134 VETEKLNARY MEDICINE AND SURGERY. 



which, in a healthy state, the tears are discharged. The obstruction is 

 generally due to a thickening of the raucous membrane of the duct, 

 arising from inflammation. No remedy is known for this affection. It 

 is unsightly, but not serious. A similar effect may be produced by loss 

 of the lower eyelid. 



A trickling unconnected with disease may arise from an excessive se- 

 cretion of tears caused by some external irritation, by inflammation of 

 the conjunctival membrane, or from swelling of the eyelids, which then 

 obstruct the entrance of the tears into the lachrymal duct. In these 

 cases, the effect will cease with the removal or cessation of the cause. 



FOREIGN BODIES IN THE EYE. 



Are mostly confined to seeds and particles of hay and straw or small 

 grains of dirt getting within the eyelids. 



Symptoms. — The trouble commonly occurs at night. The horse 

 will be found in the morning with the affected eye closed and tears more 

 or less profusely running from it. 



Treatment. — The trouble will generally be found under the upper 

 eyelid, which may be gently turned back over a pencil or other small 

 smooth stick; if seen, extract as recommended in simple ophthalmia, 

 page 124. Afterward bathe the eye with lukewarm water and cover it 

 with a wet cloth. 



WORM IN THE EYE. 



In India a worm is occasionally found floating in the aqueous humor. 

 The treatment consists in puncturring the cornea at its upper inner mar- 

 gin. The humor will then escape, and will carry with it the worm. The 

 humor soon re-forms, and the wound readily heels, and in general no 

 injurious after-result ensues. The inner margin is selected for the ope- 

 ration because the cornea at that part is least dense; and the upper in- 

 stead of the lower margin, because the aqueous humor, 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. This parasite very 

 rarely troubles horses in this country. 



