312 NATURAL THEOLOGY. 



an apparatus, mechanical and hydraulic, for the 

 obvious purpose of ridding the delicate surface 

 of the eye of all foreign matter. 



Can there be any thing more interesting than to 

 find the whole of this apparatus under the guid- 

 ance of a property different from that of conscious- 

 ness and volition ? 



I have seen many instances of persons deprived 

 of the sensibility of the surfaces of the eye from 

 the affection of one nerve alone, without the loss 

 of vision, or of the motions of the eyelids, or of 

 the flow of tears ; but it has been impossible, in 

 such persons, to preserve the organ, by assuring 

 them of the necessity of these motions, either 

 through the direct action of the eyelids, or by the 

 aid of their fingers. The eye's surfaces, being de- 

 prived of sensation, are no longer regularly moist- 

 ened : soot and dust rest upon them ; and although 

 they are insensible they inflame ; the transparent 

 cornea becomes opaque, and the eye is lost. This 

 is the consequence neither of the want of sensibi- 

 lity in the retina, nor of the capacity of motion in 

 the eyeball and eyelids being lost, nor of failure 

 of the spring of water that runs continually over 

 the eye : it results simply from a loss of that rela- 

 tion in the sensibilities suited to the materials and 

 influences around us, and the protecting motions 

 which they excite. It at once answers the que- 

 rist who asks, why we sufler pain ? We reply to 

 him by another question. How are we to hear or 

 see, or how enjoy the sense from impressions so 



