SIGHT. 587 



upper or lower eyelid on the sudden approach of any thing to it, 

 the motion is from fear, and as instinctive, and expressive, and 

 respiratory ! as any motion can be : yet it is accomplished by 

 the superior or inferior straight muscle of the organ, both 

 voluntary muscles. 



Not only do the motions of the straight muscles continually 

 express the passions, but the abducent or external is actually 

 the antagonist of the two obliques when, in Sir C. Bell's own 

 words, " their combined action draws the eye-ball towards the 

 nose ;" just as the two obliques when acting separately are the 

 antagonists of each other : and the circumstance of this muscle 

 antagonising not only the internal straight muscle but the com- 

 bined action of the two obliques may explain why it has a dis- 

 tinct nerve. 



He further contends that the eye-ball moves so that the 

 cornea always rises under the upper lid the moment that the 

 eyelids close (p. 294.), and in some places he says it not only 

 rises but moves inwards, (p. 328.) I have raised the upper eye- 

 lid of persons whose eyes were shut, and found the cornea 

 sometimes raised under the upper lid, but as often depressed 

 under the lower lid. I have often looked at persons whose 

 eyes were closed, and seen the cornea projecting at the centre 

 of the upper eyelid, in the same line as when the eyes were open. 

 He states that, " if we fix one eye upon an object, and close the 

 other with the finger in such a manner as to feel the convexity 

 of the cornea through the eyelid, when we shut the eye that is 

 open, we shall feel that the cornea of the other eye is instantly 

 elevated ; and that it thus rises and falls in sympathy with the 

 eye that is closed and opened." I have made this experiment 

 repeatedly, and not found my closed eye ascend when I closed 

 the other : nor have my friends, who observed the cornea pro- 

 jecting at the closed eye, seen any ascent of it on my closing 

 the other. Indeed, according to him, the closed eye ought 

 already to have ascended when it was closed, and thus could not 

 be felt or seen ascending when the other eye was closed. He says 

 that, if, closing the eyes opposite a window and still seeing the 

 light through the lids, we attempt to close them farther, we shall 

 be in momentary darkness, because during the effort the eye- 

 balls are then turning up. But there is sufficient reason for our 

 darkness in the circumstance of the eyelids becoming thickly 



