TEARS. 155 



but when it is too vivid, they approach each other, and 

 diminish, as far as necessary, the quantity of light. 



Emily. But what, pray, can be the use of the eye- 

 lashes ? Or are they merely for ornament's sake ; for 

 you know, they sometimes look very beautiful, and 

 moreover, furnish a poet a capital subject for a sonnet. 



Dr. j^.-^I apprehend they were neither designed to 

 add beauty to the human face, nor to inspire a poet's 

 muse, but for purposes of real utility. Their use is sim- 

 ilar to that of the eye-brow, for they guard the eye from 

 insects and light substances floating in the air ; and so 

 necessary are they in this respect, that persons who 

 have lost their eye-lashes, are always troubled more or 

 less with a defect of vision. For furnishing the requi- 

 site moisture, by which the parts are enabled to glide 

 over each other without experiencing any ill effects 

 from friction, the eye-lids are provided with numerous 

 little glands, from which a watery fluid is secreted. Be- 

 sides this, there is another fluid, the tears, secreted from 

 the lacrymal gland situated at the anterior and outer 

 part of the orbit, (the name of the bony socket that con- 

 tains the eye.) When any thing;irritates the eye, the 

 tears are shed in prolusion, for the purpose of washing 

 away the irritating cause. 



Emily. What becomes of the tears when not wanted 

 for this purpose ? I suppose nevertheless, that their se- 

 cretion is continually going on. 



Dr. B. This is readily explained. At the internal 

 angle of the eye, there are several minute orifices lead- 

 ing by a short canal into the nose, by which the tears 

 are conducted off, and thus prevented from coming out 

 arid falling over the cheek a circumstance which would 

 happen if these orifices were closed, as they sometimes 

 are in disease. 



Emily. And the reason why they run over the 

 cheek in crying, is, I suppose, because they are poured 

 forth in too large quantity, to be absorbed instantly by 

 these lacrymal orifices. 



