the cornea ; the sides of the wound will then fall into close con- 

 tact with each other, and be in a favourable position for uniting 



* Pekcivall's Lectures on the Veterinary Art, 



